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Krepiakevich A, Khowaja AR, Kabajaasi O, Nemetchek B, Ansermino JM, Kissoon N, Mugisha NK, Tayebwa M, Kabakyenga J, Wiens MO. Out of pocket costs and time/productivity losses for pediatric sepsis in Uganda: a mixed-methods study. BMC Health Serv Res 2021; 21:1252. [PMID: 34798891 PMCID: PMC8605527 DOI: 10.1186/s12913-021-07272-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 10/27/2021] [Indexed: 11/10/2022] Open
Abstract
Background Sepsis disproportionately affects children from socioeconomically disadvantaged families in low-resource settings, where care seeking may consume scarce family resources and lead to financial hardships. Those financial hardships may, in turn, contribute to late presentation or failure to seek care and result in high mortality during hospitalization and during the post discharge period, a period of increasingly recognized vulnerability. The purpose of this study is to explore the out-of-pocket costs related to sepsis hospitalizations and post-discharge care among children admitted with sepsis in Uganda. Methods This mixed-methods study was comprised of focus group discussions (FGD) with caregivers of children admitted for sepsis, which then informed a quantitative cross-sectional household survey to measure out-of-pocket costs of sepsis care both during initial admission and during the post-discharge period. All participants were families of children enrolled in a concurrent sepsis study. Results Three FGD with mothers (n = 20) and one FGD with fathers (n = 7) were conducted. Three primary themes that emerged included (1) financial losses, (2) time and productivity losses and (3) coping with costs. A subsequently developed cross-sectional survey was completed for 153 households of children discharged following admission for sepsis. The survey revealed a high cost of care for families attending both private and public facilities, although out-of-pocket cost were higher at private facilities. Half of those surveyed reported loss of income during hospitalization and a third sold household assets, most often livestock, to cover costs. Total mean out-of-pocket costs of hospital care and post-discharge care were 124.50 USD and 44.60 USD respectively for those seeking initial care at private facilities and 62.10 USD and 14.60 USD at public facilities, a high sum in a country with widespread poverty. Conclusions This study reveals that families incur a substantial economic burden in accessing care for children with sepsis.
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Affiliation(s)
- A Krepiakevich
- First Nations Health Authority, Vancouver, British Columbia, Canada
| | - A R Khowaja
- Faculty of Applied Health Sciences, Brock University, St. Catherines, Ontario, Canada
| | | | - B Nemetchek
- College of Nursing, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - J M Ansermino
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada.,Center for International Child Health, BC Children's Hospital, Vancouver, BC, Canada
| | - N Kissoon
- Center for International Child Health, BC Children's Hospital, Vancouver, BC, Canada.,Department of Pediatrics, University of British Columbia, Vancouver, Canada
| | | | - M Tayebwa
- Mbarara University of Science and Technology, Mbarara, Uganda
| | - J Kabakyenga
- Mbarara University of Science and Technology, Mbarara, Uganda
| | - M O Wiens
- Walimu, Kampala, Uganda.,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada.,Center for International Child Health, BC Children's Hospital, Vancouver, BC, Canada.,Mbarara University of Science and Technology, Mbarara, Uganda
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Savoca A, van Heusden K, Manca D, Ansermino JM, Dumont GA. The effect of cardiac output on the pharmacokinetics and pharmacodynamics of propofol during closed-loop induction of anesthesia. Comput Methods Programs Biomed 2020; 192:105406. [PMID: 32155533 DOI: 10.1016/j.cmpb.2020.105406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/31/2020] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVE Intraoperative hemodynamic stability is essential to safety and post-operative well-being of patients and should be optimized in closed-loop control of anesthesia. Cardiovascular changes inducing variations in pharmacokinetics may require dose modification. Rigorous investigational tools can strengthen current knowledge of the anesthesiologists and support clinical practice. We quantify the cardiovascular response of high-risk patients to closed-loop anesthesia and propose a new application of physiologically-based pharmacokinetic-pharmacodynamic (PBPK-PD) simulations to examine the effect of hemodynamic changes on the depth of hypnosis (DoH). METHODS We evaluate clinical hemodynamic changes in response to anesthesia induction in high-risk patients from a study on closed-loop anesthesia. We develop and validate a PBPK-PD model to simulate the effect of changes in cardiac output (CO) on plasma levels and DoH. The wavelet-based anesthetic value for central nervous system monitoring index (WAVCNS) is used as clinical end-point of propofol hypnotic effect. RESULTS The median (interquartile range, IQR) changes in CO and arterial pressure (AP), 3 min after induction of anesthesia, are 22.43 (14.82-36.0) % and 26.60 (22.39-35.33) % respectively. The decrease in heart rate (HR) is less marked, i.e. 8.82 (4.94-12.68) %. The cardiovascular response is comparable or less enhanced than in manual propofol induction studies. PBPK simulations show that the marked decrease in CO coincides with high predicted plasma levels and deep levels of hypnosis, i.e. WAVCNS < 40. PD model identification is improved using the PBPK model rather than a standard three-compartment PK model. PD simulations reveal that a 30% drop in CO can cause a 30% change in WAVCNS. CONCLUSIONS Significant CO drops produce increased predicted plasma concentrations corresponding to deeper anesthesia, which is potentially dangerous for elderly patients. PBPK-PD model simulations allow studying and quantifying these effects to improve clinical practice.
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Affiliation(s)
- A Savoca
- PSE-Lab, Process Systems Engineering Laboratory, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano 20133, Italy
| | - K van Heusden
- Department of Electrical & Computer Engineering, The University of British Columbia, Vancouver, British Columbia, Canada
| | - D Manca
- PSE-Lab, Process Systems Engineering Laboratory, Dipartimento di Chimica, Materiali e Ingegneria Chimica "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci 32, Milano 20133, Italy.
| | - J M Ansermino
- Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - G A Dumont
- Department of Electrical & Computer Engineering, The University of British Columbia, Vancouver, British Columbia, Canada; Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
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3
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Affiliation(s)
- R Lin
- British Columbia Children's Hospital, Vancouver, BC, Canada
| | - J M Ansermino
- University of British Columbia, Vancouver, BC, Canada
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4
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Nakitende I, Namujwiga T, Dunsmuir D, Ansermino JM, Wasingya-Kasereka L, Kellett J. Respiratory rates observed over 15 seconds compared with rates measured using the RRate app. Practice-based evidence from an observational study of acutely ill adult medical patients during their hospital admission. Acute Med 2020; 19:15-20. [PMID: 32226952] [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: 06/10/2023]
Abstract
BACKGROUND counting respiratory rate over 60 seconds can be impractical in a busy clinical setting. METHODS 870 respiratory rates of 272 acutely ill medical patients estimated from observations over 15 seconds and those calculated by a computer algorithm were compared. RESULTS The bias of 15 seconds of observations was 1.85 breaths per minute and 0.11 breaths per minute for the algorithm derived rate, which took 16.2 SD 8.1 seconds. The algorithm assigned 88% of respiratory rates their correct National Early Warning Score points, compared with 80% for rates from 15 seconds of observation. CONCLUSION The respiratory rates of acutely ill patients are measured nearly as quickly and more reliably by a computer algorithm than by observations over 15 seconds.
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Affiliation(s)
- I Nakitende
- Department of Medicine, Enrolled Nurse, Department of Medicine, Kitovu Hospital, Masaka, Uganda
| | - T Namujwiga
- Department of Medicine, Enrolled Midwife, Department of Medicine, Kitovu Hospital, Masaka, Uganda
| | - D Dunsmuir
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, Canada
| | - J M Ansermino
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, Canada
| | | | - J Kellett
- Department of Emergency Medicine, Hospital of South West Jutland, Esbjerg, Denmark
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Rimbi M, Dunsmuir D, Ansermino JM, Nakitende I, Namujwiga T, Kellett J. Respiratory rates observed over 15 and 30 s compared with rates measured over 60 s: practice-based evidence from an observational study of acutely ill adult medical patients during hospital admission. QJM 2019; 112:513-517. [PMID: 30888422 DOI: 10.1093/qjmed/hcz065] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/08/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Respiratory rate is often measured over a period shorter than 1 min and then multiplied to produce a rate per minute. There are few reports of the performance of such estimates compared with rates measured over a full minute. AIM Compare performance of respiratory rates calculated from 15 and 30 s of observations with measurements over 1 min. DESIGN A prospective single center observational study. METHODS The respiratory rates calculated from observations for 15 and 30 s were compared with simultaneous respiratory rates measured for a full minute on acutely ill medical patients during their admission to a resource poor hospital in sub-Saharan Africa using a novel respiratory rate tap counting software app. RESULTS There were 770 respiratory rates recorded on 321 patients while they were in the hospital. The bias (limits of agreement) between the rate derived from 15 s of observations and the full minute was -1.22 breaths per minute (bpm) (-7.16 to 4.72 bpm), and between the rate derived from 30 s and the full minute was -0.46 bpm (-3.89 to 2.97 bpm). Rates observed over 1 min that scored 3 National Early Warning Score points were not identified by half the rates derived from 15 s and a quarter of the rates derived from 30 s. CONCLUSION Practice-based evidence shows that abnormal respiratory rates are more reliably detected with measurements made over a full minute, and respiratory rate measurement 'short-cuts' often fail to identify sick patients.
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Affiliation(s)
- M Rimbi
- Department of Medicine, Kitovu Hospital, Masaka, Uganda
| | - D Dunsmuir
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, Canada
| | - J M Ansermino
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, Canada
| | - I Nakitende
- Department of Medicine, Kitovu Hospital, Masaka, Uganda
| | - T Namujwiga
- Department of Medicine, Kitovu Hospital, Masaka, Uganda
| | - J Kellett
- Department of Emergency Medicine, Hospital of South West Jutland, Esbjerg, Denmark
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Wiens MO, Kumbakumba E, Larson CP, Ansermino JM, Singer J, Kissoon N, Wong H, Ndamira A, Kabakyenga J, Kiwanuka J, Zhou G. Postdischarge mortality in children with acute infectious diseases: derivation of postdischarge mortality prediction models. BMJ Open 2015; 5:e009449. [PMID: 26608641 PMCID: PMC4663423 DOI: 10.1136/bmjopen-2015-009449] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/16/2015] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVES To derive a model of paediatric postdischarge mortality following acute infectious illness. DESIGN Prospective cohort study. SETTING 2 hospitals in South-western Uganda. PARTICIPANTS 1307 children of 6 months to 5 years of age were admitted with a proven or suspected infection. 1242 children were discharged alive and followed up 6 months following discharge. The 6-month follow-up rate was 98.3%. INTERVENTIONS None. PRIMARY AND SECONDARY OUTCOME MEASURES The primary outcome was postdischarge mortality within 6 months following the initial hospital discharge. RESULTS 64 children died during admission (5.0%) and 61 died within 6 months of discharge (4.9%). Of those who died following discharge, 31 (51%) occurred within the first 30 days. The final adjusted model for the prediction of postdischarge mortality included the variables mid-upper arm circumference (OR 0.95, 95% CI 0.94 to 0.97, per 1 mm increase), time since last hospitalisation (OR 0.76, 95% CI 0.61 to 0.93, for each increased period of no hospitalisation), oxygen saturation (OR 0.96, 95% CI 0.93 to 0·99, per 1% increase), abnormal Blantyre Coma Scale score (OR 2.39, 95% CI 1·18 to 4.83), and HIV-positive status (OR 2.98, 95% CI 1.36 to 6.53). This model produced a receiver operating characteristic curve with an area under the curve of 0.82. With sensitivity of 80%, our model had a specificity of 66%. Approximately 35% of children would be identified as high risk (11.1% mortality risk) and the remaining would be classified as low risk (1.4% mortality risk), in a similar cohort. CONCLUSIONS Mortality following discharge is a poorly recognised contributor to child mortality. Identification of at-risk children is critical in developing postdischarge interventions. A simple prediction tool that uses 5 easily collected variables can be used to identify children at high risk of death after discharge. Improved discharge planning and care could be provided for high-risk children.
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Affiliation(s)
- M O Wiens
- School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - E Kumbakumba
- Department of Pediatrics, Mbarara University of Science and Technology, Mbarara, Uganda
| | - C P Larson
- Center for International Child Health, BC Children's Hospital, Child and Family Research Institute, Vancouver, Canada
| | - J M Ansermino
- Department of Pediatric Anesthesiology, BC Children's Hospital and University of British Columbia, Vancouver, Canada
| | - J Singer
- School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada Canadian HIV Trials Network, St. Paul's Hospital and University of British Columbia, Vancouver, Canada
| | - N Kissoon
- Department of Pediatrics, BC Children's Hospital and University of British Columbia, Vancouver, Canada
| | - H Wong
- School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - A Ndamira
- Department of Pediatrics, Mbarara University of Science and Technology, Mbarara, Uganda
| | - J Kabakyenga
- Maternal, Newborn and Child Health Institute, Mbarara University of Science and Technology, Mbarara, Uganda
| | - J Kiwanuka
- Department of Pediatrics, Mbarara University of Science and Technology, Mbarara, Uganda
| | - G Zhou
- Department of Statistics, University of British Columbia, Vancouver, Canada
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Brown ZE, Görges M, Cooke E, Malherbe S, Dumont GA, Ansermino JM. Changes in cardiac index and blood pressure on positioning children prone for scoliosis surgery. Anaesthesia 2013; 68:742-6. [PMID: 23710730 DOI: 10.1111/anae.12310] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2013] [Indexed: 01/01/2023]
Abstract
In this prospective observational study we investigated the changes in cardiac index and mean arterial pressure in children when positioned prone for scoliosis correction surgery. Thirty children (ASA 1-2, aged 13-18 years) undergoing primary, idiopathic scoliosis repair were recruited. The cardiac index and mean arterial blood pressure (median (IQR [range])) were 2.7 (2.3-3.1 [1.4-3.7]) l.min(-1).m(-2) and 73 (66-80 [54-91]) mmHg, respectively, at baseline; 2.9 (2.5-3.2 [1.7-4.4]) l.min(-1).m(-2) and 73 (63-81 [51-96]) mmHg following a 5-ml.kg(-1) fluid bolus; and 2.5 (2.2-2.7 [1.4-4.8]) l.min(-1).m(-2) and 69 (62-73 [46-85]) mmHg immediately after turning prone. Turning prone resulted in a median reduction in cardiac index of 0.5 l.min(-1).m(-2) (95% CI 0.3-0.7 l.min(-1).m(-2), p=0.001), or 18.5%, with a large degree of inter-subject variability (+10.3% to -40.9%). The changes in mean arterial blood pressure were not significant. Strategies to predict, prevent and treat decreases in cardiac index need to be developed.
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Affiliation(s)
- Z E Brown
- Department of Anesthesiology, Pharmacology & Therapeutic, The University of British Columbia, Vancouver, British Columbia, Canada
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Hudson J, Nguku SM, Sleiman J, Karlen W, Dumont GA, Petersen CL, Warriner CB, Ansermino JM. Usability testing of a prototype Phone Oximeter with healthcare providers in high- and low-medical resource environments. Anaesthesia 2012; 67:957-67. [PMID: 22861503 DOI: 10.1111/j.1365-2044.2012.07196.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To increase the use of pulse oximetry by capitalise on the wide availability of mobile phones, we have designed, developed and evaluated a prototype pulse oximeter interfaced to a mobile phone. Usability of this Phone Oximeter was tested as part of a rapid prototyping process. Phase 1 of the study (20 subjects) was performed in Canada. Users performed 23 tasks, while thinking aloud. Time for completion of tasks and analysis of user response to a mobile phone usability questionnaire were used to evaluate usability. Five interface improvements were made to the prototype before evaluation in Phase 2 (15 subjects) in Uganda. The lack of previous pulse oximetry experience and mobile phone use increased median (IQR [range]) time taken to perform tasks from 219 (160-247 [118-274]) s in Phase 1 to 228 (151-501 [111-2661]) s in Phase 2. User feedback was positive and overall usability high (Phase 1--82%, Phase 2--78%).
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Affiliation(s)
- J Hudson
- Department of Anaesthesiology, Pharmacology, and Therapeutics, University of British Columbia, British Columbia Children's Hospital, Vancouver, Canada.
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Karlen W, Kobayashi K, Ansermino JM, Dumont GA. Photoplethysmogram signal quality estimation using repeated Gaussian filters and cross-correlation. Physiol Meas 2012; 33:1617-29. [DOI: 10.1088/0967-3334/33/10/1617] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Chandler JR, Cooke E, Petersen C, Karlen W, Froese N, Lim J, Ansermino JM. Pulse oximeter plethysmograph variation and its relationship to the arterial waveform in mechanically ventilated children. J Clin Monit Comput 2012; 26:145-51. [DOI: 10.1007/s10877-012-9347-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 02/25/2012] [Indexed: 12/01/2022]
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Khosravi S, Jin-Oh Hahn, Dumont GA, Ansermino JM. A Monitor-Decoupled Pharmacodynamic Model of Propofol in Children Using State Entropy as Clinical Endpoint. IEEE Trans Biomed Eng 2012; 59:736-43. [DOI: 10.1109/tbme.2011.2179033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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King A, Daniels J, Lim J, Cochrane DD, Taylor A, Ansermino JM. Time to listen: a review of methods to solicit patient reports of adverse events. Qual Saf Health Care 2011; 19:148-57. [PMID: 20351164 DOI: 10.1136/qshc.2008.030114] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Patients have been shown to report accurate observations of medical errors and adverse events. Various methods of introducing patient reporting into patient safety systems have been published with little consensus among researchers on the most effective method. Terminology for use in patient safety reporting has yet to be standardised. METHODS Two databases, PubMed and MEDLINE, were searched for literature on patient reporting of medical errors and adverse events. Comparisons were performed to identify the optimal method for eliciting patient initiated events. RESULTS Seventeen journal publications were reviewed by patient population, type of healthcare setting, contact method, reporting method, duration, terminology and reported response rate. CONCLUSION Few patient reporting studies have been published, and those identified in this review covered a wide range of methods in diverse settings. Definitive comparisons and conclusions are not possible. Patient reporting has been shown to be reliable. Higher incident rates were observed when open-ended questions were used and when respondents were asked about personal experiences in hospital and primary care. Future patient reporting systems will need a balance of closed-ended questions for cause analysis and classification, and open-ended narratives to allow for patient's limited understanding of terminology. Establishing the method of reporting that is most efficient in collecting reliable reports and standardising terminology for patient use should be the focus of future research.
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Affiliation(s)
- A King
- Department of Anesthesia, British Columbia Children's Hospital, 4480 Oak Street, Vancouver, British Columbia, Canada
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Menzies J, Magee LA, MacNab YC, Ansermino JM, Li J, Douglas MJ, Gruslin A, Kyle P, Lee SK, Moore MP, Moutquin JM, Smith GN, Walker JJ, Walley KR, Russell JA, von Dadelszen P. Current CHS and NHBPEP Criteria for Severe Preeclampsia Do Not Uniformly Predict Adverse Maternal or Perinatal Outcomes. Hypertens Pregnancy 2009; 26:447-62. [DOI: 10.1080/10641950701521742] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Ng F, Wong S, Gomis P, Lim J, Passariello G, Ansermino JM. Probabilistic assessment of Autonomic Nervous System fluctuations during tilt table tests. Annu Int Conf IEEE Eng Med Biol Soc 2009; 2008:4692-5. [PMID: 19163763 DOI: 10.1109/iembs.2008.4650260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A number of reports have advocated the use of Heart Rate Variability (HRV) as a non invasive method of monitoring the Autonomic Nervous System (ANS). In the anesthesia and critical care monitoring settings, the development of an instrument able to provide real-time information about the ANS state at different stages of any procedure would provide improved safety for patients undergoing diagnostic or therapeutic interventions. However, real-time analysis of HRV can be particularly challenging since larger effective lengths of observation provide better spectral resolution. Our study explores a probabilistic approach that analyzes changes in HRV parameters obtained from an autoregressive (AR) model technique using Burg's methods to evaluate very short observation windows while preserving appropriate frequency resolution. These HRV parameters are continuosly compared to a baseline state, and a probability trend is updated during provocative maneuvers. Preliminary results show that trends from classical parameters such as RMSSD and LFn are consistent and reliable instruments capable of providing significant information about ANS fluctuations in a timely fashion.
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Affiliation(s)
- F Ng
- Department of Anesthesiology, Pharmacology and Therapeutics. The University of British Columbia, Vancouver, Canada.
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Ng G, Barralon P, Schwarz SKW, Dumont G, Ansermino JM. Evaluation of a tactile display around the waist for physiological monitoring under different clinical workload conditions. Annu Int Conf IEEE Eng Med Biol Soc 2009; 2008:1288-91. [PMID: 19162902 DOI: 10.1109/iembs.2008.4649399] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this study, we have assessed the usability of a tactile belt prototype for clinical monitoring of physiologic patient data in the operating room under low workload (LW) and high workload (HW) conditions. In previous investigations, we have evaluated tactile technology in clinical settings and demonstrated that anesthesiologists have enhanced situational awareness towards adverse clinical events when a tactile display prototype is used as a supplemental monitoring device. To further evaluate the effectiveness of our tactile belt prototype, we compared the effects of workload on the performance of anesthesiologists in terms of accuracy and response time in tactile alert identification. We also administered a post-study questionnaire to evaluate the usability of the tactile belt as well as users' opinions about the device. We found that the response time to tactile alert identification to be faster under LW than under HW, however the accuracy of identification was not statistically different. Participants rated the tactile belt prototype as comfortable to use and the tactile alert scheme as easy to learn. Our findings further support the feasibility and efficacy of vibrotactile devices for enhancing physiological monitoring of patients in clinical environments.
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Affiliation(s)
- G Ng
- Department of Electrical and Computer Engineering, The Univ. of British Columbia, Vancouver, CANADA
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Abstract
SNOMED CT (Systematized NOmenclature of MEDicine Clinical Terms) is a standardized multilingual healthcare terminology. It was developed to meet the needs of our electronic world so that care can be documented and clinicians can retrieve and transmit data in electronic format. It is anticipated that SNOMED CT will provide the core general terminology for electronic health records and, as such, replace existing classification systems such as the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10). At present, there is no special interest group for the hypertensive disorders of pregnancy (HDP) within the SNOMED CT initiative. We believe that members of the ISSHP, and others interested in the HDP, should take a leadership role in this regard for a number of reasons.
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Affiliation(s)
- K A Massey
- UBC, Obstetrics and Gynaecology, Vancouver, British Columbia, Canada.
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Dosani M, Lim J, Yang P, Brouse C, Daniels J, Dumont G, Ansermino JM. Clinical evaluation of algorithms for context-sensitive physiological monitoring in children. Br J Anaesth 2009; 102:686-91. [PMID: 19329468 DOI: 10.1093/bja/aep045] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Subtle changes in monitored physiological signals might be used to guide clinical actions and give early warning of potential adverse events. Automated early warning systems could enhance the clinician's interpretation of data by instantaneously processing new information and presenting it within the context of previous observations. In this study, we tested algorithms for tracking the behaviour of dynamic physiological systems and automatically detecting key events over time. METHODS Algorithms were activated in real-time during anaesthesia to run context-sensitive monitoring of six variables (end-tidal PCO(2), heart rate, exhaled minute ventilation, non-invasive arterial pressure, respiratory rate, and oxygen saturation), alongside standard physiological monitors. The clinical evaluation included real-time feedback on each change point (change in the physiological trend) detected by the algorithms and the completion of a usability questionnaire. RESULTS Fifteen anaesthetists completed the evaluation during paediatric surgical cases. A total of 38 cases were evaluated, with a mean duration of 103 (102) min. The mean number of change points per case was 22.8 (23.4). Sixty-one per cent of all rated change points were considered clinically significant, and <7% were due to artifacts. CONCLUSIONS The algorithms were able to detect a range of clinically significant physiological changes during paediatric anaesthesia, and were considered useful by participating anaesthetists. These findings indicate that automated detection of context-sensitive changes is possible and could be used by early warning systems during physiological monitoring. Further investigations are required to assess how this information can best be communicated to the anaesthetist.
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Affiliation(s)
- M Dosani
- Department of Anesthesiology, Pharmacology and Therapeutics, The University of British Columbia, Vancouver, Canada
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Chou E, Lim J, Brant R, Ford S, Ansermino JM. Accuracy of detecting changes in auditory heart rate in a simulated operating room environment*. Anaesthesia 2008; 63:1181-6. [DOI: 10.1111/j.1365-2044.2008.05629.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ng G, Barralon P, Dumont G, Schwarz SKW, Ansermino JM. Optimizing the tactile display of physiological information: vibro-tactile vs. electro-tactile stimulation, and forearm or wrist location. ACTA ACUST UNITED AC 2008; 2007:4202-5. [PMID: 18002929 DOI: 10.1109/iembs.2007.4353263] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Anesthesiologists use physiological data monitoring systems with visual and auditory displays of information to monitor patients in the operating room (OR). The efficacy of visual-audio systems may impose an increase in patient risk when the demand for constant switching of attention between the patient and the visual monitoring system is high. This is evidenced by auditory alarms frequently being neglected in a noisy OR environment. Hence, the use of a complementary patient data monitoring system, which utilizes other sensory modalities, could be of great value. In this paper, we describe a series of experiments designed to determine the performances of a tactile display that could be used to convey patient's physiological information to the attending anesthesiologist. We tested both vibro-tactile and electro-tactile display prototypes in their ability to convey information using an alert scheme of four distinct tactile stimuli. Using pseudo-clinical data, the display was designed, for example, to provide an alert when a change in the monitored heart rate occurred. Based on previous research in human physiology and psychophysics, we selected the forearm and wrist of the user's non-dominant hand as the stimulation site. In our study of 30 subjects, we evaluated the response time and accuracy of tactile pattern recognition to compare (1) the performance of a vibro-tactile display on the forearm (VF) and an electro-tactile display on the forearm (EF), and (2) the localization of stimulation between the forearm (VF) and a vibro-tactile display on the wrist (VW). A post-study questionnaire was completed by each subject to assess the comfort and usability of the three prototypes. We found that both VF and VW were superior to the EF in both accuracy and comfort and, that there were no differences between the wrist and the forearm. In conclusion, the tactile-display prototypes designed to alert the clinician of adverse changes in a patient's physiological state efficaciously and unobtrusively delivered these data and warranted further investigation and development.
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Affiliation(s)
- G Ng
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, BC, Canada
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Barralon P, Ng G, Dumont G, Schwarz SKW, Ansermino JM. Evaluations of tactile displays of physiological monitoring. Annu Int Conf IEEE Eng Med Biol Soc 2008; 2008:1025. [PMID: 19162833 DOI: 10.1109/iembs.2008.4649330] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Physiological monitoring devices are used in the operating room (OR) to identify abnormal changes. They are currently detected by the anesthesiologist from direct observation of visual displays or by auditory cues. In an effort to improve OR safety, we explored the use of an alternative sensory modality, touch, to effectively and accurately convey patients' physiological information. To be accepted [1] such devices need to fulfill five criteria: learnability, errors, efficiency, memorability and satisfaction. We designed and compared various tactile displays in respect to some of these criteria.
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Affiliation(s)
- P Barralon
- Department of Electrical and Computer Engineering, Univ. of British Columbia, Vancouver BC, Canada
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Barralon P, Dumont G, Schwarz SKW, Ansermino JM. Autonomic nervous system response to vibrating and electrical stimuli on the forearm and wrist. Annu Int Conf IEEE Eng Med Biol Soc 2008; 2008:931-934. [PMID: 19162810 DOI: 10.1109/iembs.2008.4649307] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In today's operating rooms, anesthesiologists use physiological data monitoring systems with visual and auditory cues to receive patient information. The efficacy of these visual-audio systems is limited by the human limitations of these modalities. Previous studies have shown the potential use of a complementary, or alternate, patient data monitoring technology utilizing another psychophysically relevant modality: the sense of touch via vibro-tactile or electro-tactile stimulation. In this paper, we describe an experiment designed to determine whether the specific type and/or location of such a tactile stimulation device on the arm affects the autonomic nervous system response. In our study, each of 10 participants tested a vibro-tactile display on the forearm (VF), a vibro-tactile display on the wrist (VW), and an electro-tactile display on the forearm (EF) in random order. Using the LifeShirt, system, electrocardiogram (ECG), respiratory rate (Br), tidal volume (Vt) data were collected. Results showed a higher value of the heart rate and heart rate variability (HRV) when using the VF compared to the VW and EF. We also found that the HRV response for the three tactile prototypes was correlated with the accuracy of tactile pattern identification.
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Affiliation(s)
- P Barralon
- Department of Electrical and Computer Engineering, the Univ. of British Columbia, Vancouver, Canada
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Ford S, Ford S, Birmingham E, Dumont G, Lim J, Daniels J, Ansermino JM. How often do anesthesiologists really check their monitors? Can J Anaesth 2007. [DOI: 10.1007/bf03019969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Abstract
PURPOSE To evaluate the effect of adding clonidine to ropivacaine, for axillary brachial plexus blockade, on the onset and duration of sensory and motor block and duration of analgesia. METHODS In a prospective randomised double blind placebo controlled study axillary brachial plexus blockade was performed in 50 patients using 40 ml ropivacaine 0.75%. Group (A) had 150 microg clonidine and Group (B) 1 ml normal saline added to the local anesthetic. Sensory function was tested using pinprick (sharp sensation, blunt sensation or no sensation) and temperature with an ice cube compared with the opposite arm, (cold/not cold). Motor function was assessed using a modified Bromage scale. Postoperative analgesia was standardised. Onset and duration of sensory and motor blockade, duration of analgesia, postoperative pain score, and analgesic requirement were compared. RESULTS The clonidine patients showed an increase in duration of sensory loss from 489 min to 628 min with a mean difference of 138 min (95% confidence interval of 90 to 187 min), motor blockade from 552 min to 721 min with a mean difference of 170 min (95% confidence interval of 117 to 222 min), and analgesia from 587 min to 828 min with mean difference of 241 min (95% confidence interval of 188 to 294 min). There was no difference in onset time. No side effects were noted. CONCLUSION The addition of 150 microg of clonidine to ropivacaine, for brachial plexus blockade, prolongs motor and sensory block and analgesia, without an increased incidence of side effects.
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Affiliation(s)
- A H El Saied
- Anaesthetic Department, St. Andrews Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, Essex, United Kingdom
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Ansermino JM, Than M, Swallow PD. Pre-operative blood tests in children undergoing plastic surgery. Ann R Coll Surg Engl 1999; 81:175-8. [PMID: 10364949 PMCID: PMC2503173] [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: 02/12/2023] Open
Abstract
In a retrospective review of 1177 children presenting for plastic surgical procedures, investigations were performed in 487 and abnormal results were found in 138 as defined by variation from the local laboratory reference range. Most of the abnormalities were of no clinical significance. Twenty one children had abnormal haemoglobin results (the lowest was 9 g/dl) and 101 children had clinically insignificant platelet or white cell abnormalities. One child, with a family history of sickle cell trait, was confirmed as sickle-cell trait. No case was postponed as a result of these investigations. The non-selective ordering of pre-operative blood tests leads to unnecessary patient discomfort, the potential for additional superfluous investigations and higher costs.
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Affiliation(s)
- J M Ansermino
- St Andrew's Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, Essex, UK
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Ansermino JM, Sommerlad BC. Neonatal cleft lip repair. Paediatr Anaesth 1998; 8:94-6. [PMID: 9483610] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
PURPOSE To determine whether detection of residual blockade is improved by using the accelerograph. A secondary objective was to compare acceleromyographic measurements with those obtained by electromyography. METHODS In a prospective, randomized, double-blind investigation, 22 anaesthetized children were studied during recovery from neuromuscular blockade following 0.1 mg.kg-1 vecuronium i.v.. Assessments of depth of block began 10 min after injection and were repeated at one minute intervals using electromyography (Datex, Relaxograph) in one hand, and acceleromyography (Biometer, Tofguard) in the other, to measure response of the adductor pollicis to train-of-four (TOF) stimulation of the ulnar nerve. Monitoring was stopped when no fade was visible and TOF ratio > or = 0.7. The electromyographic (EMG) and acceleromyographic (AMG) data were compared with corresponding observations of the number of twitches and TOF fade in the visible responses of the thumb, made by the attending anaesthetist. The method of Bland and Altman was used to compare differences between AMG and EMG data. RESULTS During recovery from neuromuscular blockade, fade was no longer visible clinically 38.6 +/- 10.4 min (mean +/- SD) after the administration of vecuronium. This corresponded to TOF ratios of 0.04 +/- 0.23 by AMG and 0.34 +/- 0.21 by EMG. Usually, two twitches were visible before AMG detected the first twitch. The time to TOF ratio > or = 0.7 by AMG and EMG was similar at 49.1 +/- 10.5 and 50.9 +/- 9.0 min, respectively. The bias between AMG and EMG was one minute, with limits of agreement from -10 to nine min. CONCLUSION AMG is superior to visual assessment in detecting residual neuromuscular block and provides similar estimates of recovering block as the more cumbersome EMG.
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Affiliation(s)
- J M Ansermino
- Department of Anaesthesia, British Columbia's Children's Hospital, Vancouver, Canada
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Bevan DR, Kahwaji R, Ansermino JM, Reimer E, Smith MF, O'Connor GA, Bevan JC. Residual block after mivacurium with or without edrophonium reversal in adults and children. Anesthesiology 1996; 84:362-7. [PMID: 8602667 DOI: 10.1097/00000542-199602000-00014] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [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: 01/31/2023]
Abstract
BACKGROUND The rapid recovery from mivacurium- induced neuromuscular block has encouraged omission of its reversal. The purpose of this study was to determine, in children and in adults, whether failure to reverse mivacurium neuromuscular block was associated with residual neuromuscular block on arrival in the postanesthesia care unit. METHODS In 50 children, aged 2-12 yr, and 50 adults, aged 20-60 yr, anesthesia was induced and maintained with propofol and fentanyl, and neuromuscular block was achieved by an infusion of mivacurium, to maintain one or two visible responses to train-of-four (TOF) stimulation of the ulnar nerve. At the end of surgery, mivacurium infusion was stopped, and 10 min later, reversal was attempted with saline or 0.5 mg x kg(-1) edrophonium by random allocation. On arrival in the postanesthesia care unit, a blinded observer assessed patients clinically and by stimulation of the ulnar nerve with a Datex electromyogram in the uncalibrated TOF mode. RESULTS Children arrived in the postanesthesia care unit 8.2 +/- 3-4 min after reversal of neuromuscular block and showed no sign of weakness, either clinically or by TOF stimulation. Although TOF ratio was greater in children who had received edrophonium (1.00 +/- 0.05 vs. 0.93 +/- 0.01, P<0.01), TOF was >0.7 in all children. Adults arrived in the postanesthesia care unit 12.9 +/- 5.3 min after reversal of neuromuscular block(P<0.01 vs. children). Six in the saline group demonstrated weakness (two required immediate reversal of neuromuscular block, and TOF was <0.7 in four others), compared with TOF <0.7 in only one of the edrophonium group (P<0.05). CONCLUSIONS This study demonstrated that, in adults, failure to reverse mivacurium neuromuscular block was associated with an increased incidence of residual block. Such weakness was not observed in children receiving similar anesthetic and neuromuscular blocking regimens.
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Affiliation(s)
- D R Bevan
- Department of Anaesthesia, Vancouver Hospital and Health Sciences Centre, British Columbia, Canada
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Ansermino JM, Burke MA, Upton PM, McVittie J, Blogg CE. Suxamethonium-induced muscle pains are not related to cholinesterase activity. Anaesthesia 1993; 48:1097-100. [PMID: 8285336 DOI: 10.1111/j.1365-2044.1993.tb07538.x] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have investigated the possibility of using the pre-operative measurement of cholinesterase activity to predict the postoperative development of myalgia following the administration of suxamethonium. Seventy-seven patients presenting for elective extraction of wisdom teeth were entered in the study. All patients received a standard anaesthetic regimen, including suxamethonium to facilitate tracheal intubation, and standardised postoperative analgesia. Myalgia was assessed postoperatively and no correlation between muscle pains and cholinesterase activity was found.
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Abstract
We have studied 42 female patients undergoing elective day-case surgery allocated randomly to two groups. After induction of anaesthesia an attempt was made to insert a laryngeal mask airway after application of cricoid pressure in one group or with no cricoid pressure in the other. The anaesthetist was unaware of the application, or not, of cricoid pressure. Successful insertion was achieved at the first or second attempt in 19 of the 22 patients in the non-cricoid pressure group, but in only three of the 20 patients in the cricoid pressure group (chi 2 18.62, P < 0.001). The laryngeal mask airway was then inserted successfully in all 17 patients after removal of cricoid pressure. The implications of having to remove cricoid pressure if a laryngeal mask airway is to be inserted are discussed.
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Affiliation(s)
- J M Ansermino
- Nuffield Department of Anaesthetics, Churchill Hospital, Oxford
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