I. Re Heo

Background: Rapid and accurate identification of respiratory pathogens and antimicrobial resistance is essential for optimizing antimicrobial therapy in pneumonia. Conventional culture-based diagnostics are limited by delayed turnaround times and reduced sensitivity, particularly after prior antibiotic exposure. The BioFire FilmArray Pneumonia Panel enables rapid multiplex detection of respiratory pathogens and antimicrobial resistance genes directly from clinical specimens. Objective: To evaluate the diagnostic performance and clinical impact of the BioFire FilmArray Pneumonia Panel in hospitalized patients with pneumonia. Methods: We conducted a retrospective observational study comparing the diagnostic performance of the FilmArray Pneumonia Panel with conventional culture using 558 bronchoalveolar lavage and sputum specimens collected between December 2022 and December 2023. Diagnostic performance, pathogen detection, antimicrobial resistance genes, and polymicrobial detection patterns were evaluated. The clinical impact of FilmArray implementation was also assessed in 494 hospitalized patients by comparing antibiotic management and clinical outcomes between the FilmArray period and pre-implementation period (January to November 2022). Multivariable regression analyses were performed to adjust for baseline differences. Results: The FilmArray panel detected a broad spectrum of bacterial pathogens, respiratory viruses, and antimicrobial resistance genes, with a substantial proportion of specimens being culture-negative but FilmArray-positive, particularly sputum specimens. Compared with the pre-implementation period, the FilmArray period showed a significantly higher frequency of result-driven antibiotic actions (40.5% vs. 26.5%; adjusted odds ratio, 1.86; 95% confidence interval [CI], 1.24–2.79; P = 0.003) and a shorter time from microbiological result reporting to antibiotic action (adjusted mean difference, −0.59 days; 95% CI, −1.07 to −0.10; P = 0.019). Measured from specimen sampling, the interval to the antibiotic action was more than three days shorter (adjusted mean difference, −3.53 days; 95% CI, −4.08 to −2.99; P < 0.001), reflecting the faster turnaround of the panel (median, 0 vs. 3 days). Hospital length of stay was also shorter (adjusted mean difference, −1.61 days; 95% CI, −3.07 to −0.15; P = 0.031). However, total antibiotic exposure was modestly longer (adjusted mean difference, 1.86 days; 95% CI, 0.29–3.44; P = 0.021), and antibiotic de-escalation rates did not differ significantly between the two periods. Conclusions: The BioFire FilmArray Pneumonia Panel improved pathogen detection and facilitated earlier and more frequent microbiology-guided antibiotic management, and was associated with a modest reduction in hospital length of stay. However, it modestly increased overall antibiotic exposure and did not increase antibiotic de-escalation. Rapid molecular diagnostics may improve the timeliness and precision of antimicrobial therapy, but their full clinical benefit is likely to be realized only when they are used as a complementary tool alongside conventional microbiological methods and integrated within a structured antimicrobial stewardship program.

Background: Understanding of the life-sustaining treatment (LST) decisions in critically ill coronavirus disease 2019 (COVID-19) patients remains limited. This study aimed to identify factors influencing LST decisions, and compare clinical outcomes between patients with, and without, LST.Methods: This multicenter, retrospective cohort study analyzed data from 1,081 COVID-19 patients admitted to intensive care units (ICUs) across Korea from January 1, 2020, to August 31, 2021. Patients were divided into LST and non-LST groups. Demographic, clinical, and outcome data were collected and compared.Results: Of 1,081 patients, 207 (19.2 %) received LST. LST patients were older (median age: 76 years vs. 67 years, p<0.001), and had more comorbidities (85.5% vs. 70.4%, p<0.001), especially cardiovascular and chronic lung disease. They showed higher blood urea nitrogen, lower albumin, and elevated D-dimer levels (all p<0.05). ICU interventions, including mechanical ventilation (82.6% vs. 50.9%, p<0.001) and extracorporeal membrane oxygenation (ECMO) (18.8% vs. 9.8%, p<0.001), were more common. ICU and hospital mortality rates were significantly higher in LST patients (82.6% and 94.2%, respectively, p<0.001). Logistic regression identified age (odds ratio [OR], 1.054 per year; p<0.001), mechanical ventilation (OR, 2.789; p=0.002), and ECMO use (OR, 3.580; p=0.002) as independent predictors of LST.Conclusion: Age, comorbidities, and ICU interventions significantly influence LST decisions, highlighting the need for ethical and evidence-based critical care guidelines.

Background: The coronavirus disease 2019 pandemic, which emerged in 2020, disrupted healthcare systems globally, affecting tuberculosis (TB) diagnosis and reporting. This study assessed the impact of the pandemic on the incidence of TB, multidrug-resistant TB (MDR-TB), and TB-related deaths in Korea between 2016 and 2023.Methods: Data from annual reports from 2016 to 2023 were used to analyze the incidence of TB and MDR-TB, as well as TB-related deaths. Trends before and after the pandemic were compared to assess the pandemic’s impact on TB management. Key variables included age and sex-based TB incidence, MDR-TB incidence, and number of TB-related deaths.Results: From 2016 to 2023, the total number of TB cases declined from 39,245 to 19,540, while new TB cases dropped from 30,892 to 15,640, representing reductions of 50.2% and 49.4%, respectively. The most pronounced decline occurred between 2020 and 2023. Individuals ≥65 years of age consistently had the highest TB burden, although the number of cases decreased by 28.6%. MDR-TB cases declined to 399 in 2020 but subsequently rose to 551 in 2023. TB-related deaths decreased from 2,186 in 2016 to 1,322 in 2022, with most deaths occurring in individuals ≥65 years of age.Conclusions: While the incidence of TB and TB-related deaths decreased during the study period, MDR-TB exhibited an upward trend after 2020. Continued monitoring is needed to understand whether these changes were driven by pandemic-related disruptions or healthcare improvements.

Pulmonary neuroendocrine proliferations and neoplasms represent a broad spectrum of diseases, ranging from neuroendocrine cell hyperplasia and tumorlets to carcinoid tumors. Carcinoid tumorlets are most commonly located in the peripheral airways and are often incidentally detected as pulmonary micronodules on chest CT. We report the radiological, bronchoscopic, and pathological findings of a case of carcinoid tumorlets presenting as endobronchial nodules in the left main bronchus. The patient had previously undergone a left lower lobectomy five years earlier for a typical carcinoid tumor. Follow-up imaging revealed new endobronchial nodules, which were subsequently confirmed as carcinoid tumorlets through histopathologic analysis. This case highlights the rare presentation of carcinoid tumorlets in the central airways, emphasizing the importance of recognizing their potential for late recurrence and atypical localization. It underscores the necessity for physicians to be aware that pulmonary neuroendocrine tumors can recur over the long term and may present in a multicentric fashion within the disease spectrum.

Background: Acute eosinophilic pneumonia (AEP) is a rare and severe lung condition characterized by a rapid accumulation of eosinophils in the alveoli, leading to respiratory distress. This study analyzed the clinical characteristics of affected patients, aiming to shed light on the relationship between cigarette smoking and AEP.Methods: This retrospective study analyzed 17 cases of AEP, focusing on patients' smoking habits, clinical symptoms, diagnostic findings, and treatment outcomes. Data were collected from medical records, imaging studies, and bronchoalveolar lavage (BAL) findings.Results: The study cohort consisted primarily of male military personnel (94.1%), with a mean age of 20.8 years. Symptoms generally appeared approximately 2.82 days prior to hospitalization, with a mean body temperature at admission of 37.6 °C. The mean initial peripheral blood white blood cell count was 15.3×103/μL, with eosinophil percentages starting at 0.2%, peaking at a mean of 16.1%, and reaching as high as 32.4%. BAL fluid analysis showed a mean eosinophil level of 46.6%±15.1% (range, 17%–67%). In most cases, radiological examinations revealed bilateral ground-glass opacities, interlobular septal thickening, various degrees of airspace consolidation, and bilateral pleural effusions. Steroid treatment was administered to 70.5% of patients, lasting a mean of 8.3 days and resulting in significant improvements.Conclusions: These cases reinforce the strong link between cigarette smoking and AEP. Additionally, these cases demonstrate the importance of obtaining a detailed smoking history and thorough diagnostic assessments, including BAL, in order to facilitate a more rapid diagnosis and early initiation of corticosteroid treatment.

Authors’ Response: Additional Analyses of Nutritional Intake and Muscle Strength in Individuals with Airflow Limitation

Background: We investigated whether nutritional intake is associated with physical activity (PA) and handgrip strength (HGS) in individuals with airflow limitation.Methods: This study analyzed data from the 2014 and 2016 Korean National Health and Nutrition Examination Survey. We assessed total protein intake (g/day), caloric intake (kcal/day), and other nutritional intakes, using a 24-hour dietary recall questionnaire. HGS was measured three times for each hand using a digital grip strength dynamometer, and PA was assessed as health-enhancing PA. Airflow limitation was defined as a forced expiratory volume/forced vital capacity ratio of 0.7 in individuals over 40 years of age. Participants were categorized into groups based on their PA levels and HGS measurements: active aerobic PA vs. non-active aerobic PA, and normal HGS vs. low HGS.Results: Among the 622 individuals with airflow limitation, those involved in active aerobic PA and those with higher HGS had notably higher total food, calorie, water, protein, and lipid intake. The correlations between protein and caloric intake with HGS were strong (correlation coefficients=0.344 and 0.346, respectively). The forest plots show that higher intakes of food, water, calories, protein, and lipids are positively associated with active aerobic PA, while higher intakes of these nutrients are inversely associated with low HGS. However, in the multivariate logistic regression analysis, no significant associations were observed between nutritional intake and active aerobic PA or HGS.Conclusion: Nutritional intake was found to not be an independent factor associated with PA and HGS. However, the observed correlations suggest potential indirect effects that warrant further investigation.

Background: The objective of this study was to investigate whether alcohol consumption might affect the quality of life (QOL), depressive mood, and metabolic syndrome in patients with obstructive lung disease (OLD).Methods: Data were obtained from the Korean National Health and Nutrition Examination Survey from 2014 and 2016. OLD was defined as spirometry of forced expiratory volume in 1 second/forced vital capacity <0.7 in those aged more than 40 years. QOL was evaluated using the European Quality of Life Questionnaire-5D (EQ-5D) index. Patient Health Questionnaire-9 (PHQ-9) was used to assess the severity of depressive mood. Alcohol consumption was based on a history of alcohol ingestion during the previous month.Results: A total of 984 participants with OLD (695 males, 289 females, age 65.8±9.7 years) were enrolled. The EQ-5D index was significantly higher in alcohol drinkers (n=525) than in non-alcohol drinkers (n=459) (0.94±0.11 vs. 0.91±0.13, p=0.002). PHQ- 9 scores were considerably lower in alcohol drinkers than in non-alcohol drinkers (2.15±3.57 vs. 2.78±4.13, p=0.013). However, multiple logistic regression analysis showed that alcohol consumption was not associated with EQ-5D index or PHQ-9 score. Body mass index ≥25 kg/m2, triglyceride ≥150 mg/dL, high-density lipoprotein <40 mg/dL in men and <50 mg/dL in women, and blood pressure ≥130/85 mm Hg were significantly more common in alcohol drinkers than in non-alcohol drinkers (all p<0.05).Conclusion: Alcohol consumption did not change the QOL or depressive mood of OLD patients. However, metabolic syndrome-related factors were more common in alcohol drinkers than in non-alcohol drinkers.

Background/Aims: The effect of hyperammonemia on the mortality in patients with liver cirrhosis is well documented. However, little is known about the impact of hyperammonemia on mortality among intensive care unit patients without hepatic disease. We aimed to investigate factors associated with non-hepatic hyperammonemia among intensive care unit patients and to evaluate the factors related to the 7- and 90-day mortality.Methods: Between February 2016 and February 2020, 948 patients without hepatic disease who had 972 episodes of admission to the intensive care unit were retrospectively enrolled and classified as hyperammonemia grades 0 (≤ 80 µg/dL; 585 [60.2%]), 1 (≤ 160 µg/dL; 291 [29.9%]), 2 (≤ 240 µg/dL; 55 [5.7%]), and 3 (> 240 µg/dL; 41 [4.2%]). Factors associated with hyperammonemia and the 7- and 90-day mortality were evaluated by multivariate logistic regression analysis and Cox regression analysis, respectively. Kaplan-Meier survival curves for the 7- and 90-day mortality were constructed.Results: The independent risk factors for hyperammonemia were male sex (odds ratio, 1.517), age (0.984/year), acute brain failure (2.467), acute kidney injury (1.437), prothrombin time-international normalized ratio (2.272/unit), and albumin (0.694/g/dL). The 90-day mortality rate in the entire cohort was 24.3% and gradually increased with increasing hyperammonemia grade at admission (17.9%, 28.2%, 43.6%, and 61.0% in patients with grades 0, 1, 2, and 3, respectively). Additionally, non-hepatic hyperammonemia was an independent predictor of the 90- day mortality in intensive care unit patients.Conclusions: Non-hepatic hyperammonemia is common (39.8%) and associated with the 90-day mortality among intensive care unit patients.

Background and objectives: The advanced lung inflammation index (ALI) was developed to assess the degree of systemic inflammation and has an association with prognosis in patients with lung malignancy. The prognostic value of ALI has not yet been evaluated in patients with acute respiratory distress syndrome (ARDS). Materials and Methods: Between January 2014 and May 2018, patients with ARDS in the medical intensive care unit (ICU) were reviewed retrospectively. The ALI value was calculated as the (body mass index × serum albumin level)/neutrophil-lymphocyte ratio. The cut-off value for distinguishing low from high ALI was defined according to receiver-operating characteristic curve analysis. Results: A total of 164 patients were analyzed. Their median age was 73 years, and 73% was male. The main cause of ARDS was pneumonia (95.7%, 157/164). ICU and in-hospital mortality rates were 59.8% (98/164) and 64% (105/164), respectively. The 30 day mortality was 60.9% (100/164). The median ALI value in non-survivors was lower than that in survivors at 30 day (3.81 vs. 7.39, p = 0.005). In multivariate analysis, low ALI value (≤5.38) was associated with increased 30 day mortality (odds ratio, 2.944, confidence interval 1.178–7.355, p = 0.021). Conclusions: A low ALI value was associated with increased 30 day mortality in patients with ARDS.