An Approach to Diversifying the Selection of a Guideline Panel-The Process Utilized for the Updated Adult Critical Care Ultrasound Guidelines.

OBJECTIVES: Clinical practice guidelines are essential for promoting evidence-based healthcare. While diversification of panel members can reduce disparities in care, processes for panel selection lack transparency. We aim to share our approach in forming a diverse expert panel for the updated Adult Critical Care Ultrasound Guidelines. DESIGN: This process evaluation aims to understand whether the implementation of a transparent and intentional approach to guideline panel selection would result in the creation of a diverse expert guideline panel. SETTING: This study was conducted in the setting of creating a guideline panel for the updated Adult Critical Care Ultrasound Guidelines. PATIENTS: Understanding that family/patient advocacy in guideline creations can promote the impact of a clinical practice guideline, patient representation on the expert panel was prioritized. INTERVENTIONS: Interventions included creation of a clear definition of expertise, an open invitation to the Society of Critical Care Medicine membership to apply for the panel, additional panel nomination by guideline leadership, voluntary disclosure of pre-identified diversity criteria by potential candidates, and independent review of applications including diversity criteria. This resulted in an overall score per candidate per reviewer and an open forum for discussion and final consensus. MEASUREMENTS AND MAIN RESULTS: The variables of diversity were collected and analyzed after panel selection. These were compared with historical data on panel composition. The final guideline panel comprised of 33 panelists from six countries: 45% women and 79% historically excluded people and groups. The panel has representation from nonphysician professionals and patients advocates. Of the healthcare professionals, there is representation from early, mid, and late career stages. CONCLUSIONS: Our intentional and transparent approach resulted in a panel with improved gender parity and robust diversity along ethnic, racial, and professional lines. We hope it can serve as a starting point as we strive to become a more inclusive and diverse discipline that creates globally representative guidelines.

Society of Critical Care Medicine Guidelines on Glycemic Control for Critically Ill Children and Adults 2024.

RATIONALE: Maintaining glycemic control of critically ill patients may impact outcomes such as survival, infection, and neuromuscular recovery, but there is equipoise on the target blood levels, monitoring frequency, and methods. OBJECTIVES: The purpose was to update the 2012 Society of Critical Care Medicine and American College of Critical Care Medicine (ACCM) guidelines with a new systematic review of the literature and provide actionable guidance for clinicians. PANEL DESIGN: The total multiprofessional task force of 22, consisting of clinicians and patient/family advocates, and a methodologist applied the processes described in the ACCM guidelines standard operating procedure manual to develop evidence-based recommendations in alignment with the Grading of Recommendations Assessment, Development, and Evaluation Approach (GRADE) methodology. Conflict of interest policies were strictly followed in all phases of the guidelines, including panel selection and voting. METHODS: We conducted a systematic review for each Population, Intervention, Comparator, and Outcomes question related to glycemic management in critically ill children (≥ 42 wk old adjusted gestational age to 18 yr old) and adults, including triggers for initiation of insulin therapy, route of administration, monitoring frequency, role of an explicit decision support tool for protocol maintenance, and methodology for glucose testing. We identified the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the GRADE approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak or as a good practice statement. In addition, "In our practice" statements were included when the available evidence was insufficient to support a recommendation, but the panel felt that describing their practice patterns may be appropriate. Additional topics were identified for future research. RESULTS: This guideline is an update of the guidelines for the use of an insulin infusion for the management of hyperglycemia in critically ill patients. It is intended for adult and pediatric practitioners to reassess current practices and direct research into areas with inadequate literature. The panel issued seven statements related to glycemic control in unselected adults (two good practice statements, four conditional recommendations, one research statement) and seven statements for pediatric patients (two good practice statements, one strong recommendation, one conditional recommendation, two "In our practice" statements, and one research statement), with additional detail on specific subset populations where available. CONCLUSIONS: The guidelines panel achieved consensus for adults and children regarding a preference for an insulin infusion for the acute management of hyperglycemia with titration guided by an explicit clinical decision support tool and frequent (≤ 1 hr) monitoring intervals during glycemic instability to minimize hypoglycemia and against targeting intensive glucose levels. These recommendations are intended for consideration within the framework of the patient's existing clinical status. Further research is required to evaluate the role of individualized glycemic targets, continuous glucose monitoring systems, explicit decision support tools, and standardized glycemic control metrics.

Implementation of Lung-Protective Ventilation in Patients With Acute Respiratory Failure.

OBJECTIVES: We implemented a computerized protocol for low tidal volume ventilation (LTVV) to improve management and outcomes of mechanically ventilated patients with, and without, the acute respiratory distress syndrome (ARDS). DESIGN: Pragmatic, nonrandomized stepped wedge type II hybrid implementation/effectiveness trial. SETTING: Twelve hospitals in an integrated healthcare system over a 2-year period. PATIENTS: Patients greater than or equal to 18 years old who had initiation of mechanical ventilation in the emergency department or ICU. We excluded patients who died or transitioned to comfort care on the day of admission to the ICU. We defined a subgroup of patients with ARDS for analysis. INTERVENTIONS: Implementation of ventilator protocols for LTVV in the ICU. MEASUREMENTS AND MAIN RESULTS: Our primary clinical outcome was ventilator-free days (VFDs) to day 28. Our primary process outcome was median initial set tidal volume. We included 8,692 mechanically ventilated patients, 3,282 (38%) of whom had ARDS. After implementation, set tidal volume reported as mL/kg predicted body weight decreased from median 6.1 mL/kg (interquartile range [IQR], 6.0-6.8 mL/kg) to 6.0 mL/kg (IQR, 6.0-6.6 mL/kg) ( p = 0.009). The percent of patients receiving LTVV (tidal volume ≤ 6.5 mL/kg) increased from 69.8% ( n = 1,721) to 72.5% ( n = 1,846) ( p = 0.036) after implementation. The percent of patients receiving greater than 8 mL/kg initial set tidal volume was reduced from 9.0% ( n = 222) to 6.7% ( n = 174) ( p = 0.005) after implementation. Among patients with ARDS, day 1 positive end-expiratory pressure increased from 6.7 to 8.0 cm H 2 O ( p < 0.001). We observed no difference in VFD (adjusted odds ratio, 1.06; 95% CI, 0.91-1.24; p = 0.44), or in secondary outcomes of length of stay or mortality, either within the main cohort or the subgroup of patients with ARDS. CONCLUSIONS: We observed improved adherence to optimal ventilator management with implementation of a computerized protocol and reduction in the number of patients receiving tidal volumes greater than 8 mL/kg. We did not observe improvement in clinical outcomes.

Alveolar macrophages from EVALI patients and e-cigarette users: a story of shifting phenotype.

Exposure to e-cigarette vapors alters important biologic processes including phagocytosis, lipid metabolism, and cytokine activity in the airways and alveolar spaces. Little is known about the biologic mechanisms underpinning the conversion to e-cigarette, or vaping, product use-associated lung injury (EVALI) from normal e-cigarette use in otherwise healthy individuals. We compared cell populations and inflammatory immune populations from bronchoalveolar lavage fluid in individuals with EVALI to e-cigarette users without respiratory disease and healthy controls and found that e-cigarette users with EVALI demonstrate a neutrophilic inflammation with alveolar macrophages skewed towards inflammatory (M1) phenotype and cytokine profile. Comparatively, e-cigarette users without EVALI demonstrate lower inflammatory cytokine production and express features associated with a reparative (M2) phenotype. These data indicate macrophage-specific changes are occurring in e-cigarette users who develop EVALI.

Renin-Angiotensin System Modulation With Synthetic Angiotensin (1-7) and Angiotensin II Type 1 Receptor-Biased Ligand in Adults With COVID-19: Two Randomized Clinical Trials.

Importance: Preclinical models suggest dysregulation of the renin-angiotensin system (RAS) caused by SARS-CoV-2 infection may increase the relative activity of angiotensin II compared with angiotensin (1-7) and may be an important contributor to COVID-19 pathophysiology. Objective: To evaluate the efficacy and safety of RAS modulation using 2 investigational RAS agents, TXA-127 (synthetic angiotensin [1-7]) and TRV-027 (an angiotensin II type 1 receptor-biased ligand), that are hypothesized to potentiate the action of angiotensin (1-7) and mitigate the action of the angiotensin II. Design, Setting, and Participants: Two randomized clinical trials including adults hospitalized with acute COVID-19 and new-onset hypoxemia were conducted at 35 sites in the US between July 22, 2021, and April 20, 2022; last follow-up visit: July 26, 2022. Interventions: A 0.5-mg/kg intravenous infusion of TXA-127 once daily for 5 days or placebo. A 12-mg/h continuous intravenous infusion of TRV-027 for 5 days or placebo. Main Outcomes and Measures: The primary outcome was oxygen-free days, an ordinal outcome that classifies a patient's status at day 28 based on mortality and duration of supplemental oxygen use; an adjusted odds ratio (OR) greater than 1.0 indicated superiority of the RAS agent vs placebo. A key secondary outcome was 28-day all-cause mortality. Safety outcomes included allergic reaction, new kidney replacement therapy, and hypotension. Results: Both trials met prespecified early stopping criteria for a low probability of efficacy. Of 343 patients in the TXA-127 trial (226 [65.9%] aged 31-64 years, 200 [58.3%] men, 225 [65.6%] White, and 274 [79.9%] not Hispanic), 170 received TXA-127 and 173 received placebo. Of 290 patients in the TRV-027 trial (199 [68.6%] aged 31-64 years, 168 [57.9%] men, 195 [67.2%] White, and 225 [77.6%] not Hispanic), 145 received TRV-027 and 145 received placebo. Compared with placebo, both TXA-127 (unadjusted mean difference, -2.3 [95% CrI, -4.8 to 0.2]; adjusted OR, 0.88 [95% CrI, 0.59 to 1.30]) and TRV-027 (unadjusted mean difference, -2.4 [95% CrI, -5.1 to 0.3]; adjusted OR, 0.74 [95% CrI, 0.48 to 1.13]) resulted in no difference in oxygen-free days. In the TXA-127 trial, 28-day all-cause mortality occurred in 22 of 163 patients (13.5%) in the TXA-127 group vs 22 of 166 patients (13.3%) in the placebo group (adjusted OR, 0.83 [95% CrI, 0.41 to 1.66]). In the TRV-027 trial, 28-day all-cause mortality occurred in 29 of 141 patients (20.6%) in the TRV-027 group vs 18 of 140 patients (12.9%) in the placebo group (adjusted OR, 1.52 [95% CrI, 0.75 to 3.08]). The frequency of the safety outcomes was similar with either TXA-127 or TRV-027 vs placebo. Conclusions and Relevance: In adults with severe COVID-19, RAS modulation (TXA-127 or TRV-027) did not improve oxygen-free days vs placebo. These results do not support the hypotheses that pharmacological interventions that selectively block the angiotensin II type 1 receptor or increase angiotensin (1-7) improve outcomes for patients with severe COVID-19. Trial Registration: ClinicalTrials.gov Identifier: NCT04924660.

Initial Derivation of a Predictive Model for Left Ventricular Longitudinal Strain (LS) in Early Sepsis.

Septic shock is a common deadly disease often associated with cardiovascular dysfunction. Left ventricular longitudinal strain (LV LS) has been proposed as a sensitive marker to measure cardiovascular function; however, it is not available universally in standard clinical echocardiograms. We sought to derive a predictive model for LV LS, using machine learning techniques with the hope that we may uncover surrogates for LV LS. We found that left ventricular ejection fraction, tricuspid annular plane systolic excursion, sepsis source, height, mitral valve Tei index, LV systolic dimension, aortic valve ejection time, and peak acceleration rate were all predictive of LV LS in this initial exploratory model. Future modeling work may uncover combinations of these variables which may be powerful surrogates for LV LS and cardiovascular function.

Long-Term Implications of Abnormal Left Ventricular Strain During Sepsis.

OBJECTIVES: Septic cardiomyopathy develops frequently in patients with sepsis and likely increases short-term mortality. However, whether septic cardiomyopathy is associated with long-term outcomes after sepsis is unknown. We investigated whether septic patients with septic cardiomyopathy have worse long-term outcomes than septic patients without septic cardiomyopathy. DESIGN: Retrospective cohort study. SETTING: Adult ICU. PATIENTS: Adult ICU patients with sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Left ventricular global longitudinal systolic strain was our primary measure of septic cardiomyopathy. We employed a suite of multivariable survival analyses to explore linear and nonlinear associations between left ventricular global longitudinal systolic strain and major adverse cardiovascular events, which included death, stroke, and myocardial infarction. Our primary outcome was major adverse cardiovascular event through 24 months after ICU discharge. Among 290 study patients, median left ventricular global longitudinal systolic strain was -16.8% (interquartile range, -20.4% to -12.6%), and 38.3% of patients (n = 111) experienced a major adverse cardiovascular event within 24 months after discharge. On our primary, linear analysis, there was a trend (p = 0.08) toward association between left ventricular global longitudinal systolic strain and major adverse cardiovascular event (odds ratio, 1.03; CI, < 1 to 1.07). On our nonlinear analysis, the association was highly significant (p < 0.001) with both high and low left ventricular global longitudinal systolic strain associated with major adverse cardiovascular event among patients with pre-existing cardiac disease. This association was pronounced among patients who were younger (age < 65 yr) and had Charlson Comorbidity Index greater than 5. CONCLUSIONS: Among patients with sepsis and pre-existing cardiac disease who survived to ICU discharge, left ventricular global longitudinal systolic strain demonstrated a U-shaped association with cardiovascular outcomes through 24 months. The relationship was especially strong among younger patients with more comorbidities. These observations are likely of use to design of future trials.

Clinical presentation, treatment, and short-term outcomes of lung injury associated with e-cigarettes or vaping: a prospective observational cohort study.

BACKGROUND: An ongoing outbreak of lung injury associated with e-cigarettes or vaping (also known as E-VALI or VALI) started in March, 2019, in the USA. The cause, diagnosis, treatment, and course of this disease remains unknown. METHODS: In this multicentre, prospective, observational, cohort study, we collected data on all patients with lung injury associated with e-cigarettes or vaping seen in Intermountain Healthcare, an integrated health system based in Utah, USA, between June 27 and Oct 4, 2019. Telecritical care, based in Salt Lake City, UT, USA, was used as the central repository for case validation, public reporting, and system-wide dissemination of expertise, which included a proposed diagnosis and treatment guideline for lung injury associated with e-cigarettes or vaping. We extracted data on patient presentation, treatment, and short-term follow-up (2 weeks after discharge) from chart review and interviews with patients undertaken by the Utah Department of Health (Salt Lake City, UT, USA). FINDINGS: 60 patients presented with lung injury associated with e-cigarettes or vaping at 13 hospitals or outpatient clinics in the integrated health system. 33 (55%) of 60 were admitted to an intensive care unit (ICU). 53 (88%) of 60 patients presented with constitutional symptoms, 59 (98%) with respiratory symptoms, and 54 (90%) with gastrointestinal symptoms. 54 (90%) of 60 were given antibiotics and 57 (95%) were given steroids. Six (10%) of 60 patients were readmitted to an ICU or hospital within 2 weeks, three (50%) of whom had relapsed with vaping or e-cigarette use. Of 26 patients who were followed up within 2 weeks, despite clinical and radiographic improvement in all, many had residual abnormalities on chest radiographs (ten [67%] of 15) and pulmonary function tests (six [67%] of nine). Two patients died and lung injury associated with e-cigarettes or vaping was thought to be a contributing factor, but not the cause of death, for both. INTERPRETATION: Lung injury associated with e-cigarettes or vaping is an emerging illness associated with severe lung injury and constitutional and gastrointestinal symptoms. Increased awareness has led to identification of a broad spectrum of severity of illness in patients who were treated with antibiotics and steroids. Despite improvement, at short-term follow-up many patients had residual abnormalities. Lung injury associated with e-cigarettes or vaping remains a clinical diagnosis with symptoms that overlap infectious and other lung diseases. Maintaining a high index of suspicion for this disease is important as work continues in understanding the cause or causes, optimal therapy, and long-term outcomes of these patients. FUNDING: Intermountain Healthcare.

Variation in Fluid and Vasopressor Use in Shock With and Without Physiologic Assessment: A Multicenter Observational Study.

OBJECTIVES: To characterize the association between the use of physiologic assessment (central venous pressure, pulmonary artery occlusion pressure, stroke volume variation, pulse pressure variation, passive leg raise test, and critical care ultrasound) with fluid and vasopressor administration 24 hours after shock onset and with in-hospital mortality. DESIGN: Multicenter prospective cohort study between September 2017 and February 2018. SETTINGS: Thirty-four hospitals in the United States and Jordan. PATIENTS: Consecutive adult patients requiring admission to the ICU with systolic blood pressure less than or equal to 90 mm Hg, mean arterial blood pressure less than or equal to 65 mm Hg, or need for vasopressor. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Of 1,639 patients enrolled, 39% had physiologic assessments. Use of physiologic assessment was not associated with cumulative fluid administered within 24 hours of shock onset, after accounting for baseline characteristics, etiology and location of shock, ICU types, Acute Physiology and Chronic Health Evaluation III, and hospital (beta coefficient, 0.04; 95% CI, -0.07 to 0.15). In multivariate analysis, the use of physiologic assessment was associated with a higher likelihood of vasopressor use (adjusted odds ratio, 1.98; 95% CI, 1.45-2.71) and higher 24-hour cumulative vasopressor dosing as norepinephrine equivalent (beta coefficient, 0.37; 95% CI, 0.19-0.55). The use of vasopressor was associated with increased odds of in-hospital mortality (adjusted odds ratio, 1.88; 95% CI, 1.27-2.78). In-hospital mortality was not associated with the use of physiologic assessment (adjusted odds ratio, 0.86; 95% CI, 0.63-1.18). CONCLUSIONS: The use of physiologic assessment in the 24 hours after shock onset is associated with increased use of vasopressor but not with fluid administration.

Evaluation of Vasopressor Exposure and Mortality in Patients With Septic Shock.

OBJECTIVES: The objectives of this study were to: 1) determine the association between vasopressor dosing intensity during the first 6 hours and first 24 hours after the onset of septic shock and 30-day in-hospital mortality; 2) determine whether the effect of vasopressor dosing intensity varies by fluid resuscitation volume; and 3) determine whether the effect of vasopressor dosing intensity varies by dosing titration pattern. DESIGN: Multicenter prospective cohort study between September 2017 and February 2018. Vasopressor dosing intensity was defined as the total vasopressor dose infused across all vasopressors in norepinephrine equivalents. SETTING: Thirty-three hospital sites in the United States (n = 32) and Jordan (n = 1). PATIENTS: Consecutive adults requiring admission to the ICU with septic shock treated with greater than or equal to 1 vasopressor within 24 hours of shock onset. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Out of 1,639 patients screened, 616 were included. Norepinephrine (93%) was the most common vasopressor. Patients received a median of 3,400 mL (interquartile range, 1,851-5,338 mL) during the 24 hours after shock diagnosis. The median vasopressor dosing intensity during the first 24 hours of shock onset was 8.5 µg/min norepinephrine equivalents (3.4-18.1 µg/min norepinephrine equivalents). In the first 6 hours, increasing vasopressor dosing intensity was associated with increased odds ratio of 30-day in-hospital mortality, with the strength of association dependent on concomitant fluid administration. Over the entire 24 hour period, every 10 µg/min increase in vasopressor dosing intensity was associated with an increased risk of 30-day mortality (adjusted odds ratio, 1.33; 95% CI, 1.16-1.53), and this association did not vary with the amount of fluid administration. Compared to an early high/late low vasopressor dosing strategy, an early low/late high or sustained high vasopressor dosing strategy was associated with higher mortality. CONCLUSIONS: Increasing vasopressor dosing intensity during the first 24 hours after septic shock was associated with increased mortality. This association varied with the amount of early fluid administration and the timing of vasopressor titration.

Multi-organ point-of-care ultrasound for COVID-19 (PoCUS4COVID): international expert consensus.

COVID-19 has caused great devastation in the past year. Multi-organ point-of-care ultrasound (PoCUS) including lung ultrasound (LUS) and focused cardiac ultrasound (FoCUS) as a clinical adjunct has played a significant role in triaging, diagnosis and medical management of COVID-19 patients. The expert panel from 27 countries and 6 continents with considerable experience of direct application of PoCUS on COVID-19 patients presents evidence-based consensus using GRADE methodology for the quality of evidence and an expedited, modified-Delphi process for the strength of expert consensus. The use of ultrasound is suggested in many clinical situations related to respiratory, cardiovascular and thromboembolic aspects of COVID-19, comparing well with other imaging modalities. The limitations due to insufficient data are highlighted as opportunities for future research.

Driving pressure is not associated with mortality in mechanically ventilated patients without ARDS.

BACKGROUND: In patients with acute respiratory distress syndrome (ARDS), low tidal volume ventilation has been associated with reduced mortality. Driving pressure (tidal volume normalized to respiratory system compliance) may be an even stronger predictor of ARDS survival than tidal volume. We sought to study whether these associations hold true in acute respiratory failure patients without ARDS. METHODS: This is a retrospectively cohort analysis of mechanically ventilated adult patients admitted to ICUs from 12 hospitals over 2 years. We used natural language processing of chest radiograph reports and data from the electronic medical record to identify patients who had ARDS. We used multivariable logistic regression and generalized linear models to estimate associations between tidal volume, driving pressure, and respiratory system compliance with adjusted 30-day mortality using covariates of Acute Physiology Score (APS), Charlson Comorbidity Index (CCI), age, and PaO2/FiO2 ratio. RESULTS: We studied 2641 patients; 48% had ARDS (n = 1273). Patients with ARDS had higher mean APS (25 vs. 23, p < .001) but similar CCI (4 vs. 3, p = 0.6) scores. For non-ARDS patients, tidal volume was associated with increased adjusted mortality (OR 1.18 per 1 mL/kg PBW increase in tidal volume, CI 1.04 to 1.35, p = 0.010). We observed no association between driving pressure or respiratory compliance and mortality in patients without ARDS. In ARDS patients, both ΔP (OR1.1, CI 1.06-1.14, p < 0.001) and tidal volume (OR 1.17, CI 1.04-1.31, p = 0.007) were associated with mortality. CONCLUSIONS: In a large retrospective analysis of critically ill non-ARDS patients receiving mechanical ventilation, we found that tidal volume was associated with 30-day mortality, while driving pressure was not.

Septic Cardiomyopathy.

OBJECTIVES: To describe, with an emphasis on clinical applications, what is known about the pathophysiology, management, and implications of septic cardiomyopathy in the adult ICU. DATA SOURCES AND STUDY SELECTION: A PubMed literature review was performed for relevant articles. Only articles in English that studied human adults with sepsis were included. DATA EXTRACTION AND DATA SYNTHESIS: Multiple competing definitions for septic cardiomyopathy hinder understanding of this entity. Although many patients with sepsis develop cardiac dysfunction, the impact of septic cardiomyopathy on prognosis and therapy remains to be demonstrated. Treatment of septic cardiomyopathy is aimed at treating the underlying sepsis and providing specific supportive care for cardiogenic shock when present. CONCLUSIONS: Septic cardiomyopathy is an important contributor to organ dysfunction in sepsis. Guided treatment of septic cardiomyopathy may affect patients' prognosis, especially when their cardiac index is substantially decreased. The implication of septic cardiomyopathy for both short- and long-term outcomes is an important area for future investigation.

Randomized Feasibility Trial of a Low Tidal Volume-Airway Pressure Release Ventilation Protocol Compared With Traditional Airway Pressure Release Ventilation and Volume Control Ventilation Protocols.

OBJECTIVES: Low tidal volume (= tidal volume ≤ 6 mL/kg, predicted body weight) ventilation using volume control benefits patients with acute respiratory distress syndrome. Airway pressure release ventilation is an alternative to low tidal volume-volume control ventilation, but the release breaths generated are variable and can exceed tidal volume breaths of low tidal volume-volume control. We evaluate the application of a low tidal volume-compatible airway pressure release ventilation protocol that manages release volumes on both clinical and feasibility endpoints. DESIGN: We designed a prospective randomized trial in patients with acute hypoxemic respiratory failure. We randomized patients to low tidal volume-volume control, low tidal volume-airway pressure release ventilation, and traditional airway pressure release ventilation with a planned enrollment of 246 patients. The study was stopped early because of low enrollment and inability to consistently achieve tidal volumes less than 6.5 mL/kg in the low tidal volume-airway pressure release ventilation arm. Although the primary clinical study endpoint was PaO2/FIO2 on study day 3, we highlight the feasibility outcomes related to tidal volumes in both arms. SETTING: Four Intermountain Healthcare tertiary ICUs. PATIENTS: Adult ICU patients with hypoxemic respiratory failure anticipated to require prolonged mechanical ventilation. INTERVENTIONS: Low tidal volume-volume control, airway pressure release ventilation, and low tidal volume-airway pressure release ventilation. MEASUREMENTS AND MAIN RESULTS: We observed wide variability and higher tidal (release for airway pressure release ventilation) volumes in both airway pressure release ventilation (8.6 mL/kg; 95% CI, 7.8-9.6) and low tidal volume-airway pressure release ventilation (8.0; 95% CI, 7.3-8.9) than volume control (6.8; 95% CI, 6.2-7.5; p = 0.005) with no difference between airway pressure release ventilation and low tidal volume-airway pressure release ventilation (p = 0.58). Recognizing the limitations of small sample size, we observed no difference in 52 patients in day 3 PaO2/ FIO2 (p = 0.92). We also observed no significant difference between arms in sedation, vasoactive medications, or occurrence of pneumothorax. CONCLUSIONS: Airway pressure release ventilation resulted in release volumes often exceeding 12 mL/kg despite a protocol designed to target low tidal volume ventilation. Current airway pressure release ventilation protocols are unable to achieve consistent and reproducible delivery of low tidal volume ventilation goals. A large-scale efficacy trial of low tidal volume-airway pressure release ventilation is not feasible at this time in the absence of an explicit, generalizable, and reproducible low tidal volume-airway pressure release ventilation protocol.

Relative Bradycardia in Patients With Septic Shock Requiring Vasopressor Therapy.

OBJECTIVES: Tachycardia is common in septic shock, but many patients with septic shock are relatively bradycardic. The prevalence, determinants, and implications of relative bradycardia (heart rate, < 80 beats/min) in septic shock are unknown. To determine mortality associated with patients who are relatively bradycardic while in septic shock. DESIGN: Retrospective study of patients admitted for septic shock to study ICUs during 2005-2013. SETTING: One large academic referral hospital and two community hospitals. PATIENTS: Adult patients with septic shock requiring vasopressors. INTERVENTION: None. MEASUREMENTS: Primary outcome was 28-day mortality. We used multivariate logistic regression to evaluate the association between relative bradycardia and mortality, controlling for confounding with inverse probability treatment weighting using a propensity score. RESULTS: We identified 1,554 patients with septic shock, of whom 686 (44%) met criteria for relative bradycardia at some time. Twenty-eight-day mortality in this group was 21% compared to 34% in the never-bradycardic group (p < 0.001). Relatively bradycardic patients were older (65 vs 60 yr; p < 0.001) and had slightly lower illness severity (Sequential Organ Failure Assessment, 10 vs 11; p = 0.004; and Acute Physiology and Chronic Health Evaluation II, 27 vs 28; p = 0.008). After inverse probability treatment weighting, covariates were balanced, and the association between relative bradycardia and survival persisted (p < 0.001). CONCLUSIONS: Relative bradycardia in patients with septic shock is associated with lower mortality, even after adjustment for confounding. Our data support expanded investigation into whether inducing relative bradycardia will benefit patients with septic shock.

Systolic blood pressure variability in patients with early severe sepsis or septic shock: a prospective cohort study.

BACKGROUND: Severe sepsis and septic shock are often lethal syndromes, in which the autonomic nervous system may fail to maintain adequate blood pressure. Heart rate variability has been associated with outcomes in sepsis. Whether systolic blood pressure (SBP) variability is associated with clinical outcomes in septic patients is unknown. The propose of this study is to determine whether variability in SBP correlates with vasopressor independence and mortality among septic patients. METHODS: We prospectively studied patients with severe sepsis or septic shock, admitted to an intensive care unit (ICU) with an arterial catheter. We analyzed SBP variability on the first 5-min window immediately following ICU admission. We performed principal component analysis of multidimensional complexity, and used the first principal component (PC1) as input for Firth logistic regression, controlling for mean systolic pressure (SBP) in the primary analyses, and Acute Physiology and Chronic Health Evaluation (APACHE) II score or NEE dose in the ancillary analyses. Prespecified outcomes were vasopressor independence at 24 h (primary), and 28-day mortality (secondary). RESULTS: We studied 51 patients, 51% of whom achieved vasopressor independence at 24 h. Ten percent died at 28 days. PC1 represented 26% of the variance in complexity measures. PC1 was not associated with vasopressor independence on Firth logistic regression (OR 1.04; 95% CI: 0.93-1.16; p = 0.54), but was associated with 28-day mortality (OR 1.16, 95% CI: 1.01-1.35, p = 0.040). CONCLUSIONS: Early SBP variability appears to be associated with 28-day mortality in patients with severe sepsis and septic shock.

Multi-complexity measures of heart rate variability and the effect of vasopressor titration: a prospective cohort study of patients with septic shock.

BACKGROUND: Septic shock is a common and often devastating syndrome marked by severe cardiovascular dysfunction commonly managed with vasopressors. Whether markers of heart rate complexity before vasopressor up-titration could be used to predict success of the up-titration is not known. METHODS: We studied patients with septic shock requiring vasopressor, newly admitted to the intensive care unit. We measured the complexity of heart rate variability (using the ratio of fractal exponents from detrended fluctuation analysis) in the 5 min before all vasopressor up-titrations in the first 24 h of an intensive care unit (ICU) admission. A successful up-titration was defined as one that did not require further up-titration (or decrease in mean arterial pressure) for 60 min. RESULTS: We studied 95 patients with septic shock, with a median APACHE II of 27 (IQR: 20-37). The median number of up-titrations, normalized to 24 h, was 12.2 (IQR: 8-17) with a maximum of 49. Of the up-titrations, the median proportion of successful interventions was 0.28 (IQR: 0.12-0.42). The median of mean arterial pressure (MAP) at the time of a vasopressor up-titration was 66 mmHg; the average infusion rate of norepinephrine at the time of an up-titration was 0.11 mcg/kg/min. The ratio of fractal exponents was not associated with successful up-titration on univariate or multivariate regression. On exploratory secondary analyses, however, the long-term fractal exponent was associated (p = 0.003) with success of up-titration. Independent of heart rate variability, MAP was associated (p < 0.001) with success of vasopressor up-titration, while neither Sequential Organ Failure Assessment (SOFA) nor Acute Physiology and Chronic Health Evaluation II (APACHE II) score was associated with vasopressor titration. CONCLUSIONS: Only a third of vasopressor up-titrations were successful among patients with septic shock. MAP and the long-term fractal exponent were associated with success of up-titration. These two, complementary variables may be important to the development of rational vasopressor titration protocols.

Application of a simplified definition of diastolic function in severe sepsis and septic shock.

BACKGROUND: Left ventricular diastolic dysfunction is common in patients with severe sepsis or septic shock, but the best approach to categorization is unknown. We assessed the association of common measures of diastolic function with clinical outcomes and tested the utility of a simplified definition of diastolic dysfunction against the American Society of Echocardiography (ASE) 2009 definition. METHODS: In this prospective observational study, patients with severe sepsis or septic shock underwent transthoracic echocardiography within 24 h of onset of sepsis (median 4.3 h). We measured echocardiographic parameters of diastolic function and used random forest analysis to assess their association with clinical outcomes (28-day mortality and ICU-free days to day 28) and thereby suggest a simplified definition. We then compared patients categorized by the ASE 2009 definition and our simplified definition. RESULTS: We studied 167 patients. The ASE 2009 definition categorized only 35 % of patients. Random forest analysis demonstrated that the left atrial volume index and deceleration time, central to the ASE 2009 definition, were not associated with clinical outcomes. Our simplified definition used only e' and E/e', omitting the other measurements. The simplified definition categorized 87 % of patients. Patients categorized by either ASE 2009 or our novel definition had similar clinical outcomes. In both definitions, worsened diastolic function was associated with increased prevalence of ischemic heart disease, diabetes, and hypertension. CONCLUSIONS: A novel, simplified definition of diastolic dysfunction categorized more patients with sepsis than ASE 2009 definition. Patients categorized according to the simplified definition did not differ from patients categorized according to the ASE 2009 definition in respect to clinical outcome or comorbidities.