Integrative Physiology of Pneumonia.

Pneumonia is a type of acute lower respiratory infection that is common and severe. The outcome of lower respiratory infection is determined by the degrees to which immunity is protective and inflammation is damaging. Intercellular and interorgan signaling networks coordinate these actions to fight infection and protect the tissue. Cells residing in the lung initiate and steer these responses, with additional immunity effectors recruited from the bloodstream. Responses of extrapulmonary tissues, including the liver, bone marrow, and others, are essential to resistance and resilience. Responses in the lung and extrapulmonary organs can also be counterproductive and drive acute and chronic comorbidities after respiratory infection. This review discusses cell-specific and organ-specific roles in the integrated physiological response to acute lung infection, and the mechanisms by which intercellular and interorgan signaling contribute to host defense and healthy respiratory physiology or to acute lung injury, chronic pulmonary disease, and adverse extrapulmonary sequelae. Pneumonia should no longer be perceived as simply an acute infection of the lung. Pneumonia susceptibility reflects ongoing and poorly understood chronic conditions, and pneumonia results in diverse and often persistent deleterious consequences for multiple physiological systems.

Effectiveness of Fludrocortisone Plus Hydrocortisone versus Hydrocortisone Alone in Septic Shock: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials.

Rationale: The use of hydrocortisone in adult patients with septic shock is controversial, and the effectiveness of adding fludrocortisone to hydrocortisone remains uncertain. Objectives: To assess the comparative effectiveness and safety of fludrocortisone plus hydrocortisone, hydrocortisone alone, and placebo or usual care in adults with septic shock. Methods: A systematic review and a Bayesian network meta-analysis of peer-reviewed randomized trials were conducted. The primary outcome was all-cause mortality at last follow-up. Treatment effects are presented as relative risks (RRs) with 95% credible intervals (CrIs). Placebo or usual care was the reference treatment. Measurements and Main Results: Among 7,553 references, we included 17 trials (7,688 patients). All-cause mortality at last follow-up was lowest with fludrocortisone plus hydrocortisone (RR, 0.85; 95% CrI, 0.72-0.99; 98.3% probability of superiority, moderate-certainty evidence), followed by hydrocortisone alone (RR, 0.97; 95% CrI, 0.87-1.07; 73.1% probability of superiority, low-certainty evidence). The comparison of fludrocortisone plus hydrocortisone versus hydrocortisone alone was based primarily on indirect evidence (only two trials with direct evidence). Fludrocortisone plus hydrocortisone was associated with a 12% lower risk of all-cause mortality compared with hydrocortisone alone (RR, 0.88; 95% CrI, 0.74-1.03; 94.2% probability of superiority, moderate-certainty evidence). Conclusions: In adult patients with septic shock, fludrocortisone plus hydrocortisone was associated with lower risk of all-cause mortality at last follow-up than placebo and hydrocortisone alone. The scarcity of head-to-head trials comparing fludrocortisone plus hydrocortisone versus hydrocortisone alone led our network meta-analysis to rely primarily on indirect evidence for this comparison. Although we undertook several sensitivity analyses and assessments, these findings should be considered while also acknowledging the heterogeneity of included trials.

An Update on Management of Adult Patients with Acute Respiratory Distress Syndrome: An Official American Thoracic Society Clinical Practice Guideline.

Background: This document updates previously published Clinical Practice Guidelines for the management of patients with acute respiratory distress syndrome (ARDS), incorporating new evidence addressing the use of corticosteroids, venovenous extracorporeal membrane oxygenation, neuromuscular blocking agents, and positive end-expiratory pressure (PEEP). Methods: We summarized evidence addressing four "PICO questions" (patient, intervention, comparison, and outcome). A multidisciplinary panel with expertise in ARDS used the Grading of Recommendations, Assessment, Development, and Evaluation framework to develop clinical recommendations. Results: We suggest the use of: 1) corticosteroids for patients with ARDS (conditional recommendation, moderate certainty of evidence), 2) venovenous extracorporeal membrane oxygenation in selected patients with severe ARDS (conditional recommendation, low certainty of evidence), 3) neuromuscular blockers in patients with early severe ARDS (conditional recommendation, low certainty of evidence), and 4) higher PEEP without lung recruitment maneuvers as opposed to lower PEEP in patients with moderate to severe ARDS (conditional recommendation, low to moderate certainty), and 5) we recommend against using prolonged lung recruitment maneuvers in patients with moderate to severe ARDS (strong recommendation, moderate certainty). Conclusions: We provide updated evidence-based recommendations for the management of ARDS. Individual patient and illness characteristics should be factored into clinical decision making and implementation of these recommendations while additional evidence is generated from much-needed clinical trials.

Variation in Use of Medications for Opioid Use Disorder in Critically Ill Patients Across the United States.

OBJECTIVES: To describe practice patterns surrounding the use of medications to treat opioid use disorder (MOUD) in critically ill patients. DESIGN: Retrospective, multicenter, observational study using the Premier AI Healthcare Database. SETTING: The study was conducted in U.S. ICUs. PATIENTS: Adult (≥ 18 yr old) patients with a history of opioid use disorder (OUD) admitted to an ICU between 2016 and 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 108,189 ICU patients (658 hospitals) with a history of OUD, 20,508 patients (19.0%) received MOUD. Of patients receiving MOUD, 13,745 (67.0%) received methadone, 2,950 (14.4%) received buprenorphine, and 4,227 (20.6%) received buprenorphine/naloxone. MOUD use occurred in 37.9% of patients who received invasive mechanical ventilation. The median day of MOUD initiation was hospital day 2 (interquartile range [IQR] 1-3) and the median duration of MOUD use was 4 days (IQR 2-8). MOUD use per hospital was highly variable (median 16.0%; IQR 10-24; range, 0-70.0%); admitting hospital explained 8.9% of variation in MOUD use. A primary admitting diagnosis of unintentional poisoning (aOR 0.41; 95% CI, 0.38-0.45), presence of an additional substance use disorder (aOR 0.66; 95% CI, 0.64-0.68), and factors indicating greater severity of illness were associated with reduced odds of receiving MOUD in the ICU. CONCLUSIONS: In a large multicenter, retrospective study, there was large variation in the use of MOUD among ICU patients with a history of OUD. These results inform future studies seeking to optimize the approach to MOUD use during critical illness.

A novel measure to summarize blood transfusion practice during critical illness.

BACKGROUND: Large-scale observational studies have summarized transfusion practice using traditional measures of central tendency (e.g., the mean hemoglobin concentration at the time of transfusion). However, the mean hemoglobin concentration fails to identify specific hemoglobin concentration thresholds that drive practice. In the following brief report, we propose a novel measure of "practice discontinuity" that identifies specific practice-defining hemoglobin thresholds. STUDY DESIGN AND METHODS: We used the PINC AI Database (2016-2022) to identify adult patients admitted to an intensive care unit with at least one hemoglobin concentration measurement. For each day that hemoglobin was measured, we identified whether the patient received a red blood cell transfusion using hospital charge codes. We defined the "practice discontinuity" measure as the hemoglobin concentration at which there was the largest increase in transfusion use going from a higher to an incrementally lower hemoglobin concentration. We also calculated the mean and median pretransfusion hemoglobin concentrations. RESULTS: We identified 1,298,367 patients and 4,905,839 patient-days for inclusion. RBC transfusion occurred in a total of 530,654 (10.8%) patient-days. The overall pre-transfusion mean and median hemoglobin concentrations were 8.4 and 8.0 g/dL, respectively. The practice discontinuity measure identified 7.0 g/dL as the hemoglobin concentration at which transfusion use increased the most, from 46.6% of patient-days at a concentration of 7.0 g/dL to 74.8% of patient-days at a concentration of 6.9 g/dL. DISCUSSION: We propose that future studies of red blood cell transfusion practice consider inclusion of the practice discontinuity measure to more fully summarize clinical practice.

SNAP: Supportive non-invasive ventilation for acute chest syndrome prevention for hospitalized children with sickle cell disease: Perspectives of patients, parents, and the healthcare team.

RATIONALE: Acute chest syndrome (ACS) often develops during hospitalizations for sickle cell disease (SCD) vaso-occlusive episodes and may be triggered by a combination of chest wall splinting, opioid use, hypoventilation, and atelectasis. In 2017, Boston Medical Center's general pediatric inpatient unit instituted the novel use of bi-level positive airway pressure (BiPAP) as "supportive non-invasive ventilation for ACS prevention" (SNAP) to prevent ACS and respiratory decompensation. OBJECTIVE: The goals of this qualitative study were to identify perceived benefits, harms, facilitators, and barriers to use of SNAP. METHODS: We conducted semi-structured key informant interviews at three sites with different levels of SNAP implementation (Site 1: extensive implementation; Site 2: limited implementation; Site 3: not yet implemented) regarding experiences with and/or perceptions of SNAP. Interviews and coding were guided by the Promoting Action on Research Implementation in Health Services (PARiHS) framework. RESULTS: Thirty-four participants (physicians, nurses, respiratory therapists, child life specialists, psychologists, youth with SCD, and parents) completed interviews. Major themes included: (i) participants perceive BiPAP as effective at preventing ACS, and for those with medically stable ACS, for preventing respiratory decompensation. (ii) BiPAP use is appropriate on the general pediatric inpatient unit for medically stable patients with SCD. (iii) Improving the patient experience is the most important factor to optimize acceptance of BiPAP by patients and families. CONCLUSION/FUTURE DIRECTIONS: SNAP is perceived as effective and appropriate for hospitalized pediatric patients with SCD. Improving the patient experience is the biggest challenge. These data will inform a future protocol for a multicenter hybrid effectiveness/implementation trial of SNAP.

Safety-Net Primary Care and Endocrinology Clinicians' Knowledge and Perspectives on Screening for Nonalcoholic Fatty Liver Disease: A Mixed-Methods Evaluation.

OBJECTIVE: Clinical guidelines have expanded the indications for nonalcoholic fatty liver disease (NAFLD) screening to type 2 diabetes mellitus and obesity, which are conditions common in populations who receive care in urban safety-net settings. This study aimed to evaluate safety-net primary care and endocrinology clinicians' knowledge of NAFLD, determine barriers and facilitators to screening, and examine perspectives on the use of electronic health record tools for risk assessment. METHODS: Sequential explanatory mixed methods using survey and qualitative interviews with primary care, primary care subspecialty, and endocrinology clinicians in an urban safety-net health care system. RESULTS: A total of 109 participants completed the survey (36.5% response rate), and 13 participated in interviews. Most respondents underestimated or did not know the prevalence of NAFLD (68%), did not use the recommended noninvasive tests for risk stratification (65%), and few were comfortable with screening for (27%) or managing (17%) NAFLD. Endocrinologists had greater knowledge of risk factors but lower rates of comfort and more often felt that screening was not their responsibility. The qualitative themes included the following: (1) lack of knowledge about screening, (2) concern for underdiagnosing NAFLD, (3) perception of severity impacts beliefs about screening, (4) screening should occur in primary care but is not normative practice, (5) concerns exist about benefit, (6) competing demands with a complex population hinder screening, and (7) a need for easier ways to integrate screening into practice. CONCLUSION: Knowledge gaps may hamper uptake of new guidelines for NAFLD screening in primary care and endocrinology clinics in an urban safety-net health care system. Implementation strategies focused on training and educating clinicians and informed by behavioral economics may increase screening.

The Relationship Between Hospital Capability and Mortality in Sepsis: Development of a Sepsis-Related Hospital Capability Index.

OBJECTIVES: Regionalized sepsis care could improve sepsis outcomes by facilitating the interhospital transfer of patients to higher-capability hospitals. There are no measures of sepsis capability to guide the identification of such hospitals, although hospital case volume of sepsis has been used as a proxy. We evaluated the performance of a novel hospital sepsis-related capability (SRC) index as compared with sepsis case volume. DESIGN: Principal component analysis (PCA) and retrospective cohort study. SETTING: A total of 182 New York (derivation) and 274 Florida and Massachusetts (validation) nonfederal hospitals, 2018. PATIENTS: A total of 89,069 and 139,977 adult patients (≥ 18 yr) with sepsis were directly admitted into the derivation and validation cohort hospitals, respectively. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We derived SRC scores by PCA of six hospital resource use characteristics (bed capacity, annual volumes of sepsis, major diagnostic procedures, renal replacement therapy, mechanical ventilation, and major therapeutic procedures) and classified hospitals into capability score tertiles: high, intermediate, and low. High-capability hospitals were mostly urban teaching hospitals. Compared with sepsis volume, the SRC score explained more variation in hospital-level sepsis mortality in the derivation (unadjusted coefficient of determination [ R2 ]: 0.25 vs 0.12, p < 0.001 for both) and validation (0.18 vs 0.05, p < 0.001 for both) cohorts; and demonstrated stronger correlation with outward transfer rates for sepsis in the derivation (Spearman coefficient [ r ]: 0.60 vs 0.50) and validation (0.51 vs 0.45) cohorts. Compared with low-capability hospitals, patients with sepsis directly admitted into high-capability hospitals had a greater number of acute organ dysfunctions, a higher proportion of surgical hospitalizations, and higher adjusted mortality (odds ratio [OR], 1.55; 95% CI, 1.25-1.92). In stratified analysis, worse mortality associated with higher hospital capability was only evident among patients with three or more organ dysfunctions (OR, 1.88 [1.50-2.34]). CONCLUSIONS: The SRC score has face validity for capability-based groupings of hospitals. Sepsis care may already be de facto regionalized at high-capability hospitals. Low-capability hospitals may have become more adept at treating less complicated sepsis.

Hospital Variation in Mortality and Ventilator Management among Mechanically Ventilated Patients with ARDS.

RATIONALE: Acute Respiratory Distress Syndrome (ARDS) is associated with significant mortality. Despite the mortality benefits of lung protective ventilation, adherence rates to evidence-based ventilator practice have remained low and ARDS mortality has remained high. OBJECTIVE: Determine variation in ARDS mortality and adherence to low tidal volume ventilation (LTV) across US hospitals. MATERIALS AND METHODS: We identified mechanically ventilated patients with ARDS using data from Philips eICU (2014-2015). We then used multi-variable hierarchical logistic regression models with hospital site as the random effect and patient and hospital level factors as fixed effects to assess the hospital risk adjusted mortality rate and median odds ratio for the association between mortality and hospital site. We then assessed associations between adherence to LTV (defined as 4-8 mL/kg PBW) and hospital risk adjusted mortality rates using Spearman correlation. RESULTS: Among 4441 patients admitted at 110 hospitals with ARDS, the hospital risk-adjusted mortality rate ranged from 19% to 39%, and the MOR for hospital of admission was 1.33 (95% CI 1.25-1.41). Among 3070 patients at 72 hospitals with available ventilator data, 73% of patients had a median set Vt between 4 to 8 mL/kg PBW; hospital adherence rates to LTV ranged from 13% to 95%. There was no association between hospital adherence to LTV and risk-adjusted mortality rate (spearman correlation coefficient -0.01, p = .93). Similarly, among 956 patients who started with a Vt > 8 mL/kg PBW, there was no association between the percent of patients at each hospital whose Vt was decreased to ≤ 8 mL/kg PBW and risk adjusted mortality rate (spearman correlation coefficient .05, p = .73). CONCLUSION: Risk adjusted mortality and use of LTV for patients with ARDS varied widely across hospitals. However, hospital adherence to LTV was not associated with ARDS mortality rates. Further evaluation of hospital practices associated with lower ARDS mortality are warranted.

Biomarker-Concordant Steroid Administration in Severe Coronavirus Disease-2019.

BACKGROUND: Although corticosteroids have become the standard of care for patients with coronavirus disease-2019 (COVID-19) on supplemental oxygen, there is growing evidence of differential treatment response. This study aimed to evaluate if there was an association between biomarker-concordant corticosteroid treatment and COVID-19 outcomes. METHODS: This registry-based cohort study included adult COVID-19 hospitalized patients between January 2020 and December 2021 from 109 institutions. Patients with available C-reactive protein (CRP) levels within 48 h of admission were evaluated. Those on steroids before admission, stayed in the hospital for <48 h, or were not on oxygen support were excluded. Corticosteroid treatment was biomarker-concordant if given with high baseline CRP ≥150 mg/L or withheld with low CRP (<150 mg/L) and vice-versa was considered discordant (low CRP with steroids, high CRP without steroids). Hospital mortality was the primary outcome. Sensitivity analyses were conducted using varying CRP level thresholds. The model interaction was tested to determine steroid effectiveness with increasing CRP levels. RESULTS: Corticosteroid treatment was biomarker-concordant in 1778 (49%) patients and discordant in 1835 (51%). The concordant group consisted of higher-risk patients than the discordant group. After adjusting for covariates, the odds of in-hospital mortality were significantly lower in the concordant group than the discordant (odds ratio [95% confidence interval (C.I.)] = 0.71 [0.51, 0.98]). Similarly, adjusted mortality difference was significant at the CRP thresholds of 100 and 200 mg/L (odds ratio [95% C.I.] = 0.70 [0.52, 0.95] and 0.57 [0.38, 0.85], respectively), and concordant steroid use was associated with lower need for invasive ventilation for 200 mg/L threshold (odds ratio [95% C.I.] = 0.52 [0.30, 0.91]). In contrast, no outcome benefit was observed at CRP threshold of 50. When the model interaction was tested, steroids were more effective at reducing mortality as CRP levels increased. CONCLUSION: Biomarker-concordant corticosteroid treatment was associated with lower odds of in-hospital mortality in severe COVID-19.

Discharge Disposition and Loss of Independence Among Survivors of COVID-19 Admitted to Intensive Care: Results From the SCCM Discovery Viral Infection and Respiratory Illness Universal Study (VIRUS).

OBJECTIVES: To describe incidence and risk factors of loss of previous independent living through nonhome discharge or discharge home with health assistance in survivors of intensive care unit (ICU) admission for coronavirus disease 2019 (COVID-19). DESIGN: Multicenter observational study including patients admitted to the ICU from January 2020 till June 30, 2021. HYPOTHESIS: We hypothesized that there is a high risk of nonhome discharge in patients surviving ICU admission due to COVID-19. SETTING: Data were included from 306 hospitals in 28 countries participating in the SCCM Discovery Viral Infection and Respiratory Illness Universal Study COVID-19 registry. PATIENTS: Previously independently living adult ICU survivors of COVID-19. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was nonhome discharge. Secondary outcome was the requirement of health assistance among patients who were discharged home. Out of 10 820 patients, 7101 (66%) were discharged alive; 3791 (53%) of these survivors lost their previous independent living status, out of those 2071 (29%) through nonhome discharge, and 1720 (24%) through discharge home requiring health assistance. In adjusted analyses, loss of independence on discharge among survivors was predicted by patient age ≥ 65 years (adjusted odds ratio [aOR] 2.78, 95% confidence interval [CI] 2.47-3.14, P < .0001), former and current smoking status (aOR 1.25, 95% CI 1.08-1.46, P = .003 and 1.60 (95% CI 1.18-2.16), P = .003, respectively), substance use disorder (aOR 1.52, 95% CI 1.12-2.06, P = .007), requirement for mechanical ventilation (aOR 4.17, 95% CI 3.69-4.71, P < .0001), prone positioning (aOR 1.19, 95% CI 1.03-1.38, P = .02), and requirement for extracorporeal membrane oxygenation (aOR 2.28, 95% CI 1.55-3.34, P < .0001). CONCLUSIONS: More than half of ICU survivors hospitalized for COVID-19 are unable to return to independent living status, thereby imposing a significant secondary strain on health care systems worldwide.

Coronavirus Disease 2019 in Pediatric Oncology Patients: A Matched-Cohort Analysis of the SCCM Discovery Viral Infection and Respiratory Illness Universal Study COVID-19 Registry.

BACKGROUND: There is a paucity of multicenter data describing the impact of coronavirus disease 2019 (COVID-19) on hospitalized pediatric oncology patients. Using a large, multicenter, Society of Critical Care Medicine (SCCM) Discovery Viral Infection and Respiratory Illness University Study (VIRUS) database, we aimed at assessing outcomes of COVID-19 infection in this population. METHOD: This is a matched-cohort study involving children below 18 years of age hospitalized with COVID-19 between March 2020 and January 2021. Using the VIRUS; COVID-19 Registry database, children with oncologic diseases were compared with propensity score matched (age groups, sex, race, and ethnicity) cohort of children without oncologic diseases for the prevalence of Multisystem Inflammatory Syndrome in Children (MIS-C), intensive care unit (ICU) admission, interventions, hospital, and ICU length of stay. RESULTS: The number of children in the case and control groups was 45 and 180, respectively. ICU admission rate was similar in both groups ([47.7 vs 51.7%], P =0.63). The proportion of children requiring noninvasive and invasive mechanical ventilation, and its duration were similar between groups, same as hospital mortality. Interestingly, MIS-C was significantly lower in the oncology group compared with the control (2.4 vs 24.6%; P =0.0002). CONCLUSIONS: In this study using a multicenter VIRUS database, ICU admission rate, interventions, and outcomes of COVID-19 were similar in children with the oncologic disease compared with control patients. The incidence of MIS-C is lower in oncologic patients.

WITHDRAWN: Update in Critical Care 2021.

Ahead of Print article withdrawn by publisher.

At the intersection of trust and mistrust: A qualitative analysis of motivators and barriers to research participation at a safety-net hospital.

INTRODUCTION: The underrepresentation of Black, Indigenous, and People of Color (BIPOC) individuals in healthcare research limits generalizability and contributes to healthcare inequities. Existing barriers and attitudes toward research participation must be addressed to increase the representation of safety net and other underserved populations. METHODS: We conducted semi-structured qualitative interviews with patients at an urban safety net hospital, focusing on facilitators, barriers, motivators, and preferences for research participation. We conducted direct content analysis guided by an implementation framework and used rapid analysis methods to generate final themes. RESULTS: We completed 38 interviews and identified six major themes related to preferences for engagement in research participation: (1) wide variation in research recruitment preferences; (2) logistical complexity negatively impacts willingness to participate; (3) risk contributes to hesitation toward research participation; (4) personal/community benefit, interest in study topic, and compensation serve as motivators for research participation; (5) continued participation despite reported shortcomings of informed consent process; and (6) mistrust could be overcome by relationship or credibility of information sources. CONCLUSION: Despite barriers to participation in research studies among safety-net populations, there are also facilitators that can be implemented to increase knowledge and comprehension, ease of participation, and willingness to join research studies. Study teams should vary recruitment and participation methods to ensure equal access to research opportunities. PATIENT/PUBLIC CONTRIBUTION: Our analysis methods and study progress were presented to individuals within the Boston Medical Center healthcare system. Through this process community engagement specialists, clinical experts, research directors, and others with significant experience working with safety-net populations supported data interpretation and provided recommendations for action following the dissemination of data.

Facilitators and barriers to the implementation of new critical care practices during COVID-19: a multicenter qualitative study using the Consolidated Framework for Implementation Research (CFIR).

BACKGROUND: The COVID-19 pandemic produced unprecedented demands and rapidly changing evidence and practices within critical care settings. The purpose of this study was to identify factors and strategies that hindered and facilitated effective implementation of new critical care practices and policies in response to the pandemic. METHODS: We used a cross-sectional, qualitative study design to conduct semi-structured in-depth interviews with critical care leaders across the United States. The interviews were audio-taped and professionally transcribed verbatim. Guided by the Consolidated Framework for Implementation Research (CFIR), three qualitative researchers used rapid analysis methods to develop relevant codes and identify salient themes. RESULTS: Among the 17 hospitals that agreed to participate in this study, 31 clinical leaders were interviewed. The CFIR-driven rapid analysis of the interview transcripts generated 12 major themes, which included six implementation facilitators (i.e., factors that promoted the implementation of new critical care practices) and six implementation barriers (i.e., factors that hindered the implementation of new critical care practices). These themes spanned the five CFIR domains (Intervention Characteristics, Outer Setting, Inner Setting, Characteristics of Individuals, and Process) and 11 distinct CFIR constructs. Salient facilitators to implementation efforts included staff resilience, commitment, and innovation, which were supported through collaborative feedback and decision-making mechanisms between leadership and frontline staff. Major identified barriers included lack of access to reliable and transferable information, available resources, uncollaborative leadership and communication styles. CONCLUSIONS: Through applying the CFIR to organize and synthesize our qualitative data, this study revealed important insights into implementation determinants that influenced the uptake of new critical care practices during COVID-19. As the pandemic continues to burden critical care units, clinical leaders should consider emulating the effective change management strategies identified. The cultivation of streamlined, engaging, and collaborative leadership and communication mechanisms not only supported implementation of new care practices across sites, but it also helped reduce salient implementation barriers, particularly resource and staffing shortages. Future critical care implementation studies should seek to capitalize on identified facilitators and reduce barriers.

Association of Renin Angiotensin Aldosterone System Inhibitors and Outcomes of Hospitalized Patients With COVID-19.

OBJECTIVES: To determine the association of prior use of renin-angiotensin-aldosterone system inhibitors (RAASIs) with mortality and outcomes in hospitalized patients with COVID-19. DESIGN: Retrospective observational study. SETTING: Multicenter, international COVID-19 registry. SUBJECTS: Adult hospitalized COVID-19 patients on antihypertensive agents (AHAs) prior to admission, admitted from March 31, 2020, to March 10, 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Data were compared between three groups: patients on RAASIs only, other AHAs only, and those on both medications. Multivariable logistic and linear regressions were performed after controlling for prehospitalization characteristics to estimate the effect of RAASIs on mortality and other outcomes during hospitalization. Of 26,652 patients, 7,975 patients were on AHAs prior to hospitalization. Of these, 1,542 patients (19.3%) were on RAASIs only, 3,765 patients (47.2%) were on other AHAs only, and 2,668 (33.5%) patients were on both medications. Compared with those taking other AHAs only, patients on RAASIs only were younger (mean age 63.3 vs 66.9 yr; p < 0.0001), more often male (58.2% vs 52.4%; p = 0.0001) and more often White (55.1% vs 47.2%; p < 0.0001). After adjusting for age, gender, race, location, and comorbidities, patients on combination of RAASIs and other AHAs had higher in-hospital mortality than those on RAASIs only (odds ratio [OR] = 1.28; 95% CI [1.19-1.38]; p < 0.0001) and higher mortality than those on other AHAs only (OR = 1.09; 95% CI [1.03-1.15]; p = 0.0017). Patients on RAASIs only had lower mortality than those on other AHAs only (OR = 0.87; 95% CI [0.81-0.94]; p = 0.0003). Patients on ACEIs only had higher mortality compared with those on ARBs only (OR = 1.37; 95% CI [1.20-1.56]; p < 0.0001). CONCLUSIONS: Among patients hospitalized for COVID-19 who were taking AHAs, prior use of a combination of RAASIs and other AHAs was associated with higher in-hospital mortality than the use of RAASIs alone. When compared with ARBs, ACEIs were associated with significantly higher mortality in hospitalized COVID-19 patients.

Association of hypothyroidism with outcomes in hospitalized adults with COVID-19: Results from the International SCCM Discovery Viral Infection and Respiratory Illness Universal Study (VIRUS): COVID-19 Registry.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is associated with high rates of morbidity and mortality. Primary hypothyroidism is a common comorbid condition, but little is known about its association with COVID-19 severity and outcomes. This study aims to identify the frequency of hypothyroidism in hospitalized patients with COVID-19 as well as describe the differences in outcomes between patients with and without pre-existing hypothyroidism using an observational, multinational registry. METHODS: In an observational cohort study we enrolled patients 18 years or older, with laboratory-confirmed severe acute respiratory syndrome coronavirus-2 infection between March 2020 and February 2021. The primary outcomes were (1) the disease severity defined as per the World Health Organization Scale for Clinical Improvement, which is an ordinal outcome corresponding with the highest severity level recorded during a patient's index COVID-19 hospitalization, (2) in-hospital mortality and (3) hospital-free days. Secondary outcomes were the rate of intensive care unit (ICU) admission and ICU mortality. RESULTS: Among the 20,366 adult patients included in the study, pre-existing hypothyroidism was identified in 1616 (7.9%). The median age for the Hypothyroidism group was 70 (interquartile range: 59-80) years, and 65% were female and 67% were White. The most common comorbidities were hypertension (68%), diabetes (42%), dyslipidemia (37%) and obesity (28%). After adjusting for age, body mass index, sex, admission date in the quarter year since March 2020, race, smoking history and other comorbid conditions (coronary artery disease, hypertension, diabetes and dyslipidemia), pre-existing hypothyroidism was not associated with higher odds of severe disease using the World Health Organization disease severity index (odds ratio [OR]: 1.02; 95% confidence interval [CI]: 0.92, 1.13; p = .69), in-hospital mortality (OR: 1.03; 95% CI: 0.92, 1.15; p = .58) or differences in hospital-free days (estimated difference 0.01 days; 95% CI: -0.45, 0.47; p = .97). Pre-existing hypothyroidism was not associated with ICU admission or ICU mortality in unadjusted as well as in adjusted analysis. CONCLUSIONS: In an international registry, hypothyroidism was identified in around 1 of every 12 adult hospitalized patients with COVID-19. Pre-existing hypothyroidism in hospitalized patients with COVID-19 was not associated with higher disease severity or increased risk of mortality or ICU admissions. However, more research on the possible effects of COVID-19 on the thyroid gland and its function is needed in the future.

Attention to Immortal Time Bias in Critical Care Research.

Observational studies in critical care medicine offer a popular and practical approach to questions of treatment effectiveness. Although observational research is widely understood to be susceptible to design and interpretation challenges, one well-described source of bias-immortal time bias (ITB)-is frequently present yet often overlooked. ITB may be introduced by study design oversights or mishandled during data analysis. When present, ITB can create inappropriate estimates of the benefit or harm of an exposure or intervention. Studies examining treatments in critically ill patients may be particularly susceptible to ITB, with consequences for clinical adoption and design and initiation of randomized trials. In this Critical Care Perspective, we illustrate the persistent problem of ITB in observational research using recent studies of hydrocortisone, ascorbic acid, and thiamine therapy in patients with sepsis and septic shock. Of the eight studies examined, none contained enough design or reporting elements to rule out the presence of ITB. To mitigate the influence of ITB in future observational studies, we present a novel checklist to help readers assess the features of study design, analysis, and reporting that introduce ITB or obscure its presence. We recommend that commonly used tools designed to evaluate observational research studies should include an ITB assessment.

Association between Troponin I Levels during Sepsis and Postsepsis Cardiovascular Complications.

Rationale: Sepsis commonly results in elevated serum troponin levels and increased risk for postsepsis cardiovascular complications; however, the association between troponin levels during sepsis and cardiovascular complications after sepsis is unclear.Objectives: To evaluate the association between serum troponin levels during sepsis and 1 year after sepsis cardiovascular events.Methods: We analyzed adults aged ⩾40 years without preexisting cardiovascular disease within 5 years, admitted with sepsis across 21 hospitals from 2011 to 2017. Peak serum troponin I levels during sepsis were grouped as normal (⩽0.04 ng/ml) or tertiles of abnormal (>0.04 to ⩽0.09 ng/ml, >0.09 to ⩽0.42 ng/ml, or >0.42 ng/ml). Multivariable adjusted cause-specific Cox proportional hazards models with death as a competing risk were used to assess associations between peak troponin I levels and a composite cardiovascular outcome (atherosclerotic cardiovascular disease, atrial fibrillation, and heart failure) in the year following sepsis. Models were adjusted for presepsis and intrasepsis factors considered potential confounders.Measurements and Main Results: Among 14,046 eligible adults with troponin I measured, 2,012 (14.3%) experienced the composite cardiovascular outcome, including 832 (10.9%) patients with normal troponin levels, as compared with 370 (17.3%), 376 (17.6%), and 434 (20.3%) patients within each sequential abnormal troponin tertile, respectively (P < 0.001). Patients within the elevated troponin tertiles had increased risks of adverse cardiovascular events (adjusted hazard ratio [aHR]troponin0.04-0.09 = 1.37; 95% confidence interval [CI], 1.20-1.55; aHRtroponin0.09-0.42 = 1.44; 95% CI, 1.27-1.63; and aHRtroponin>0.42 = 1.77; 95% CI, 1.56-2.00).Conclusions: Among patients without preexisting cardiovascular disease, troponin elevation during sepsis identified patients at increased risk for postsepsis cardiovascular complications. Strategies to mitigate cardiovascular complications among this high-risk subset of patients are warranted.