Effect of Lowering Vt on Mortality in Acute Respiratory Distress Syndrome Varies with Respiratory System Elastance.

Rationale: If the risk of ventilator-induced lung injury in acute respiratory distress syndrome (ARDS) is causally determined by driving pressure rather than by Vt, then the effect of ventilation with lower Vt on mortality would be predicted to vary according to respiratory system elastance (Ers). Objectives: To determine whether the mortality benefit of ventilation with lower Vt varies according to Ers. Methods: In a secondary analysis of patients from five randomized trials of lower- versus higher-Vt ventilation strategies in ARDS and acute hypoxemic respiratory failure, the posterior probability of an interaction between the randomized Vt strategy and Ers on 60-day mortality was computed using Bayesian multivariable logistic regression. Measurements and Main Results: Of 1,096 patients available for analysis, 416 (38%) died by Day 60. The posterior probability that the mortality benefit from lower-Vt ventilation strategies varied with Ers was 93% (posterior median interaction odds ratio, 0.80 per cm H2O/[ml/kg]; 90% credible interval, 0.63-1.02). Ers was classified as low (<2 cm H2O/[ml/kg], n = 321, 32%), intermediate (2-3 cm H2O/[ml/kg], n = 475, 46%), and high (>3 cm H2O/[ml/kg], n = 224, 22%). In these groups, the posterior probabilities of an absolute risk reduction in mortality ≥ 1% were 55%, 82%, and 92%, respectively. The posterior probabilities of an absolute risk reduction ≥ 5% were 29%, 58%, and 82%, respectively. Conclusions: The mortality benefit of ventilation with lower Vt in ARDS varies according to elastance, suggesting that lung-protective ventilation strategies should primarily target driving pressure rather than Vt.

Driving pressure and survival in the acute respiratory distress syndrome.

BACKGROUND: Mechanical-ventilation strategies that use lower end-inspiratory (plateau) airway pressures, lower tidal volumes (VT), and higher positive end-expiratory pressures (PEEPs) can improve survival in patients with the acute respiratory distress syndrome (ARDS), but the relative importance of each of these components is uncertain. Because respiratory-system compliance (CRS) is strongly related to the volume of aerated remaining functional lung during disease (termed functional lung size), we hypothesized that driving pressure (ΔP=VT/CRS), in which VT is intrinsically normalized to functional lung size (instead of predicted lung size in healthy persons), would be an index more strongly associated with survival than VT or PEEP in patients who are not actively breathing. METHODS: Using a statistical tool known as multilevel mediation analysis to analyze individual data from 3562 patients with ARDS enrolled in nine previously reported randomized trials, we examined ΔP as an independent variable associated with survival. In the mediation analysis, we estimated the isolated effects of changes in ΔP resulting from randomized ventilator settings while minimizing confounding due to the baseline severity of lung disease. RESULTS: Among ventilation variables, ΔP was most strongly associated with survival. A 1-SD increment in ΔP (approximately 7 cm of water) was associated with increased mortality (relative risk, 1.41; 95% confidence interval [CI], 1.31 to 1.51; P<0.001), even in patients receiving "protective" plateau pressures and VT (relative risk, 1.36; 95% CI, 1.17 to 1.58; P<0.001). Individual changes in VT or PEEP after randomization were not independently associated with survival; they were associated only if they were among the changes that led to reductions in ΔP (mediation effects of ΔP, P=0.004 and P=0.001, respectively). CONCLUSIONS: We found that ΔP was the ventilation variable that best stratified risk. Decreases in ΔP owing to changes in ventilator settings were strongly associated with increased survival. (Funded by Fundação de Amparo e Pesquisa do Estado de São Paulo and others.).

High-frequency oscillation in early acute respiratory distress syndrome.

BACKGROUND: Previous trials suggesting that high-frequency oscillatory ventilation (HFOV) reduced mortality among adults with the acute respiratory distress syndrome (ARDS) were limited by the use of outdated comparator ventilation strategies and small sample sizes. METHODS: In a multicenter, randomized, controlled trial conducted at 39 intensive care units in five countries, we randomly assigned adults with new-onset, moderate-to-severe ARDS to HFOV targeting lung recruitment or to a control ventilation strategy targeting lung recruitment with the use of low tidal volumes and high positive end-expiratory pressure. The primary outcome was the rate of in-hospital death from any cause. RESULTS: On the recommendation of the data monitoring committee, we stopped the trial after 548 of a planned 1200 patients had undergone randomization. The two study groups were well matched at baseline. The HFOV group underwent HFOV for a median of 3 days (interquartile range, 2 to 8); in addition, 34 of 273 patients (12%) in the control group received HFOV for refractory hypoxemia. In-hospital mortality was 47% in the HFOV group, as compared with 35% in the control group (relative risk of death with HFOV, 1.33; 95% confidence interval, 1.09 to 1.64; P=0.005). This finding was independent of baseline abnormalities in oxygenation or respiratory compliance. Patients in the HFOV group received higher doses of midazolam than did patients in the control group (199 mg per day [interquartile range, 100 to 382] vs. 141 mg per day [interquartile range, 68 to 240], P<0.001), and more patients in the HFOV group than in the control group received neuromuscular blockers (83% vs. 68%, P<0.001). In addition, more patients in the HFOV group received vasoactive drugs (91% vs. 84%, P=0.01) and received them for a longer period than did patients in the control group (5 days vs. 3 days, P=0.01). CONCLUSIONS: In adults with moderate-to-severe ARDS, early application of HFOV, as compared with a ventilation strategy of low tidal volume and high positive end-expiratory pressure, does not reduce, and may increase, in-hospital mortality. (Funded by the Canadian Institutes of Health Research; Current Controlled Trials numbers, ISRCTN42992782 and ISRCTN87124254, and ClinicalTrials.gov numbers, NCT00474656 and NCT01506401.).

Patient safety, resident well-being and continuity of care with different resident duty schedules in the intensive care unit: a randomized trial.

BACKGROUND: Shorter resident duty periods are increasingly mandated to improve patient safety and physician well-being. However, increases in continuity-related errors may counteract the purported benefits of reducing fatigue. We evaluated the effects of 3 resident schedules in the intensive care unit (ICU) on patient safety, resident well-being and continuity of care. METHODS: Residents in 2 university-affiliated ICUs were randomly assigned (in 2-month rotation-blocks from January to June 2009) to in-house overnight schedules of 24, 16 or 12 hours. The primary patient outcome was adverse events. The primary resident outcome was sleepiness, measured by the 7-point Stanford Sleepiness Scale. Secondary outcomes were patient deaths, preventable adverse events, and residents' physical symptoms and burnout. Continuity of care and perceptions of ICU staff were also assessed. RESULTS: We evaluated 47 (96%) of 49 residents, all 971 admissions, 5894 patient-days and 452 staff surveys. We found no effect of schedule (24-, 16- or 12-h shifts) on adverse events (81.3, 76.3 and 78.2 events per 1000 patient-days, respectively; p = 0.7) or on residents' sleepiness in the daytime (mean rating 2.33, 2.61 and 2.30, respectively; p = 0.3) or at night (mean rating 3.06, 2.73 and 2.42, respectively; p = 0.2). Seven of 8 preventable adverse events occurred with the 12-hour schedule (p = 0.1). Mortality rates were similar for the 3 schedules. Residents' somatic symptoms were more severe and more frequent with the 24-hour schedule (p = 0.04); however, burnout was similar across the groups. ICU staff rated residents' knowledge and decision-making worst with the 16-hour schedule. INTERPRETATION: Our findings do not support the purported advantages of shorter duty schedules. They also highlight the trade-offs between residents' symptoms and multiple secondary measures of patient safety. Further delineation of this emerging signal is required before widespread system change. TRIAL REGISTRATION: ClinicalTrials.gov, no. NCT00679809.

Oxygenation response to positive end-expiratory pressure predicts mortality in acute respiratory distress syndrome. A secondary analysis of the LOVS and ExPress trials.

RATIONALE: Previous trials of higher positive end-expiratory pressure (PEEP) for acute respiratory distress syndrome (ARDS) failed to demonstrate mortality benefit, possibly because of differences in lung recruitability among patients with ARDS. OBJECTIVES: To determine whether the physiological response to increased PEEP is associated with mortality. METHODS: In a secondary analysis of the Lung Open Ventilation Study (LOVS, n = 983), we examined the relationship between the initial response to changes in PEEP after randomization and mortality. We sought to corroborate our findings using data from a different trial of higher PEEP (ExPress, n = 749). MEASUREMENTS AND MAIN RESULTS: The oxygenation response (change in ratio of arterial partial pressure of oxygen to fraction of inspired oxygen: P/F) after the initial change in PEEP after randomization varied widely (median, 9.5 mm Hg; interquartile range, -16 to 47) and was only weakly related to baseline P/F or the magnitude of PEEP change. Among patients in whom PEEP was increased after randomization, an increase in P/F was associated with reduced mortality (multivariable logistic regression; adjusted odds ratio, 0.80 [95% confidence interval, 0.72-0.89] per 25-mm Hg increase in P/F), particularly in patients with severe disease (baseline P/F [less-than-or-equal-to] 150 mm Hg). Changes in compliance and dead space were not associated with mortality. These findings were confirmed by a similar analysis of data from the ExPress trial. CONCLUSIONS: Patients with ARDS who respond to increased PEEP by improved oxygenation have a lower risk of death. The oxygenation response to PEEP might be used to predict whether patients will benefit from higher versus lower PEEP.

Functional disability 5 years after acute respiratory distress syndrome.

BACKGROUND: There have been few detailed, in-person interviews and examinations to obtain follow-up data on 5-year outcomes among survivors of the acute respiratory distress syndrome (ARDS). METHODS: We evaluated 109 survivors of ARDS at 3, 6, and 12 months and at 2, 3, 4, and 5 years after discharge from the intensive care unit. At each visit, patients were interviewed and examined; underwent pulmonary-function tests, the 6-minute walk test, resting and exercise oximetry, chest imaging, and a quality-of-life evaluation; and reported their use of health care services. RESULTS: At 5 years, the median 6-minute walk distance was 436 m (76% of predicted distance) and the Physical Component Score on the Medical Outcomes Study 36-Item Short-Form Health Survey was 41 (mean norm score matched for age and sex, 50). With respect to this score, younger patients had a greater rate of recovery than older patients, but neither group returned to normal predicted levels of physical function at 5 years. Pulmonary function was normal to near-normal. A constellation of other physical and psychological problems developed or persisted in patients and family caregivers for up to 5 years. Patients with more coexisting illnesses incurred greater 5-year costs. CONCLUSIONS: Exercise limitation, physical and psychological sequelae, decreased physical quality of life, and increased costs and use of health care services are important legacies of severe lung injury.

Complications from recruitment maneuvers in patients with acute lung injury: secondary analysis from the lung open ventilation study.

BACKGROUND: There are limited data on the safety and efficacy of recruitment maneuvers (RMs) in acute lung injury (ALI) patients. OBJECTIVE: To evaluate the frequency, timing, and risk factors for complications from RMs in adult ALI patients. METHODS: Secondary analysis of data from a randomized controlled trial of a lung open ventilation strategy that included sustained inflation RMs. RESULTS: Respiratory (eg, desaturation) and cardiovascular (eg, hypotension) complications from recruitment maneuvers were common (22% of all patients receiving RMs), and the majority occurred within 7 days of enrollment. New air leak through an existing chest tube was uncommon (< 5%). As compared to patients receiving 1 or fewer RMs, the number of RMs received was associated with increased risk in both younger (age ≤ 56 y) and older patients (age > 56 y): 2 RMs odds ratio [OR] 6.92 (95% CI 1.70-28.2), ≥ 3 RMs OR 15.4 (95% CI 4.77-49.6), and 2 RMs OR 5.43 (95% CI 1.76-16.8), ≥ 3 RMs OR 4.93 (95% CI 1.78-13.7), respectively. Patients with extrapulmonary ALI had decreased odds of developing complications (OR 0.42, 95% CI 0.22-0.80). CONCLUSIONS: Complications in adult ALI patients receiving RMs were common, but serious complications (eg, new air leak through an existing chest tube) were infrequent. There is a significant association between the number of RMs received and complications, even after controlling for illness severity and duration. Given their uncertain benefit in ALI patients, and the potential for complications with repeated application, the routine use of sustained inflation RMs is not justified.

Preparing your intensive care unit for the second wave of H1N1 and future surges.

Faced with increased demands for critical care services as a result of the novel H1N1 pandemic, hospitals must prepare a surge response in an attempt to manage these needs. In preparing for a surge response, factors to consider are staff, stuff (supplies and equipment), space, and systems necessary to respond to the event. This article uses this general framework to discuss surge issues in the context of H1N1 challenges that we are facing currently and to provide specific advice for hospitals. Particular attention is given to how hospitals can estimate the potential impact of H1N1 and pharmaceutical stockpiling.

The quick and the deadly: growth vs virulence in a seed bank pathogen.

*We studied the relationship between virulence (ability to kill nondormant Bromus tectorum seeds) and mycelial growth index in the necrotrophic seed pathogen Pyrenophora semeniperda. Seed pathosystems involving necrotrophs differ from those commonly treated in traditional evolution-of-virulence models in that host death increases pathogen fitness by preventing germination, thereby increasing available resources. Because fast-germinating, nondormant B. tectorum seeds commonly escape mortality, we expected virulence to be positively correlated with mycelial growth index. *We performed seed inoculations using conidia from 78 pathogen isolates and scored subsequent mortality. For a subset of 40 of these isolates, representing a range of virulence phenotypes, we measured mycelial growth index. *Virulence varied over a wide range (3-43% seed mortality) and was significantly negatively correlated with mycelial growth index (R(2) = 0.632). More virulent isolates grew more slowly than less virulent isolates. *We concluded that there is an apparent tradeoff between virulence and growth in this pathogen, probably because the production of toxins necessary for necrotrophic pathogenesis competes with metabolic processes associated with growth. Variation in both virulence and growth rate in this pathosystem may be maintained in part by seasonal variation in the relative abundance of rapidly germinating vs dormant host seeds available to the pathogen.

Exogenous natural surfactant for treatment of acute lung injury and the acute respiratory distress syndrome.

RATIONALE: Compositional changes in surfactant and/or decreased surfactant content of the lungs are common features in patients with acute respiratory failure. Instillation of exogenous surfactant into the lungs of neonates with respiratory distress syndrome or pediatric patients with acute respiratory distress syndrome (ARDS) has resulted in improved survival. OBJECTIVES: We conducted this trial to determine whether the instillation of exogenous surfactant would improve the Day 28 outcome of adult patients with acute lung injury (ALI) or ARDS. METHODS: A total of 418 patients with ALI and ARDS were included in an international, multicenter, stratified, randomized, controlled, open, parallel-group study. We randomly assigned 418 patients to receive usual care either with or without instillation of exogenous natural porcine surfactant HL 10 as large boluses. MEASUREMENTS AND MAIN RESULTS: The primary endpoint was death rate before or on Day 28. Secondary endpoints were adverse event and death rate on day 180. The 28-day death rate in the usual care group was 24.5% compared with 28.8% in the HL 10 group. The estimated odds ratio for death at Day 28 in the usual care group versus the HL 10 group was 0.75 (95% CI, 0.48-1.18; P = 0.22). The most common adverse events related to HL 10 administration were temporary hypoxemia defined as oxygen saturation less than 88% (51.9% in HL 10 group vs. 25.2% in usual care) and hypotension defined as mean arterial blood pressure less than 60 mm Hg (34.1% in HL 10 group vs. 17.1% in usual care). CONCLUSIONS: In this study, instillation of a large bolus of exogenous natural porcine surfactant HL 10 into patients with acute lung injury and ARDS did not improve outcome and showed a trend toward increased mortality and adverse effects. Clinical trial registered with www.clinicaltrials.gov (NCT 00742482).

Has mortality from acute respiratory distress syndrome decreased over time?: A systematic review.

RATIONALE: It is commonly stated that mortality from acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) is decreasing. OBJECTIVES: To systematically review the literature assessing ARDS mortality over time and to determine patient- and study-level factors independently associated with mortality. METHODS: We searched multiple databases (MEDLINE, EMBASE, CINAHL, Cochrane CENTRAL) for prospective observational studies or randomized controlled trials (RCTs) published during the period 1984 to 2006 that enrolled 50 or more patients with ALI/ARDS and reported mortality. We pooled mortality estimates using random-effects meta-analysis and examined mortality trends before and after 1994 (when a consensus definition of ALI/ARDS was published) and factors associated with mortality using meta-regression models. MEASUREMENTS AND MAIN RESULTS: Of 4,966 studies, 89 met inclusion criteria (53 observational, 36 RCTs). There was a total of 18,900 patients (mean age 51.6 years; 39% female). Overall pooled weighted mortality was 44.3% (95% confidence interval [CI], 41.8-46.9). Mortality decreased with time in observational studies conducted before 1994; no temporal associations with mortality were demonstrated in RCTs (any time) or observational studies (after 1994). Pooled mortality from 1994 to 2006 was 44.0% (95% CI, 40.1-47.5) for observational studies, and 36.2% (95% CI, 32.1-40.5) for RCTs. Meta-regression identified study type (observational versus RCT, odds ratio, 1.36; 95% CI, 1.08-1.73) and patient age (odds ratio per additional 10 yr, 1.27; 95% CI, 1.07-1.50) as the only factors associated with mortality. CONCLUSIONS: A decrease in ARDS mortality was only seen in observational studies from 1984 to 1993. Mortality did not decrease between 1994 (when a consensus definition was published) and 2006, and is lower in RCTs than observational studies.

Higher vs lower positive end-expiratory pressure in patients with acute lung injury and acute respiratory distress syndrome: systematic review and meta-analysis.

CONTEXT: Trials comparing higher vs lower levels of positive end-expiratory pressure (PEEP) in adults with acute lung injury or acute respiratory distress syndrome (ARDS) have been underpowered to detect small but potentially important effects on mortality or to explore subgroup differences. OBJECTIVES: To evaluate the association of higher vs lower PEEP with patient-important outcomes in adults with acute lung injury or ARDS who are receiving ventilation with low tidal volumes and to investigate whether these associations differ across prespecified subgroups. DATA SOURCES: Search of MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (1996-January 2010) plus a hand search of conference proceedings (2004-January 2010). STUDY SELECTION: Two reviewers independently screened articles to identify studies randomly assigning adults with acute lung injury or ARDS to treatment with higher vs lower PEEP (with low tidal volume ventilation) and also reporting mortality. DATA EXTRACTION: Data from 2299 individual patients in 3 trials were analyzed using uniform outcome definitions. Prespecified effect modifiers were tested using multivariable hierarchical regression, adjusting for important prognostic factors and clustering effects. RESULTS: There were 374 hospital deaths in 1136 patients (32.9%) assigned to treatment with higher PEEP and 409 hospital deaths in 1163 patients (35.2%) assigned to lower PEEP (adjusted relative risk [RR], 0.94; 95% confidence interval [CI], 0.86-1.04; P = .25). Treatment effects varied with the presence or absence of ARDS, defined by a value of 200 mm Hg or less for the ratio of partial pressure of oxygen to fraction of inspired oxygen concentration (P = .02 for interaction). In patients with ARDS (n = 1892), there were 324 hospital deaths (34.1%) in the higher PEEP group and 368 (39.1%) in the lower PEEP group (adjusted RR, 0.90; 95% CI, 0.81-1.00; P = .049); in patients without ARDS (n = 404), there were 50 hospital deaths (27.2%) in the higher PEEP group and 44 (19.4%) in the lower PEEP group (adjusted RR, 1.37; 95% CI, 0.98-1.92; P = .07). Rates of pneumothorax and vasopressor use were similar. CONCLUSIONS: Treatment with higher vs lower levels of PEEP was not associated with improved hospital survival. However, higher levels were associated with improved survival among the subgroup of patients with ARDS.

Establishing an antimicrobial stewardship program.

Hospitals are faced with increasing challenges of antibiotic-resistant organisms and rising antimicrobial costs despite widespread attention to infection prevention and control measures. Government, professional organizations and accreditation bodies are all signalling an urgent need for the establishment of programs in hospitals to address antibiotic misuse. Although variations of such "antimicrobial stewardship programs" have been functioning in Canada for some time, a formal approach using change management and quality improvement principles has largely been lacking. We describe how we have established such a program in a teaching hospital, modelled on John Kotter's eight steps of leading change.

Ventilation practices and critical events during transport of ventilated patients outside of hospital: a retrospective cohort study.

INTRODUCTION: Little is known about mechanical ventilation practices during patient transport outside of hospital in the civilian setting, although these practices may have clinical impact. Objective. We set out to describe ventilation practice, the use of lung-protective ventilation strategies, administration of sedation and neuromuscular blockade, and related critical events during out-of-hospital transport of ventilated patients. METHODS: We conducted a population-based retrospective cohort study. Ventilator, pharmacy, and clinical data were extracted from the database of the provincial transport medicine agency in Ontario, Canada. Patients at risk for acute lung injury were identified by explicit screening criteria and lung-protective ventilation was assessed according to evidence-based thresholds. Critical events occurring during transport consisting of clinical deterioration or resuscitative procedures were recorded. RESULTS. We identified 1,735 mechanically ventilated adults who received out-of-hospital transport. Volume control and pressure control were the most commonly used ventilation modes. The median tidal volume delivered during transport was 500 mL (interquartile range 450-600) with positive end-expiratory pressure (PEEP) of 5 cmH(2)O (5-7) and peak inspiratory pressure of 24 cmH(2)O (20-29). Most patients (92%) were ventilated with peak pressures < or = 35 cmH(2)O; 22% of patients were ventilated with PEEP < 5 cmH(2)O. Ventilation in patients at risk of acute lung injury was not significantly different, and 68% of this subgroup was ventilated within lung-protective thresholds. Sedation was administered in 1,235 transports (71.2%) with frequent repeat administration. Neuromuscular blockade was administered in 385 transports (22.2%). Critical events occurred during 297 (17.1%) transports, due primarily to new-onset hypotension (n = 208). New in-transit hypotension was independently associated with sedative administration. CONCLUSIONS: In-transit mechanical ventilation practices are variable, although patient exposure to potentially injurious pressures and volumes is uncommon. The application of PEEP is modest. In-transit hypotension is common and associated with sedative administration. The extent to which these practices impact patient outcome is unclear.

Recruitment maneuvers for acute lung injury: a systematic review.

RATIONALE: There are conflicting data regarding the safety and efficacy of recruitment maneuvers (RMs) in patients with acute lung injury (ALI). OBJECTIVES: To summarize the physiologic effects and adverse events in adult patients with ALI receiving RMs. METHODS: Systematic review of case series, observational studies, and randomized clinical trials with pooling of study-level data. MEASUREMENTS AND MAIN RESULTS: Forty studies (1,185 patients) met inclusion criteria. Oxygenation (31 studies; 636 patients) was significantly increased after an RM (PaO2): 106 versus 193 mm Hg, P = 0.001; and PaO2/FiO2 ratio: 139 versus 251 mm Hg, P < 0.001). There were no persistent, clinically significant changes in hemodynamic parameters after an RM. Ventilatory parameters (32 studies; 548 patients) were not significantly altered by an RM, except for higher PEEP post-RM (11 versus 16 cm H2O; P = 0.02). Hypotension (12%) and desaturation (9%) were the most common adverse events (31 studies; 985 patients). Serious adverse events (e.g., barotrauma [1%] and arrhythmias [1%]) were infrequent. Only 10 (1%) patients had their RMs terminated prematurely due to adverse events. CONCLUSIONS: Adult patients with ALI receiving RMs experienced a significant increase in oxygenation, with few serious adverse events. Transient hypotension and desaturation during RMs is common but is self-limited without serious short-term sequelae. Given the uncertain benefit of transient oxygenation improvements in patients with ALI and the lack of information on their influence on clinical outcomes, the routine use of RMs cannot be recommended or discouraged at this time. RMs should be considered for use on an individualized basis in patients with ALI who have life-threatening hypoxemia.

Critically Ill patients with 2009 influenza A(H1N1) in Mexico.

CONTEXT: In March 2009, novel 2009 influenza A(H1N1) was first reported in the southwestern United States and Mexico. The population and health care system in Mexico City experienced the first and greatest early burden of critical illness. OBJECTIVE: To describe baseline characteristics, treatment, and outcomes of consecutive critically ill patients in Mexico hospitals that treated the majority of such patients with confirmed, probable, or suspected 2009 influenza A(H1N1). DESIGN, SETTING, AND PATIENTS: Observational study of 58 critically ill patients with 2009 influenza A(H1N1) at 6 hospitals between March 24 and June 1, 2009. Demographic data, symptoms, comorbid conditions, illness progression, treatments, and clinical outcomes were collected using a piloted case report form. MAIN OUTCOME MEASURES: The primary outcome measure was mortality. Secondary outcomes included rate of 2009 influenza (A)H1N1-related critical illness and mechanical ventilation as well as intensive care unit (ICU) and hospital length of stay. RESULTS: Critical illness occurred in 58 of 899 patients (6.5%) admitted to the hospital with confirmed, probable, or suspected 2009 influenza (A)H1N1. Patients were young (median, 44.0 [range, 10-83] years); all presented with fever and all but 1 with respiratory symptoms. Few patients had comorbid respiratory disorders, but 21 (36%) were obese. Time from hospital to ICU admission was short (median, 1 day [interquartile range {IQR}, 0-3 days]), and all patients but 2 received mechanical ventilation for severe acute respiratory distress syndrome and refractory hypoxemia (median day 1 ratio of Pao(2) to fraction of inspired oxygen, 83 [IQR, 59-145] mm Hg). By 60 days, 24 patients had died (41.4%; 95% confidence interval, 28.9%-55.0%). Patients who died had greater initial severity of illness, worse hypoxemia, higher creatine kinase levels, higher creatinine levels, and ongoing organ dysfunction. After adjusting for a reduced opportunity of patients dying early to receive neuraminidase inhibitors, neuraminidase inhibitor treatment (vs no treatment) was associated with improved survival (odds ratio, 8.5; 95% confidence interval, 1.2-62.8). CONCLUSION: Critical illness from 2009 influenza A(H1N1) in Mexico occurred in young individuals, was associated with severe acute respiratory distress syndrome and shock, and had a high case-fatality rate.

Occupational Burnout among Otolaryngology-Head and Neck Surgery Trainees in Australia.

OBJECTIVES: Surgical trainee burnout has gained attention recently as a significant factor leading to poorer quality of patient care, decreased productivity, and personal dysfunction. As a result, we aimed to determine the prevalence and associated risk factors for burnout among otolaryngology-head and neck surgery (OHNS) trainees in Australia. STUDY DESIGN: Cross-sectional survey. SETTING: National cohort of accredited OHNS trainees in Australia. SUBJECTS AND METHODS: Participants completed the Maslach Burnout Inventory (MBI). Trainee burnout was defined if any threshold of the 3 MBI domains-emotional exhaustion, depersonalization, or personal accomplishment-reached an established high threshold. Demographic data on potential predictors of burnout, such as stressors, workload, satisfaction, and support systems, were collected from survey responses. Predictors were compared with the burnout status. RESULTS: Of 67 OHNS trainees, 60 responded (66.7% men). Burnout was common among respondents, with 73.3% suffering from burnout in at least 1 of the 3 MBI domains (70.0%, emotional exhaustion; 46.7%, depersonalization; 18.3%, personal accomplishment). Trainee burnout was significantly influenced by training location (chi-square, P = .05), living geographically apart from social supports (odds ratio [OR], 3.49; chi-square, P = .007), number of years trained rurally or away from social supports (Kendall's tau-B, P = .03), difficulty balancing work and nonwork commitments (OR, 10.0; chi-square, P = .03), training negatively affecting their partner or family (OR, 14.30; chi-square, P = .05), and feeling uncomfortable approaching a supervisor (OR, 2.50; chi-square, P < .0001). CONCLUSION: Burnout was found to be very common among OHNS trainees in Australia. The statistically significant predictors identified should be addressed to minimize trainee burnout.

Acute respiratory distress syndrome 40 years later: time to revisit its definition.

OBJECTIVE: Acute respiratory distress syndrome is a common disorder associated with significant mortality and morbidity. The aim of this article is to critically evaluate the definition of acute respiratory distress syndrome and examine the impact the definition has on clinical practice and research. DATA SOURCES: Articles from a MEDLINE search (1950 to August 2007) using the Medical Subject Heading respiratory distress syndrome, adult, diagnosis, limited to the English language and human subjects, their relevant bibliographies, and personal collections, were reviewed. DATA SYNTHESIS: The definition of acute respiratory distress syndrome is important to researchers, clinicians, and administrators alike. It has evolved significantly over the last 40 years, culminating in the American-European Consensus Conference definition, which was published in 1994. Although the American-European Consensus Conference definition is widely used, it has some important limitations that may impact on the conduct of clinical research, on resource allocation, and ultimately on the bedside management of such patients. These limitations stem partially from the fact that as defined, acute respiratory distress syndrome is a heterogeneous entity and also involve the reliability and validity of the criteria used in the definition. This article critically evaluates the American-European Consensus Conference definition and its limitations. Importantly, it highlights how these limitations may contribute to clinical trials that have failed to detect a potential true treatment effect. Finally, recommendations are made that could be considered in future definition modifications with an emphasis on the significance of accurately identifying the target population in future trials and subsequently in clinical care. CONCLUSION: How acute respiratory distress syndrome is defined has a significant impact on the results of randomized, controlled trials and epidemiologic studies. Changes to the current American-European Consensus Conference definition are likely to have an important role in advancing the understanding and management of acute respiratory distress syndrome.

A randomized trial of daily awakening in critically ill patients managed with a sedation protocol: a pilot trial.

OBJECTIVE: Protocolized sedation (PS) and daily sedative interruption (DI) in critically ill patients have both been shown to shorten the durations of mechanical ventilation (MV) and intensive care unit (ICU) stay. Our objective was to determine the safety and feasibility of a randomized trial to determine whether adults managed with both PS + DI have a shorter duration of MV than patients managed with PS alone. DESIGN: Prospective randomized, concealed, unblinded, multicenter, pilot trial. SETTING: Three university-affiliated medical-surgical ICUs. PATIENTS: Sixty-five adults anticipated to require MV >48 hrs and receiving sedative/analgesic infusions. INTERVENTIONS: Patients were randomized to PS alone, or PS + DI. PS was implemented by bedside nurses; sedatives/analgesics were titrated to achieve Sedation Agitation Score (SAS) 3-4. The PS + DI group also had infusions interrupted daily until the patients awoke. MEASUREMENTS AND MAIN RESULTS: Diagnosis, age [mean +/- SD] (53 +/- 18.3 vs. 62.1 +/- 16.7 yrs) and Acute Physiology and Chronic Health Evaluation II (27.7 +/- 8.4 vs. 26.6 +/- 8.4) were similar in the PS and PS + DI groups, respectively. The median duration of MV in the PS and PS + DI groups was 8.0 vs. 10.5 days, and ICU stay was 10.0 vs. 13.0 days, respectively. The SAS was within target range (3-4) in 59% of 9,611 measurements, and within an acceptable range (2-5) in 86% of measurements. Self-assessed nursing and respiratory therapist workload was low in the majority of the cohort. Adverse events were similar in both groups. Patient recruitment was slower than projected (1.5 patients/mo). CONCLUSION: This pilot trial comparing PS vs. PS + DI confirmed the safety and acceptability of the sedation protocol and DI, and guided important modifications to the protocol, thus enhancing the feasibility of a future multicenter trial. This trial was not designed to detect small but significant differences in clinically important outcomes.

Current role of high frequency oscillatory ventilation and airway pressure release ventilation in acute lung injury and acute respiratory distress syndrome.

Lung protective ventilatory strategies using conventional ventilators have resulted in decreased mortality in adult patients who have acute lung injury and acute respiratory distress syndrome. Conceptually, high frequency oscillatory ventilation and airway pressure release ventilation appear not only able to fulfill the goals of lung protection, but also to offer some additional advantages over conventional ventilation. Although early data for each of these modes in adults have been encouraging, their widespread use--particularly outside of a rescue situation--cannot be recommended without further evidence.