Rethinking Acute Respiratory Distress Syndrome after COVID-19: If a "Better" Definition Is the Answer, What Is the Question?

The definition of acute respiratory distress syndrome (ARDS) has a somewhat controversial history, with some even questioning the need for the term "ARDS." This controversy has been amplified by the coronavirus disease (COVID-19) pandemic given the marked increase in the incidence of ARDS, the relatively new treatment modalities that do not fit neatly with the Berlin definition, and the difficulty of making the diagnosis in resource-limited settings. We propose that attempts to revise the definition of ARDS should apply the framework originally developed by psychologists and social scientists and used by other medical disciplines to generate and assess definitions of clinical syndromes that do not have gold standards. This framework is structured around measures of reliability, feasibility, and validity. Future revisions of the definition of ARDS should contain the purpose, the methodology, and the framework for empirically testing any proposed definition. Attempts to revise critical illness syndromes' definitions usually hope to make them "better"; our recommendation is that future attempts use the same criteria used by other fields in defining what "better" means.

Linking Acute Physiology to Outcomes in the ICU: Challenges and Solutions for Research.

ICU clinicians rely on bedside physiological measurements to inform many routine clinical decisions. Because deranged physiology is usually associated with poor clinical outcomes, it is tempting to hypothesize that manipulating and intervening on physiological parameters might improve outcomes for patients. However, testing these hypotheses through mathematical models of the relationship between physiology and outcomes presents a number of important methodological challenges. These models reflect the theories of the researcher and can therefore be heavily influenced by one's assumptions and background beliefs. Model building must therefore be approached with great care and forethought, because failure to consider relevant sources of measurement error, confounding, coupling, and time dependency or failure to assess the direction of causality for associations of interest before modeling may give rise to spurious results. This paper outlines the main challenges in analyzing and interpreting these models and offers potential solutions to address these challenges.

Estimating the attributable fraction of mortality from acute respiratory distress syndrome to inform enrichment in future randomised clinical trials.

BACKGROUND: Efficiency of randomised clinical trials of acute respiratory distress syndrome (ARDS) depends on the fraction of deaths attributable to ARDS (AFARDS) to which interventions are targeted. Estimates of AFARDS in subpopulations of ARDS could improve design of ARDS trials. METHODS: We performed a matched case-control study using the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE cohort. Primary outcome was intensive care unit mortality. We used nearest neighbour propensity score matching without replacement to match ARDS to non-ARDS populations. We derived two separate AFARDS estimates by matching patients with ARDS to patients with non-acute hypoxaemic respiratory failure (non-AHRF) and to patients with AHRF with unilateral infiltrates only (AHRF-UL). We also estimated AFARDS in subgroups based on severity of hypoxaemia, number of lung quadrants involved and hyperinflammatory versus hypoinflammatory phenotypes. Additionally, we derived AFAHRF estimates by matching patients with AHRF to non-AHRF controls, and AFAHRF-UL estimates by matching patients with AHRF-UL to non-AHRF controls. RESULTS: Estimated AFARDS was 20.9% (95% CI 10.5% to 31.4%) when compared with AHRF-UL controls and 38.0% (95% CI 34.4% to 41.6%) compared with non-AHRF controls. Within subgroups, estimates for AFARDS compared with AHRF-UL controls were highest in patients with severe hypoxaemia (41.1% (95% CI 25.2% to 57.1%)), in those with four quadrant involvement on chest radiography (28.9% (95% CI 13.4% to 44.3%)) and in the hyperinflammatory subphenotype (26.8% (95% CI 6.9% to 46.7%)). Estimated AFAHRF was 33.8% (95% CI 30.5% to 37.1%) compared with non-AHRF controls. Estimated AFAHRF-UL was 21.3% (95% CI 312.8% to 29.7%) compared with non-AHRF controls. CONCLUSIONS: Overall AFARDS mean values were between 20.9% and 38.0%, with higher AFARDS seen with severe hypoxaemia, four quadrant involvement on chest radiography and hyperinflammatory ARDS.

Mortality As a Measure of Treatment Effect in Clinical Trials Recruiting Critically Ill Patients.

OBJECTIVES: All-cause mortality is a common measure of treatment effect in ICU-based randomized clinical trials (RCTs). We sought to understand the performance characteristics of a mortality endpoint by evaluating its temporal course, responsiveness to differential treatment effects, and impact when used as an outcome measure in trials of acute illness. DATA SOURCES: We searched OVID Medline for RCTs published from 1990 to 2018. STUDY SELECTION: We reviewed RCTs that had randomized greater than or equal to 100 patients, were published in one of five high-impact general medical or eight critical care journals, and reported mortality at two or more distinct time points. We excluded trials recruiting pediatric or neonatal patients and cluster RCTs. DATA EXTRACTION: Mortality by randomization group was recorded from the article or estimated from survival curves. Trial impact was assessed by inclusion of results in clinical practice guidelines. DATA SYNTHESIS: From 2,592 potentially eligible trials, we included 343 RCTs (228,784 adult patients). While one third of all deaths by 180 days had occurred by day 7, the risk difference between study arms continued to increase until day 60 (p = 0.01) and possibly day 90 (p = 0.07) and remained stable thereafter. The number of deaths at ICU discharge approximated those at 28-30 days (95% [interquartile range [IQR], 86-106%]), and deaths at hospital discharge approximated those at 60 days (99% [IQR, 94-104%]). Only 13 of 43 interventions (30.2%) showing a mortality benefit have been adopted into widespread clinical practice. CONCLUSIONS: Our findings provide a conceptual framework for choosing a time horizon and interpreting mortality outcome in trials of acute illness. Differential mortality effects persist for 60 to 90 days following recruitment. Location-based measures approximate time-based measures for trials conducted outside the United States. The documentation of a mortality reduction has had a modest impact on practice.

Risk Factors for Cytomegalovirus Reactivation and Association With Outcomes in Critically Ill Adults With Sepsis: A Pooled Analysis of Prospective Studies.

We performed multivariable analysis of potential risk factors (including cytomegalovirus [CMV] reactivation) for clinical outcomes by day 28 (death or continued hospitalization, ventilator-free days, intensive care unit (ICU)-free days, hospital-free days) from pooled cohorts of 2 previous prospective studies of CMV-seropositive adults with sepsis. CMV reactivation at any level, >100 IU/mL, >1000 IU/mL, peak viral load, and area under the curve were independently associated with the clinical outcomes. We identified the potential effect size of CMV on outcomes that could be used as end points for future interventional trials of CMV prevention using antiviral prophylaxis in ICU patients with sepsis.

Outcome of acute hypoxaemic respiratory failure: insights from the LUNG SAFE Study.

BACKGROUND: Current incidence and outcome of patients with acute hypoxaemic respiratory failure requiring mechanical ventilation in the intensive care unit (ICU) are unknown, especially for patients not meeting criteria for acute respiratory distress syndrome (ARDS). METHODS: An international, multicentre, prospective cohort study of patients presenting with hypoxaemia early in the course of mechanical ventilation, conducted during four consecutive weeks in the winter of 2014 in 459 ICUs from 50 countries (LUNG SAFE). Patients were enrolled with arterial oxygen tension/inspiratory oxygen fraction ratio ≤300 mmHg, new pulmonary infiltrates and need for mechanical ventilation with a positive end-expiratory pressure of ≥5 cmH2O. ICU prevalence, causes of hypoxaemia, hospital survival and factors associated with hospital mortality were measured. Patients with unilateral versus bilateral opacities were compared. FINDINGS: 12 906 critically ill patients received mechanical ventilation and 34.9% with hypoxaemia and new infiltrates were enrolled, separated into ARDS (69.0%), unilateral infiltrate (22.7%) and congestive heart failure (CHF; 8.2%). The global hospital mortality was 38.6%. CHF patients had a mortality comparable to ARDS (44.1% versus 40.4%). Patients with unilateral-infiltrate had lower unadjusted mortality, but similar adjusted mortality compared to those with ARDS. The number of quadrants on chest imaging was associated with an increased risk of death. There was no difference in mortality comparing patients with unilateral-infiltrate and ARDS with only two quadrants involved. INTERPRETATION: More than one-third of patients receiving mechanical ventilation have hypoxaemia and new infiltrates with a hospital mortality of 38.6%. Survival is dependent on the degree of pulmonary involvement whether or not ARDS criteria are reached.

Compliance With Evidence-Based Processes of Care After Transitions Between Staff Intensivists.

OBJECTIVES: We sought to evaluate the impact of transitions of care among staff intensivists on the compliance with evidence-based processes of care. DESIGN: Cohort study using data from the Toronto Intensive Care Observational Registry. SETTING: Seven academic ICUs in Toronto, Ontario. PATIENTS: Critically ill mechanically ventilated adult patients. INTERVENTIONS: We explored the effects of the weekly transition of care among staff intensivists on compliance with three evidence-based processes of care (spontaneous breathing trials, lung-protective ventilation, and neuromuscular blocking agents). Two practices that are less guided by evidence (early discontinuation of antibiotics and extubation attempts) served as positive controls. We conducted the analysis using generalized estimating equations to account for clustering at the patient level. MEASUREMENTS AND MAIN RESULTS: The cohort consisted of 10,570 patients admitted between June 2014 and August 2018. Compliance varied for each practice (63.6%, 42.5%, and 21.1% for lung-protective ventilation, spontaneous breathing trials, and neuromuscular blockade, respectively). There was no effect of transitions of care on compliance with spontaneous breathing trials (odds ratio, 1.00; 95% CI, 0.95-1.07), lung-protective ventilation (odds ratio, 1.07, 95% CI, 0.90-1.26), or neuromuscular blockade use (odds ratio, 0.95; 95% CI, 0.75-1.20). However, early antibiotic discontinuation was more likely (odds ratio, 1.23; 95% CI, 1.06-1.42) and extubation attempts were less frequent (odds ratio, 0.77; 95% CI, 0.65-0.93) after a transition of care. CONCLUSIONS: We observed no significant impact of transitions of care between individual staff physicians on evidence-based processes of care for mechanically ventilated adult patients. However, transitions were associated with a lower likelihood of extubation and higher odds of earlier discontinuation of antibiotics.

Alive and Ventilator Free: A Hierarchical, Composite Outcome for Clinical Trials in the Acute Respiratory Distress Syndrome.

OBJECTIVES: Survival from acute respiratory distress syndrome is improving, and outcomes beyond mortality may be important for testing new treatments. The "ventilator-free days" score, is an established composite that equates ventilation on day 28 to death. A hierarchical outcome treating death as a worse than prolonged ventilation would enhance face validity, but performance characteristics and reporting of such an outcome are unknown. We therefore evaluated the performance of a novel hierarchical composite endpoint, the Alive and Ventilator Free score. DESIGN: Using data from four Acute Respiratory Distress Syndrome Network clinical trials, we compared Alive and Ventilator Free to the ventilator-free days score. Alive and Ventilator Free compares each patient with every other patient in a win-lose-tie for each comparison. Duration of mechanical ventilation is only compared if both patients survived. We evaluated power of Alive and Ventilator Free versus ventilator-free days score under various circumstances. SETTING: ICUs within the Acute Respiratory Distress Syndrome Network. PATIENTS: Individuals enrolled in four Acute Respiratory Distress Syndrome Network trials. INTERVENTIONS: None for this analysis. MEASUREMENTS AND MAIN RESULTS: Within the four trials (n = 2,410 patients), Alive and Ventilator Free and ventilator-free days score had similar power, with Alive and Ventilator Free slightly more powerful when a mortality difference was present, and ventilator-free days score slightly more powerful with a difference in duration of mechanical ventilation. Alive and Ventilator Free less often found in favor of treatments that increased mortality and increased days free of ventilation among survivors. CONCLUSIONS: A hierarchical composite endpoint, Alive and Ventilator Free, preserves statistical power while improving face validity. Alive and Ventilator Free is less prone to favor a treatment with discordant effects on survival and days free of ventilation. This general approach can support complex outcome hierarchies with multiple constituent outcomes. Approaches to interpretation of differences in Alive and Ventilator Free are also presented.

Barriers and Facilitators to Early Rehabilitation in the ICU: A Theory Driven Delphi Study.

OBJECTIVES: There is conflicting evidence for the effectiveness of early rehabilitation in the intensive care and marked variation in rates of implementation in practice. We aimed to identify barriers and facilitators to early rehabilitation in mechanically ventilated patients and their relevance to practice, as perceived by key ICU clinicians across North America. DESIGN: A Delphi study using the Theoretical Domains Framework, consisting of an initial qualitative round and subsequent quantitative rounds, was conducted to gather clinician agreement and perceived importance of barriers and facilitators to early rehabilitation. The survey included questions on the range of individual, sociocultural, and broader organizational influence on behaviors. SETTING: Clinical practice in North America. SUBJECTS: Four clinician groups (intensive care physicians, nurses, therapists, and respiratory therapists). INTERVENTIONS: A three-round Delphi study. MEASUREMENTS AND MAIN RESULTS: Fifty of 74 (67%) of invited clinicians completed the study. Agreement and consensus with Delphi survey items were high in both rounds within and between professional groups. Agreement was highest for items related to the domain "Beliefs about Consequences" (e.g., mortality reduction) and lowest for items related to the domain "Behavioral Regulation" (e.g., team discussion of barriers). Beliefs expressed about improved mortality and improvements in a variety of other long-term outcomes were not consistent with the current evidence base. Individual agreement scores changed very little from Round 2 to Round 3 of the Delphi, suggesting stability of beliefs and existing consensus. CONCLUSIONS: This study identified a wide range of beliefs about early rehabilitation that may influence provider behavior and the success and appropriateness of further implementation. The apparent inconsistency between the optimism of stakeholders regarding mortality reductions and a low level of implementation reported elsewhere represent the most major challenge to future implementation success. Other foci for future implementation work include planning, barriers, feedback, and education of staff.

Population enrichment for critical care trials: phenotypes and differential outcomes.

PURPOSE OF REVIEW: Sepsis and acute respiratory distress syndrome (ARDS) are two heterogenous acute illnesses where numerous RCTs have indeterminate results. We present a narrative review on the recent developments in enriching patient populations for future sepsis and ARDS trials. RECENT FINDINGS: Many researchers are actively pursuing enrichment strategies to reduce heterogeneity to increase the sensitivity of future trials. Enrichment refers to the use of measurable patient characteristics, known before randomisation, to refine trial populations. Biomarkers could increase the diagnostic certainty of sepsis, whereas chest radiology training to enhance reliability of interpretation and stabilisation period of mechanical ventilation have been considered to increase the diagnostic certainty of ARDS. Clinical and biomarker data analyses identifies four to six sepsis clinical phenotypes and two ARDS clinical phenotypes. Similarly, leukocyte gene expression data identifies two to four sepsis molecular phenotypes. Use of a test-dose identifies ARDS subpopulations who are likely to benefit from higher PEEP. Early-phase trials report how a biomarker that is altered by the intervention, such as lymphocyte count for recombinant interleukin-7 therapy and higher check point inhibitor expression for anti-check point treatments in sepsis, could identify a higher treatment effect population for future trials. SUMMARY: Enrichment reduces heterogeneity and will enhance the sensitivity of future trials. However, enrichment, even when it identifies more homogenous populations, may not be efficient to deploy in trials or clinical practice.

Mechanical Ventilation-induced Diaphragm Atrophy Strongly Impacts Clinical Outcomes.

RATIONALE: Diaphragm dysfunction worsens outcomes in mechanically ventilated patients, but the clinical impact of potentially preventable changes in diaphragm structure and function caused by mechanical ventilation is unknown. OBJECTIVES: To determine whether diaphragm atrophy developing during mechanical ventilation leads to prolonged ventilation. METHODS: Diaphragm thickness was measured daily by ultrasound in adults requiring invasive mechanical ventilation; inspiratory effort was assessed by thickening fraction. The primary outcome was time to liberation from ventilation. Secondary outcomes included complications (reintubation, tracheostomy, prolonged ventilation, or death). Associations were adjusted for age, severity of illness, sepsis, sedation, neuromuscular blockade, and comorbidity. MEASUREMENTS AND MAIN RESULTS: Of 211 patients enrolled, 191 had two or more diaphragm thickness measurements. Thickness decreased more than 10% in 78 patients (41%) by median Day 4 (interquartile range, 3-5). Development of decreased thickness was associated with a lower daily probability of liberation from ventilation (adjusted hazard ratio, 0.69; 95% confidence interval [CI], 0.54-0.87; per 10% decrease), prolonged ICU admission (adjusted duration ratio, 1.71; 95% CI, 1.29-2.27), and a higher risk of complications (adjusted odds ratio, 3.00; 95% CI, 1.34-6.72). Development of increased thickness (n = 47; 24%) also predicted prolonged ventilation (adjusted duration ratio, 1.38; 95% CI, 1.00-1.90). Decreasing thickness was related to abnormally low inspiratory effort; increasing thickness was related to excessive effort. Patients with thickening fraction between 15% and 30% (similar to breathing at rest) during the first 3 days had the shortest duration of ventilation. CONCLUSIONS: Diaphragm atrophy developing during mechanical ventilation strongly impacts clinical outcomes. Targeting an inspiratory effort level similar to that of healthy subjects at rest might accelerate liberation from ventilation.

Impact of ICU Structure and Processes of Care on Outcomes After Severe Traumatic Brain Injury: A Multicenter Cohort Study.

OBJECTIVES: It is uncertain whether dedicated neurocritical care units are associated with improved outcomes for critically ill neurologically injured patients in the era of collaborative protocol-driven care. We examined the association between dedicated neurocritical care units and mortality and the effects of standardized management protocols for severe traumatic brain injury. DESIGN: We surveyed trauma medical directors from centers participating in the American College of Surgeons Trauma Quality Improvement Program to obtain information about ICU structure and processes of care. Survey data were then linked to the Trauma Quality Improvement Program registry, and random-intercept hierarchical multivariable modeling was used to evaluate the association between dedicated neurocritical care units, the presence of standardized management protocols and mortality. SETTING: Trauma centers in North America participating in Trauma Quality Improvement Program. PATIENTS: Data were analyzed from 9,773 adult patients with isolated severe traumatic brain injury admitted to 134 Trauma Quality Improvement Program centers between 2011 and 2013. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Only 50 ICUs (37%) were dedicated neurocritical care units, whereas 84 (63%) were general ICUs. Rates of standardized management protocols were similar comparing dedicated neurocritical care units and general ICUs. Among severe TBI patients admitted to trauma centers enrolled in Trauma Quality Improvement Program, care in a dedicated neurocritical care unit did not improve risk-adjusted in-hospital survival (odds ratio, 0.97; 95% CI, 0.80-1.19; p = 0.79). However, the presence of a standardized management protocol for these patients was associated with lower risk-adjusted in-hospital mortality (odds ratio, 0.77; 95% CI, 0.63-0.93; p = 0.009). CONCLUSIONS: Compared with dedicated neurocritical care models, standardized management protocols for severe traumatic brain injured patients are process-targeted intervention strategies that may improve clinical outcomes.

The Randomized Educational Acute Respiratory Distress Syndrome Diagnosis Study: A Trial to Improve the Radiographic Diagnosis of Acute Respiratory Distress Syndrome.

OBJECTIVES: Radiographic criteria for acute respiratory distress syndrome have been criticized for poor reliability. Our objective was to test an educational intervention to improve the radiographic identification of acute respiratory distress syndrome by participants in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure study. DESIGN: Randomized controlled trial. SETTINGS: Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure study centers. SUBJECTS: Study coordinators in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure study. INTERVENTIONS: Participants were randomized to either an online training module followed by a test module (intervention) or test module followed by training module (control). MEASUREMENTS AND MAIN RESULTS: The primary outcome was the number of radiographs correctly identified as meeting criteria for acute respiratory distress syndrome on an online test module (out of 11). Prespecified secondary analyses included a comparison of agreement between the groups and subgroup analyses by profession, age, years of experience, and stated familiarity with diagnostic criteria for acute respiratory distress syndrome. Four-hundred sixty-three study participants consented to participate. There was no effect of the intervention on correct answers by participants (proportion correct 58% [intervention] vs 56% [control]; p = 0.15), or in any subgroup analyses. Overall agreement between raters was 0.296 for the intervention and 0.272 for the control (p < 0.001). CONCLUSIONS: Participant recognition of radiographic criteria for acute respiratory distress syndrome was low, with poor agreement. This was not impacted by an educational intervention designed to improve accuracy of identification of radiographic criteria for acute respiratory distress syndrome.

Fifty Years of Research in ARDS. The Epidemiology of Acute Respiratory Distress Syndrome. A 50th Birthday Review.

Since its first description 50 years ago, no other intensive care syndrome has been as extensively studied as acute respiratory distress syndrome (ARDS). Despite this extensive body of research, many basic epidemiologic questions remain unsolved. The lack of gold standard tests jeopardizes accurate diagnosis and translational research. Wide variation in the population incidence has been reported, making even simple estimates of the burden of disease problematic. Despite these limitations, there has been an increase in the understanding of pathophysiology and important risk factors both for the development of ARDS and for important patient-centered outcomes like mortality. In this Critical Care Perspective, we discuss the historical context of ARDS description and attempts at its definition. We highlight the epidemiologic challenges of studying ARDS, as well as other intensive care syndromes, and propose solutions to address them. We update the current knowledge of ARDS trends in incidence and mortality, risk factors, and recently described endotypes.

Noninvasive Ventilation of Patients with Acute Respiratory Distress Syndrome. Insights from the LUNG SAFE Study.

RATIONALE: Noninvasive ventilation (NIV) is increasingly used in patients with acute respiratory distress syndrome (ARDS). The evidence supporting NIV use in patients with ARDS remains relatively sparse. OBJECTIVES: To determine whether, during NIV, the categorization of ARDS severity based on the PaO2/FiO2 Berlin criteria is useful. METHODS: The LUNG SAFE (Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure) study described the management of patients with ARDS. This substudy examines the current practice of NIV use in ARDS, the utility of the PaO2/FiO2 ratio in classifying patients receiving NIV, and the impact of NIV on outcome. MEASUREMENTS AND MAIN RESULTS: Of 2,813 patients with ARDS, 436 (15.5%) were managed with NIV on Days 1 and 2 following fulfillment of diagnostic criteria. Classification of ARDS severity based on PaO2/FiO2 ratio was associated with an increase in intensity of ventilatory support, NIV failure, and intensive care unit (ICU) mortality. NIV failure occurred in 22.2% of mild, 42.3% of moderate, and 47.1% of patients with severe ARDS. Hospital mortality in patients with NIV success and failure was 16.1% and 45.4%, respectively. NIV use was independently associated with increased ICU (hazard ratio, 1.446 [95% confidence interval, 1.159-1.805]), but not hospital, mortality. In a propensity matched analysis, ICU mortality was higher in NIV than invasively ventilated patients with a PaO2/FiO2 lower than 150 mm Hg. CONCLUSIONS: NIV was used in 15% of patients with ARDS, irrespective of severity category. NIV seems to be associated with higher ICU mortality in patients with a PaO2/FiO2 lower than 150 mm Hg. Clinical trial registered with www.clinicaltrials.gov (NCT 02010073).

An Official American Thoracic Society/European Society of Intensive Care Medicine/Society of Critical Care Medicine Clinical Practice Guideline: Mechanical Ventilation in Adult Patients with Acute Respiratory Distress Syndrome.

BACKGROUND: This document provides evidence-based clinical practice guidelines on the use of mechanical ventilation in adult patients with acute respiratory distress syndrome (ARDS). METHODS: A multidisciplinary panel conducted systematic reviews and metaanalyses of the relevant research and applied Grading of Recommendations, Assessment, Development, and Evaluation methodology for clinical recommendations. RESULTS: For all patients with ARDS, the recommendation is strong for mechanical ventilation using lower tidal volumes (4-8 ml/kg predicted body weight) and lower inspiratory pressures (plateau pressure < 30 cm H2O) (moderate confidence in effect estimates). For patients with severe ARDS, the recommendation is strong for prone positioning for more than 12 h/d (moderate confidence in effect estimates). For patients with moderate or severe ARDS, the recommendation is strong against routine use of high-frequency oscillatory ventilation (high confidence in effect estimates) and conditional for higher positive end-expiratory pressure (moderate confidence in effect estimates) and recruitment maneuvers (low confidence in effect estimates). Additional evidence is necessary to make a definitive recommendation for or against the use of extracorporeal membrane oxygenation in patients with severe ARDS. CONCLUSIONS: The panel formulated and provided the rationale for recommendations on selected ventilatory interventions for adult patients with ARDS. Clinicians managing patients with ARDS should personalize decisions for their patients, particularly regarding the conditional recommendations in this guideline.

Sleep on the ward in intensive care unit survivors: a case series of polysomnography.

BACKGROUND: Few studies have investigated sleep in patients after intensive care despite the possibility that inadequate sleep might further complicate an acute illness impeding recovery. AIMS: To assess the quality and quantity of a patient's sleep on the ward by polysomnography (PSG) within a week of intensive care unit (ICU) discharge and to explore the prevalence of key in-ICU risk factors for persistent sleep fragmentation. METHODS: We enrolled 20 patients after they have been mechanically ventilated for at least 3 days and survived to ICU discharge. We included all patients over the age of 16 years and excluded patients with advanced cognitive impairment or who were unable to follow simple commands before their acute illness, primary admission diagnosis of neurological injury, uncontrolled psychiatric illness or not fluent in English. RESULTS: Twenty patients underwent an overnight PSG recording on day 7 after ICU discharge (SD, 1 day). ICU survivors provided 292.8 h of PSG recording time with median recording times of 16.8 h (Interquartile range (IQR), 15.0-17.2 h). The median total sleep time per patient was 5.3 h (IQR, 2.6-6.3 h). In a multivariable regression model, postoperative admission diagnosis (P = 0.04) and patient report of poor ICU sleep (P = 0.001) were associated with less slow-wave (restorative) sleep on the wards after ICU discharge. CONCLUSIONS: Patients reported poor sleep while in the ICU, and a postoperative admission diagnosis may identify a high-risk subgroup of patients who may derive greater benefit from interventions to improve sleep hygiene.

Using Selective Serotonin Reuptake Inhibitors and Serotonin-Norepinephrine Reuptake Inhibitors in Critical Care: A Systematic Review of the Evidence for Benefit or Harm.

OBJECTIVE: Selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitors are among the most commonly prescribed drugs in patients admitted to the ICU. Our objective was to systematically review available literature for evidence of benefit or harm in ICU patients resulting from chronic effects, continued use, or withdrawal. DATA SOURCES: Medline, Embase, and Cochrane Central Register of Controlled Trials (1990 to November 2014). STUDY SELECTION: We searched for studies of ICU patients with recorded selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor prescription before or during admission, and reporting morbidity, mortality, adverse events, and resource measures like ICU length of stay. We considered all study designs. We excluded studies of deliberate overdose and depression in non-ICU settings. Two authors independently and in duplicate screened citations and reviewed text of studies to apply selection criteria. DATA EXTRACTION: Two authors abstracted data on patient characteristics in exposed and control groups; use of selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitors previously or during ICU; comparator intervention; and outcomes, and also assessed methodologic quality. DATA SYNTHESIS: The database search retrieved 4,172 unique citations, of which 289 were reviewed, and 13 studies representing a total of 20,048 patients met selection criteria. There were five cohort studies, one case series, and seven case reports. Only one case report suggested benefit from selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor use and 11 studies reported morbidity in patients using these medications at admission to ICU. However, due to inadequate drug administration reporting, it was generally unclear if outpatient selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitors were continued in ICU, complicating interpretation. CONCLUSIONS: There may be excess morbidity in critically ill selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor users, but uncertainty remains whether this is due to chronic effects, ongoing use, or drug withdrawal. Further research with improved standards of drug administration reporting is needed to help clinicians decide when to use selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitors in critically ill patients.

The Association Between Visiting Intensivists and ICU Outcomes.

OBJECTIVES: We hypothesized that intensivists unfamiliar with an ICU team and the context of that ICU would affect patient outcomes. We examined differences in mortality when ICU patients were admitted under intensivists routinely working in that ICU and compared with those admitted by intensivists familiar with an ICU elsewhere in the same hospital. DESIGN, SETTINGS, AND PATIENTS: A 5-year natural experimental crossover study involving patients admitted to four ICUs in a large U.K. teaching hospital. INTERVENTIONS: During a period of service reconfiguration, intensivists routinely rostered to work in one ICU worked in another of the hospital's four ICUs. "Home" intensivists were those who continued to work in their usual ICU; "visitor" intensivists were those who delivered care in an unfamiliar ICU. Patient data were obtained from electronic patient records to provide analysis on sex, age, admission Sequential Organ Failure Assessment score, date and time of admission, and admission type (elective, transfer, or unplanned). MEASUREMENTS AND MAIN RESULTS: We analyzed 9,981 admissions to four separate ICUs over a 5-year period. In total, 34.5% of patients were admitted by intensivists working in nonfamiliar surroundings. Visitor intensivists admitted patients with similar age and gender distributions but with greater physiologic derangement (mean Sequential Organ Failure Assessment score, 4.1 ± 2.8 vs 3.9 ± 2.8; p < 0.001) than home intensivists. Overall ICU mortality rates were higher in visitor intensivists, albeit not significantly so (11.5% vs 10.2%; p = 0.052). However, when the ICUs were analyzed separately, visitor mortality rates were found to be significantly higher than for home intensivists in two of the four ICUs (p = 0.017, 0.006). A multivariable analysis adjusting for confounding factors and the clustering of consultants revealed that the overall mortality rate was significantly higher for visitors (odds ratio, 1.18; 95% CI, 1.02-1.37; p = 0.024). A significant interaction between the ICU and visitor status was also detected (p = 0.046), with the visitor effect remaining significant in the two ICUs identified previously (both p = 0.009). CONCLUSIONS: Visitor intensivists in some ICUs were associated with higher mortality. The reasons are unknown but could relate to intensivists' practices, unfamiliarity with the patients, or the interaction with the interprofessional team.