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Yau STY, Leung E, Wong MCS, Hung CT, Chong KC, Lee A, Yeoh EK. Metabolic dysfunction-associated profiles and subsequent site-specific risk of obesity-related cancers among Chinese patients with diabetes: a retrospective cohort study. BMJ Open 2024; 14:e082414. [PMID: 38569684 DOI: 10.1136/bmjopen-2023-082414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/05/2024] Open
Abstract
OBJECTIVES To compare metabolic dysfunction-associated profiles between patients with diabetes who developed different obesity-related site-specific cancers and those who remained free of cancer during follow-up. DESIGN Retrospective cohort study. SETTING Public general outpatient clinics in Hong Kong. PARTICIPANTS Patients with diabetes without a history of malignancy (n=391 921). PRIMARY OUTCOME MEASURES The outcomes of interest were diagnosis of site-specific cancers (colon and rectum, liver, pancreas, bladder, kidney and stomach) during follow-up. Cox proportional hazards regression was applied to assess the associations between metabolic dysfunction and other clinical factors with each site-specific cancer. RESULTS Each 0.1 increase in waist-to-hip ratio was associated with an 11%-35% elevated risk of colorectal, bladder and liver cancers. Each 1% increase in glycated haemoglobin was linked to a 4%-9% higher risk of liver and pancreatic cancers. While low-density lipoprotein cholesterol and triglycerides were inversely associated with the risk of liver and pancreatic cancers, high-density lipoprotein cholesterol was negatively associated with pancreatic, gastric and kidney cancers, but positively associated with liver cancer. Furthermore, liver cirrhosis was linked to a 56% increased risk of pancreatic cancer. No significant association between hypertension and cancer risk was found. CONCLUSIONS Metabolic dysfunction-associated profiles contribute to different obesity-related cancer outcomes differentially among patients with diabetes. This study may provide evidence to help identify cancer prevention targets during routine diabetes care.
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Affiliation(s)
- Sarah Tsz Yui Yau
- JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Eman Leung
- JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Martin Chi Sang Wong
- JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Tim Hung
- JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Ka Chun Chong
- JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Albert Lee
- JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Eng Kiong Yeoh
- JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
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Petersen CA, Sise CV, Dewing JX, Yun J, Zimmerman BK, Guo XE, Hung CT, Ateshian GA. Immature bovine cartilage wear is due to fatigue failure from repetitive compressive forces and not reciprocating frictional forces. Osteoarthritis Cartilage 2023; 31:1594-1601. [PMID: 37633593 PMCID: PMC10841040 DOI: 10.1016/j.joca.2023.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 08/28/2023]
Abstract
OBJECTIVE Wear of articular cartilage is not well understood. We hypothesize that cartilage wears due to fatigue failure in repetitive compression instead of reciprocating friction. DESIGN This study compares reciprocating sliding of immature bovine articular cartilage against glass in two testing configurations: (1) a stationary contact area configuration (SCA), which results in static compression, interstitial fluid depressurization, and increasing friction coefficient during reciprocating sliding, and (2) a migrating contact area configuration (MCA), which maintains pressurization and low friction while producing repetitive compressive loading in addition to reciprocating sliding. Contact pressure, sliding duration, and sliding distance were controlled to be similar between test groups. RESULTS SCA tests exhibited an average friction coefficient of μ=0.084±0.032, while MCA tests exhibited a lower average friction coefficient of μ=0.020±0.008 (p<10-4). Despite the lower friction, MCA cartilage samples exhibited clear surface damage with a significantly greater average surface deviation from a fitted plane after wear testing (Rq=0.125±0.095 mm) than cartilage samples slid in a SCA configuration (Rq=0.044±0.017 mm, p=0.002), which showed minimal signs of wear. Polarized light microscopy confirmed that delamination damage occurred between the superficial and middle zones of the articular cartilage in MCA samples. CONCLUSIONS The greatest wear was observed in the group with lowest friction coefficient, subjected to cyclical instead of static compression, implying that friction is not the primary driver of cartilage wear. Delamination between superficial and middle zones implies the main mode of wear is fatigue failure under cyclical compression, not fatigue or abrasion due to reciprocating frictional sliding.
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Affiliation(s)
- C A Petersen
- Department of Mechanical Engineering, Columbia University, New York, NY, United States
| | - C V Sise
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - J X Dewing
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - J Yun
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - B K Zimmerman
- Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - X E Guo
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - C T Hung
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - G A Ateshian
- Department of Mechanical Engineering, Columbia University, New York, NY, United States; Department of Biomedical Engineering, Columbia University, New York, NY, United States.
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Zhao S, Guo Z, Sun S, Hung CT, Leung EYM, Wei Y, Wang H, Li K, Yam CHK, Chow TY, Gao J, Jia KM, Chong KC, Yeoh EK. Effectiveness of BNT162b2 and Sinovac vaccines against the transmission of SARS-CoV-2 during Omicron-predominance in Hong Kong: A retrospective cohort study of COVID-19 cases. J Clin Virol 2023; 166:105547. [PMID: 37453162 DOI: 10.1016/j.jcv.2023.105547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/30/2023] [Accepted: 07/09/2023] [Indexed: 07/18/2023]
Abstract
BACKGROUND In 2022, SARS-CoV-2 Omicron variants circulated globally, generating concerns about increased transmissibility and immune escape. Hong Kong, having an infection-naive population with a moderate 2-dose vaccine coverage (63% by the end of 2021), experienced a COVID-19 epidemic largely seeded by Omicron BA.2 variants that led to the greatest outbreak in the region to date. Little remains known about the protection of commonly-administered vaccines against transmission of Omicron BA.2 variants. METHODS In this retrospective cohort study, we identified 17 535 laboratory-confirmed COVID-19 cases using contact tracing information during the Omicron-predominant period between January and June 2022 in Hong Kong. Demographic characteristics, time from positive test result to case reporting, isolation, or hospital admission, as well as contact tracing history and contact setting were extracted. Transmission pairs were reconstructed through suspected epidemiological links according to contact tracing history, and the number of secondary cases was determined for each index case as a measurement for risk of transmission. The effectiveness of mRNA vaccine (BNT162b2) and inactivated vaccine (Sinovac) against transmission of BA.2 variants was estimated using zero-inflated negative binomial regression models. RESULTS Vaccine effectiveness against transmission for patients who received the 2-dose BNT162b2 vaccine was estimated at 56.2% (95% CI: 14.5, 77.6), 30.6% (95% CI: 13.0, 44.6), and 21.3% (95% CI: 2.9, 36.2) on 15 - 90, 91 - 180, and 181 - 270 days after vaccination, respectively, showing a significant decrease over time. For 3-dose vaccines, vaccine effectiveness estimates were 41.0% (95% CI: 11.3, 60.7) and 41.9% (95% CI: 6.1, 64.0) on 15 - 180 days after booster doses of Sinovac and BNT162b2, respectively. Although significant vaccine effectiveness was detected in household settings, no evidence of such protective association was detected in non-household settings for either Sinovac or BNT162b2. CONCLUSION Moderate and significant protection against Omicron BA.2 variants' transmission was found for 2 and 3 doses of Sinovac or BNT162b2 vaccines. Although protection by 2-dose BNT162b2 may evidently wane with time, protection could be restored by the booster dose. Here, we highlight the importance of continuously evaluating vaccine effectiveness against transmission for emerging SARS-CoV-2 variants.
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Affiliation(s)
- Shi Zhao
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China; CUHK Shenzhen Research Institute, Shenzhen, China; Centre for Health Systems and Policy Research, Chinese University of Hong Kong, Hong Kong, China
| | - Zihao Guo
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
| | - Shengzhi Sun
- Department of Epidemiology and Biostatistics, School of Public Health, Capital Medical University, Beijing 100069, China
| | - Chi Tim Hung
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
| | - Eman Yee Man Leung
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
| | - Yuchen Wei
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
| | - Huwen Wang
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
| | - Kehang Li
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
| | - Carrie Ho Kwan Yam
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
| | - Tsz Yu Chow
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
| | - Jian Gao
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
| | - Katherine Min Jia
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States
| | - Ka Chun Chong
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China; CUHK Shenzhen Research Institute, Shenzhen, China; Centre for Health Systems and Policy Research, Chinese University of Hong Kong, Hong Kong, China.
| | - Eng-Kiong Yeoh
- JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China; Centre for Health Systems and Policy Research, Chinese University of Hong Kong, Hong Kong, China
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Chong KC, Chan PK, Hung CT, Wong CK, Xiong X, Wei Y, Zhao S, Guo Z, Wang H, Yam CH, Chow TY, Li C, Jiang X, Leung SY, Kwok KL, Yeoh EK, Li K. Changes in all-cause and cause-specific excess mortality before and after the Omicron outbreak of COVID-19 in Hong Kong. J Glob Health 2023; 13:06017. [PMID: 37114968 PMCID: PMC10143112 DOI: 10.7189/jogh.13.06017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
Background While coronavirus 2019 (COVID-19) deaths were generally underestimated in many countries, Hong Kong may show a different trend of excess mortality due to stringent measures, especially for deaths related to respiratory diseases. Nevertheless, the Omicron outbreak in Hong Kong evolved into a territory-wide transmission, similar to other settings such as Singapore, South Korea, and recently, mainland China. We hypothesized that the excess mortality would differ substantially before and after the Omicron outbreak. Methods We conducted a time-series analysis of daily deaths stratified by age, reported causes, and epidemic wave. We determined the excess mortality from the difference between observed and expected mortality from 23 January 2020 to 1 June 2022 by fitting mortality data from 2013 to 2019. Results During the early phase of the pandemic, the estimated excess mortality was -19.92 (95% confidence interval (CI) = -29.09, -10.75) and -115.57 (95% CI = -161.34, -69.79) per 100 000 population overall and for the elderly, respectively. However, the overall excess mortality rate was 234.08 (95% CI = 224.66, 243.50) per 100 000 population overall and as high as 928.09 (95% CI = 885.14, 971.04) per 100 000 population for the elderly during the Omicron epidemic. We generally observed negative excess mortality rates of non-COVID-19 respiratory diseases before and after the Omicron outbreak. In contrast, increases in excess mortality were generally reported in non-respiratory diseases after the Omicron outbreak. Conclusions Our results highlighted the averted mortality before 2022 among the elderly and patients with non-COVID-19 respiratory diseases, due to indirect benefits from stringent non-pharmaceutical interventions. The high excess mortality during the Omicron epidemic demonstrated a significant impact from the surge of COVID-19 infections in a SARS-CoV-2 infection-naive population, particularly evident in the elderly group.
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Affiliation(s)
- Ka Chun Chong
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
- Clinical Trials and Biostatistics Laboratory, Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Paul Ks Chan
- Department of Microbiology, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Chi Tim Hung
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Carlos Kh Wong
- Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong Special Administrative Region, China
- Department of Family Medicine and Primary Care, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Xi Xiong
- Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Yuchen Wei
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Shi Zhao
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
- Clinical Trials and Biostatistics Laboratory, Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Zihao Guo
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Huwen Wang
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Carrie Hk Yam
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Tsz Yu Chow
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Conglu Li
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Xiaoting Jiang
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Shuk Yu Leung
- Department of Paediatrics, Kwong Wah Hospital, Hong Kong, China
| | - Ka Li Kwok
- Department of Paediatrics, Kwong Wah Hospital, Hong Kong, China
| | - Eng Kiong Yeoh
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Kehang Li
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
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Chong KC, Li K, Guo Z, Jia KM, Leung EYM, Zhao S, Hung CT, Yam CHK, Chow TY, Dong D, Wang H, Wei Y, Yeoh EK. Dining-Out Behavior as a Proxy for the Superspreading Potential of SARS-CoV-2 Infections: Modeling Analysis. JMIR Public Health Surveill 2023; 9:e44251. [PMID: 36811849 PMCID: PMC9994464 DOI: 10.2196/44251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/01/2023] [Accepted: 02/14/2023] [Indexed: 02/24/2023] Open
Abstract
BACKGROUND While many studies evaluated the reliability of digital mobility metrics as a proxy of SARS-CoV-2 transmission potential, none examined the relationship between dining-out behavior and the superspreading potential of COVID-19. OBJECTIVE We employed the mobility proxy of dining out in eateries to examine this association in Hong Kong with COVID-19 outbreaks highly characterized by superspreading events. METHODS We retrieved the illness onset date and contact-tracing history of all laboratory-confirmed cases of COVID-19 from February 16, 2020, to April 30, 2021. We estimated the time-varying reproduction number (Rt) and dispersion parameter (k), a measure of superspreading potential, and related them to the mobility proxy of dining out in eateries. We compared the relative contribution to the superspreading potential with other common proxies derived by Google LLC and Apple Inc. RESULTS A total of 6391 clusters involving 8375 cases were used in the estimation. A high correlation between dining-out mobility and superspreading potential was observed. Compared to other mobility proxies derived by Google and Apple, the mobility of dining-out behavior explained the highest variability of k (ΔR-sq=9.7%, 95% credible interval: 5.7% to 13.2%) and Rt (ΔR-sq=15.7%, 95% credible interval: 13.6% to 17.7%). CONCLUSIONS We demonstrated that there was a strong link between dining-out behaviors and the superspreading potential of COVID-19. The methodological innovation suggests a further development using digital mobility proxies of dining-out patterns to generate early warnings of superspreading events.
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Affiliation(s)
- Ka Chun Chong
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Kehang Li
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Zihao Guo
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Katherine Min Jia
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States
| | - Eman Yee Man Leung
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Shi Zhao
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Chi Tim Hung
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Carrie Ho Kwan Yam
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Tsz Yu Chow
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Dong Dong
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Huwen Wang
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Yuchen Wei
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
| | - Eng Kiong Yeoh
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, New Territories, Hong Kong
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Guo Z, Zhao S, Lee SS, Hung CT, Wong NS, Chow TY, Yam CHK, Wang MH, Wang J, Chong KC, Yeoh EK. A statistical framework for tracking the time-varying superspreading potential of COVID-19 epidemic. Epidemics 2023; 42:100670. [PMID: 36709540 PMCID: PMC9872564 DOI: 10.1016/j.epidem.2023.100670] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 10/29/2022] [Accepted: 01/17/2023] [Indexed: 01/26/2023] Open
Abstract
Timely detection of an evolving event of an infectious disease with superspreading potential is imperative for territory-wide disease control as well as preventing future outbreaks. While the reproduction number (R) is a commonly-adopted metric for disease transmissibility, the transmission heterogeneity quantified by dispersion parameter k, a metric for superspreading potential is seldom tracked. In this study, we developed an estimation framework to track the time-varying risk of superspreading events (SSEs) and demonstrated the method using the three epidemic waves of COVID-19 in Hong Kong. Epidemiological contact tracing data of the confirmed COVID-19 cases from 23 January 2020 to 30 September 2021 were obtained. By applying branching process models, we jointly estimated the time-varying R and k. Individual-based outbreak simulations were conducted to compare the time-varying assessment of the superspreading potential with the typical non-time-varying estimate of k over a period of time. We found that the COVID-19 transmission in Hong Kong exhibited substantial superspreading during the initial phase of the epidemics, with only 1 % (95 % Credible interval [CrI]: 0.6-2 %), 5 % (95 % CrI: 3-7 %) and 10 % (95 % CrI: 8-14 %) of the most infectious cases generated 80 % of all transmission for the first, second and third epidemic waves, respectively. After implementing local public health interventions, R estimates dropped gradually and k estimates increased thereby reducing the risk of SSEs to approaching zero. Outbreak simulations indicated that the non-time-varying estimate of k may overlook the possibility of large outbreaks. Hence, an estimation of the time-varying k as a compliment of R as a monitoring of both disease transmissibility and superspreading potential, particularly when public health interventions were relaxed is crucial for minimizing the risk of future outbreaks.
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Affiliation(s)
- Zihao Guo
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Shi Zhao
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Centre for Health Systems and Policy Research, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Shui Shan Lee
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Stanley Ho Centre for Emerging Infectious Diseases, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Chi Tim Hung
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Centre for Health Systems and Policy Research, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Ngai Sze Wong
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Stanley Ho Centre for Emerging Infectious Diseases, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Tsz Yu Chow
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Centre for Health Systems and Policy Research, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Carrie Ho Kwan Yam
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Centre for Health Systems and Policy Research, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Maggie Haitian Wang
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Jingxuan Wang
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Ka Chun Chong
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Centre for Health Systems and Policy Research, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
| | - Eng Kiong Yeoh
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Centre for Health Systems and Policy Research, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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Wang H, Wei Y, Hung CT, Jiang X, Li C, Jia KM, Leung EYM, Yam CHK, Chow TY, Zhao S, Guo Z, Li K, Wang Z, Yeoh EK, Chong KC. Relationship between antidepressants and severity of SARS-CoV-2 Omicron infection: a retrospective cohort study using real-world data. Lancet Reg Health West Pac 2023; 34:100716. [PMCID: PMC9970034 DOI: 10.1016/j.lanwpc.2023.100716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 03/02/2023]
Abstract
Background Few studies have used real-world data to evaluate the impact of antidepressant use on the risk of developing severe outcomes after SARS-CoV-2 Omicron infection. Methods This is a retrospective cohort study using propensity-score matching to examine the relationship between antidepressant use and COVID-19 severity. Inpatient and medication records of all adult COVID-19 patients in Hong Kong during the Omicron-predominated period were obtained. Severe clinical outcomes including intensive care unit admission and inpatient death after the first positive results of reverse transcription polymerase chain reaction as well as a composite outcome of both were studied. Cox proportional hazard models were applied to estimate the crude and adjusted hazard ratios (HR). Findings Of 60,903 hospitalised COVID-19 patients admitted, 40,459 were included for matching, among which 3821 (9.4%) were prescribed antidepressants. The rates of intensive care unit admission, inpatient death, and the composite event were 3.9%, 25.5%, and 28.3% respectively in the unexposed group, 1.3%, 20.0%, and 21.1% respectively in the exposed group, with adjusted HR equal to 0.332 (95% CI, 0.245–0.449), 0.868 (95% CI, 0.800–0.942), and 0.786 (95% CI, 0.727–0.850) respectively. The result was generally consistent when stratified by selective serotonin reuptake inhibitors (SSRIs) and non-SSRIs. Antidepressants with functional inhibition of acid sphingomyelinase activity, specifically fluoxetine, were also negatively associated with the outcomes. The effect of antidepressants was more apparent in female and fully vaccinated COVID-19 patients. Interpretation Antidepressant use was associated with a lower risk of severe COVID-19. The findings support the continuation of antidepressants in patients with COVID-19, and provide evidence for the treatment potential of antidepressants for severe COVID-19. Funding This research was supported by Health and Medical Research Fund [grant numbers COVID190105, COVID19F03, INF-CUHK-1], Collaborative Research Fund of University Grants Committee [grant numbers C4139-20G], 10.13039/501100001809National Natural Science Foundation of China (NSFC) [71974165], and Group Research Scheme from The 10.13039/501100004853Chinese University of Hong Kong.
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Affiliation(s)
- Huwen Wang
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Yuchen Wei
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Tim Hung
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoting Jiang
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Conglu Li
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Katherine Min Jia
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States
| | - Eman Yee Man Leung
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Carrie Ho Kwan Yam
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Tsz Yu Chow
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Shi Zhao
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Zihao Guo
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Kehang Li
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Ziqing Wang
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Eng Kiong Yeoh
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China,Corresponding author. Centre for Health Systems and Policy Research, School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Ka Chun Chong
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China,Corresponding author. Centre for Health Systems and Policy Research, School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
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Fu BQ, Zhong CCW, Wong CHL, Ho FF, Nilsen P, Hung CT, Yeoh EK, Chung VCH. Barriers and Facilitators to Implementing Interventions for Reducing Avoidable Hospital Readmission: Systematic Review of Qualitative Studies. Int J Health Policy Manag 2023; 12:7089. [PMID: 37579466 PMCID: PMC10125127 DOI: 10.34172/ijhpm.2023.7089] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 01/04/2023] [Indexed: 08/16/2023] Open
Abstract
BACKGROUND Avoidable hospital readmission is a major problem among health systems. Although there are effective peri-discharge interventions for reducing avoidable hospital readmission, successful implementation is challenging. This systematic review of qualitative studies aimed to identify barriers and facilitators to implementing peri-discharge interventions from providers' and service users' perspectives. METHODS We searched four databases for potentially eligible qualitative studies from databases' inception to March 2020, and updated literature search for studies published between January 2020 to October 2021. Barriers and facilitators to implementing peri-discharge interventions were identified and mapped onto the Consolidated Framework for Implementation Research (CFIR) constructs. Inductive analysis of the CFIR constructs was performed to yield thematic areas that illustrated the relationship between various facilitators and barriers, generating practical insights to key implementation issues. RESULTS Thirteen qualitative studies were included in this systematic review. Key issues were clustered in the CFIR constructs of Design Quality and Complexity of the intervention, strength of Network and Communication, being responsive to Patient Needs with sufficient Resource support, and External Incentives. The three thematic areas were rationality of the interventions, readiness and effort of multidisciplinary implementation teams, and influence of external stakeholders. Common barriers included (i) limited resources, (ii) poor communication among team members, (iii) incompatibility between the new intervention and existing work routine, (iv) complicated implementation process, (v) low practicality of supporting instruments, and (vi) lack of understanding about the content and effectiveness of the new interventions. Common facilitators were (i) information sharing via regular meetings on implementation issues, (ii) organizational culture that values quality and accountability, (iii) financial penalties for hospitals with high avoidable readmissions rates, (iv) external support offered via quality improvement programs and community resources, and (v) senior leadership support. CONCLUSION This study synthesized commonly-presenting barriers and facilitators to implementing peri-discharge interventions among different healthcare organizations. Findings may inform development of implementation strategies in different health systems after appropriate tailoring, based on a consensus-based formative research process.
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Affiliation(s)
- Becky Q Fu
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Claire CW Zhong
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Charlene HL Wong
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Fai Fai Ho
- School of Chinese Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Per Nilsen
- Department of Medicine, Health and Caring Sciences, Linköping University, Linköping, Sweden
| | - Chi Tim Hung
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Eng Kiong Yeoh
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Vincent CH Chung
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
- School of Chinese Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
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Wei Y, Jia KM, Zhao S, Hung CT, Mok CKP, Poon PKM, Man Leung EY, Wang MH, Yam CHK, Chow TY, Guo Z, Yeoh EK, Chong KC. Estimation of Vaccine Effectiveness of CoronaVac and BNT162b2 Against Severe Outcomes Over Time Among Patients With SARS-CoV-2 Omicron. JAMA Netw Open 2023; 6:e2254777. [PMID: 36735253 PMCID: PMC9898822 DOI: 10.1001/jamanetworkopen.2022.54777] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
IMPORTANCE Few studies have evaluated the waning of vaccine effectiveness against severe outcomes caused by SARS-CoV-2 Omicron infection. Hong Kong is providing inactivated and mRNA vaccines, but the population had limited protection from natural infections before the Omicron variant emerged. OBJECTIVE To examine the change in vaccine effectiveness against hospitalization and mortality due to the Omicron variant over time. DESIGN, SETTING, AND PARTICIPANTS This case-control study included adults with SARS-CoV-2 Omicron variant infection who died or were hospitalized in Hong Kong from January 1 to June 5, 2022 (ie, case participants), and adults with SARS-CoV-2 Omicron, sampled from the public health registry during the study period (ie, control participants), who were matched to case participants by propensity score. EXPOSURES Vaccination status of the individuals. MAIN OUTCOMES AND MEASURES Estimated vaccine effectiveness against death, death or hospitalization, and death among hospitalized patients. Vaccine effectiveness was calculated as 1 - adjusted odds ratio obtained by conditional logistic regression adjusted with covariates for each period following vaccination. RESULTS There were 32 823 case participants (25 546 [77.8%] ≥65 years; 16 930 [47.4%] female) and 131 328 control participants (100 041 [76.2%] ≥65 years; 66 625 [46.6%] female) in the sample analyzed for the death or hospitalization outcome. Vaccine effectiveness against death or hospitalization was maintained for at least 6 months after the second dose of both CoronaVac (74.0%; 95% CI, 71.8%-75.8%) and BNT162b2 (77.4%; 95% CI, 75.5%-79.0%) vaccines. Vaccine effectiveness against death in those aged 18 to 49 years was 86.4% (95% CI, 85.8%-87.0%) and 92.9% (95% CI, 92.6%-93.2%) for those receiving 2 doses of CoronaVac and BNT162b2, respectively, while for patients aged 80 years or older, it dropped to 61.4% (95% CI, 59.8%-63.2%) and 52.7% (95% CI, 50.2%-55.6%) for CoronaVac and BNT162b2, respectively. Nevertheless, overall vaccine effectiveness against death at 4 to 6 months after the third dose was greater than 90% for CoronaVac, BNT162b2, and the mixed vaccine schedule (eg, mixed vaccines: vaccine effectiveness, 92.2%; 95% CI, 89.2%-95.1%). CONCLUSIONS AND RELEVANCE While vaccines were generally estimated to be effective against severe outcomes caused by SARS-CoV-2 Omicron infection, this analysis found that protection in older patients was more likely to wane 6 months after the second dose. Hence, a booster dose is recommended for older patients to restore immunity. This is especially critical in a setting like Hong Kong, where third-dose coverage is still insufficient among older residents.
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Affiliation(s)
- Yuchen Wei
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Katherine Min Jia
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Shi Zhao
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Tim Hung
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Chris Ka Pun Mok
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
- Li Ka Shing Institute of Health Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Paul Kwok Ming Poon
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Eman Yee Man Leung
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Maggie Haitian Wang
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Carrie Ho Kwan Yam
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Tsz Yu Chow
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Zihao Guo
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Eng Kiong Yeoh
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Ka Chun Chong
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
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Guo Z, Zhao S, Ryu S, Mok CKP, Hung CT, Chong KC, Yeoh EK. Superspreading potential of infection seeded by the SARS-CoV-2 Omicron BA.1 variant in South Korea. J Infect 2022; 85:e77-e79. [PMID: 35659549 PMCID: PMC9158374 DOI: 10.1016/j.jinf.2022.05.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 05/29/2022] [Indexed: 11/17/2022]
Affiliation(s)
- Zihao Guo
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Shi Zhao
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Sukhyun Ryu
- Department of Preventive Medicine, Konyang University College of Medicine, Daejeon 35365, Korea
| | - Chris Ka Pun Mok
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Chi Tim Hung
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Centre for Health Systems and Policy Research, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Ka Chun Chong
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Centre for Health Systems and Policy Research, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
| | - Eng Kiong Yeoh
- Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Centre for Health Systems and Policy Research, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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Sun KS, Lau TSM, Yeoh EK, Chung VCH, Leung YS, Yam CHK, Hung CT. Effectiveness of different types and levels of social distancing measures: a scoping review of global evidence from earlier stage of COVID-19 pandemic. BMJ Open 2022; 12:e053938. [PMID: 35410924 PMCID: PMC9002256 DOI: 10.1136/bmjopen-2021-053938] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE Social distancing is one of the main non-pharmaceutical interventions used in the control of the COVID-19 pandemic. This scoping review aims to synthesise research findings on the effectiveness of different types and levels of social distancing measures in the earlier stage of COVID-19 pandemic without the confounding effect of mass vaccination. DESIGN Scoping review. DATA SOURCES MEDLINE, Embase, Global Health and four other databases were searched for eligible studies on social distancing for COVID-19 published from inception of the databases to 30 September 2020. STUDY SELECTION AND DATA EXTRACTION Effectiveness studies on social distancing between individuals, school closures, workplace/business closures, public transport restrictions and partial/full lockdown were included. Non-English articles, studies in healthcare settings or not based on empirical data were excluded. RESULTS After screening 1638 abstracts and 8 additional articles from other sources, 41 studies were included for synthesis of findings. The review found that the outcomes of social distancing measures were mainly indicated by changes in Rt , incidence and mortality, along with indirect indicators such as daily contact frequency and travel distance. There was adequate empirical evidence for the effect of social distancing at the individual level, and for partial or full lockdown at the community level. However, at the level of social settings, the evidence was moderate for school closure, and was limited for workplace/business closures as single targeted interventions. There was no evidence for a separate effect of public transport restriction. CONCLUSIONS In the community setting, there was stronger evidence for the combined effect of different social distancing interventions than for a single intervention. As fatigue of preventive behaviours is an issue in public health agenda, future studies should analyse the risks in specific settings such as eateries and entertainment to implement and evaluate measures which are proportionate to the risk.
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Affiliation(s)
- Kai Sing Sun
- Centre for Health Systems and Policy Research, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Terence See Man Lau
- Centre for Health Systems and Policy Research, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Eng Kiong Yeoh
- Centre for Health Systems and Policy Research, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Vincent Chi Ho Chung
- Centre for Health Systems and Policy Research, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Yin Shan Leung
- Centre for Health Systems and Policy Research, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Carrie Ho Kwan Yam
- Centre for Health Systems and Policy Research, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Tim Hung
- Centre for Health Systems and Policy Research, The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
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12
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Zhong CCW, Wong CHL, Cheung WKW, Yeoh EK, Hung CT, Yip BHK, Wong ELY, Wong SYS, Chung VCH. Effectiveness of Peri-Discharge Complex Interventions for Reducing 30-Day Readmissions among COPD Patients: Overview of Systematic Reviews and Network Meta-Analysis. Int J Integr Care 2022; 22:7. [PMID: 35136388 PMCID: PMC8815439 DOI: 10.5334/ijic.6018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 01/27/2022] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND An overview of systematic reviews(SRs) and network meta-analysis(NMA) were conducted to evaluate the comparative effectiveness of peri-discharge complex interventions for reducing 30-day readmissions among chronic obstructive pulmonary disease(COPD) patients. METHODS Five databases were searched for SRs of randomized controlled trials(RCTs). An additional search was conducted for updated RCTs from database inception until Jun 2020. Pooled effect of peri-discharge complex interventions was assessed using random-effect pairwise meta-analyses. Comparative effectiveness across different peri-discharge complex interventions was evaluated using NMA. RESULTS Nine SRs and 11 eligible RCTs(n = 1,422) assessing eight different peri-discharge complex interventions were included. For reducing 30-day all-cause readmissions, pairwise meta-analysis showed no significant difference between peri-discharge complex interventions and usual care, while NMA indicated no significant differences among different peri-discharge complex interventions as well as usual care. For reducing 30-day COPD-related readmissions, peri-discharge complex interventions were significantly more effective than usual care (pooled RR = 0.45, 95% CI:0.24-0.84). CONCLUSIONS Peri-discharge complex interventions may not differ from usual care in reducing 30-day all-cause readmissions among COPD patients but some are more effective for lowering 30-day COPD-related readmission. Thus, complex intervention comprising core components of patient education, self-management, patient-centred discharge instructions, and telephone follow up may be considered for implementation, but further evaluation is warranted.
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Affiliation(s)
- Claire C. W. Zhong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, HK
| | - Charlene H. L. Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, HK
| | - William K. W. Cheung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, HK
| | - Eng-kiong Yeoh
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, HK
| | - Chi Tim Hung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, HK
| | - Benjamin H. K. Yip
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, HK
| | - Eliza L. Y. Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, HK
| | - Samuel Y. S. Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, HK
| | - Vincent C. H. Chung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, HK
- School of Chinese Medicine, The Chinese University of Hong Kong, Shatin, HK
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13
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Chong KC, Jia K, Lee SS, Hung CT, Wong NS, Lai FTT, Chau N, Yam CHK, Chow TY, Wei Y, Guo Z, Yeoh EK. Characterization of Unlinked Cases of COVID-19 and Implications for Contact Tracing Measures: Retrospective Analysis of Surveillance Data. JMIR Public Health Surveill 2021; 7:e30968. [PMID: 34591778 PMCID: PMC8598156 DOI: 10.2196/30968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/12/2021] [Accepted: 09/19/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Contact tracing and intensive testing programs are essential for controlling the spread of COVID-19. However, conventional contact tracing is resource intensive and may not result in the tracing of all cases due to recall bias and cases not knowing the identity of some close contacts. Few studies have reported the epidemiological features of cases not identified by contact tracing ("unlinked cases") or described their potential roles in seeding community outbreaks. OBJECTIVE For this study, we characterized the role of unlinked cases in the epidemic by comparing their epidemiological profile with the linked cases; we also estimated their transmission potential across different settings. METHODS We obtained rapid surveillance data from the government, which contained the line listing of COVID-19 confirmed cases during the first three waves in Hong Kong. We compared the demographics, history of chronic illnesses, epidemiological characteristics, clinical characteristics, and outcomes of linked and unlinked cases. Transmission potentials in different settings were assessed by fitting a negative binomial distribution to the observed offspring distribution. RESULTS Time interval from illness onset to hospital admission was longer among unlinked cases than linked cases (median 5.00 days versus 3.78 days; P<.001), with a higher proportion of cases whose condition was critical or serious (13.0% versus 8.2%; P<.001). The proportion of unlinked cases was associated with an increase in the weekly number of local cases (P=.049). Cluster transmissions from the unlinked cases were most frequently identified in household settings, followed by eateries and workplaces, with the estimated probability of cluster transmissions being around 0.4 for households and 0.1-0.3 for the latter two settings. CONCLUSIONS The unlinked cases were positively associated with time to hospital admission, severity of infection, and epidemic size-implying a need to design and implement digital tracing methods to complement current conventional testing and tracing. To minimize the risk of cluster transmissions from unlinked cases, digital tracing approaches should be effectively applied in high-risk socioeconomic settings, and risk assessments should be conducted to review and adjust the policies.
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Affiliation(s)
- Ka Chun Chong
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Katherine Jia
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Shui Shan Lee
- Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Chi Tim Hung
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Ngai Sze Wong
- Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Francisco Tsz Tsun Lai
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, Hong Kong
| | - Nancy Chau
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Carrie Ho Kwan Yam
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Tsz Yu Chow
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Yuchen Wei
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Zihao Guo
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong
| | - Eng Kiong Yeoh
- Centre for Health Systems and Policy Research, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, Hong Kong
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Zhong C, Wong C, Cheung W, Yeoh EK, Hung CT, Yip B, Wong E, Wong S, Chung V. Peri-discharge complex interventions for reducing 30-day hospital readmissions among heart failure patients: overview of systematic reviews and network meta-analysis. Perspect Public Health 2021; 142:263-277. [PMID: 33719733 DOI: 10.1177/1757913920985258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
AIMS An overview of systematic reviews (SRs) and network meta-analysis (NMA) was conducted to synthesize evidence of comparative effectiveness of different peri-discharge complex interventions for reducing 30-day hospital readmissions among heart failure (HF) patients. METHODS We searched five databases for SRs from their inception to August 2019 and conducted additional search for randomized controlled trials (RCTs) published between 2003 and 2020. We used random-effect pairwise meta-analysis with pooled risk ratios (RRs) and 95% confidence intervals (CIs) to quantify the effect of complex interventions, and NMA to evaluate comparative effectiveness among complex interventions. Primary outcome was 30-day all-cause hospital readmissions, while secondary outcomes were 30-day HF-related hospital readmissions, 30-day mortality, and 30-day emergency department visits. RESULTS From 20 SRs and additional RCT search, 21 eligible RCTs (n = 5362) assessing eight different peri-discharge complex interventions were included. Pairwise meta-analysis showed no significant difference between peri-discharge complex interventions and controls on all outcomes, except that peri-discharge complex interventions were significantly more effective than controls in reducing 30-day mortality (pooled RR = 0.68, 95% CI: 0.49-0.95, 5 RCTs). NMA indicated that for reducing 30-day all-cause hospital readmissions, supportive-educative intervention had the highest probability to be the best intervention, followed by disease management; while for reducing 30-day HF-related hospital readmissions, disease management is likely to be the best intervention. CONCLUSIONS Our results suggest that disease management has the best potential to reduce 30-day all-cause and HF-related hospital readmissions. Benefits of the interventions may vary across health system contexts. Evidence-based complex interventions require local adaptation prior to implementation.
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Affiliation(s)
- Ccw Zhong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Chl Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Rm 509, Prince of Wales Hospital, Shatin, Hong Kong
| | - Wkw Cheung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - E-K Yeoh
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - C T Hung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Bhk Yip
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ely Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Sys Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Vch Chung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong; School of Chinese Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
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15
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Wong CH, Cheung WK, Zhong CC, Yeoh EK, Hung CT, Yip BH, Wong EL, Wong SY, Chung VC. Effectiveness of nurse-led peri-discharge interventions for reducing 30-day hospital readmissions: Network meta-analysis. Int J Nurs Stud 2021; 117:103904. [PMID: 33691220 DOI: 10.1016/j.ijnurstu.2021.103904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 01/02/2023]
Abstract
BACKGROUND Existing systematic reviews have compared the effectiveness of nurse-led peri-discharge interventions comprising different components with usual care on reducing all-cause 30-day hospital readmissions. However, conflicting results were reported. OBJECTIVE We conducted a network meta-analysis to evaluate the comparative effectiveness of different nurse-led peri-discharge interventions, compared with usual care, for reducing all-cause 30-day hospital readmissions. DESIGN Network meta-analysis. METHODS A total of five international databases were searched for systematic reviews of randomized controlled trials. Additional searches for most updated randomized controlled trials published between 2014 to 2019 were conducted. Data from included randomized controlled trials were extracted for random-effect pairwise meta-analyses. Pooled risk ratios with 95% confidence interval were used to quantify impact of nurse-led peri-discharge interventions on all-cause 30-day hospital readmissions. Network meta-analysis was used to evaluate the comparative effectiveness of different interventions. RESULTS From two systematic reviews and additional randomized controlled trial searches, 12 eligible randomized controlled trials (n=150,840) assessing 15 different nurse-led peri-discharge interventions were included. For reducing all-cause 30-day hospital readmissions, pairwise meta-analysis showed that there was no significant difference between nurse-led peri-discharge interventions and usual care (pooled risk ratios = 0.86, 95% confidence interval: 0.71-1.04, moderate quality of evidence). Network meta-analysis indicated no significant difference across different interventions despite variation in complexity. CONCLUSIONS Our results indicated that nurse-led peri-discharge interventions were not significantly different from usual care for reducing all-cause 30-day hospital readmissions. Simpler nurse-led peri-discharge interventions are on par with more complex interventions in terms of effectiveness. Benefits of nurse-led peri-discharge interventions may vary across health system context. Therefore, careful consideration is required prior to implementation. REGISTRATION DETAILS The protocol for this study has been registered in PROSPERO (Registration No. CRD42020186938). Tweetable abstract: This study suggested that nurse-led peri-discharge interventions do not differ from usual care for reducing all-cause 30-day hospital readmissions.
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Affiliation(s)
- Charlene Hl Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - William Kw Cheung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Claire Cw Zhong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong.
| | - Eng-Kiong Yeoh
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Chi Tim Hung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Benjamin Hk Yip
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Eliza Ly Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Samuel Ys Wong
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Vincent Ch Chung
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong; School of Chinese Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
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Yeoh EK, Chong KC, Chiew CJ, Lee VJ, Ng CW, Hashimoto H, Kwon S, Wang W, Chau NNS, Yam CHK, Chow TY, Hung CT. Assessing the impact of non-pharmaceutical interventions on the transmissibility and severity of COVID-19 during the first five months in the Western Pacific Region. One Health 2021; 12:100213. [PMID: 33506086 PMCID: PMC7816004 DOI: 10.1016/j.onehlt.2021.100213] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 12/30/2020] [Accepted: 01/02/2021] [Indexed: 12/17/2022] Open
Abstract
While most countries in the Western Pacific Region (WPR) had similar trajectories of COVID-19 from January to May, their implementations of non-pharmaceutical interventions (NPIs) differed by transmission stages. To offer a better understanding for an implementation of multidisciplinary policies in COVID-19 control, we compared the impact of NPIs by assessing the transmissibility and severity of COVID-19 in different phases of the epidemic during the first five months in WPR. In this study, we estimated the piecewise instantaneous reproduction number (Rt) and the reporting delay-adjusted case-fatality ratio (dCFR) of COVID-19 in seven WPR jurisdictions: Hong Kong Special Administrative Region, Japan, Malaysia, Shanghai, Singapore, South Korea, and Taiwan. According to the results, implementing NPIs was associated with an apparent reduction of the piecewise Rt in two epidemic waves in general. However, large cluster outbreaks raised the piecewise Rt to a high level. We also observed relaxing the NPIs could result in an increase of Rt. The estimated dCFR ranged from 0.09% to 1.59% among the jurisdictions, except in Japan where an estimate of 5.31% might be due to low testing efforts. To conclude, in conjunction with border control measures to reduce influx of imported cases which might cause local outbreaks, other NPIs including social distancing measures along with case finding by rapid tests are also necessary to prevent potential large cluster outbreaks and transmissions from undetected cases. A comparatively lower CFR may reflect the health system capacity of these jurisdictions. In order to keep track of sustained disease transmission due to resumption of economic activities, a close monitoring of disease transmissibility is recommended in the relaxation phase. The report of transmission of SARS CoV-2 to pets in Hong Kong and to mink in farm outbreaks highlight for the control of COVID-19 and emerging infectious disease, the One Health approach is critical in understanding and accounting for how human, animals and environment health are intricately connected. Multidisciplinary One Health policies to combat COVID-19 are required in WPR. NPIs were associated with an apparent reduction in transmissibility of COVID-19. However, some large cluster outbreaks raised the transmissibility to a high level. We observed an increase in transmissibility when NPIs were partially lifted. A lower case-fatality ratio in WPR may reflect the health system capacity.
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Affiliation(s)
- Eng Kiong Yeoh
- Centre for Health Systems and Policy Research, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Ka Chun Chong
- Centre for Health Systems and Policy Research, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | | | - Vernon J Lee
- Singapore Ministry of Health, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Singapore
| | - Chiu Wan Ng
- Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, Malaysia
| | | | - Soonman Kwon
- School of Public Health, Seoul National University, South Korea
| | - Weibing Wang
- School of Public Health, Fudan University, Shanghai, China
| | - Nancy Nam Sze Chau
- Centre for Health Systems and Policy Research, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Carrie Ho Kwan Yam
- Centre for Health Systems and Policy Research, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Tsz Yu Chow
- Centre for Health Systems and Policy Research, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Tim Hung
- Centre for Health Systems and Policy Research, JC School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
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17
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Tan ST, Hung CT, Lai A, Chuah JC. Letter to the Editor. HONG KONG J EMERG ME 2017. [DOI: 10.1177/102490790200900209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- ST Tan
- Queen Elizabeth Hospital, Department of Anaesthesiology
| | - CT Hung
- Queen Elizabeth Hospital, Department of Anaesthesiology
| | - A Lai
- Queen Elizabeth Hospital, Department of Anaesthesiology
| | - JC Chuah
- Queen Elizabeth Hospital, Department of Anaesthesiology
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18
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Lai CK, Wong SY, Lee SS, Siu HK, Chiu CY, Tsang DN, Ip MP, Hung CT. A hospital-wide screening programme to control an outbreak of vancomycin-resistant enterococci in a large tertiary hospital in Hong Kong. Hong Kong Med J 2017; 23:140-9. [PMID: 28232642 DOI: 10.12809/hkmj164939] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
INTRODUCTION Apart from individual small-scale outbreaks, infections with vancomycin-resistant enterococci are uncommon in Hong Kong. A major outbreak of vancomycin-resistant enterococci, however, occurred at a large tertiary hospital in 2013. We describe the successful control of this outbreak and share the lessons learned. METHODS In 2013, there was an abnormal increase in the incidence of vancomycin-resistant enterococci carriage compared with baseline in multiple clinical departments at Queen Elizabeth Hospital. A multipronged approach was adopted that included a 10-week hospital-wide active screening programme, which aimed to identify and isolate hidden vancomycin-resistant enterococci carriers among all in-patients. The identified carriers were completely segregated in designated wards where applicable. Other critical infection control measures included directly observed hand hygiene and environmental hygiene. A transparent and open disclosure approach was adopted throughout the outbreak. RESULTS The infection control measures were successfully implemented. The active screening of vancomycin-resistant enterococci was conducted between 30 September and 10 November 2013. A total of 7053 rectal swabs were collected from patients in 46 hospital wards from 11 departments. The overall carriage rate of vancomycin-resistant enterococci was 2.8% (201/7053). Pulsed-field gel electrophoresis showed a predominant outbreak clone. We curbed the outbreak and kept the colonisation of vancomycin-resistant enterococci among patients at a pre-upsurge low level. CONCLUSIONS We report the largest cohesive effort to control spread of vancomycin-resistant enterococci in Hong Kong. Coupled with other infection control measures, we successfully controlled vancomycin-resistant enterococci to the pre-outbreak level. We have demonstrated that the monumental tasks can be achieved with meticulous planning, and thorough communication and understanding between all stakeholders.
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Affiliation(s)
- C Kc Lai
- Department of Pathology, Queen Elizabeth Hospital, Hong Kong.,Infection Control Team, Queen Elizabeth Hospital, Hong Kong
| | - S Yn Wong
- Department of Pathology, Queen Elizabeth Hospital, Hong Kong.,Infection Control Team, Queen Elizabeth Hospital, Hong Kong
| | - S Sy Lee
- Infection Control Team, Queen Elizabeth Hospital, Hong Kong
| | - H K Siu
- Chief Infection Control Officer's Office, Hospital Authority, Hong Kong
| | - C Y Chiu
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong
| | - D Nc Tsang
- Department of Pathology, Queen Elizabeth Hospital, Hong Kong.,Infection Control Team, Queen Elizabeth Hospital, Hong Kong.,Chief Infection Control Officer's Office, Hospital Authority, Hong Kong
| | - M Py Ip
- Department of Microbiology, The Chinese University of Hong Kong, Hong Kong
| | - C T Hung
- Queen Elizabeth Hospital, Hong Kong
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Yang PW, Hsieh MH, Chen MC, Tasia FY, Huang JW, Hung CT, Shie PS, Lin CY, Chen YH. The measurements to reduce the rate of surgical site infection in a tertiary teaching hospital. Antimicrob Resist Infect Control 2015. [PMCID: PMC4474703 DOI: 10.1186/2047-2994-4-s1-p84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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20
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Hung CT, Hsieh MH, Yang PW, Wu SW, Lin CY, Chen YH. Decrease ventilator-associated pneumonia by bundle care in cardiac surgery intensive care unit. Antimicrob Resist Infect Control 2015. [PMCID: PMC4475200 DOI: 10.1186/2047-2994-4-s1-p241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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21
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Jao Y, Wu SW, Lin TY, Hung CT, Yang PW, Huang CH, Lin CY, Lin WR, Chen YH, Lu PL. Free-flow duration prior as an influential factor on microorganism and endotoxin amount of reverse osmosis water for dialysis. Antimicrob Resist Infect Control 2015. [PMCID: PMC4474847 DOI: 10.1186/2047-2994-4-s1-p65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Abstract
Cartilage repair in terms of replacement, or
regeneration of damaged or diseased articular cartilage with functional tissue,
is the ‘holy grail’ of joint surgery. A wide spectrum of strategies
for cartilage repair currently exists and several of these techniques
have been reported to be associated with successful clinical outcomes
for appropriately selected indications. However, based on respective
advantages, disadvantages, and limitations, no single strategy, or
even combination of strategies, provides surgeons with viable options
for attaining successful long-term outcomes in the majority of patients.
As such, development of novel techniques and optimisation of current techniques
need to be, and are, the focus of a great deal of research from
the basic science level to clinical trials. Translational research
that bridges scientific discoveries to clinical application involves
the use of animal models in order to assess safety and efficacy
for regulatory approval for human use. This review article provides
an overview of animal models for cartilage repair. Cite this article: Bone Joint Res 2014;4:89–94.
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Affiliation(s)
- J L Cook
- University of Missouri, ComparativeOrthopaedic Laboratory and Missouri Orthopaedic Institute, Columbia, Missouri, USA
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23
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Taylor RB, Hung CT. An Ion Pairing H.P.L.C. Investigation of the Acidity Produced in Thermally Degraded Dextrose Solution. J Pharm Pharmacol 2011. [DOI: 10.1111/j.2042-7158.1981.tb11760.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R B Taylor
- School of Pharmacy, Robert Gordon's Institute of Technology, Schoolhill, Aberdeen, AB9 1FR, UK
| | - C T Hung
- School of Pharmacy, Robert Gordon's Institute of Technology, Schoolhill, Aberdeen, AB9 1FR, UK
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24
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Bian L, Lima EG, Angione SL, Ng KW, Williams DY, Xu D, Stoker AM, Cook JL, Ateshian GA, Hung CT. Mechanical and biochemical characterization of cartilage explants in serum-free culture. J Biomech 2008; 41:1153-9. [PMID: 18374344 DOI: 10.1016/j.jbiomech.2008.01.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 01/28/2008] [Accepted: 01/31/2008] [Indexed: 10/22/2022]
Abstract
Allografts of articular cartilage are both used clinically for tissue-transplantation procedures and experimentally as model systems to study the physiological behavior of chondrocytes in their native extracellular matrix. Long-term maintenance of allograft tissue is challenging. Chemical mediators in poorly defined culture media can stimulate cells to quickly degrade their surrounding extracellular matrix. This is particularly true of juvenile cartilage which is generally more responsive to chemical stimuli than mature tissue. By carefully modulating the culture media, however, it may be possible to preserve allograft tissue over the long-term while maintaining its original mechanical and biochemical properties. In this study juvenile bovine cartilage explants (both chondral and osteochondral) were cultured in both chemically defined medium and serum-supplemented medium for up to 6 weeks. The mechanical properties and biochemical content of explants cultured in chemically defined medium were enhanced after 2 weeks in culture and thereafter remained stable with no loss of cell viability. In contrast, the mechanical properties of explants in serum-supplemented medium were degraded by ( approximately 70%) along with a concurrent loss of biochemical content (30-40% GAG). These results suggest that long-term maintenance of allografts can be extended significantly by the use of a chemically defined medium.
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Affiliation(s)
- L Bian
- Cellular Engineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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25
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Lima EG, Bian L, Ng KW, Mauck RL, Byers BA, Tuan RS, Ateshian GA, Hung CT. The beneficial effect of delayed compressive loading on tissue-engineered cartilage constructs cultured with TGF-beta3. Osteoarthritis Cartilage 2007; 15:1025-33. [PMID: 17498976 PMCID: PMC2724596 DOI: 10.1016/j.joca.2007.03.008] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 03/11/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine whether the functional properties of tissue-engineered constructs cultured in a chemically-defined medium supplemented briefly with TGF-beta3 can be enhanced with the application of dynamic deformational loading. METHODS Primary immature bovine cells (2-3 months old) were encapsulated in agarose hydrogel (2%, 30 x 10(6)cells/ml) and cultured in chemically-defined medium supplemented for the first 2 weeks with transforming growth factor beta 3 (TGF-beta3) (10 microg/ml). Physiologic deformational loading (1 Hz, 3 h/day, 10% unconfined deformation initially and tapering to 2% peak-to-peak deformation by day 42) was applied either concurrent with or after the period of TGF-beta3 supplementation. Mechanical and biochemical properties were evaluated up to day 56. RESULTS Dynamic deformational loading applied concurrently with TGF-beta3 supplementation yielded significantly lower (-90%) overall mechanical properties when compared to free-swelling controls. In contrast, the same loading protocol applied after the discontinuation of the growth factor resulted in significantly increased (+10%) overall mechanical properties relative to free-swelling controls. Equilibrium modulus values reach 1306+/-79 kPa and glycosaminoglycan levels reach 8.7+/-1.6% w.w. during this 8-week period and are similar to host cartilage properties (994+/-280 kPa, 6.3+/-0.9% w.w.). CONCLUSIONS An optimal strategy for the functional tissue engineering of articular cartilage, particularly to accelerate construct development, may incorporate sequential application of different growth factors and applied deformational loading.
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Affiliation(s)
- E G Lima
- Department of Biomedical Engineering, Columbia University, 1210 Amsterdam Avenue, New York, NY 10027, USA
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26
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Ng KW, DeFrancis JG, Kugler LE, Kelly TAN, Ho MM, O'Conor CJ, Ateshian GA, Hung CT. Amino acids supply in culture media is not a limiting factor in the matrix synthesis of engineered cartilage tissue. Amino Acids 2007; 35:433-8. [PMID: 17713744 PMCID: PMC3769193 DOI: 10.1007/s00726-007-0583-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 07/02/2007] [Indexed: 10/22/2022]
Abstract
Increased amino acid supplementation (0.5 x, 1.0 x, and 5.0 x recommended concentrations or additional proline) was hypothesized to increase the collagen content in engineered cartilage. No significant differences were found between groups in matrix content or dynamic modulus. Control constructs possessed the highest compressive Young's modulus on day 42. On day 42, compared to controls, decreased type II collagen was found with 0.5 x, 1.0 x, and 5.0 x supplementation and significantly increased DNA content found in 1.0 x and 5.0 x. No effects were observed on these measures with added proline. These results lead us to reject our hypothesis and indicate that the low collagen synthesis in engineered cartilage is not due to a limited supply of amino acids in media but may require a further stimulatory signal. The results of this study also highlight the impact that culture environment can play on the development of engineered cartilage.
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Affiliation(s)
- K W Ng
- Cellular Engineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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27
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Chan AOK, Lam CW, Tong SF, Cheng MT, Yung K, Chan YW, Au KM, Yuen YP, Hung CT, Ng KP, Shek CC. Gene symbol: BCHE. Hum Genet 2007; 121:288. [PMID: 17598201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
- A O K Chan
- Chemical Pathology Laboratory, Queen Elizabeth Hospital, Kowloon, Hong Kong.
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28
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Chan AOK, Lam CW, Tong SF, Tung CM, Yung K, Chan YW, Au KM, Yuen YP, Hung CT, Ng KP, Shek CC. Gene symbol: BCHE. Hum Genet 2007; 121:289. [PMID: 17598228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
- A O K Chan
- Chemical Pathology Laboratory, Queen Elizabeth Hospital, Kowloon, Hong Kong.
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Abstract
BACKGROUND We explored the sympatholytic property of dexmedetomidine, especially its role in intraocular pressure (IOP) reduction, haemodynamic stability, and attenuation of extubation response. METHOD In this double-blind, randomized, controlled trial approved by the Hospital Ethics Committee, 60 patients undergoing elective vitreoretinal surgery were allocated to two groups, receiving either placebo or dexmedetomidine. A loading dose of dexmedetomidine 2.5 microg kg(-1) h(-1) (or placebo in same volume) was infused for 10 min immediately before induction of anaesthesia with propofol, followed by a maintenance dexmedetomidine or placebo infusion at 0.4 microg kg(-1) h(-1) till 30 min before the end of the operation. Anaesthesia was maintained with isoflurane, oxygen, and air mixture. IOP was measured before the loading dose and 1 min after tracheal intubation. The mean arterial pressure (MAP) and heart rate (HR) during loading, induction, maintenance, extubation, and recovery period were measured. The degree of strain on extubation was graded from 0 to 5. RESULTS The use of vasopressor/labetalol/atropine and the reduction in IOP were comparable between the two groups. There was a significant variation in MAP and HR over time within group, but not between groups. The median degree of strain was significantly lower (P = 0.049), and the time to reach Aldrete score of 10 shorter (P = 0.031) in the dexmedetomidine group. CONCLUSION Dexmedetomidine can be used without undue haemodynamic fluctuation and can decrease the excitatory response during extubation. The reduction in IOP with dexmedetomidine was comparable with placebo.
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Affiliation(s)
- Y Y S Lee
- Department of Anaesthesia, Queen Elizabeth Hospital, Hong Kong, China.
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30
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Chong DYC, Greenland KB, Tan ST, Irwin MG, Hung CT. The clinical implication of the vocal cords–carina distance in anaesthetized Chinese adults during orotracheal intubation. Br J Anaesth 2006; 97:489-95. [PMID: 16873383 DOI: 10.1093/bja/ael186] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Previous studies have identified no strong correlation between patients' height and tracheal length in anaesthetized patients. We have attempted to compare vocal cords-carina distance (VCD) in Chinese patients with the dimensions of five commonly used tracheal tubes. In addition, we attempted to find a surface anatomy measurement that would identify patients with 'short tracheas'. METHODS We measured VCD in 130 anaesthetized Chinese patients with a fibreoptic bronchoscope. Also measurements were obtained of the distal ends of five commonly used tracheal tubes. We undertook various surface anatomy measurements on the patients' chest and neck region to predict those patients with short tracheas. RESULTS VCD averaged 12.6 (SD 1.4) cm. In seven patients (5%) this distance was particularly short (between 8.8 and 10.4 cm). Many of the commonly used tracheal tubes would be placed close to or beyond the carina when the black intubation guide mark(s) is (are) at the level of the vocal cords. The VCD of <or=11 cm (short trachea) could be predicted by patient height of <or=167.5 cm and a thyrosternal distance of <or=28.5 cm with limited reliability. CONCLUSIONS A significant number of patients with short VCD in our study group could be at risk of endobronchial intubation with many of the tracheal tubes. Patient height and thyrosternal distance can be useful in predicting short tracheas.
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Affiliation(s)
- D Y C Chong
- Department of Anaesthesiology, Queen Elizabeth Hospital, Kowloon, Hong Kong SAR
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31
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Chahine NO, Ateshian GA, Hung CT. The effect of finite compressive strain on chondrocyte viability in statically loaded bovine articular cartilage. Biomech Model Mechanobiol 2006; 6:103-11. [PMID: 16821016 DOI: 10.1007/s10237-006-0041-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2005] [Accepted: 01/06/2006] [Indexed: 11/29/2022]
Abstract
Recent studies have reported that certain regimes of compressive loading of articular cartilage result in increased cell death in the superficial tangential zone (STZ). The objectives of this study were (1) to test the prevalent hypothesis that preferential cell death in the STZ results from excessive compressive strain in that zone, relative to the middle and deep zones, by determining whether cell death correlates with the magnitude of compressive strain and (2) to test the corollary hypothesis that the viability response of cells is uniform through the thickness of the articular layer when exposed to the same loading environment. Live cartilage explants were statically compressed by approximately 65% of their original thickness, either normal to the articular surface (axial loading) or parallel to it (transverse loading). Cell viability after 12 h was compared to the local strain distribution measured by digital image correlation. Results showed that the strain distribution in the axially loaded samples was highest in the STZ (77%) and lowest in the deep zone (55%), whereas the strain was uniformly distributed in the transversely loaded samples (64%). In contrast, axially and transversely loaded samples exhibited very similar profiles of cell death through the depth, with a preferential distribution in the STZ. Unloaded control samples showed negligible cell death. Thus, under prolonged static loading, depth-dependent variations in chondrocyte death did not correlate with the local depth-dependent compressive strain, and the prevalent hypothesis must be rejected. An alternative hypothesis, suggested by these results, is that superficial zone chondrocytes are more vulnerable to prolonged static loading than chondrocytes in the middle and deep zones.
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Affiliation(s)
- N O Chahine
- Musculoskeletal Biomechanics Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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Abstract
Because of the avascular nature of adult cartilage, nutrients and waste products are transported to and from the chondrocytes by diffusion and convection through the extracellular matrix. The convective interstitial fluid flow within and around chondrocytes is poorly understood. This theoretical study demonstrates that the incorporation of a semi-permeable membrane when modeling the chondrocyte leads to the following findings: under mechanical loading of an isolated chondrocyte the intracellular fluid pressure is on the order of tens of Pascals and the transmembrane fluid outflow, on the order of picometers per second, takes several days to subside; consequently, the chondrocyte behaves practically as an incompressible solid whenever the loading duration is on the order of minutes or hours. When embedded in its extracellular matrix (ECM), the chondrocyte response is substantially different. Mechanical loading of the tissue leads to a fluid pressure difference between intracellular and extracellular compartments on the order of tens of kilopascals and the transmembrane outflow, on the order of a nanometer per second, subsides in about 1 h. The volume of the chondrocyte decreases concomitantly with that of the ECM. The interstitial fluid flow in the extracellular matrix is directed around the cell, with peak values on the order of tens of nanometers per second. The viscous fluid shear stress acting on the cell surface is several orders of magnitude smaller than the solid matrix shear stresses resulting from the ECM deformation. These results provide new insight toward our understanding of water transport in chondrocytes.
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Affiliation(s)
- G A Ateshian
- Department of Biomedical Engineering, Columbia University, 500 West 120th St. 242 S.W. Mudd, MC4703, New York, NY 10027, USA.
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Abstract
BACKGROUND In this study, we evaluated the learning curve and performance of the Viewmax laryngoscope during simulated difficult laryngoscopy in an intubation manikin (Laerdal Airway Management Trainer). METHODS To determine the learning curve, 25 anaesthesiologists without previous experience with the Viewmax laryngoscope performed 10 successive intubations in an intubation manikin with a normal airway. Time to intubation and failed intubation attempts were recorded. Another manikin was modified to enable comparison of the Viewmax laryngoscope with Macintosh and McCoy laryngoscopes. The time to intubation, number of failed intubation attempts, modified Cormack and Lehane (MCL) laryngeal view grading, percentage of glottic opening (POGO score), use of gum elastic bougie and subjective rating of degree of difficulty were recorded. RESULTS The learning curve for the Viewmax laryngoscope showed a progressive decrease in time to successful intubation and reached a plateau at the sixth attempt. In simulated difficult laryngoscopy, the Viewmax laryngoscope demonstrated significantly better laryngeal view than the Macintosh and McCoy laryngoscopes in terms of MCL grading (Macintosh, P = 0.01; McCoy, P < 0.01) and POGO score (Macintosh, P < 0.01; McCoy, P < 0.01). The time required for intubation in simulated difficult laryngoscopy for the Viewmax laryngoscope was significantly longer than that for the Macintosh (P = 0.02) and McCoy (P < 0.01) laryngoscopes. There was no significant difference in the degree of difficulty, number of failed intubations and use of gum elastic bougie. CONCLUSION When compared with the Macintosh and McCoy laryngoscopes in a manikin, the Viewmax laryngoscope appears to improve the view of the larynx but requires a longer time for tracheal intubation.
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Affiliation(s)
- Y Y Leung
- Department of Anaesthesiology, Queen Elizabeth Hospital, Kowloon, Hong Kong.
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Kwok CY, Hung CT. Clinical experience of trainee anaesthesiologists: logbook analysis. Hong Kong Med J 2006; 12:125-32. [PMID: 16603780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023] Open
Abstract
OBJECTIVE To study the clinical experience acquired by trainee anaesthesiologists after 6 years of training in Hong Kong. DESIGN Retrospective observational study. SETTING Recognised anaesthesiology training posts in the Hong Kong Hospital Authority. PARTICIPANTS All anaesthesiology trainees who sat the Exit Assessment between January 2001 and June 2002 after completing more than 48 months of anaesthetic training. MAIN OUTCOME MEASURES Anaesthetic experience of trainees. RESULTS All data provided by 25 trainees were computed for analysis. Each trainee administered a mean of 2668 anaesthetics over a 6-year period, including 57 anaesthetics for thoracic surgery, 15 for cardiac surgery, 213 for caesarian section (34% under general anaesthesia), and 100 for neurosurgical operations. The paediatric anaesthesia exposure involved a mean of 12 neonates and 180 children who were younger than 4 years. Apart from cardiac and thoracic anaesthesia, there was no statistical difference in subspecialty anaesthetic experience among trainees from different parent hospitals. CONCLUSION The current training system provides sufficient anaesthetic experience in terms of case variety and subspecialty case numbers. There was uneven exposure to cardiac, thoracic, and paediatric anaesthesia. An accurate logbook that is reviewed regularly by a supervisor will help ensure adequate subspecialty exposure. An electronic logbook will facilitate a more comprehensive reviewing process.
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Affiliation(s)
- C Y Kwok
- Department of Anaesthesiology, Queen Elizabeth Hospital, 30 Gascoigne Road, Hong Kong.
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Takai E, Landesberg R, Katz RW, Hung CT, Guo XE. Substrate modulation of osteoblast adhesion strength, focal adhesion kinase activation, and responsiveness to mechanical stimuli. Mol Cell Biomech 2006; 3:1-12. [PMID: 16711067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Osteoblast interactions with extracellular matrix (ECM) proteins are known to influence many cell functions, which may ultimately affect osseointegration of implants with the host bone tissue. Some adhesion-mediated events include activation of focal adhesion kinase, and subsequent changes in the cytoskeleton and cell morphology, which may lead to changes in adhesion strength and cell responsiveness to mechanical stimuli. In this study we examined focal adhesion kinase activation (FAK), F-actin cytoskeleton reorganization, adhesion strength, and osteoblast responsiveness to fluid shear when adhered to type I collagen (ColI), glass, poly-L-lysine (PLL), fibronectin (FN), vitronectin (VN), and serum (FBS). In general, surfaces that bind cells through integrins (FN, VN, FBS) elicited the highest adhesion strength, FAK activation, and F-actin stress fiber formation after both 15 and 60 minutes of adhesion. In contrast, cells attached through non-integrin mediated means (PLL, glass) showed the lowest FAK activation, adhesion strength, and little F-actin stress fiber formation. When subjected to steady fluid shear using a parallel plate flow chamber, osteoblasts plated on FN released significantly more PGE2 compared to those on glass. In contrast, PGE2 release of osteoblasts attached to FN or glass was not different in the absence of fluid shear, suggesting that differences in binding alone are insufficient to alter PGE2 secretion. The increased adhesion strength as well as PGE2 secretion of osteoblasts adhered via integrins may be due to increased F-actin fiber formation, which leads to increased cell stiffness.
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Affiliation(s)
- E Takai
- Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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Lam KW, Cheng F, Chan JWM, Cheung GSY, Lee MWM, Hung CT. Ethical attitudes of non-intensive care unit clinicians upon end-of-life issue: more training is necessary. Hong Kong Med J 2004; 10:438. [PMID: 15591608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
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Krishnan R, Caligaris M, Mauck RL, Hung CT, Costa KD, Ateshian GA. Removal of the superficial zone of bovine articular cartilage does not increase its frictional coefficient. Osteoarthritis Cartilage 2004; 12:947-55. [PMID: 15564061 PMCID: PMC2828954 DOI: 10.1016/j.joca.2004.08.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Accepted: 08/18/2004] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate the role of the superficial zone in regulating the frictional response of articular cartilage. This zone contains the superficial protein (SZP), a proteoglycan synthesized exclusively by superficial zone chondrocytes and implicated in reducing the friction coefficient of cartilage. DESIGN Unconfined compression creep tests with sliding of cartilage against glass in saline were carried out on fresh bovine cylindrical plugs (slashed circle Ø6 mm, n=35) obtained from 16 bovine shoulder joints (ages 1-3 months). In the first two experiments, friction tests were carried out before and after removal of the superficial zone ( approximately 100 microm), in a control and treatment group, using two different applied load magnitudes (4.4 N and 22.2 N). In the third experiment, friction tests were conducted on intact surfaces and the corresponding microtomed deep zone of the same specimen. RESULTS In all tests the friction coefficient exhibited a transient response, increasing from a minimum value (mu(min)) to a near-equilibrium final value (micro(eq)). No statistical change (P>0.5) was found in micro(min) before and after removal of the superficial zone in both experiments 1 and 2. However, micro(eq) was observed to decrease significantly (P<0.001) after removal of the surface zone. Results from the third experiment confirm that micro(eq) is even lower at the deep zone. Surface roughness measurements with atomic force microscopy (AFM) revealed an increase in surface roughness after microtoming. Immunohistochemical staining confirmed the presence of SZP in intact specimens and its removal in microtomed specimens. CONCLUSIONS The topmost ( approximately 100 microm) superficial zone of articular cartilage does not have special properties which enhances its frictional response.
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Affiliation(s)
- R Krishnan
- Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA
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Abstract
OBJECTIVE The objective of this study was to characterize the dynamic modulus and compressive strain magnitudes of bovine articular cartilage at physiological compressive stress levels and loading frequencies. DESIGN Twelve distal femoral cartilage plugs (3mm in diameter) were loaded in a custom apparatus under load control, with a load amplitude up to 40 N and loading frequencies of 0.1, 1, 10 and 40 Hz, resulting in peak Cauchy stress amplitudes of 4.8 MPa (engineering stress 5.7 MPa). RESULTS The equilibrium Young's modulus under a tare load of 0.4N was 0.49+/-0.10 MPa. In the limit of zero applied stress, the incremental dynamic modulus derived from the slope of the stress-strain curve increased from 14.6+/-6.9 MPa at 0.1 Hz to 28.7+/-7.8 MPa at 40 Hz. At 4 MPa of applied stress, the corresponding increase was from 48.2+/-13.5 MPa at 0.1 Hz to 64.8+/-13.0 MPa at 40 Hz. Peak compressive strain amplitudes varied from 15.8+/-3.4% at 0.1 Hz to 8.7+/-1.8% at 40 Hz. The phase angle decreased from 28.8 degrees +/-6.7 degrees at 0.1 Hz to-0.5 degrees +/-3.8 degrees at 40 Hz. DISCUSSION These results are representative of the functional properties of articular cartilage under physiological load magnitudes and frequencies. The viscoelasticity and nonlinearity of the tissue helps to maintain the compressive strains below 20% under the physiological compressive stresses achieved in this study. These findings have implications for our understanding of cartilage metabolism and chondrocyte viability under various loading regimes. They also help establish guidelines for cartilage functional tissue engineering studies.
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Affiliation(s)
- S Park
- Columbia University, Department of Mechanical Engineering, New York, NY 10027, USA
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Mauck RL, Wang CCB, Oswald ES, Ateshian GA, Hung CT. The role of cell seeding density and nutrient supply for articular cartilage tissue engineering with deformational loading. Osteoarthritis Cartilage 2003; 11:879-90. [PMID: 14629964 DOI: 10.1016/j.joca.2003.08.006] [Citation(s) in RCA: 242] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Functional tissue engineering (FTE) of articular cartilage involves the use of physiologically relevant mechanical signals to encourage the growth of engineered constructs. The goal of this study was to determine the utility of deformational loading in enhancing the mechanical properties of chondrocyte-seeded agarose hydrogels, and to investigate the role of initial cell seeding density and nutrient supply in this process. DESIGN Chondrocyte-seeded agarose hydrogels were cultured in free-swelling conditions or with intermittent deformational loading (10% deformation, 1 Hz, 1 h on/ 1 h off, 3 h per day, five days per week) over a two-month culture period. Disks were seeded at lower (10 million cells/ml) and higher (60 million cells/ml) seeding densities in the context of a greater medium supply than previous studies (decreasing the number of cells/ml feed medium/day) and with an increasing concentration of fetal bovine serum (10 or 20% FBS). RESULTS Under these more optimal nutrient conditions, at higher seeding densities and high serum concentration (20% FBS), dynamically loaded constructs show >2-fold increases in material properties relative to free-swelling controls. After two months of culture, dynamically loaded constructs achieved a Young's modulus of approximately 185 kPa and a dynamic modulus (at 1 Hz) of approximately 1.6 MPa, with a frequency dependent response similar to that of the native tissue. These values represent approximately 3/4 and approximately 1/4 the values measured for the native tissue, respectively. While significant differences were found in mechanical properties, staining and bulk measurements of both proteoglycan and collagen content of higher seeding density constructs revealed no significant differences between free-swelling and loading groups. This finding indicates that deformational loading may act to increase material properties via differences in the structural organization, the production of small linker ECM molecules, or by modulating the size of macromolecular proteoglycan aggregates. CONCLUSIONS Taken together, these results point to the utility of dynamic deformational loading in the mechanical preconditioning of engineered articular cartilage constructs and the necessity for increasing feed media volume and serum supplementation with increasing cell seeding densities.
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Affiliation(s)
- R L Mauck
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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Tan ST, Hung CT. Acute-on-chronic subdural haematoma: a rare complication after spinal anaesthesia. Hong Kong Med J 2003; 9:384-6. [PMID: 14530536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023] Open
Abstract
An 88-year-old woman with an undiagnosed chronic subdural haematoma underwent emergency repair of a femoral hernia under spinal anaesthesia. The patient complained of headache postoperatively, and a subsequent computed tomography brain scan showed an acute-on-chronic subdural haematoma, with midline shift and impending coning. The patient recovered completely after surgical decompression. The difficulty in diagnosing chronic subdural haematoma in the elderly patient with no history of trauma is discussed, along with the differential diagnosis of headache following spinal anaesthetic in this age-group.
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Affiliation(s)
- S T Tan
- Department of Anaesthesiology, Queen Elizabeth Hospital, 30 Gascoigne Road, Kowloon, Hong Kong, ROC.
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Hung CT, Lau LL, Chan CK, Chow B, Chui PT, Ho B, Kung MC, Lui J, Hui T, Ho E, Chan SF, Chen PP. Acute pain services in Hong Kong: facilities, volume, and quality. Hong Kong Med J 2002; 8:196-201. [PMID: 12055366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Acute pain services in public hospitals in Hong Kong were studied. Audit data on the volume and quality of acute pain services were collected prospectively from 1997 to 1999, and data on related facilities were collected in 2000. About 20% of patients undergoing a major operation received an acute pain service; of these, 78.6% were satisfied with the treatment provided. In 2000, 86% (18/21) of hospitals providing anaesthetic services were running an acute pain service. Staffing was better in hospitals providing a high volume of acute pain services, ranging from a full-time specialist anaesthesiologist assisted by a half-time trainee to a half-time specialist assisted by a full- or half-time trainee. However, only four hospitals were staffed with pain nurses. In total, 57% of patients received intravenous patient-controlled analgesia and 32% epidural analgesia. The mean duration of acute pain service treatment was 3.1 days. Currently anaesthesiologist-based acute pain services take care of a limited number of patients. To expand the coverage, there should be a move towards an anaesthesiologist-led, pain nurse-based, acute pain service. The present shortage of pain nurses should be addressed.
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Affiliation(s)
- C T Hung
- Department of Anaesthesiology, Queen Elizabeth Hospital, 30 Gascoigne Road, Hong Kong
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Abstract
A case is presented of haemorrhage into a thyroid cyst after endotracheal intubation for an elective nasal operation in a healthy young man. The haemorrhagic cyst compressed the trachea and the patient was taken to the intensive care unit with the endotracheal tube left in situ. Hemithyroidectomy was performed uneventfully two days later. Causes of haemorrhage into thyroid cysts are reviewed.
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Affiliation(s)
- L D Szeto
- Department of Anaesthesiology, Queen Elizabeth Hospital, Kowloon, Hong Kong, SAR
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Cheng B, Hung CT, Chiu W. Herbal medicine and anaesthesia. Hong Kong Med J 2002; 8:123-30. [PMID: 11937667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
Herbal medicines are increasingly used in both western and Chinese societies. This is partly attributed to the alleged limitations of scientific medicine in the cure and control of chronic diseases. Many patients do not disclose that they have used herbs before surgery and hence their physicians remain unaware of the potential herb-drug interactions. With respect to anaesthesia, herbs can cause coagulation disorders, cardiovascular side-effects, water and electrolyte disturbances, endocrine effects, hepatotoxicity, and prolongation of the effects of anaesthetic agents. Anaesthesiologists should obtain a history of herbal medicine use from patients and work out the adverse perioperative herb-drug interactions in advance of the actual operation. If in doubt, the herbal medicine should be stopped for 2 weeks prior to anaesthesia and surgery.
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Affiliation(s)
- B Cheng
- Department of Anaesthesia, Pamela Youde Nethersole Eastern Hospital, 3 Lok Man Road, Chai Wan, Hong Kong
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Hung CT, Chow YF, Fung CF, Koo CH, Lui KC, Lam A. Safety and comfort during sedation for diagnostic or therapeutic procedures. Hong Kong Med J 2002; 8:114-22. [PMID: 11937666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
Sedation during diagnostic or therapeutic procedures must be safe and comfortable for patients. To achieve this, additional suitably qualified staff must be available throughout the procedure to administer sedation and monitor the patient. Anaesthesiologists possess the necessary knowledge and skills to perform sedation safely but are often unavailable. Non-anaesthesiologists performing sedation should be fully trained in the physiology of sedation, the pharmacology of sedatives and analgesics, the monitoring of patients, and in airway support, ventilatory care, and cardiopulmonary resuscitation. The presence of an anaesthesiologist is desirable when dealing with patients at high-risk of complications. Good sedation practice involves presedation assessment and optimal selection of patients, careful monitoring and support from dedicated staff, and adherence to recovery and discharge criteria.
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Affiliation(s)
- C T Hung
- Department of Anaesthesiology, Queen Elizabeth Hospital, 30 Gascoigne Road, Kowloon, Hong Kong
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Abstract
BACKGROUND Rapid serology test is a simple and convenient way for diagnosing Helicobacter pylori infection. However performances of these tests are usually less satisfactory than expected, particularly in developing countries. AIM To evaluate the performances of two newly developed rapid serology tests for Helicobacter pylori infection. PATIENTS Consecutive Chinese dyspeptic patients undergoing upper gastrointestinal endoscopy. METHODS Gastric biopsies were obtained from antrum and corpus for rapid urease test and histological examination. Diagnosis of Helicobacter pylori infection was based on two or more positive results in rapid urease test, histology and [13C] urea breath test. Patients' sera were tested against two rapid serology tests: ASSURE Hp Rapid Test (Genelabs Diagnostics, Singapore) and SureStep (Applied Biotech, San Diego, CA, USA). RESULTS A total of 148 patients were evaluated and Helicobacter pylori infection was diagnosed in 78 (53%) patients by gold standard. The sensitivities of ASSURE Hp and SureStep were, respectively, 94% and 71% (p=0.0003). Specificities of the two test kits were both 90%. The overall accuracy of ASSURE Hp was significantly higher than SureStep (92% versus 80%, p=0.004). CONCLUSION Both rapid serology tests appear to be specific in diagnosing Helicobacter pylori infection in the Chinese populations. However the ASSURE Hp test is more sensitive and accurate than the SureStep test.
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Affiliation(s)
- C T Hung
- Department of Medicine & Therapeutics, the Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
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Palmer GD, Chao Ph PH, Raia F, Mauck RL, Valhmu WB, Hung CT. Time-dependent aggrecan gene expression of articular chondrocytes in response to hyperosmotic loading. Osteoarthritis Cartilage 2001; 9:761-70. [PMID: 11795996 DOI: 10.1053/joca.2001.0473] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate the effects of increasing extracellular osmolality on aggrecan gene expression and cell size in cultured chondrocytes. DESIGN Aggrecan promoter activity and mRNA levels were measured in bovine monolayer chondrocytes subjected to hyperosmotic loading for different time periods, using transient transfection assays or RT-PCR. Cell size changes were also determined using an epifluorescence microscopy system. RESULTS Hyperosmotic loading for 24 h suppressed aggrecan promoter activity and mRNA levels approximately two-fold. However no suppression of promoter activity was observed when exon 1 was deleted from the human aggrecan promoter construct. Osmotic regulation of aggrecan gene expression was time-dependent and found to correlate with cell shrinking and swelling. No suppression in promoter activity was observed when the hyperosmotic stimulus was applied in a cyclic manner, or when serum was present in the culture medium. CONCLUSION Hyperosmotic loading regulates aggrecan gene expression and cell size in isolated chondrocytes. Osmotic regulation of gene expression is also affected by the time-varying nature of loading and the presence of serum.
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Affiliation(s)
- G D Palmer
- Cellular Engineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
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Abstract
In a prospective, randomized study, the effect of age on recovery from remifentanil anaesthesia was evaluated. Twenty consecutive patients classified as ASA 1 and 2 and having elective laparotomy were recruited to one of two groups based on age (Group 1 age <60 y and Group 2 age >60 y). Remifentanil boluses and infusion were used for induction and maintenance of anaesthesia. Dosage was titrated against clinical response to perioperative stimulation and the infusion was terminated at the end of the operation. Time intervals between termination of remifentanil infusion and 1) spontaneous respiration, 2) adequate respiration, 3) eye opening, 4) limb movement, 5) extubation, 6) Aldrete score >9, 7) discharge to recovery room and 8) discharge to the ward were recorded. Patient controlled analgesia with morphine was used for postoperative pain control. Student's t test was used to compare the differences in these time intervals between Groups 1 and 2. A P value <0.05 was taken as significant. We found that the younger age group regained spontaneous respiration (0.8+/-0.7 min vs 3.2+/-3.6 min), adequate respiration (3.4+/-3.7 min vs 7.6+/-5.8 min), opened their eyes (0.9+/-1.0 min vs 3.6+/-4.4 min), had their endotracheal tubes removed (5.0+/-4.6 min vs 9.0+/-6.5 min) and were discharged to recovery room (8.8+/-4.3 min vs 14.5+/-7.1 min) earlier than their older counterparts. In conclusion, age was a co-variate for recovery from remifentanil anaesthesia.
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Affiliation(s)
- A Lai
- Department of Anaesthesia, Queen Elizabeth Hospital, King's Park, Hong Kong, PRC
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Lau LL, Hung CT, Chan CK, Chow B, Chui PT, Ho B, Kung MC, Lui J, Hui T, Ho E, Chan SF, So HY. Anaesthetic clinical indicators in public hospitals providing anaesthetic care in Hong Kong: prospective study. Hong Kong Med J 2001; 7:251-60. [PMID: 11590266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
OBJECTIVES To assess the quality of anaesthetic services as defined in the six anaesthetic clinical indicators against preset standards and to identify risk factors for adverse events in the recovery room. DESIGN Prospective study. SETTING All public hospitals providing anaesthetic care in Hong Kong. PATIENTS Eighteen thousand, seven hundred and fifty-nine patients receiving elective or emergency anaesthesia administered by anaesthetists from June 1998 to July 1998. MAIN OUTCOME MEASURES Patient demographics, American Society of Anesthesiologists status, category and nature of operation, presence of preoperative anaesthetic visit in ward, type of anaesthesia, reasons for a recovery room stay of more than a 2-hour duration, intubation to relieve respiratory distress in the recovery room, presence of hypothermia in the recovery room for operations lasting more than 2 hours, and dental or ocular injuries attributable to anaesthesia. RESULTS There are two major findings from this study. Firstly, a high incidence of hypothermia in the recovery room was reported. Secondly, a greater risk of prolonged stay in the recovery room was identified for patients older than 65 years, major operations, and anaesthetic techniques using combined general and regional anaesthesia. CONCLUSION The six anaesthetic clinical indicators reflected the provision of anaesthetic care in public hospitals in Hong Kong. Good compliance to the preset standard of the anaesthetic clinical indicators was achieved during the study period.
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Affiliation(s)
- L L Lau
- Department of Anaesthesia and Intensive Care, Tuen Mun Hospital, Tsing Chung Koon Road, New Territories, Hong Kong
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Abstract
An accurate description of the mechanical environment around chondrocytes embedded within their dense extracellular matrix (ECM) is essential for the study of mechano-signal transduction mechanism(s) in explant experiments. New methods have been developed to determine the inhomogeneous strain distribution throughout the depth of the ECM during compression (Schinagl et al., 1996, Annals of Biomedical Engineering 24, 500-512; Schinagl et al 1997. Journal of Orthopaedics Research 15, 499-506) and the corresponding depth-dependent aggregate modulus distribution (Wang and Mow, 1998. Transactions of the Orthopaedics Research Society 23, 484; Chen and Sah, 1999. Transactions of the Orthopaedics Research Society 24, 635). These results provide the motivation for the current investigation to assess the influence of tissue inhomogeneity on the chondrocyte milieu in situ, e.g. stress, strain, fluid velocity and pressure fields within articular cartilage. To describe this inhomogeneity, we adopted the finite deformation biphasic constitutive law developed by Holmes and Mow (1990 Journal of Biomechanics 23, 1145-1156). Our calculations show that the mechanical environment inside an inhomogeneous tissue differs significantly from that inside a homogeneous tissue. Furthermore, our results indicate that the need to incorporate an inhomogeneous aggregate modulus. or an anisotropy, into the biphasic theory to describe articular cartilage depends largely on the motivation for the study.
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Affiliation(s)
- C C Wang
- Department of Orthopaedic Surgery, Columbia University, New York, NY 10032, USA
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50
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Abstract
We investigated the effect of newborn bovine serum on the intracellular calcium [Ca(2+)](i) response of primary cultured bone cells stimulated by fluid flow. As it has been previously established that these cells exhibit [Ca(2+)](i) responses to fluid flow shear stress in saline media without growth factors or other chemically stimulatory factors, we hypothesized that the addition of serum to the flow medium would enhance the mechanosensitivity of the cells. We examined the effect of a short-term (10-15min) exposure of the cells to 2 and 10% serum prior to flow stimulation (pretreated) compared to not exposing the cells prior to flow stimulation (unpretreated). The cells were subjected to a well-defined, 90-s flow stimulus with shear stress levels ranging from 0.02 to 3.5Pa in a laminar flow chamber using a saline medium supplemented with 2 or 10% serum. For pretreatment, the serum concentration was the same from pre-flow to flow exposure. We observed a differential effect in the magnitude of the peak [Ca(2+)](i) response modulated by the concentration of serum in the pre-flow medium. Additionally, ATP-supplemented flow was examined as a comparison to the serum-supplemented flow and exhibited a similar trend in the peak [Ca(2+)](i) flow response that was dependent on ATP concentration and pre-flow exposure conditions. These findings demonstrate that under the conditions of this study, chemical agonist exposure can modulate the [Ca(2+)](i) response in bone cells subjected to fluid flow-induced shear stress.
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Affiliation(s)
- F D Allen
- Department of Bioengineering, University of Pennsylvania, 19104, Philadelphia, PA, USA.
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