Factors Affecting Life-Sustaining Treatment Decisions and Changes in Clinical Practice after Enforcement of the Life-Sustaining Treatment Decision (LST) Act: A Tertiary Hospital Experience in Korea.

Purpose: In Korea, the act on hospice and palliative care and decisions on life-sustaining treatment (LST) was implemented on February 4, 2018. We aimed to investigate relevant factors and clinical changes associated with LST decisions after law enforcement. Materials and Methods: This single-center retrospective study included patients who completed LST documents using legal forms at Asan Medical Center from February 5, 2018, to June 30, 2020. Results: 5896 patients completed LST documents, of which 2704 (45.8%) signed the documents in person, while family members of 3,192 (54%) wrote the documents on behalf of the patients. Comparing first year and following year of implementation of the act, the self-documentation rate increased (43.9% to 47.2%, p=0.014). Moreover, the number of LST decisions made during or after ICU admission decreased (37.8% vs. 35.2%, p=0.045), and the completion rate of LST documents during chemotherapy increased (6.6% vs. 8.9%, p=0.001). In multivariate analysis, age < 65 (OR, 1.724; 95% CI, 1.538-1.933; p<0.001), unmarried status (OR, 1.309; 95% CI, 1.097-1.561; p=0.003), palliative care consultation (OR, 1.538; 95% CI, 1.340-1.765; p<0.001), malignancy (OR, 1.864; 95% CI, 1.628-2.133; p<0.001), and changes in timing on the first year versus following year (OR, 1.124, 95% CI, 1.003-1.260, p=0.045) were related to a higher self-documentation rate. Conclusion: Age < 65, unmarried status, malignancy, and referral to a palliative care team were associated with patients making LST decisions themselves. Furthermore, the subject and timing of LST decisions have changed with the LST act.

The association of arterial partial oxygen pressure with mortality in critically ill sepsis patients: a nationwide observational cohort study.

BACKGROUND: Although several trials were conducted to optimize the oxygenation range in intensive care unit (ICU) patients, no studies have yet reached a universal recommendation on the optimal a partial pressure of oxygen in arterial blood (PaO2) range in patients with sepsis. Our aim was to evaluate whether a relatively high arterial oxygen tension is associated with longer survival in sepsis patients compared with conservative arterial oxygen tension. METHODS: From the Korean Sepsis Alliance nationwide registry, patients treated with liberal PaO2 (PaO2 ≥ 80 mm Hg) were 1:1 matched with those treated with conservative PaO2 (PaO2 < 80 mm Hg) over the first three days after ICU admission according to the propensity score. The primary outcome was 28-day mortality. RESULTS: The median values of PaO2 over the first three ICU days in 1211 liberal and 1211 conservative PaO2 groups were, respectively, 107.2 (92.0-134.0) and 84.4 (71.2-112.0) in day 1110.0 (93.4-132.0) and 80.0 (71.0-100.0) in day 2, and 106.0 (91.9-127.4) and 78.0 (69.0-94.5) in day 3 (all p-values < 0.001). The liberal PaO2 group showed a lower likelihood of death at day 28 (14.9%; hazard ratio [HR], 0.79; 95% confidence interval [CI] 0.65-0.96; p-value = 0.017). ICU (HR, 0.80; 95% CI 0.67-0.96; p-value = 0.019) and hospital mortalities (HR, 0.84; 95% CI 0.73-0.97; p-value = 0.020) were lower in the liberal PaO2 group. On ICU days 2 (p-value = 0.007) and 3 (p-value < 0.001), but not ICU day 1, hyperoxia was associated with better prognosis compared with conservative oxygenation., with the lowest 28-day mortality, especially at PaO2 of around 100 mm Hg. CONCLUSIONS: In critically ill patients with sepsis, higher PaO2 (≥ 80 mm Hg) during the first three ICU days was associated with a lower 28-day mortality compared with conservative PaO2.

Severe Human Parainfluenza Virus Community- and Healthcare-Acquired Pneumonia in Adults at Tertiary Hospital, Seoul, South Korea, 2010-2019.

The characteristics of severe human parainfluenza virus (HPIV)-associated pneumonia in adults have not been well evaluated. We investigated epidemiologic and clinical characteristics of 143 patients with severe HPIV-associated pneumonia during 2010-2019. HPIV was the most common cause (25.2%) of severe virus-associated hospital-acquired pneumonia and the third most common cause (15.7%) of severe virus-associated community-acquired pneumonia. Hematologic malignancy (35.0%), diabetes mellitus (23.8%), and structural lung disease (21.0%) were common underlying conditions. Co-infections occurred in 54.5% of patients admitted to an intensive care unit. The 90-day mortality rate for HPIV-associated pneumonia was comparable to that for severe influenza virus-associated pneumonia (55.2% vs. 48.4%; p = 0.22). Ribavirin treatment was not associated with lower mortality rates. Fungal co-infections were associated with 82.4% of deaths. Clinicians should consider the possibility of pathogenic co-infections in patients with HPIV-associated pneumonia. Contact precautions and environmental cleaning are crucial to prevent HPIV transmission in hospital settings.

Prognosis of mechanically ventilated patients with COVID-19 after failure of high-flow nasal cannula: a retrospective cohort study.

BACKGROUND: There is an argument whether the delayed intubation aggravate the respiratory failure in Acute respiratory distress syndrome (ARDS) patients with coronavirus disease 2019 (COVID-19). We aimed to investigate the effect of high-flow nasal cannula (HFNC) failure before mechanical ventilation on clinical outcomes in mechanically ventilated patients with COVID-19. METHODS: This retrospective cohort study included mechanically ventilated patients who were diagnosed with COVID-19 and admitted to the intensive care unit (ICU) between February 2020 and December 2021 at Asan Medical Center. The patients were divided into HFNC failure (HFNC-F) and mechanical ventilation (MV) groups according to the use of HFNC before MV. The primary outcome of this study was to compare the worst values of ventilator parameters from day 1 to day 3 after mechanical ventilation between the two groups. RESULTS: Overall, 158 mechanically ventilated patients with COVID-19 were included in this study: 107 patients (67.7%) in the HFNC-F group and 51 (32.3%) in the MV group. The two groups had similar profiles of ventilator parameter from day 1 to day 3 after mechanical ventilation, except of dynamic compliance on day 3 (28.38 mL/cmH2O in MV vs. 30.67 mL/H2O in HFNC-F, p = 0.032). In addition, the HFNC-F group (5.6%) had a lower rate of ECMO at 28 days than the MV group (17.6%), even after adjustment (adjusted hazard ratio, 0.30; 95% confidence interval, 0.11-0.83; p = 0.045). CONCLUSIONS: Among mechanically ventilated COVID-19 patients, HFNC failure before mechanical ventilation was not associated with deterioration of respiratory failure.

Risk Factors for the Mortality of Patients With Coronavirus Disease 2019 Requiring Extracorporeal Membrane Oxygenation in a Non-Centralized Setting: A Nationwide Study.

BACKGROUND: Limited data are available on the mortality rates of patients receiving extracorporeal membrane oxygenation (ECMO) support for coronavirus disease 2019 (COVID-19). We aimed to analyze the relationship between COVID-19 and clinical outcomes for patients receiving ECMO. METHODS: We retrospectively investigated patients with COVID-19 pneumonia requiring ECMO in 19 hospitals across Korea from January 1, 2020 to August 31, 2021. The primary outcome was the 90-day mortality after ECMO initiation. We performed multivariate analysis using a logistic regression model to estimate the odds ratio (OR) of 90-day mortality. Survival differences were analyzed using the Kaplan-Meier (KM) method. RESULTS: Of 127 patients with COVID-19 pneumonia who received ECMO, 70 patients (55.1%) died within 90 days of ECMO initiation. The median age was 64 years, and 63% of patients were male. The incidence of ECMO was increased with age but was decreased after 70 years of age. However, the survival rate was decreased linearly with age. In multivariate analysis, age (OR, 1.048; 95% confidence interval [CI], 1.010-1.089; P = 0.014) and receipt of continuous renal replacement therapy (CRRT) (OR, 3.069; 95% CI, 1.312-7.180; P = 0.010) were significantly associated with an increased risk of 90-day mortality. KM curves showed significant differences in survival between groups according to age (65 years) (log-rank P = 0.021) and receipt of CRRT (log-rank P = 0.004). CONCLUSION: Older age and receipt of CRRT were associated with higher mortality rates among patients with COVID-19 who received ECMO.

Age Distribution and Clinical Results of Critically Ill Patients above 65-Year-Old in an Aging Society: A Retrospective Cohort Study.

BACKGROUND: Increasing age has been observed among patients admitted to the intensive care unit (ICU). Age traditionally considered a risk factor for ICU mortality. We investigated how the epidemiology and clinical outcomes of older ICU patients have changed over a decade. METHODS: We analyzed patients admitted to the ICU at a university hospital in Seoul, South Korea. We defined patients aged 65 and older as older patients. Changes in age groups and mortality risk factors over the study period were analyzed. RESULTS: A total of 32,322 patients were enrolled who aged ≥65 years admitted to the ICUs between January 1, 2007, and December 31, 2017. Patients aged ≥65 years accounted for 35% and of these, the older (O, 65 to 74 years) comprised 19,630 (66.5%), very older (VO, 75 to 84 years) group 8,573 (29.1%), and very very older (VVO, ≥85 years) group 1,300 (4.4%). The mean age of ICU patients over the study period increased (71.9±5.6 years in 2007 vs. 73.2±6.1 years in 2017) and the proportions of the VO and VVO group both increased. Over the period, the proportion of female increased (37.9% in 2007 vs. 43.3% in 2017), and increased ICU admissions for medical reasons (39.7% in 2007 vs. 40.2% in 2017). In-hospital mortality declined across all older age groups, from 10.3% in 2007 to 7.6% in 2017. Hospital length of stay (LOS) decreased in all groups, but ICU LOS decreased only in the O and VO groups. CONCLUSION: The study indicates a changing demographic in ICUs with an increase in older patients, and suggests a need for customized ICU treatment strategies and resources.

Automatic adjustment of oxygen concentration during high-flow nasal cannula treatment using a targeted SpO2 feedback system.

AIM: To test whether targeted SpO2 feedback (TSF), an automatic control system for fraction of inspired oxygen (FiO2), achieves more time in the optimal SpO2 range and/or reduces the frequency of manual adjustments to administered FiO2 compared with conventional manual titration in patients with hypoxia on high-flow nasal cannula (HFNC) therapy. STUDY DESIGN: Twenty-two patients were recruited from two hospitals. For each, two sessions of manual mode and two sessions of TSF were applied in a random order, each session lasting 2 h. The target SpO2 on TSF was 95%. Oxygen monitoring levels were classified into four SpO2 ranges: hypoxia (≤ 89%), borderline (90%-93%), optimal (94%-96%) and hyperoxia (≥ 97%). The two modes were compared based on the proportion of time spent in each SpO2 range and the number of manual FiO2 adjustments. RESULTS: The proportion of time in the optimal SpO2 range was 20.5% under manual titration mode and 65.4% under TSF (p < .01). The proportions of time in the hypoxia range were 1.1% and 0.4%, respectively (p = .31), in the borderline range 4.7% and 3.5%, respectively (p = .54), and in the hyperoxia range 73.7% and 30.7%, respectively (p < .01). There were statistical differences only in the optimal and hyperoxia SpO2 ranges. During the 8 h, the frequency of manual FiO2 adjustment was 0.7 times for the manual mode and 0.2 times for TSF, showing no statistically significant difference (p = 0.076). CONCLUSION: Compared with manual titration, TSF achieved greater time of the optimal SpO2 and less time of hyperoxia during HFNC. The frequency of manual adjustments on TSF tended to be less than on manual titration mode. RELEVANCE TO CLINICAL PRACTICE: Automatic closed-loop algorithm FiO2 monitoring systems can achieve better oxygen treatments than conventional monitoring and may reduce nurse workloads. In the era of pandemic respiratory diseases, this system can also facilitate contactless SpO2 monitoring during HFNC therapy.

Highly secreted tryptophanyl tRNA synthetase 1 as a potential theranostic target for hypercytokinemic severe sepsis.

Despite intensive clinical and scientific efforts, the mortality rate of sepsis remains high due to the lack of precise biomarkers for patient stratification and therapeutic guidance. Secreted human tryptophanyl-tRNA synthetase 1 (WARS1), an endogenous ligand for Toll-like receptor (TLR) 2 and TLR4 against infection, activates the genes that signify the hyperinflammatory sepsis phenotype. High plasma WARS1 levels stratified the early death of critically ill patients with sepsis, along with elevated levels of cytokines, chemokines, and lactate, as well as increased numbers of absolute neutrophils and monocytes, and higher Sequential Organ Failure Assessment (SOFA) scores. These symptoms were recapitulated in severely ill septic mice with hypercytokinemia. Further, injection of WARS1 into mildly septic mice worsened morbidity and mortality. We created an anti-human WARS1-neutralizing antibody that suppresses proinflammatory cytokine expression in marmosets with endotoxemia. Administration of this antibody into severe septic mice attenuated cytokine storm, organ failure, and early mortality. With antibiotics, the antibody almost completely prevented fatalities. These data imply that blood-circulating WARS1-guided anti-WARS1 therapy may provide a novel theranostic strategy for life-threatening systemic hyperinflammatory sepsis.

Clinical impact of pre-existing acute exacerbation in patients with interstitial lung disease who underwent lung transplantation.

BACKGROUND: Acute exacerbation of interstitial lung disease (AE-ILD) significantly impacts prognosis, leading to high mortality rates. Although lung transplantation is a life-saving treatment for selected patients with ILD, its outcomes in those presenting with AE-ILD have yielded conflicting results compared with those with stable ILD. This study aims to investigate the impact of pre-existing AE on the prognosis of ILD patients who underwent lung transplantation. METHOD: We conducted a single-center retrospective study by reviewing the medical records of 108 patients who underwent lung transplantation for predisposing ILD at Asan Medical Center, Seoul, South Korea, between 2008 and 2022. The primary objective was to compare the survival of patients with AE-ILD at the time of transplantation with those without AE-ILD. RESULTS: Among the 108 patients, 52 (48.1%) experienced AE-ILD at the time of lung transplantation, and 81 (75.0%) required pre-transplant mechanical ventilation. Although the type of ILD (IPF vs. non-IPF ILD) did not affect clinical outcomes after transplantation, AE-ILD was associated with worse survival outcomes. The survival probabilities at 90 days, 1 year, and 3 years post-transplant for patients with AE-ILD were 86.5%, 73.1%, and 60.1%, respectively, while those for patients without AE-ILD were higher, at 92.9%, 83.9%, and 79.6% (p = 0.032). In the multivariable analysis, pre-existing AE was an independent prognostic factor for mortality in ILD patients who underwent lung transplantation. CONCLUSIONS: Although lung transplantation remains an effective treatment option for ILD patients with pre-existing AE, careful consideration is needed, especially in patients requiring pre-transplant mechanical respiratory support.

Pseudomonas aeruginosa-Derived DnaJ Induces the Expression of IL-1ß by Engaging the Interplay of p38 and ERK Signaling Pathways in Macrophages.

As members of pathogen-associated molecular patterns, bacterial heat shock proteins (HSPs) are widely recognized for their role in initiating innate immune responses. This study aimed to examine the impact of DnaJ, a homolog of HSP40 derived from Pseudomonas aeruginosa (P. aeruginosa), on the regulation of IL-1ß expression in macrophages. We demonstrated that DnaJ modulates macrophages to secrete IL-1ß by activating NF-κB and MAPK signaling pathways. Specifically, ERK was identified as a positive mediator for IL-1ß expression, while p38 acted as a negative mediator. These results suggest that the reciprocal actions of these two crucial MAPKs play a vital role in controlling IL-1ß expression. Additionally, the reciprocal actions of MAPKs were found to regulate the activation of inflammasome-related molecules, including vimentin, NLRP3, caspase-1, and GSDMD. Furthermore, our investigation explored the involvement of CD91/CD40 in ERK signaling-mediated IL-1ß production from DnaJ-treated macrophages. These findings emphasize the importance of understanding the signaling mechanisms underlying IL-1ß induction and suggest the potential utility of DnaJ as an adjuvant for stimulating inflammasome activation.

Extended Versus Intermittent Meropenem Infusion in the Treatment of Nosocomial Pneumonia: A Retrospective Single-Center Study.

The efficacy of extended meropenem infusions in patients with nosocomial pneumonia is not well defined. Therefore, we compared the clinical outcomes of extended versus intermittent meropenem infusions in the treatment of nosocomial pneumonia. We performed a retrospective analysis of extended versus intermittent meropenem infusions in adult patients who had been treated for nosocomial pneumonia at a medical ICU between 1 May 2018 and 30 April 2020. The primary outcome was mortality at 14 days. Overall, 64 patients who underwent an extended infusion and 97 with an intermittent infusion were included in this study. At 14 days, 10 (15.6%) patients in the extended group and 22 (22.7%) in the intermittent group had died (adjusted hazard ratio (HR), 0.55; 95% confidence interval (CI): 0.23-1.31; p = 0.174). In the subgroup analysis, significant differences in mortality at day 14 were observed in patients following empirical treatment with meropenem (adjusted HR, 0.17; 95% CI: 0.03-0.96; p = 0.045) and in Gram-negative pathogens identified by blood or sputum cultures (adjusted HR, 0.01; 95% CI: 0.01-0.83; p = 0.033). Extended infusion of meropenem compared with intermittent infusion as a treatment option for nosocomial pneumonia may have a potential advantage in specific populations.

Impact of a cumulative positive fluid balance during the first three ICU days in patients with sepsis: a propensity score-matched cohort study.

BACKGROUND: The optimal strategy for fluid management during the first few days of ICU in sepsis patients remains controversial. We aimed to investigate the impact of cumulative fluid balance during the first three days of ICU on the mortality of patients with sepsis. METHODS: This study analyzed prospectively collected data from the Korean Sepsis Alliance Database, which registered 11,981 sepsis patients from 20 hospitals. We selected three propensity score-matched cohorts consisting of patients with a negative or positive cumulative fluid balance during the first three ICU days: from ICU admission to the first midnight as the D1 cohort, until the second midnight as the D2 cohort, and until the third midnight as the D3 cohort. The propensity score for fluid balance was calculated using covariates including the amount of fluid output during the first three ICU days. The primary outcome was mortality at day 28 in the ICU. RESULTS: From a total of 11,981 patients, 2516 patients were included for propensity score matching. After matching in a 1:1 ratio, there were 483, 373, and 392 matched pairs of patients assigned to the D1, D2, and D3 cohorts, respectively. In the D1 cohort, there were no significant differences in mortality at day 28 (hazard ratio [HR], 1.17; 95% confidence interval [CI] 0.85-1.60; P = 0.354) between the two groups. The positive fluid groups in both the D2 (HR, 2.13; 95% CI 1.48-3.06; P < 0.001) and D3 (HR, 1.56; 95% CI 1.10-2.22; P = 0.012) cohorts had significantly higher mortality rates than the negative fluid groups. CONCLUSIONS: In patients with sepsis, a positive fluid balance on the first ICU day was not associated with mortality at day 28. In contrast, cumulative positive fluid balances on the second and third ICU days were associated with higher mortality at day 28.

False positive Aspergillus galactomannan assay results caused by specific parenteral nutrition.

In September 2022, the proportion of clinically false positive results with high index values for the galactomannan (GM) assay increased dramatically in our hospital and remained high until November 2022. We aimed to identify the possible causative agent that led to the dramatic increase in false positivity in GM assay. A case-control-control study was conducted, and patients admitted to two intensive care units between September and November 2022 were included. We defined each time point at which the GM assay was conducted in a patient as an episode and classified episodes into strong-positive (≥10.0 index; case), positive (control), and negative (<0.5 index; control) groups. We compared the medications administered in three groups and measured GM levels in relevant medications, including parenteral nutrition (PN). In total, 118 episodes in 33 patients were classified into three groups. There were 46 negative, 23 positive, and 49 strong-positive episodes, and there was a significant difference in the use of Winuf® PNs (P < .001) between the three groups. Forty episodes (82%) in the strong-positive group received Winuf®, compared with three (6.5%) in the negative group and one (4.3%) in the positive group (P < .001). All samples of Winuf® PNs used in the five patients whose GM results were repeatedly strong-positive were strongly positive for GM. False positivity in GM assay can be caused by the administration of specific PNs. A thorough investigation of prescribed medications should be considered when there is an abrupt increase in the proportion of strong-positive or positive GM results.

Contributed Session II: Immune cell speed changes over 5 orders of magnitude in response to inflammation in the retina.

Inflammation in vascularized tissues is mediated by circulating immune cells that are recruited to damaged tissue. Immune cells undergo dramatic changes in speed and motility indicating the severity and staging of inflammation. Here, we characterize the spectrum of retinal leukocyte kinetics in response to an acute inflammatory stimulus using adaptive optics scanning light ophthalmoscopy (AOSLO) in living mice. C57BL/6J male mice were injected intravitreally with 1 µL lipopolysaccharide (LPS) and imaged at 6, 24 and 72 hours after LPS injection using phase contrast and fluorescence AOSLO. Speed of circulating leukocytes (n= 286 cells, 2 mice) was measured with 15kHz point-scan imaging using automated approach (Joseph et al. 2019). Rolling leukocytes (n=300 cells, 5 mice, 6 hrs after LPS) and extravasated cells (n=92 cells, 8 mice) were visualized with time-lapse imaging and manually tracked using ImageJ. Using our custom AOSLO, we observed leukocyte speeds spanning 5 orders of magnitude in the living retina. The fastest speeds were the circulating leukocytes (13,257.37 ± 7,086.41 µm/s). After LPS, leukocytes roll along the venular wall, where cell speed was 1000x slower (11.45 ± 7.45 µm/s.) When immune cells extravasated into the tissue, cell speed dropped further by 100x (0.3 ± 0.15 µm/s). Observed leukocyte speeds cluster around three distinct velocity bands that stratify the unique and purposeful behavior of these cells as they progress through the inflammatory cascade.

A targeted metabolomics approach for sepsis-induced ARDS and its subphenotypes.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is etiologically and clinically a heterogeneous disease. Its diagnostic characteristics and subtype classification, and the application of these features to treatment, have been of considerable interest. Metabolomics is becoming important for identifying ARDS biology and distinguishing its subtypes. This study aimed to identify metabolites that could distinguish sepsis-induced ARDS patients from non-ARDS controls, using a targeted metabolomics approach, and to identify whether sepsis-induced direct and sepsis-induced indirect ARDS are metabolically distinct groups, and if so, confirm their metabolites and associated pathways. METHODS: This study retrospectively analyzed 54 samples of ARDS patients from a sepsis registry that was prospectively collected from March 2011 to February 2018, along with 30 non-ARDS controls. The cohort was divided into direct and indirect ARDS. Metabolite concentrations of five analyte classes (energy metabolism, free fatty acids, amino acids, phospholipids, sphingolipids) were measured using liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry by targeted metabolomics. RESULTS: In total, 186 metabolites were detected. Among them, 102 metabolites could differentiate sepsis-induced ARDS patients from the non-ARDS controls, while 14 metabolites could discriminate sepsis-induced ARDS subphenotypes. Using partial least-squares discriminant analysis, we showed that sepsis-induced ARDS patients were metabolically distinct from the non-ARDS controls. The main distinguishing metabolites were lysophosphatidylethanolamine (lysoPE) plasmalogen, PE plasmalogens, and phosphatidylcholines (PCs). Sepsis-induced direct and indirect ARDS were also metabolically distinct subgroups, with differences in lysoPCs. Glycerophospholipid and sphingolipid metabolism were the most significant metabolic pathways involved in sepsis-induced ARDS biology and in sepsis-induced direct/indirect ARDS, respectively. CONCLUSION: Our study demonstrated a marked difference in metabolic patterns between sepsis-induced ARDS patients and non-ARDS controls, and between sepsis-induced direct and indirect ARDS subpheonotypes. The identified metabolites and pathways can provide clues relevant to the diagnosis and treatment of individuals with ARDS.

Epidemiology and Characteristics of Respiratory Syncytial Virus Pneumonia in Critically Ill Adults.

Background: Severe respiratory syncytial virus (RSV)-associated pneumonia in adults has rarely been addressed. We investigated the burden and clinical characteristics of severe RSV-associated pneumonia in critically ill adult patients. Methods: We analyzed a prospective cohort of 2865 adults with severe pneumonia who were admitted to the intensive care unit in a 2700-bed tertiary care hospital from 2010 to 2019. The epidemiology, characteristics, and outcomes of 92 cases of severe RSV-associated pneumonia and 163 cases of severe influenza virus (IFV)-associated pneumonia were compared. Results: Of 1589 cases of severe community-acquired pneumonia, the incidence of RSV-associated pneumonia was less than half that of IFV-associated pneumonia (3.4% vs 8.1%). However, among 1276 cases of severe hospital-acquired pneumonia (HAP), there were slightly more cases of RSV-associated than IFV-associated pneumonia (3.8% vs 3.5%). During the 9 epidemic seasons, RSV-A (5 seasons) and RSV-B (4 seasons) predominated alternately. Structural lung disease, diabetes mellitus, and malignancy were common underlying diseases in both groups. Immunocompromise (57.6% vs 34.4%; P < .001) and hospital acquisition (47.8% vs 23.9%; P < .001) were significantly more common in the RSV group. Coinfection with Streptococcus pneumoniae (3.3% vs 9.8%; P = .08) and methicillin-susceptible Staphylococcus aureus (1.1% vs 6.8%; P = .06) tended to be less frequent in the RSV group. The 90-day mortality was high in both groups (39.1% vs 40.5%; P = .89). Conclusions: RSV infection was associated with substantial morbidity and mortality in critically ill adult patients, similar to IFV. The relatively higher incidence of RSV in severe HAP suggests that the transmissibility of RSV can exceed that of IFV in a hospital setting.

Gut microbiota alterations in critically Ill patients with carbapenem-resistant Enterobacteriaceae colonization: A clinical analysis.

Background: Carbapenem-resistant Enterobacteriaceae (CRE) are an emerging concern for global health and are associated with high morbidity and mortality in critically ill patients. Risk factors for CRE acquisition include broad-spectrum antibiotic use and microbiota dysbiosis in critically ill patients. Therefore, we evaluated the alteration of the intestinal microbiota associated with CRE colonization in critically ill patients. Methods: Fecal samples of 41 patients who were diagnosed with septic shock or respiratory failure were collected after their admission to the intensive care unit (ICU). The gut microbiota profile determined using 16S rRNA gene sequencing and quantitative measurement of fecal short-chain fatty acids were evaluated in CRE-positive (n = 9) and CRE negative (n = 32) patients. The analysis of bacterial metabolic abundance to identify an association between CRE acquisition and metabolic pathway was performed. Results: CRE carriers showed a significantly increased proportion of the phyla Proteobacteria and decreased numbers of the phyla Bacteroidetes as compared to the CRE non-carriers. Linear discriminant analysis (LDA) with linear discriminant effect size showed that the genera Erwinia, Citrobacter, Klebsiella, Cronobacter, Kluyvera, Dysgomonas, Pantoea, and Alistipes had an upper 2 LDA score in CRE carriers. The alpha-diversity indices were significantly decreased in CRE carriers, and beta-diversity analysis demonstrated that the two groups were clustered significantly apart. Among short-chain fatty acids, the levels of isobutyric acid and valeric acid were significantly decreased in CRE carriers. Furthermore, the PICRUSt-predicted metabolic pathways revealed significant differences in five features, including ATP-binding cassette transporters, phosphotransferase systems, sphingolipid metabolism, other glycan degradation, and microbial metabolism, in diverse environments between the two groups. Conclusion: Critically ill patients with CRE have a distinctive gut microbiota composition and community structure, altered short-chain fatty acid production and changes in the metabolic pathways. Further studies are needed to determine whether amino acids supplementation improves microbiota dysbiosis in patients with CRE.

Analysis of immune responses in patients with CLL after heterologous COVID-19 vaccination.

Patients with chronic lymphocytic leukemia (CLL) treated with B-cell pathway inhibitors and anti-CD20 antibodies exhibit low humoral response rates following SARS-CoV-2 vaccination. To investigate this observation, a prospective single-institution study was conducted comparing peripheral blood mononuclear cell transcriptional response with antibody and T-cell response rates following heterologous BNT162b2/ChAdOx1 vaccination of 15 patients with CLL/small lymphocytic lymphoma (SLL). Two-dose antibody response rate was 40%, increasing to 53% after booster. Patients on Bruton tyrosine kinase inhibitor (BTKi) and venetoclax ± anti-CD20 antibody within 12 months of vaccination responded inferiorly compared with those under BTKi alone. The 2-dose-T-cell response rate was 80%, which increased to 93% after the booster dose. Key transcriptional findings were that interferon-mediated signaling activation including activation of the JAK-STAT pathway generally occurred within days of vaccination, but was independent from the magnitude of the antibody response. Increasing counts of IGHV genes were associated with B-cell reconstitution and improved humoral response rate in the vaccinated patients. T-cell responses in patients with CLL appeared independent of treatment status, whereas higher humoral response rate was associated with BTKi treatment and B-cell reconstitution. Boosting was particularly effective when intrinsic immune status was improved by CLL treatment. Limitations included studying a relatively small cohort, with different treatments and vaccination schedules.

Predictors of early hospital readmission in patients receiving home mechanical ventilation.

BACKGROUND: Although the proportion of patients with chronic respiratory failure requiring home mechanical ventilation (HMV) is increasing, hospital readmissions in these patients are also increasing. OBJECTIVE: We investigated the factors for early readmission in patients receiving HMV. METHODS: We retrospectively analyzed the data of adult patients readmitted to the hospital within a year who first received HMV and were discharged from the Asan Medical Center between March 2014 and February 2019. We compared the clinical characteristics at discharge before readmission between the early (readmission within 30 days) and late readmission groups (readmission between day 31 and 1 year) and investigated the clinical characteristics and outcomes at readmission. RESULTS: Of the 116 patients identified, 36.2% had been readmitted early. The patients who received invasive HMV had a higher rate of early readmission than those who received non-invasive HMV. Pneumonia was the most common reason of readmission in the two groups. The rate of aspiration was significantly higher in the early readmission group (28.6% vs. 8.1%; P = .003). In multivariate logistic regression analysis, nasogastric tube feeding, sequelae of pneumonia or acute respiratory distress syndrome, and central nervous system disorders as causes for HMV were significantly associated with early readmission. CONCLUSION: Feeding methods and causes for HMV were associated with early readmission. Educating caregivers on respiratory care (suction and feeding methods) is important for preventing early readmission.