The impact of discontinuing single-room isolation of patients with vancomycin-resistant enterococci: a quasi-experimental single-centre study in South Korea

OBJECTIVES

There is limited data on the effects of discontinuing single-room isolation while maintaining contact precautions, such as the use of gowns and gloves. In April 2021, our hospital ceased single-room isolation for patients with vancomycin-resistant enterococci (VRE) because of single-room unavailability. This study assessed the impact of this policy by examining the incidence of hospital-acquired VRE bloodstream infections (HA-VRE BSI).

METHODS

This retrospective quasi-experimental study was conducted at a tertiary-care hospital in Seoul, South Korea. Time-series analysis was used to evaluate HA-VRE BSI incidence at the hospital level and in the haematology unit before (phase 1) and after (phase 2) the policy change.

RESULTS

At the hospital level, HA-VRE BSI incidence level (VRE BSI per 1000 patient-days per month) and trend did not change significantly between phase 1 and phase 2 (coefficient -0.015, 95% confidence interval (CI): -0.053 to 0.023, P=0.45 and 0.000, 95% CI: -0.002 to 0.002, P=0.84, respectively). Similarly, HA-VRE BSI incidence level and trend in the haematology unit (-0.285, 95% CI: -0.618 to 0.048, P=0.09 and -0.018, 95% CI: -0.036 to 0.000, P = 0.054, respectively) did not change significantly across the two phases.

CONCLUSIONS

Discontinuing single-room isolation of VRE-colonized or infected patients was not associated with an increase in the incidence of VRE BSI at the hospital level or among high-risk patients in the haematology unit. Horizontal intervention for multi-drug-resistant organisms, including measures such as enhanced hand hygiene and environmental cleaning, may be more effective at preventing VRE transmission.

Repositioning of ezetimibe for the treatment of idiopathic pulmonary fibrosis

BACKGROUND

We previously identified ezetimibe, an inhibitor of Niemann-Pick C1-like intracellular cholesterol transporter 1 and European Medicines Agency-approved lipid-lowering agent, as a potent autophagy activator. However, its efficacy against pulmonary fibrosis has not yet been evaluated. This study aimed to determine whether ezetimibe has therapeutic potential against idiopathic pulmonary fibrosis.

METHODS

Primary lung fibroblasts isolated from both humans and mice were employed for mechanistic in vitro experiments. mRNA sequencing of human lung fibroblasts and gene set enrichment analysis were performed to explore the therapeutic mechanism of ezetimibe. A bleomycin-induced pulmonary fibrosis mouse model was used to examine in vivo efficacy of the drug. Tandem fluorescent-tagged microtubule-associated protein 1 light chain 3 transgenic mice were used to measure autophagic flux. Finally, the medical records of patients with idiopathic pulmonary fibrosis from three different hospitals were reviewed retrospectively, and analyses on survival and lung function were conducted to determine the benefits of ezetimibe.

RESULTS

Ezetimibe inhibited myofibroblast differentiation by restoring the mechanistic target of rapamycin complex 1-autophagy axis with fine control of intracellular cholesterol distribution. Serum response factor, a potential autophagic substrate, was identified as a primary downstream effector in this process. Similarly, ezetimibe ameliorated bleomycin-induced pulmonary fibrosis in mice by inhibiting mechanistic target of rapamycin complex 1 activity and increasing autophagic flux, as observed in mouse lung samples. Patients with idiopathic pulmonary fibrosis who regularly used ezetimibe showed decreased rates of all-cause mortality and lung function decline.

CONCLUSION

Our study presents ezetimibe as a potential novel therapeutic for idiopathic pulmonary fibrosis.

Development and validation of novel simple prognostic model for predicting mortality in Korean intensive care units using national insurance claims data

Background/Aims

Intensive care unit (ICU) quality is largely determined by the mortality rate. Therefore, we aimed to develop and validate a novel prognostic model for predicting mortality in Korean ICUs, using national insurance claims data.

Methods

Data were obtained from the health insurance claims database maintained by the Health Insurance Review and Assessment Service of South Korea. From patients who underwent the third ICU adequacy evaluation, 42,489 cases were enrolled and randomly divided into the derivation and validation cohorts. Using the models derived from the derivation cohort, we analyzed whether they accurately predicted death in the validation cohort. The models were verified using data from one general and two tertiary hospitals.

Results

Two severity correction models were created from the derivation cohort data, by applying variables selected through statistical analysis, through clinical consensus, and from performing multiple logistic regression analysis. Model 1 included six categorical variables (age, sex, Charlson comorbidity index, ventilator use, hemodialysis or continuous renal replacement therapy, and vasopressor use). Model 2 additionally included presence/absence of ICU specialists and nursing grades. In external validation, the performance of models 1 and 2 for predicting in-hospital and ICU mortality was not inferior to that of pre-existing scoring systems.

Conclusions

The novel and simple models could predict in-hospital and ICU mortality and were not inferior compared to the pre-existing scoring systems.

Differences of respiratory mechanics in mechanical ventilation of acute respiratory distress syndrome between patients with COVID-19 and Influenza A

BACKGROUND

Whether COVID-19-induced acute respiratory distress syndrome (ARDS) should be approached differently in terms of mechanical ventilation therapy compared to other virus-induced ARDS is debatable. Therefore, we aimed to ascertain whether the respiratory mechanical characteristics of COVID-19-induced ARDS differ from those of influenza A induced ARDS, in order to establish a rationale for mechanical ventilation therapy in COVID-19-induced ARDS.

METHODS

This was a retrospective cohort study comparing patients with COVID-19-induced ARDS and influenza A induced ARDS. We included intensive care unit (ICU) patients with COVID-19 or Influenza A aged ≥ 19, who were diagnosed with ARDS according to the Berlin definition between January 2015 and July 2021. Ventilation parameters for respiratory mechanics were collected at specific times on days one, three, and seven after intubation.

RESULTS

The median age of the 87 participants was 71.0 (62.0-78.0) years old, and 63.2% were male. The ratio of partial pressure of oxygen in arterial blood to the fractional of inspiratory oxygen concentration in COVID-19-induced ARDS was lower than that in influenza A induced ARDS during the initial stages of mechanical ventilation (influenza A induced ARDS 216.1 vs. COVID-19-induced ARDS 167.9, p = 0.009, day 1). The positive end expiratory pressure remained consistently higher in the COVID-19 group throughout the follow-up period (7.0 vs. 10.0, p < 0.001, day 1). COVID-19 and influenza A initially showed different directions for peak inspiratory pressure and dynamic compliance; however, after day 3, both groups exhibited similar directions. Dynamic driving pressure exhibited opposite trends between the two groups during mechanical ventilation.

CONCLUSIONS

Respiratory mechanics show clear differences between COVID-19-induced ARDS and influenza A induced ARDS. Based on these findings, we can consider future treatment strategies for COVID-19-induced ARDS.

Disease burden of bacteraemia with extended-spectrum beta-lactamase-producing and carbapenem-resistant Enterobacterales in Korea

BACKGROUND

Despite the significant impact of multi-drug-resistant bacteraemia, especially extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) and carbapenem-resistant Enterobacterales (CRE), the burden of disease has not been investigated thoroughly.

AIM

To evaluate the clinical outcomes and socio-economic burden of ESBL-E and CRE bacteraemia nationwide in the Republic of Korea.

METHODS

A search was undertaken for all cases of ESBL-E and CRE bacteraemia and matched controls in 10 hospitals in the Republic of Korea over 6 months. Patients with ESBL-E or CRE bacteraemia were classified as the R group, and matched controls with antibiotic-susceptible bacteraemia and without infection were classified as the S and N groups, respectively. Patients' clinical data were collected, and the economic burden was estimated based on medical expenses, loss of productivity and total costs.

FINDINGS

In total, 795 patients were identified, including 265 patients with ESBL-E or CRE bacteraemia and their matched controls. The mean total length of stay for patients with ESBL-E and CRE in the R group was 1.53 and 1.90 times that of patients in the S group, respectively. The 90-day mortality rates for ESBL-E in the R and S groups were 12.1% and 5.6%, respectively, and the corresponding figures for CRE were 28.6% and 12.0%. There were significant differences in the total costs between the R, S and N groups for both ESBL-E and CRE (ESBL-E: $11,151 vs $8712 vs $6063, P=0.004; CRE: $40,464 vs $8748 vs $7279, P=0.024).

CONCLUSION

The clinical and economic burden imposed by ESBL-E or CRE bacteraemia was extremely high. These findings suggest that efforts to control resistant bacteraemia are necessary to reduce this burden.

Association between mechanical power and intensive care unit mortality in Korean patients under pressure-controlled ventilation

BACKGROUND

Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality.

METHODS

We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed.

RESULTS

A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029-1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579).

CONCLUSIONS

MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.

Effects of an Ultra-Polished Scalpel on Incisional Wounds in a Diabetic Model

Inflammation after surgical incisions is related to the degree of tissue damage. Healing with low inflammation is desirable, especially in patients with compromised healing potential. This experimental study was conducted to assess the degree of inflammatory reaction and scar formation from incisions made by an ultra-polished scalpel (UPS). Two paravertebral incisions were made with a conventional scalpel (CS) and a UPS in 18 individual rats with diabetes. The fibrotic tissue (scar) area and expression levels of collagen, transforming growth factor, and matrix metalloproteinases were quantified on postoperative days 3, 7, and 30. The scar widths and areas were significantly lower in the UPS group than in the CS group. The scar widths were 64.3 ± 14.7 µm and 86.8 ± 12.1 µm in the UPS and CS groups, respectively (P = 0.03). The scar areas were 11,398 ± 1595 µm2 in the UPS group and 17,433 ± 3487 µm2 in the CS group (P = 0.014). The UPS group had less inflammation on day 3, less transforming growth factor synthesis on days 3 and 7, lower levels of matrix metalloproteinases, and less collagen synthesis on day 7 than did the CS group. The UPS achieved less local inflammation by reducing the local tissue damage in diabetic rat models, enabling better healing, and resulting in less scar formation. The UPS warrants further clinical study as it may bring beneficial outcomes for patients with impaired healing capability and patients who seek to reduce scarring.

Risk Factors for Unfavorable Outcomes of Tuberculosis in Korea: Implications for Patient-Centered Care in Tuberculosis Treatment

BACKGROUND

The treatment success rate for tuberculosis (TB) has stagnated at 80-81% in South Korea, indicating unsatisfactory outcomes. Enhancing treatment success rate necessitates the development of individualized treatment approaches for each patient. This study aimed to identify the risk factors associated with unfavorable treatment outcomes to facilitate tailored TB care.

METHODS

We retrospectively analyzed the data of patients with active TB between January 2019 and December 2020 at a single tertiary referral center. We classified unfavorable treatment outcomes according to the 2021 World Health Organization guidelines as follows: "lost to follow-up" (LTFU), "not evaluated" (NE), "death," and "treatment failure" (TF). Moreover, we analyzed risk factors for each unfavorable outcome using Cox proportional hazard regression analysis.

RESULTS

A total of 659 patients (median age 62 years; male 54.3%) were included in the study. The total unfavorable outcomes were 28.1%: 4.6% LTFU, 9.6% NE, 9.1% deaths, and 4.9% TF. Multivariate analysis showed that a culture-confirmed diagnosis of TB was associated with a lower risk of LTFU (adjusted hazard ratio [aHR], 0.25; 95% confidence interval [CI], 0.10-0.63), whereas the occurrence of adverse drug reactions (ADRs) significantly increased the risk of LTFU (aHR, 6.63; 95% CI, 2.63-16.69). Patients living far from the hospital (aHR, 4.47; 95% CI, 2.50-7.97) and those with chronic kidney disease (aHR, 3.21; 95% CI, 1.33-7.75) were at higher risk of being transferred out to other health institutions (NE). Higher mortality was associated with older age (aHR, 1.06; 95% CI, 1.04-1.09) and comorbidities. The ADRs that occurred during TB treatment were a risk factor for TF (aHR, 6.88; 95% CI, 2.24-21.13).

CONCLUSION

Unfavorable outcomes of patients with TB were substantial at a tertiary referral center, and the risk factors for each unfavorable outcome varied. To improve treatment outcomes, close monitoring and the provision of tailored care for patients with TB are necessary.

Impact of age on mortality and transfer to long-term care in patients in an intensive care unit

BACKGROUND

In the global trend of population aging, age is one of the significant factors to be considered in critically ill patients. However, the impact of age on clinical outcomes and long-term prognosis in this population varies across different studies.

METHODS

We conducted a retrospective cohort analysis for patients admitted to the medical intensive care unit (ICU) (30 beds) between January 2017 and December 2020 at the tertiary referral hospital in Korea. Patients were classified into three groups according to age: <65 years, old age (65-79 years), and very old age (≥ 80 years). Subsequently, enrolled patients were analyzed for acute mortality and long-term prognosis.

RESULTS

Among the 1584 patients, the median age was 67.0 (57.0-76.0) years, and 65.2% were male. Median ICU length of stay (LOS) (8, 9, and 10 days in < 65, 65-79, and ≥ 80 years, respectively; p = 0.006) and the proportion of patients who were transferred to long-term care hospital at the time of discharge (12.9% vs. 28.3% vs. 39.4%, respectively; p < 0.001) increased with age. Multivariable logistic analysis showed no significant difference in the 28-day mortality in the old age (adjusted odds ratio [aOR] 0.88; 95% confidence interval [CI] 0.65-1.17) and very old age (aOR 1.05; 95% CI 0.71-1.55) groups compared to that in patients with age < 65 years. However, the relevance of the proportion of ICU LOS ≥ 7 days and transfers to other hospitals after discharge increased with age.

CONCLUSIONS

Age did not affect acute mortality in critical illness patients. However, surviving older age groups required more long-term care facilities compared to patients younger than 65 years after acute management. These results indicate that in an aging society, the importance of not only acute management but also long-term care facilities may increase for critical illness patients.

Association between serum high-density lipoprotein cholesterol and lung function in adults: three cross-sectional studies from US and Korea National Health and Nutrition Examination Survey

INTRODUCTION

Cholesterol is an irreplaceable nutrient in pulmonary metabolism; however, studies on high-density lipoprotein cholesterol (HDL-C) levels have shown conflicting results regarding lung function. Therefore, we investigated the association between lung function and HDL-C levels in three cross-sectional studies conducted in the USA and South Korea.

METHODS

US National Health and Nutrition Examination Survey (NHANES) III, US NHANES 2007-2012, and Korea National Health and Nutrition Examination Survey (KNHANES) IV-VII performed spirometry and met the American Thoracic Society recommendations. Multiple linear regression models were used to determine the relationship between serum lipid levels and lung function. The models were adjusted for age, sex, household income, body mass index, smoking pack year, use of lipid-lowering medication and race. Serum HDL-C levels were classified into three groups to assess the dose-response relationship according to the guideline from the National Cholesterol Education Program-Adult Treatment Panel III.

RESULTS

The adult participants of the KNHANES (n=31 288), NHANES III (n=12 182) and NHANES 2007-2012 (n=9122) were analysed. Multivariate linear regression analysis of the serum cholesterol profiles revealed that only serum HDL-C was associated with forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) in all three studies. A 1 SD increase in the HDL-C level increased the percent predicted FVC by 0.5%-1.5% p, and the per cent predicted FEV1 by 0.5%-1.7% p. In terms of HDL-C levels, correlations between the HDL-C groups and the per cent predicted FVC and FEV1 showed dose-response relationships. Compared with the normal group, high HDL-C levels increased FVC by 0.75%-1.79% p and FEV1 by 0.55%-1.90% p, while low levels led to 0.74%-2.19% p and 0.86%-2.68% p reductions in FVC and FEV1, respectively. Subgroup analyses revealed weaker associations in females from KNHANES and NHANES III.

CONCLUSION

In the three nationwide cross-sectional studies, high HDL-C levels were associated with improved FVC and FEV1. However, future studies are needed to confirm this correlation and elucidate the underlying mechanisms.

Evaluation of Usefulness of Yeast-Based Biological Phantom and Preliminary Study for Verification of Hypoxic Effect of Flash Radiotherapy

PURPOSE/OBJECTIVE(S)

As a basic hypothesis for the effectiveness of flash radiation therapy, the effect of preserving normal tissue during flash radiation is due to the instantaneous chemical depletion of oxygen. A yeast-based biological phantom was created to verify the hypoxic effect of flash radiation therapy. A study to upgrade the previously developed X-Band LINAC to a flash irradiation mode is in progress, and a preceding study is conducted to evaluate the usefulness of a yeast-based biological phantom manufactured by analyzing the change in oxygen by irradiating a high dose in a general radiation therapy device.

MATERIALS/METHODS

Freeze-dried yeast sample (Saccharomyces cerevisiae, S288C) is activated and sub-cultured. For mass production of yeast samples, yeast culture medium is prepared by adding yeast colonies to the ypd medium. This study was conducted to verify the hypoxic effect among the biological mechanisms that occur during flash radiation therapy at the basic stage, and the oxygen concentration change during general radiation irradiation was measured in real time using a DO (Dissolved oxygen) meter and fiber optic sensor designed to do that. To prevent scatter, which is a concern during flash irradiation, the fiber form was used, and precise experiments are possible as a non-invasive oxygen concentration measurement method. Based on 10MV of general radiation therapy device, high-dose radiation of 500-10,000 cGy is irradiated to measure real-time oxygen concentration change.

RESULTS

As a result of irradiation with high-dose (500-10,000 cGy) radiation of general LINAC, it was confirmed that the oxygen concentration of the yeast culture medium decreased by 5.7-63.2%, and the usefulness of the biological phantom fabricated based on the yeast culture medium was evaluated.

CONCLUSION

Prior to the analysis of oxygen concentration change in yeast cells during X-Band LINAC flash irradiation, a preliminary study was conducted at a high dose in a general LINAC to obtain a significant result of oxygen concentration change and confirm the usefulness of the yeast-based biological phantom. Prior research was conducted and verified as a general irradiation experiment using a yeast-based biological phantom manufactured based on a DO meter and a fiber optic oxygen sensor. After irradiation with high-dose radiation, the oxygen concentration of the yeast culture medium was measured 5 times, and it was confirmed that there was a change in oxygen concentration of 5.7-63.2%, verifying the usefulness and stability of the biological phantom. The usefulness of the yeast-based biological phantom for high doses was confirmed, and it is expected that the usefulness of the biological phantom for flash radiation can be verified by additionally measuring the change in oxygen concentration of the biological phantom according to the high dose rate in the future.

Definitive Radiotherapy in Patients with Clinical T1N0M0 Esophageal Squamous Cell Carcinoma: A Multicenter Retrospective Study

PURPOSE/OBJECTIVE(S)

In this study, we aimed to assess the failure pattern and survival outcomes and to analyze the optimal treatment field of definitive RT for T1N0M0 esophageal squamous cell carcinoma (ESCC).

MATERIALS/METHODS

We performed a retrospective analysis in a multi-institutional cohort of patients with histologically confirmed T1N0M0 ESCC. We included patients who underwent RT with definitive aim from 2010 to 2019. Patterns of failure were demonstrated as in-field locoregional, out-field locoregional and distant metastasis. In the survival analysis, freedom from locoregional recurrence and their association with clinicopathologic risk factors were analyzed. We performed a propensity score matching in the cT1b patients to adjust for the heterogeneity of radiation technique, radiation dose and the use of concurrent chemotherapy.

RESULTS

A total of 168 patients were included with a median follow-up of 34.0 months, and there were 20 cT1a, 94 cT1b and 24 cT1x, (cT1, not otherwise specified) patients. The rates of all and locoregional failure were 26.9% and 23.1% for cT1a and 25.0% and 22.4% for cT1b patients. 10 (10.6%) patients experienced grade ≥ 3 adverse events. Among 116 cT1b patients, 69 patients received elective nodal irradiation (ENI) and 47 patients received involved field irradiation (IFI). After propensity score matching, the 3-year FFLRR rate was 84.5% (95% Confidence Interval, 71.0 - 92.1%). There was no significant difference between the ENI and IFI patients in FFLRR (Log-rank P = 0.831). In the multivariate analysis, the use of concurrent chemotherapy was the only factor marginally associated with FFLRR (Hazard ratio, 0.17; 95% CI, 0.02 - 1.13; P = 0.067).

CONCLUSION

cT1a patients who cannot receive endoscopic resection, showed similar rates of failure compared with cT1b patients, which questioned the accuracy of the staging and raised the need for through treatment such as chemoradiotherapy. In cT1b patients, IFI using dose of 50 to 60 Gy with concurrent chemotherapy could be a reasonable treatment option.

Myosteatosis as a prognostic factor of Mycobacterium avium complex pulmonary disease

Quantitative body composition affects the prognosis of patients with Mycobacterium avium complex pulmonary disease (MAC-PD). However, whether the qualitative body composition obtained indirectly through computed tomography (CT) affects their prognosis is debatable. We retrospectively analyzed patients with MAC-PD who underwent non-contrast CT at MAC-PD diagnosis. The cross-sectional area of the erector spinae muscle (ESM area), the Hounsfield unit of the erector spinae muscle (ESM HU), and the cross-sectional area of subcutaneous fat (SQF area) were measured at the level of the first lumbar vertebra. Myosteatosis were defined below the median value of ESM HU for each sex. Of 377 patients, 45 (11.9%) died during the follow-up. Patients who died were older and had a lower ratio of females (33.3%). In body compositions, SQF area and ESM HU were lower in the patients who died. In multivariable analysis, a low ESM HU was associated with increased mortality (ESM HU adjusted hazard ratio [aHR] 0.95, 95% confidence interval [CI] 0.93-0.97) through body composition. SQF area revealed protective effects in MAC-PD patients with body mass index ≥ 18.5 kg/m2 (aHR 0.98, 95% CI 0.95-1.00). In conclusion, the decrease in ESM HU, which indirectly reflects myosteatosis, is associated with mortality in patients with MAC-PD.

Identification of Biomarkers for the Diagnosis of Sepsis-Associated Acute Kidney Injury and Prediction of Renal Recovery in the Intensive Care Unit

PURPOSE

Acute kidney injury (AKI) following sepsis is associated with higher mortality; however, reliable biomarkers for AKI development and recovery remain to be elucidated.

MATERIALS AND METHODS

Patients with sepsis admitted to the medical intensive care unit (ICU) of Severance Hospital between June 2018 and May 2019 were prospectively analyzed. Patients were divided into those with and without AKI within 48 hours. Patients with septic AKI were subdivided into AKI-recovery and non-recovery groups based on whether their kidney injury recovered within 7 days.

RESULTS

A total of 84 patients were enrolled. The baseline creatinine (2.9 mg/dL vs. 0.8 mg/dL vs. 1.2 mg/dL, p<0.001), Charlson Comorbidity Index (4.5 vs. 2.0 vs. 3.0, p=0.002), Sequential Organ Failure Assessment (10.0 vs. 6.5 vs. 8.0, p<0.001), and Acute Physiology and Chronic Health Evaluation II scores (32.0 vs. 21.5 vs. 30.5, p=0.004) were higher in the non-recovery AKI group compared to the non-AKI and AKI-recovery groups. The Kaplan-Meier curves revealed that non-recovery from AKI was associated with lower survival (p<0.001). High-lactate (p≤0.05) and kynurenine levels (p≤0.05) were associated with non-recovery of renal function following AKI. The areas under the curve for predicting non-recovery from AKI were 0.693 and 0.721 for lactate and kynurenine, respectively. The survival rate was lower in the high-kynurenine (p=0.040) and high-lactate (p=0.010) groups.

CONCLUSION

The mortality of patients who recovered from AKI was comparable to that of patients without AKI. Lactate and kynurenine could be useful biomarkers for the diagnosis and recovery of AKI following sepsis.

Longitudinal association between adiposity changes and lung function deterioration

BACKGROUND

The longitudinal relationship between adiposity and lung function is controversial. We aimed to investigate the long-term association between adiposity changes and lung function in a middle-aged general Asian population.

METHODS

In total, 5011 participants (average age, 54 years; 45% men) were enrolled from a community-based prospective cohort. During the follow-up period (median 8 years), both spirometry and bio-electrical impedance analysis were performed biannually. Individual slopes of the fat mass index (FMI; fat mass divided by the square of height in meters) and waist-to-hip ratio (WHR) were calculated using linear regression analysis. Multivariate linear mixed regression analysis was used to determine the long-term association between adiposity changes and lung function.

RESULTS

The FMI was inversely associated with forced vital capacity (FVC) (estimated: - 31.8 mL in men, - 27.8 mL in women) and forced expiratory volume in 1 s (FEV₁) (estimated: - 38.2 mL in men, - 17.8 mL in women) after adjusting for baseline age, height, residential area, smoking exposure (pack-years, men only), initial adiposity indices, and baseline lung function. The WHR was also inversely associated with FVC (estimated = - 1242.2 mL) and FEV₁ (estimated = - 849.8 mL) in men. The WHR-increased group showed a more rapid decline in lung function than the WHR-decreased group in both the fat-gain and fat-loss groups.

CONCLUSION

Adiposity was associated with the long-term impairment of lung function. Central obesity was the main driver of lung function impairment in the middle-aged general Asian population, regardless of fat mass changes.

Clinical Outcomes and Prognosis of Patients With Interstitial Lung Disease Undergoing Lung Cancer Surgery: A Propensity Score Matching Study

BACKGROUND

Patients with interstitial lung disease (ILD) may have a poor prognosis after lung cancer surgery because of respiratory complications and increased recurrence rates due to limited resection. Few studies have investigated prognosis after surgery by matching clinical variables between patients with and without ILD.

PATIENTS AND METHODS

Medical records of patients who underwent lung cancer surgery between January 2010 and August 2020 at a referral hospital in South Korea were reviewed. Patients with ILD were identified based on preoperative computed tomography findings. Through propensity score matching, the clinical outcomes and prognoses of patients with (ILD group) and without ILD (control group) were compared.

RESULTS

Of 1629 patients, 113 (6.9%) patients with ILD were identified, of whom 104 patients were matched. Before matching, patients with ILD had higher mean age, proportion of men, and rates of sublobar resection and squamous cell carcinoma than those without ILD. After matching, there was no significant difference in postoperative mortality rates between the control and ILD groups. The 5-year survival rate was significantly lower in the ILD group (66%) than in the control group (78.8%; P= .007). The 5-year survival rate of the ILD-GAP (Gender, Age, Physiology) stage III group (12.6%) was significantly lower than that of the ILD-GAP stage I (73.5%) and II groups (72.6%; P< .0001). Multivariable Cox analysis demonstrated that idiopathic pulmonary fibrosis, higher clinical stage, and recurrence were independent prognostic factors for mortality.

CONCLUSION

Concomitant ILD negatively affects long-term prognosis after lung cancer surgery, and ILD subtype and physiological severity assessment help predict prognosis after surgery.

Clinical features and molecular genetics associated with brain metastasis in suspected early-stage non-small cell lung cancer

Introduction

Regarding whether brain magnetic resonance imaging (MRI) should be routine in patients with suspected early-stage lung cancer, guideline recommendations are inconsistent. Therefore, we performed this study to evaluate the incidence of and risk factors for brain metastasis (BM) in patients with suspected early-stage non-small-cell lung cancer (NSCLC).

Methods

A review of the medical charts of consecutive NSCLC patients diagnosed between January 2006 and May 2020 was performed. We identified 1,382 NSCLC patients with clinical staging of T1/2aN0M0 (excluding BM), and investigated the incidence, clinical predictors, and prognosis of BM in the cohort. We also performed RNA-sequencing differential expression analysis using transcriptome of 8 patients, using DESeq2 package (version 1.32.0) with R (version 4.1.0).

Results

Among 1,382 patients, nine hundred forty-nine patients (68.7%) underwent brain MRI during staging, and 34 patients (3.6%) were shown to have BM. Firth's bias-reduced logistic regression showed that tumor size (OR 1.056; 95% CI 1.009-1.106, p=0.018) was the only predictor of BM, and pathologic type was not a predictor of BM in our cohort (p>0.05). The median overall survival for patients with brain metastasis was 5.5 years, which is better than previously reported in the literature. RNA-sequencing differential expression analysis revealed the top 10 significantly upregulated genes and top 10 significantly downregulated genes. Among the genes involved in BM, Unc-79 homolog, non-selective sodium leak channel (NALCN) channel complex subunit (UNC79) was the most highly expressed gene in the lung adenocarcinoma tissues from the BM group, and an in vitro assay using A549 cells revealed that the NALCN inhibitor suppressed lung cancer cell proliferation and migration.

Conclusions

Given the incidence and favorable outcome of BM in patients with suspected early-stage NSCLC, selective screening with brain MRI may be considered, especially in patients with high-risk features.

Hyperglycemia and Hypoglycemia Are Associated with In-Hospital Mortality among Patients with Coronavirus Disease 2019 Supported with Extracorporeal Membrane Oxygenation

Metabolic abnormalities, such as preexisting diabetes or hyperglycemia or hypoglycemia during hospitalization aggravated the severity of COVID-19. We evaluated whether diabetes history, hyperglycemia before and during extracorporeal membrane oxygenation (ECMO) support, and hypoglycemia were risk factors for mortality in patients with COVID-19. This study included data on 195 patients with COVID-19, who were aged ≥19 years and were treated with ECMO. The proportion of patients with diabetes history among nonsurvivors was higher than that among survivors. Univariate Cox regression analysis showed that in-hospital mortality after ECMO support was associated with diabetes history, renal replacement therapy (RRT), and body mass index (BMI) < 18.5 kg/m2. Glucose at admission >200 mg/dL and glucose levels before ventilator >200 mg/dL were not associated with in-hospital mortality. However, glucose levels before ECMO >200 mg/dL and minimal glucose levels during hospitalization <70 mg/dL were associated with in-hospital mortality. Multivariable Cox regression analysis showed that glucose >200 mg/dL before ECMO and minimal glucose <70 mg/dL during hospitalization remained risk factors for in-hospital mortality after adjustment for age, BMI, and RRT. In conclusion, glucose >200 mg/dL before ECMO and minimal glucose level <70 mg/dL during hospitalization were risk factors for in-hospital mortality among COVID-19 patients who underwent ECMO.

Complications related to extracorporeal membrane oxygenation support as a bridge to lung transplantation and their clinical significance

BACKGROUND

Incidence of complications related extracorporeal membrane oxygenation (ECMO) support as a bridge to lung transplantation (BTT) and its association with the patient outcome in lung transplantation (LT) has not been well documented in previous studies.

OBJECTIVES

We evaluated the incidence of complications related to the use of ECMO support as a BTT, and the association between the occurrence of the complications and patient outcomes in LTs.

METHODS

This retrospective cohort study investigated 100 consecutive patients who started ECMO support as a BTT between April 2013 and March 2020. Data for the analyses were retrieved from electronic medical records.

RESULTS

Fifty-six percent of the patients experienced at least one complication during the BTT with ECMO. Major bleeding was the most common complication. In multivariate logistic regression analysis, occurrence of oxygenator thromboses (OR 16.438, P = 0.008) and the use of renal replacement therapy (RRT) (OR 32.288, P < 0.001) were associated with a failed BTT. In the subgroup analysis of the LT recipients, intracranial hemorrhages, (OR 13.825, P = 0.021), RRT use, (OR 11.395, P = 0.038), and bloodstream infection occurrence (OR 6.210; P = 0.034) were identified as risk factors for in-hospital mortality.

CONCLUSIONS

The occurrence of complications during the use of ECMO support as a BTT was associated with unfavorable outcomes in LTs. Close monitoring and the proper management of these complications may be important to achieve better outcomes in patients using ECMO support as a BTT.

Sarcopenia is associated with cardiovascular risk in men with COPD, independent of adiposity

Background

Sarcopenia is a well-established risk factor for atherosclerotic cardiovascular disease (ASCVD), but its relationship with chronic obstructive pulmonary disease (COPD) has not been fully determined. This study is aimed to investigate the association between sarcopenia and risk for ASCVD in patients with COPD, independent of central obesity and fat mass.

Methods

Data regarding 704 men with COPD (mean age: 63.4 years) were extracted from the 2008 to 2011 Korean National Health and Nutrition Examination Surveys. Sarcopenia index and fat mass were assessed using dual-energy X-ray absorptiometry. Sarcopenia was defined according to the presence of sarcopenia index values < 1 standard deviation from the cutoff (0.774) among the study participants. ASCVD risk was evaluated using American College of Cardiology/American Heart Association guidelines. High probability of ASCVD was defined as ASCVD risk > 20%.

Results

The quartile-stratified sarcopenia index was negatively associated with ASCVD risk (P < 0.001). ASCVD risk and prevalence of high ASCVD risk were significantly greater in sarcopenic participants than in non-sarcopenic participants, regardless of central obesity and fat mass (all P < 0.001). Multivariate regression analyses demonstrated an independent association between sarcopenia and ASCVD risk (estimated ± standard error = 3.63 ± 0.77%, P < 0.001) and high ASCVD risk (odds ratio [OR] = 2.32, 95% confidence interval [CI] 1.05–5.15, P = 0.039). Furthermore, sarcopenia was an independent factor for high ASCVD risk in participants with moderate to very severe airflow limitation (OR = 2.97, 95% CI 1.06–8.36, P < 0.001).

Conclusions

Sarcopenia was significantly associated with an increased risk for ASCVD in men with COPD, independent of central obesity and fat mass. High ASCVD risk was significantly associated with sarcopenia, particularly in participants with moderate to very severe airflow limitation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02109-3.

Effects of the Discharge Education Program on Family Caregivers Caring for Patients on Mechanical Home Ventilation in Korea: A Pilot Test

Patients on home ventilators rely on mechanical ventilation until their death; hence, family caregivers should perform additional caregiving, including tracheostomy, equipment management, and positive pressure ventilation by ambu-bag in emergencies. Therefore, a systematic discharge education program and evaluation of actual caregiver performance are necessary for safe home management. The program consists of suction and tracheostomy management, home ventilator management, emergency management, fundamental caregiving, and video material. To test clinical validity, family caregivers of patients about to be discharged to their homes from S hospital in Seoul, Korea, were selected by convenience sampling with a non-equivalent control group design. Of 18 participants, one refused, one died, and two became unstable after their agreement; therefore, 14 participants were finally included. To compare caregiving performance scores between the groups, we ran repeated measures ANOVA. Intergroup and period interaction of suction ( F = 6.08, p = .001) and tracheostomy management ( F = 3.00, p = .038) crucial for airway management, showed significant statistical differences. In short, the intervention group showed a faster increase in suction and tracheostomy management than the control group. Home ventilator management ( F = 22.53, p < .001), emergency management ( F = 12.01, p < .001), and fundamental caregiving ( F = 7.88, p < .001) showed significant differences within the group regarding the period. According to the results of the clinical validity test, the discharge education program increased the family caregiver’s suction and tracheostomy management performance scores. Further research is needed to demonstrate long-term effects of the program with a larger sample.

Change in management and outcome of mechanical ventilation in Korea: a prospective observational study

BACKGROUND/AIMS

There are few studies describing contemporary status of mechanical ventilation in Korea. We investigated changes in management and outcome of mechanical ventilation in Korea.

METHODS

International, prospective observational cohort studies have been conducted every 6 years since 1998. Korean intensive care units (ICUs) participated in 2010 and 2016 cohorts. We compared 2016 and 2010 Korean data.

RESULTS

Two hundred and twenty-six patients from 18 ICUs and 275 patients from 12 ICUs enrolled in 2016 and 2010, respectively. In 2016 compared to 2010, use of non-invasive ventilation outside ICU increased (10.2% vs. 2.5%, p = 0.001). Pressure-control ventilation was the most common mode in both groups. Initial tidal volume (7.1 mL/kg vs. 7.4 mL/kg, p = 0.372) and positive end-expiratory pressure (6 cmH2O vs. 6 cmH2O, p = 0.141) were similar, but peak pressure (22 cmH2O vs. 24 cmH2O, p = 0.011) was lower in 2016. More patients received sedatives (70.7% vs. 57.0%, p = 0.002) and analgesics (86.5% vs. 51.1%, p < 0.001) in 2016. The awakening (48.4% vs. 31.0%, p = 0.002) was more frequently attempted in 2016. The accidental extubation rate decreased to one tenth of what it was in 2010 (1.1% vs. 10.2%, p < 0.001). The ICU mortality did not change (31.4% 35.6%, p = 0.343) but ICU length of stay showed a decreasing trend (9 days vs. 10 days, p = 0.054) in 2016.

CONCLUSION

There were temporal changes in care of patients on mechanical ventilation including better control of pain and agitation, and active attempt of awakening.

Response After Repeated Ketamine Injections in a Rat Model of Neuropathic Pain

Ketamine, an N-methyl-D-aspartate antagonist, reduces pain by decreasing central sensitization and pain windup. However, chronic ketamine use can cause tolerance, dependency, impaired consciousness, urinary symptoms, and abdominal pain. This study aimed to investigate the effects of repeated ketamine injections and ketamine readministration after discontinuation in a rat model of neuropathic pain. To induce neuropathic pain, partial sciatic nerve ligation (PSNL) was performed in 15 male Wistar rats, and these animals were divided into three groups: PSNL (control), PSNL + ketamine 5 mg/kg (K5), and PSNL + ketamine 10 mg/kg (K10; n=5 each). Ketamine was injected intraperitoneally daily for 4 weeks, discontinued for 2 weeks, and then readministered for 1 week. Following PSNL, the mechanical withdrawal threshold was determined weekly using the Von Frey. The K10 group showed a significant increase in the mechanical withdrawal threshold, presented here as the target force (in g), at 21 and 28 days compared to the time point before ketamine injection (mean±SE, 276.0±24.0 vs. 21.6±2.7 and 300.0±0.0 vs. 21.6±2.7, respectively; P<0.01) and at 14, 21, and 28 days compared to the control group (108.2±51.2 vs. 2.7±1.3, 276.0±24.0 vs. 2.5±1.5, and 300.0±0.0 vs. 4.0±0.0, respectively; P<0.05). However, in the K10 group, the ketamine effects decreased significantly at 7 days after readministration compared to those after 28 days of repeated injections (P<0.05). In the K10 group, repeated ketamine injections showed a significant increase in antinociceptive effect for >2 weeks, but this ketamine effect decreased after drug readministration.

Reference values of skeletal muscle area for diagnosis of sarcopenia using chest computed tomography in Asian general population

BACKGROUND

Diagnostic cutoff points for sarcopenia in chest computed tomography (CT) have not been established although CT is widely used for investigating skeletal muscles. This study aimed to determine reference values for sarcopenia of thoracic skeletal muscles acquired from chest CT scans and to analyse variables related to sarcopenia using the cutoff values determined in a general Asian population.

METHODS

We retrospectively reviewed chest CT scans of 4470 participants (mean age 54.8 ± 9.9 years, 65.8% male) performed at a check-up centre in South Korea (January 2016-August 2017). To determine cutoffs, 335 participants aged 19-39 years (mean age 35.2 ± 3.6 years, 75.2% male) were selected as the healthy and younger reference group, and 4135 participants aged ≥40 years (mean age 56.4 ± 8.4 years, 65.1% male) were selected as the study group. We measured the following: cross-sectional area (CSA) of the pectoralis, intercostalis, paraspinal, serratus, and latissimus muscles at the 4^th vertebral region (T4_CSA ); T4_CSA divided by height² (T4MI); pectoralis muscle area (PM_CSA ); and PM_CSA divided by height² (PMI) at the 4^th vertebral region. Sarcopenia cutoff was defined as sex-specific values of less than -2 SD below the mean from the reference group.

RESULTS

In the reference group, T4_CSA , T4MI, PM_CSA , and PMI cutoffs for sarcopenia were 100.06cm² , 33.69cm² /m² , 29.00cm² , and 10.17cm² /m² in male, and 66.93cm² , 26.01cm² /m² , 18.29cm² , and 7.31cm² /m² in female, respectively. The prevalence of sarcopenia in the study group measured with T4_CSA , T4MI, PM_CSA and PMI cutoffs were 11.4%, 8.7%, 8.5%, and 10.1%, respectively. Correlations were observed between appendicular skeletal mass divided by height² measured by bioelectrical impedance analysis (BIA) and T4_CSA (r = 0.82; P < 0.001)/T4MI (r = 0.68; P < 0.001), and ASM/height² measured by BIA and PM_CSA (r = 0.72; P < 0.001)/PMI (r = 0.63; P < 0.001). In the multivariate logistic regression models, sarcopenia defined by T4_CSA /T4MI were related to age [odds ratio (95% confidence interval), P-values: 1.09 (1.07-1.11), <0.001/1.05 (1.04-1.07), <0.001] and diabetes [1.60 (1.14-2.25), 0.007/1.47 (1.01-2.14), 0.043]. Sarcopenia defined by PM_CSA /PMI were related to age [1.09 (1.08-1.10), <0.001/1.05 (1.03-1.06), <0.001], male sex [0.23 (0.18-0.30), <0.001/0.47 (0.32-0.71), <0.001], diabetes [2.30 (1.73-3.05), <0.001/1.63 (1.15-2.32), 0.007], history of cancer [2.51 (1.78-3.55), <0.001/1.61 (1.04-2.48), 0.033], and sufficient physical activity [0.67 (0.50-0.89), 0.007/0.74 (0.56-0.99), 0.042].

CONCLUSIONS

The reference cutoff values of a general population reported here will enable sex-specific standardization of thoracic muscle mass quantification and sarcopenia assessment.

NADPH oxidase 4 signaling in a ventilator-induced lung injury mouse model

Background

For patients with acute respiratory distress syndrome, a ventilator is essential to supply oxygen to tissues, but it may also cause lung damage. In this study, we investigated the role of NOX4 using NOX4 knockout (KO) mice and NOX4 inhibitors in a ventilator-induced lung injury (VILI) model.

Methods

Wild-type (WT) male C57BL/6J mice and NOX4 knockout (KO) male mice were divided into five groups: (1) control group; (2) high tidal ventilation (HTV) group: WT mice + HTV ± DMSO; (3) NOX4 KO group; (4) NOX4 KO with HTV group; (5) NOX4 inhibitor group: WT mice + HTV + NOX4 inhibitor. In the VILI model, the supine position was maintained at 24 mL/kg volume, 0 cm H₂O PEEP, 100/min respiratory rate, and 0.21 inspired oxygen fraction. In the NOX4 inhibitor group, 50 μL anti-GKT 137831 inhibitor was injected intraperitoneally, 2 h after ventilator use. After 5 h of HTV, mice in the ventilator group were euthanized, and their lung tissues were obtained for further analysis. In addition, the relationship between EphA2 (which is related to lung injury) and NOX4 was investigated using EphA2 KO mice, and NOX4 and EphA2 levels in the bronchoalveolar lavage fluid (BALF) of 38 patients with pneumonia were examined.

Results

Cell counts from BALFs were significantly lower in the NOX4 KO with HTV group (p < 0.01) and EphA2 KO with HTV group (p < 0.001) compared to that in the HTV group. In the NOX4 inhibitor group, cell counts and protein concentrations from BALF were significantly lower than those in the HTV group (both, p < 0.001). In the NOX4 KO group and the NOX4 inhibitor group, EphA2 levels were significantly lower than those in the HTV group (p < 0.001). In patients with respiratory disease, NOX4 and EphA2 levels were significantly higher in patients with pneumonia and patients who received ventilator treatment in the intensive care unit.

Conclusion

In the VILI model with high tidal volume, NOX4 KO, EphA2 KO or monoclonal antibodies attenuated the VILI. NOX4 and EphA2 levels were significantly higher in patients with pneumonia and especially in mechanical ventilated in the ICU. Inhibition of Nox4 is a potential therapeutic target for the prevention and reduction of VILI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01992-0.

Treatment of acute respiratory failure: invasive mechanical ventilation

Background: Acute respiratory failure is a condition in which gas exchange functions decrease due to various causes. Respiratory failure is one of the most common causes of intensive care unit admissions, and most cases require invasive mechanical ventilation.Current Concepts: Invasive mechanical ventilation is defined as the delivery of positive pressure to the lungs via an endotracheal or tracheostomy tube. Invasive mechanical ventilation is commonly used to replace the functions of spontaneous breathing, either fully or partially, by performing the breathing function for the lungs. It is also indicated in patients who require airway protection or have neuromuscular diseases. Invasive mechanical ventilation should not be delayed until the need becomes urgent. There is no universal set of ventilation protocols established as ideal for all patients. It is essential that doctors understand and apply the necessary methods to protect the lungs from injury associated with invasive mechanical ventilation.Discussion and Conclusion: The primary goals of mechanical ventilation are to optimize oxygenation while avoiding ventilator-induced lung injury. In patients with acute respiratory failure, the mortality rate has reduced dramatically with the application of the lung-protective ventilation strategy. Patients undergoing invasive mechanical ventilation will survive if they are treated and monitored according to this principle, but damage to the lungs may occur if the guidelines are not followed. Therefore, it is essential to know and adhere to the initial setup and monitoring principles.

Clinical impact of pneumothorax in patients with Pneumocystis jirovecii pneumonia and respiratory failure in an HIV-negative cohort

Background

Pneumocystis jirovecii pneumonia (PCP) with acute respiratory failure can result in development of pneumothorax during treatment. This study aimed to identify the incidence and related factors of pneumothorax in patients with PCP and acute respiratory failure and to analyze their prognosis.

Methods

We retrospectively reviewed the occurrence of pneumothorax, including clinical characteristics and results of other examinations, in 119 non-human immunodeficiency virus patients with PCP and respiratory failure requiring mechanical ventilator treatment in a medical intensive care unit (ICU) at a tertiary-care center between July 2016 and April 2019.

Results

During follow up duration, twenty-two patients (18.5%) developed pneumothorax during ventilator treatment, with 45 (37.8%) eventually requiring a tracheostomy due to weaning failure. Cytomegalovirus co-infection (odds ratio 13.9; p = 0.013) was related with occurrence of pneumothorax in multivariate analysis. And development of pneumothorax was not associated with need for tracheostomy and mortality. Furthermore, analysis of survivor after 28 days in ICU, patients without pneumothorax were significantly more successful in weaning from mechanical ventilator than the patients with pneumothorax (44% vs. 13.3%, p = 0.037). PCP patients without pneumothorax showed successful home discharges compared to those who without pneumothorax (p = 0.010).

Conclusions

The development of pneumothorax increased in PCP patient with cytomegalovirus co-infection, pneumothorax might have difficulty in and prolonged weaning from mechanical ventilators, which clinicians should be aware of when planning treatment for such patients.

Protective effect of methotrexate on lung function and mortality in rheumatoid arthritis–related interstitial lung disease: a retrospective cohort study

Background:

Studies on the risk and protective factors for lung function decline and mortality in rheumatoid arthritis–related interstitial lung disease (RA-ILD) are limited.

Objectives:

We aimed to investigate clinical factors and medication uses associated with lung function decline and mortality in RA-ILD.

Methods:

This retrospective cohort study examined the medical records of patients with RA-ILD who visited Severance Hospital between January 2006 and December 2019. We selected 170 patients with RA-ILD who had undergone at least one spirometry test and chest computed tomography scan. An absolute decline of ⩾10% in the functional vital capacity (FVC) was defined as significant decline in pulmonary function. Data for analysis were retrieved from electronic medical records.

Results:

Ninety patients (52.9%) were female; the mean age was 64.0 ± 10.2 years. Multivariate logistic regression showed that a high erythrocyte sediment rate level at baseline [odds ratio (OR) = 3.056; 95% confidence interval (CI) = 1.183–7.890] and methotrexate (MTX) use (OR = 0.269; 95% CI = 0.094–0.769) were risk and protective factors for lung function decline, respectively. Multivariate Cox regression analysis indicated that age ⩾65 years (OR = 2.723; 95% CI = 1.142–6.491), radiologic pattern of usual interstitial pneumonia (UIP) or probable UIP (OR = 3.948; 95% CI = 1.522–10.242), baseline functional vital capacity (FVC) % predicted (OR = 0.971; 95% CI = 0.948–0.994), and MTX use (OR = 0.284; 95% CI = 0.091–0.880) were predictive of mortality.

Conclusion:

We identified risk and protective factors for lung function decline and mortality in patients with RA-ILD. MTX use was associated with favorable outcome in terms of both lung function and mortality in our cohort.

Relationship of the lung microbiome with PD-L1 expression and immunotherapy response in lung cancer

Background

Lung cancer is the primary cause of cancer-related deaths worldwide. The human lung serves as a niche to a unique and dynamic bacterial community that is related to the development of multiple diseases. Here, we investigated the differences in the lung microbiomes of patients with lung cancer.

Methods

16S rRNA sequencing was performed to evaluate the respiratory tract microbiome present in the bronchoalveolar lavage fluid. Patients were stratified based on programmed death-ligand 1 (PD-L1) expression levels and immunotherapy responses.

Results

In total, 84 patients were prospectively analyzed, of which 59 showed low (< 10%), and 25 showed high (≥ 10%) PD-L1 expression levels. The alpha and beta diversities did not significantly differ between the two groups. Veillonella dispar was dominant in the high-PD-L1 group; the population of Neisseria was significantly higher in the low-PD-L1 group than in the high-PD-L1 group. In the immunotherapy responder group, V. dispar was dominant, while Haemophilus influenzae and Neisseria perflava were dominant in the non-responder group.

Conclusion

The abundances of Neisseria and V. dispar differed significantly in relation to PD-L1 expression levels and immunotherapy responses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01919-1.

Thoracic skeletal muscle quantification using computed tomography and prognosis of elderly ICU patients

In elderly ICU patients, the prevalence of skeletal muscle loss is high. Longitudinal effect of thoracic muscles, especially in elderly ICU patients, are unclear although skeletal muscle loss is related with the short- and long-term outcomes. This study aimed to evaluate whether pectoralis muscle mass loss could be a predictor of prognosis in elderly ICU patients. We retrospectively evaluated 190 elderly (age > 70 years) patients admitted to the ICU. We measured the cross-sectional area (CSA) of the pectoralis muscle (PM_CSA) at the fourth vertebral region. CT scans within two days before ICU admission were used for analysis. Mortality, prolonged mechanical ventilation, and longitudinal changes in Sequential Organ Failure Assessment (SOFA) scores were examined. PM_CSA below median was significantly related with prolonged ventilation (odds ratio 2.92) and a higher SOFA scores during the ICU stay (estimated mean = 0.94). PM_CSA below median was a significant risk for hospital mortality (hazards ratio 2.06). In elderly ICU patients, a low ICU admission PM_CSA was associated with prolonged ventilation, higher SOFA score during the ICU stay, and higher mortality. Adding thoracic skeletal muscle CSA at the time of ICU admission into consideration in deciding the therapeutic intensity in elderly ICU patients may help in making medical decisions.

Long- and short-term clinical impact of awake extracorporeal membrane oxygenation as bridging therapy for lung transplantation

Background

As lung transplantation (LTx) is becoming a standard treatment for end-stage lung disease, the use of bridging with extracorporeal membrane oxygenation (ECMO) is increasing. We examined the clinical impact of being awake during ECMO as bridging therapy in patients awaiting LTx.

Methods

In this single-center study, we retrospectively reviewed 241 consecutive LTx patients between October 2012 and March 2019; 64 patients received ECMO support while awaiting LTx. We divided into awake and non-awake groups and compared.

Results

Twenty-five patients (39.1%) were awake, and 39 (61.0%) were non-awake. The median age of awake patients was 59.0 (interquartile range, 52.5–63.0) years, and 80% of the group was men. The awake group had better post-operative outcomes than the non-awake group: statistically shorter post-operative intensive care unit length of stay [awake vs. non-awake, 6 (4–8.5) vs. 18 (11–36), p < 0.001], longer ventilator free days [awake vs. non-awake, 24 (17–26) vs. 0 (0–15), p < 0.001], and higher gait ability after LTx (awake vs. non-awake, 92% vs. 59%, p = 0.004), leading to higher 6-month and 1-year lung function (forced expiratory volume in 1 s: awake vs. non-awake, 6-month, 77.5% vs. 61%, p = 0.004, 1-year, 75% vs. 57%, p = 0.013). Furthermore, the awake group had significantly lower 6-month and 1-year mortality rates than the non-awake group (6-month 12% vs. 38.5%, p = 0.022, 1-year 24% vs. 53.8%, p = 0.018).

Conclusions

In patients with end-stage lung disease, considering the long-term and short-term impacts, the awake ECMO strategy could be useful compared with the non-awake ECMO strategy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01905-7.

A Preliminary Study on the Prognostic Impact of Neutrophil to Lymphocyte Ratio of the Bronchoalveolar Lavage Fluid in Patients with Lung Cancer

The cumulative results indicate that the neutrophil to lymphocyte ratio of peripheral blood (pbNLR) is a useful prognostic factor in patients with various cancers. In contrast to peripheral blood, the bronchoalveolar lavage (BAL) fluid is in direct contact with the lung lesion. However, no study has reported on the clinical utility of the NLR of BAL fluid (bNLR) for patients with lung cancer. To investigate the clinical utility of the bNLR as a prognostic factor in patients with lung cancer, we conducted a retrospective review of the prospectively collected data. A total of 45 patients were classified into high bNLR (n = 29) and low bNLR (n = 16) groups. A high pbNLR and high bNLR were associated with a shorter overall survival (p < 0.001 and p = 0.011, respectively). A multivariable analysis confirmed that ECOG PS (p = 0.023), M stage (p = 0.035), pbNLR (p = 0.008), and bNLR (p = 0.0160) were independent predictors of overall survival. Similar to the pbNLR, a high bNLR value was associated with a poor prognosis in patients with lung cancer. Although further studies are required to apply our results clinically, this is the first study to show the clinical value of the bNLR in patients with lung cancer.

Association of protein consumption and energy intake on sarcopenia in tuberculosis survivors

BACKGROUND

Tuberculosis (TB) causes undernutrition, and it has a long recovery time after treatment. It is accompanied by adverse health outcomes, such as sarcopenia.

OBJECTIVE

We aimed to evaluate the prevalence of sarcopenia and its association with protein and total energy intakes among Korean TB survivors.

METHODS

Data of the population-based Korea National Health and Nutrition Examination Survey (2008-2011) were analyzed, including 9,203 participants aged ⩾ 40 years. We used three definitions for sarcopenia-appendicular skeletal muscle mass (ASM, kg) divided by body mass index (BMI, kg/m2), weight (kg), or height squared (m2). Daily protein and total energy intakes were estimated with a 24-h recall method. Multiple logistic regression was used to evaluate the association between dietary protein/total energy intake and sarcopenia among TB survivors.

RESULTS

The prevalence of sarcopenia was 11.2%, 10.7%, and 24.3% among TB survivors with sarcopenia defined by ASM divided by BMI, weight, and height squared, respectively. The prevalence of sarcopenia among TB survivors was higher than among those without TB. After adjusting for age, weight, sex, education level, employment status, smoking status, and drinking status, sufficient protein and total energy intakes were associated with a lower risk of sarcopenia in TB survivors.

CONCLUSION

The prevalence of sarcopenia was higher in TB survivors than in those without TB. We suggest consuming sufficient protein intake along with increasing total energy intake in TB survivors.

The relationship between cognitive function and competence in inhaler technique in older adults with airway disease

Cognitive impairment has high prevalence in older adults with airway diseases, and may influence their competence in inhaler use, thereby negatively affecting patient prognosis. We aimed to evaluate the relationship between cognitive function and competence in inhaler technique. We enrolled 108 inhaler naïve older adults (≥60 years) with airway disease in this prospective observational study and performed the Korean version of the Mini-Mental State Examination (K-MMSE). After explaining the inhaler technique, we scored its competence. While the total K-MMSE score was unrelated to the inhaler score, the orientation for place (estimates=0.62, p = 0.009), registration (estimates=0.988, p = 0.037), and recall (estimates=0.161, p = 0.048) were positively associated with the score. Low K-MMSE scores were associated with lower odds ratio for the competence of the "exhale" step (adjusted odds ratio= 0.23, p = 0.018). Thus, a K-MMSE-mediated evaluation of cognitive function in older adults with airway disease can be a useful tool to predict inhaler competence.

Event Prediction Model Considering Time and Input Error Using Electronic Medical Records in the Intensive Care Unit: Retrospective Study

BACKGROUND

In the era of artificial intelligence, event prediction models are abundant. However, considering the limitation of the electronic medical record-based model, including the temporally skewed prediction and the record itself, these models could be delayed or could yield errors.

OBJECTIVE

In this study, we aim to develop multiple event prediction models in intensive care units to overcome their temporal skewness and evaluate their robustness against delayed and erroneous input.

METHODS

A total of 21,738 patients were included in the development cohort. Three events-death, sepsis, and acute kidney injury-were predicted. To overcome the temporal skewness, we developed three models for each event, which predicted the events in advance of three prespecified timepoints. Additionally, to evaluate the robustness against input error and delays, we added simulated errors and delayed input and calculated changes in the area under the receiver operating characteristic curve (AUROC) values.

RESULTS

Most of the AUROC and area under the precision-recall curve values of each model were higher than those of the conventional scores, as well as other machine learning models previously used. In the error input experiment, except for our proposed model, an increase in the noise added to the model lowered the resulting AUROC value. However, the delayed input did not show the performance decreased in this experiment.

CONCLUSIONS

For a prediction model that was applicable in the real world, we considered not only performance but also temporal skewness, delayed input, and input error.

The Distribution of Multidrug-resistant Microorganisms and Treatment Status of Hospital-acquired Pneumonia/Ventilator-associated Pneumonia in Adult Intensive Care Units: a Prospective Cohort Observational Study

BACKGROUND

It is essential to determine the distribution of the causative microorganisms in the region and the status of local antibiotic resistance for the proper treatment of hospital-acquired pneumonia/ventilator-associated pneumonia (HAP/VAP). This study aimed to investigate the occurrence and causative strains of HAP/VAP, distribution of resistant bacteria, use of antibiotics, and the ensuing outcomes of patients in Korea.

METHODS

A multicenter prospective observational cohort study was conducted among patients with HAP/VAP admitted to the medical intensive care unit of 5 tertiary referral centers between August 2012 and June 2015. Patients' demographic and clinical data were collected.

RESULTS

A total of 381 patients were diagnosed with HAP/VAP. Their median age was 69 (59-76) years and 71% were males. A majority of the patients (88%) had late-onset (> 5 days) HAP/VAP. One-quarter of the patients (n = 99) had at least one risk factor for multidrug-resistant (MDR) pathogens, such as prior intravenous antibiotic use within the last 90 days. Microbiological specimens were mostly obtained noninvasively (87%) using sputum or endotracheal aspirates. Pathogens were identified in 235 (62%) of the 381 patients. The most common bacterial pathogen was Acinetobacter baumannii (n = 89), followed by Staphylococcus aureus (n = 52), Klebsiella pneumoniae (n = 25) and Pseudomonas aeruginosa (n = 22). Most of isolated A. baumannii (97%) and S. aureus (88%) were multidrug resistant. The most commonly used empirical antibiotic regimens were carbapenem-based antibiotics (38%), followed by extended-spectrum penicillin/β-lactamase inhibitor (34%). Glycopeptide or linezolid were also used in combination in 54% of patients. The 28-day mortality rate of the patients with HAP/VAP was 30% and the 60-day mortality was 46%. Patients who used empirical antibiotics appropriately had significantly lower mortality rates than those who did not (28-day mortality: 25% vs. 40%, P = 0.032; 60-day mortality: 41% vs. 55%, P = 0.032, respectively). Administration of appropriate empirical antibiotics (odds ratio [OR], 0.282; confidence interval [CI], 0.092-0.859; P = 0.026), Day 7 treatment failure (OR, 4.515; CI, 1.545-13.192; P = 0.006), and APACHE II score on day 1 (OR, 1.326; CI, 0.988-1.779; P = 0.012) were the factors that determined the 28-day mortality in patients with HAP who had identified bacteria as pathogens.

CONCLUSION

In HAP/VAP patients, there was a large burden of MDR pathogens, and their associated mortality rate was high. Proper selection of empirical antibiotics was significantly associated with the patient's prognosis; however, there was a discrepancy between major pathogens and empirical antibiotic therapy.

P–205 Epothilone D as an actin cytoskeleton stabilizer improved mitochondria bioenergenesis and blastocyst formation of mouse preimplantation embryo

Study question

What is primary factor of bioenergetics product activity between microtubule instability and the functional activity of mitochondria in embryo?

Summary answer

The actin cytoskeleton instability is presumably the primary cause for the bioenergenesis of mitochondrial function to the preimplantation embryo development.

What is known already

Mitochondria are cellular organelles dynamically moving and morphological changes. It provides for homeostatic energy to the cell. The dynamic property of the mitochondria is associated with the microtubule network in the cell. However, the stability of the microtubule was clearly identified for preimplantation embryo development.

Study design, size, duration

This study is designed to assess the ATP productivity of the mitochondria, and specifically to observe what its primary factor is in terms of providing microtubule stability in mammalian cells. Additionally, we investigated the relationship between blastocyst formation and actin cytoskeleton stabilization by EpD with 2-cell mice.

Participants/materials, setting, methods

We prepared the microtubule stability regulation model with the HEK293 cell line by using the microtubule stabilizer as an Epothilone D (EpD). Then we analyzed the metabolic activity of the cells through oxidative phosphorylation (OXP) ratios analysis. Also, we performed confocal live imaging to observe mitochondria morphology depending on the cells’ microtubule. Next, we treated EpD to 2-cell culture media for the analysis of blastocyst development ratios.

Main results and the role of chance

EpD significantly increased fusion form. Also, EpD enhance bioenergy ratios like OXP in the mitochondria and functional activity related marker, like mTOR compared with the control. These results suggest that microtubule stabilization enhances mitochondrial metabolism by increasing oxygen consumption. Also, EpD in 2-cell culture media led to a significant increase in the speed of development and 50% higher hatched out blastocyst formation ratios compared to the control group.

Limitations, reasons for caution

This study had limited animal experiments. For the next study, we are planning with an aim to improve the quality and development ratios of human embryos by EpD.

Wider implications of the findings: Microtubule stabilizer has a possibility to recover the mitochondria’s functional activity in the preimplantation embryo development. Mitochondrial functional activity along the actin cytoskeleton may play a pivotal role in determining the embryo quality and development ratios for archive pregnancy.

Trial registration number

non-clinical trials

P–657 Prostaglandin D2 is correlated with follicles development and a reliable marker of ovarian reserve of poor ovarian responder patients

Study question

Is the prostaglandin D2 (PGD2) associated with growing follicles and ovarian reserve of poor ovarian responders?

Summary answer

PGD2 is correlated with ovarian stimulation activity and follicle growth. Especially, poor ovarian responders show a significant decrease in the level of follicular fluid.

What is known already

Prostaglandins (PGs) are involved in the female reproductive process, mainly ovulation, fertilization, and implantation.

Study design, size, duration

We investigated the PGD2 level in the follicular fluid of poor ovarian responders. The collection of human follicular fluid was approved by the Institutional Research and Ethical Committees of CHA University (approval number: 1044308–201611-BR–027–04) from January to December 2019. Follicular fluid was collected from patients with normal ovarian response and patients with POR.

Participants/materials, setting, methods

We studied whether prostaglandin has related to POR in the clinical key factor by measuring human follicular fluid. Follicular fluid was collected from patients with normal ovarian response and patients with POR. The concentration of PGD2 in follicular fluid was determined with ELISA kits following the manufacturer’s protocol.

Main results and the role of chance

We analyzed the level of PGD2 in the follicular fluid of patients with normal ovarian response and patients with POR using an ELISA. The PGD2 concentration was significantly lower in the follicular fluid of patients with POR than in the follicular fluid of young and old patients with normal ovarian response.

Limitations, reasons for caution

This study has an identification of biomarker of the clinical samples as POR criteria patients. Therefore, further investigations aimed at specific recovery of low PGD2 metabolic activity in the CCs during control ovarian stimulation.

Wider implications of the findings: Until now there is no specific biomarker of POR. AMH is just an ovary reserve marker for an indication of ovary function. PGD2 is one of the metabolites in steroid metabolism in the ovary. Therefore, we can find some cure through further study for improved PGD2 production to POR patients.

Trial registration number

none

P–658 Lovastatin promotes the expression of LDL receptor and enhances E2 production in the cumulus cells

Study question

Lovastatin enhanced E2 productive ratios in the cumulus cells through promoted expression of Low-density lipoprotein receptor (LDLR).

Summary answer

Lovastatin up-regulated gene expression of LDLR in the CCs. And the high expression of LDLR promoted E2 productive ratios from CCs.

What is known already

We already reported that the up-regulation of LDLR correlated with clinical pregnancy. Therefore, we found lovastatin as an up-regulator of LDLR expression of clinical pregnancy.

Study design, size, duration

This is an expended study of LDLR to enhance steroidogenesis regarding the effect of lovastatin in the CCs. The collection of human cumulus cells was approved by the Institutional Research and Ethical Committees of CHA University (approval number: 1044308–201611-BR–027–04) from January to December 2019. The CCs were collected from 12 patients with normal ovarian response after oocyte denudation for ICSI.

Participants/materials, setting, methods

We studied whether lovastatin has up-regulated LDLR expression in human CCs. Cumulus cells were collected from patients with young (∼ 36) and old aged patients (37 ∼). After culturing human CCs, they were treated lovastatin for one day. The concentration of E2 in culture medium was measured using Chemiluminescence immunoassay. The mRNA isolated from CCs was analyzed gene expression level through real time-PCR.

Main results and the role of chance

The concentration of E2 was significantly increased in the culture medium treated with lovastatin. The CCs treated with lovastatin increased the expression of LDLR and StAR which are components of the steroidogenesis pathway.

Limitations, reasons for caution

We have found that the role of lovastatin promotes the E2 production by increasing the ldlr gene of CCs. Therefore, further investigations aimed at lovastatin effect on human oocytes embryo whether enhanced quality of oocytes or not.

Wider implications of the findings: Previous data show that high activation of LDLR and StAR was associated with embryo quality and clinical pregnancy in infertile women. Our data suggest that lovastatin is stimulated LDLR expression to enhanced pregnancy ratios of IVF patients.

Trial registration number

none

Impact of non-cystic fibrosis bronchiectasis on critically ill patients in Korea: a retrospective observational study

This study investigated the impact of bronchiectasis on patients admitted to the intensive care unit (ICU) at a hospital in Korea. Patients with bronchiectasis were diagnosed using results of chest computed tomography performed before ICU admission. The severity of bronchiectasis was based on the number of affected lobes, and patients with ≥ 3 bronchiectatic lobes were classified into the severe bronchiectasis group. Overall, 823 patients were enrolled. The mean age was 66.0 ± 13.9 years, and 63.4% were men. Bronchiectasis and severe bronchiectasis were present in 148 (18.0%) and 108 (13.1%) patients, respectively. The increase in the number of bronchiectatic lobes was related to the rise in ICU mortality (P for trend = 0.012) and in-hospital mortality (P for trend = 0.004). Patients with severe bronchiectasis had higher odds for 28-day mortality [odds ratio (OR) 1.122, 95% confidence interval (CI) 1.024–1.230], ICU mortality (OR 1.119, 95% CI 1.023–1.223), and in-hospital mortality (OR 1.208, 95% CI 1.092–1.337). The severe bronchiectasis group showed lower overall survival (log-rank P < 0.001), and the adjusted hazard ratio was 1.535 (95% CI 1.178–2.001). Severe bronchiectasis had a negative impact on all-cause mortality during ICU and hospital stays, resulting in a lower survival rate.

The Association between Behavioral Risk Factors and Nontuberculous Mycobacterial Pulmonary Disease

PURPOSE

We aimed to determine the relationship between environmental exposure and nontuberculous mycobacterial pulmonary disease (NTM-PD) in Korea.

MATERIALS AND METHODS

A group of 150 patients with NTM-PD and a control group of 217 patients with other respiratory diseases were prospectively enrolled between June 2018 and December 2020 in Seoul, Korea. They were surveyed with a standardized questionnaire, and their medical records were reviewed. Odds ratio (OR) and 95% confidence intervals (CI) were calculated with multivariate logistic regression analysis.

RESULTS

The mean ages of the NTM-PD and control groups were similar (63.8±9.2 years vs. 63.5±10.0 years; p=0.737), and most patients were female (76.0% vs. 68.7%; p=0.157) and nonsmokers (82.0% vs. 72.8%; p=0.021). Mycobacterium avium (49.3%) was the most commonly identified strain among NTM-PD patients, followed by M. intracellulare (32.0%) and M. abscessus subspecies massiliense (12.7%). There were no differences in housing type or frequency of soil- or pet-related exposure between the case and the control groups. However, in subgroup analysis excluding patients with M. intracellulare infection, more case patients frequently visited public baths ≥1 time/week (35.3% vs. 19.4%, p=0.003); this remained significant after multivariate analysis (OR, 2.84; 95% CI, 1.58-5.17).

CONCLUSION

Frequent exposure to water at public baths might affect the odds of contracting NTM-PD, excluding individuals infected with M. intracellulare strains.

Diagnostic test accuracy of 18F-FDG PET/CT for prediction of programmed death ligand 1 (PD-L1) expression in solid tumours: a meta-analysis

AIM

To investigate the predictive value of integrated 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron-emission tomography/computed tomography (PET/CT) for the prediction of programmed death ligand 1 (PD-L1) expression in solid tumours via a systematic review and meta-analysis.

MATERIALS AND METHODS

The PubMed, Cochrane, and EMBASE databases, from the earliest available date of indexing through 31 October 2020, were searched for studies evaluating the diagnostic performance of ¹⁸F-FDG PET/CT for prediction of PD-L1 expression in solid tumours other than lung cancer.

RESULTS

Across seven studies (473 patients), the pooled sensitivity for ¹⁸F-FDG PET/CT was 0.75 (95% confidence interval [CI]: 0.65-0.82) without heterogeneity (I² = 47.2, p=0.08) and a pooled specificity of 0.73 (95% CI: 0.64-0.81) with heterogeneity (I² = 53.8, p=0.04). Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 2.8 (95% CI: 2.1-3.7) and negative likelihood ratio (LR-) of 0.35 (95% CI: 0.26-0.47). The pooled diagnostic odds ratio (DOR) was 8 (95% CI: 5-13). Hierarchical summary receiver operating characteristic (ROC) curve and indicates that the area under the curve was 0.80 (95% CI: 0.77-0.84).

CONCLUSION

The current meta-analysis showed a moderate sensitivity and specificity of ¹⁸F-FDG PET/CT for the prediction of PD-L1 expression in solid tumours. At present, the literature regarding the use of ¹⁸F-FDG PET/CT for the prediction of PD-L1 expression in solid tumours still limited; thus, further large multicentre studies would be necessary to substantiate the diagnostic accuracy of ¹⁸F-FDG PET/CT for prediction of PD-L1 expression in solid tumours.

Effectiveness of pirfenidone in idiopathic pulmonary fibrosis according to the autoantibody status: a retrospective cohort study

Background

Pirfenidone is an anti-fibrotic agent shown to slow the progression of idiopathic pulmonary fibrosis (IPF). However, its effectiveness in association with serological autoimmune features in IPF remains unclear.

Methods

We retrospectively reviewed the medical records of patients with IPF treated at a tertiary care hospital in South Korea. The autoantibody status was defined as positive if we detected autoantibodies meeting the serological domain criteria for interstitial pneumonia with autoimmune features or anti-neutrophil cytoplasmic antibodies.

Results

We included 142 patients with IPF treated with pirfenidone for over six months (93 were autoantibody-positive and 49 were autoantibody-negative). The mean age was 69.5 ± 7.3 years, and 77.5% of the patients were male. The adjusted mean changes over one year were − 34.4 and − 112.2 mL (p = 0.168) in forced vital capacity (FVC), and − 0.53 and − 0.72 mL/mmHg/min (p = 0.356) in the lungs diffusion capacity for carbon monoxide (DL_CO) in the autoantibody-negative and autoantibody-positive groups, respectively.

Conclusions

Reductions in FVC and DL_CO were similar in autoantibody-positive and autoantibody-negative patients with IPF treated with pirfenidone. Pirfenidone is effective in attenuating the progression of IPF, irrespective of the autoantibody status.