M. Elizabeth Wilcox

Recruitment maneuvers for acute lung injury: A systematic review

RATIONALEnThere are conflicting data regarding the safety and efficacy of recruitment maneuvers (RMs) in patients with acute lung injury (ALI).nnnOBJECTIVESnTo summarize the physiologic effects and adverse events in adult patients with ALI receiving RMs.nnnMETHODSnSystematic review of case series, observational studies, and randomized clinical trials with pooling of study-level data.nnnMEASUREMENTS AND MAIN RESULTSnForty 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.nnnCONCLUSIONSnAdult 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.

Do intensivist staffing patterns influence hospital mortality following ICU admission? A systematic review and meta-analyses.

Objective:To determine the effect of different intensivist staffing models on clinical outcomes for critically ill patients. Data Sources:A sensitive search of electronic databases and hand-search of major critical care journals and conference proceedings was completed in October 2012. Study Selection:Comparative observational studies examining intensivist staffing patterns and reporting hospital or ICU mortality were included. Data Extraction:Of 16,774 citations, 52 studies met the inclusion criteria. We used random-effects meta-analytic models unadjusted for case-mix or cluster effects and quantified between-study heterogeneity using I2. Study quality was assessed using the Newcastle-Ottawa Score for cohort studies. Data Synthesis:High-intensity staffing (i.e., transfer of care to an intensivist-led team or mandatory consultation of an intensivist), compared to low-intensity staffing, was associated with lower hospital mortality (risk ratio, 0.83; 95% CI, 0.70–0.99) and ICU mortality (pooled risk ratio, 0.81; 95% CI, 0.68–0.96). Significant reductions in hospital and ICU length of stay were seen (–0.17 d, 95% CI, –0.31 to –0.03 d and –0.38 d, 95% CI, –0.55 to –0.20 d, respectively). Within high-intensity staffing models, 24-hour in-hospital intensivist coverage, compared to daytime only coverage, did not improved hospital or ICU mortality (risk ratio, 0.97; 95% CI, 0.89–1.1 and risk ratio, 0.88; 95% CI, 0.70–1.1). The benefit of high-intensity staffing was concentrated in surgical (risk ratio, 0.84; 95% CI, 0.44–1.6) and combined medical-surgical (risk ratio, 0.76; 95% CI, 0.66–0.83) ICUs, as compared to medical (risk ratio, 1.1; 95% CI, 0.83–1.5) ICUs. The effect on hospital mortality varied throughout different decades; pooled risk ratios were 0.74 (95% CI, 0.63–0.87) from 1980 to 1989, 0.96 (95% CI, 0.69–1.3) from 1990 to 1999, 0.70 (95% CI, 0.54–0.90) from 2000 to 2009, and 1.2 (95% CI, 0.84–1.8) from 2010 to 2012. These findings were similar for ICU mortality. Conclusions:High-intensity staffing is associated with reduced ICU and hospital mortality. Within a high-intensity model, 24-hour in-hospital intensivist coverage did not reduce hospital, or ICU, mortality. Benefits seen in mortality were dependent on the type of ICU and decade of publication.

Cognitive dysfunction in ICU patients: risk factors, predictors, and rehabilitation interventions.

In contrast to other clinical outcomes, long-term cognitive function in critical care survivors has not been deeply studied. In this narrative review, we summarize the existing literature on the prevalence, mechanisms, risk factors, and prediction of cognitive impairment after surviving critical illness. Depending on the exact clinical subgroup, up to 100% of critical care survivors may suffer some degree of long-term cognitive impairment at hospital discharge; in approximately 50%, decrements in cognitive function will persist years later. Although the mechanisms of acquiring this impairment are poorly understood, several risk factors have been identified. Unfortunately, no easy means of predicting long-term cognitive impairment exists. Despite this barrier, research is ongoing to test possible treatments for cognitive impairment. In particular, the potential role of exercise on cognitive recovery is an exciting area of exploration. Opportunities exist to incorporate physical and cognitive rehabilitation strategies across a spectrum of environments (in the ICU, on the hospital ward, and at home, posthospital discharge).

Integrating mortality and morbidity outcomes: using quality-adjusted life years in critical care trials.

RATIONALEnOutcome measures that integrate mortality and morbidity, like quality-adjusted life years (QALYs), have been proposed for critical care clinical trials.nnnOBJECTIVESnWe sought to describe the distribution of QALYs in critically ill patients and estimate sample size requirements for a hypothetical trial using QALYs as the primary outcome.nnnMETHODSnWe used data from a prospective cohort study of survivors of acute respiratory distress syndrome to generate utility values and calculate QALYs at 6 and 12 months. Using multiple simulations, we estimated the required sample sizes for multiple outcome scenarios in a hypothetical trial, including a base-case wherein the intervention improved both mortality and QALYs among survivors.nnnMEASUREMENTS AND MAIN RESULTSnFrom 195 enrolled patients, follow-up was sufficient to generate QALY outcomes for 168 (86.2%) at 6 months and 159 (81.5%) at 1 year. For a hypothetical intervention that reduced mortality from 48 to 44% and improved QALYs by 0.025 in survivors at 6 months, the required per-group sample size was 571 (80% power; two-sided α = 0.05), compared with 2,436 patients needed for a comparison focusing on mortality alone. When only mortality or QALY in survivors (but not both) showed improvement by these amounts, 3,426 and 1,827 patients per group were needed, respectively. When mortality and morbidity effects moved in opposite directions, simulation results became impossible to interpret.nnnCONCLUSIONSnQALYs may be a feasible outcome in critical care trials yielding a patient-centered result and major gains in statistical power under certain conditions, but this approach is susceptible to several threats, including loss to follow-up.

Radiologic Outcomes at 5 Years After Severe ARDS

OBJECTIVEnFew studies have systematically evaluated high-resolution CT (HRCT) imaging of the thorax 5 years after severe ARDS to determine the association between radiologic fi ndings and functional disability. The primary aim of this study was to determine chest radiologic abnormalities at 5 years in survivors of severe ARDS from the University of Toronto ARDS cohort. The secondary aim was to determine the relationship between the observed radiologic abnormalities on HRCT scan and pulmonary symptoms, pulmonary function test abnormalities, and healthrelated quality of life at 5-year follow-up.nnnMETHODSnHRCT scans were obtained in 24 of 64 eligible patients. Three anatomically comparable levels were selected for scoring, and each level was divided into four quadrants. The extent and distribution of individual CT image patterns (ground glass opacifi cation, intense parenchymal opacifi cation, reticular pattern, and decreased attenuation) were also reported.nnnRESULTSnEighteen patients (75%) had abnormal fi ndings on HRCT imaging. These findings were minor and in the nondependent lung zones. No correlation was found between radiologic findings and patient symptoms, pulmonary function tests, 6-min walk distances, or heath-related quality of life measures.nnnCONCLUSIONSnExercise and functional limitations experienced by survivors of severe ARDS are unlikely to be related to structural lung disease and may be more consistent with extrapulmonary muscle weakness.

Does This Patient Have an Exudative Pleural Effusion?: The Rational Clinical Examination Systematic Review

IMPORTANCEnThoracentesis is performed to identify the cause of a pleural effusion. Although generally safe, thoracentesis may be complicated by transient hypoxemia, bleeding, patient discomfort, reexpansion pulmonary edema, and pneumothorax.nnnOBJECTIVEnTo identify the best means for differentiating between transudative and exudative effusions and also to identify thoracentesis techniques for minimizing the risk of complications by performing a systematic review the evidence.nnnDATA SOURCESnWe searched The Cochrane Library, MEDLINE, and Embase from inception to February 2014 to identify relevant studies.nnnSTUDY SELECTIONnWe included randomized and observational studies of adult patients undergoing thoracentesis that examined diagnostic tests for differentiating exudates from transudates and evaluated thoracentesis techniques associated with a successful procedure with minimal complications.nnnDATA EXTRACTION AND SYNTHESISnTwo investigators independently appraised study quality and extracted data from studies of laboratory diagnosis of pleural effusion for calculation of likelihood ratios (LRs; nu2009=u200948 studies) and factors affecting adverse event rates (nu2009=u200937 studies).nnnRESULTSnThe diagnosis of an exudate was most accurate if cholesterol in the pleural fluid was greater than 55 mg/dL (LR range, 7.1-250), lactate dehydrogenase (LDH) was greater than 200 U/L (LR, 18; 95% CI, 6.8-46), or the ratio of pleural fluid cholesterol to serum cholesterol was greater than 0.3 (LR, 14; 95% CI, 5.5-38). A diagnosis of exudate was less likely when all Lights criteria (a ratio of pleural fluid protein to serum protein >0.5, a ratio of pleural fluid LDH to serum LDH >0.6, or pleural fluid LDH >two-thirds the upper limit of normal for serum LDH) were absent (LR, 0.04; 95% CI, 0.02-0.11). The most common complication of thoracentesis was pneumothorax, which occurred in 6.0% of cases (95% CI, 4.0%-7.0%). Chest tube placement was required in 2.0% of procedures (95% CI, 0.99%-2.9%) in which a patient was determined to have radiographic evidence of a pneumothorax. With ultrasound, a radiologists marking the needle insertion site was not associated with decreased pneumothorax events (skin marking vs no skin marking odds ratio [OR], 0.37; 95% CI, 0.08-1.7). Use of ultrasound by any experienced practitioner also was not associated with decreased pneumothorax events (OR, 0.55; 95% CI, 0.06-5.3).nnnCONCLUSIONS AND RELEVANCEnLights criteria, cholesterol and pleural fluid LDH levels, and the pleural fluid cholesterol-to-serum ratio are the most accurate diagnostic indicators for pleural exudates. Ultrasound skin marking by a radiologist or ultrasound-guided thoracentesis were not associated with a decrease in pneumothorax events.

Critical Illness–Associated Cerebral Microbleeds

Background and Purpose— Cerebral microbleeds (petechial hemorrhages) are a well-known consequence of cerebral amyloid angiopathy and chronic hypertension among other causes. We report 12 patients with a clinically and radiologically distinct microbleed phenomenon in the cerebral white matter. Methods— These patients were assessed at the University Health Network (Toronto, Canada) between 2004 and 2014. Results— Median age was 40 years (range, 27–63 years), and 7 out of 12 patients were women. All patients had brain magnetic resonance imaging during or immediately after an intensive care unit admission. All patients had respiratory failure, 11 out of 12 received mechanical ventilation, and 3 out of 12 received extracorporeal life support. Magnetic resonance imaging in all 12 patients showed extensive microbleeds, diffusely involving the juxtacortical white matter and corpus callosum but sparing the cortex, deep and periventricular white matter, basal ganglia, and thalami. Several patients also had internal capsule or posterior fossa involvement. Conclusions— We have described a distinct microbleed phenomenon in the cerebral white matter of patients with critical illness. The specific cause of the microbleeds is unclear, but the pathogenesis may involve hypoxemia as the microbleeds are similar to those described with high-altitude exposure.

Is critical care ready for an economic surrogate endpoint

Intensive care is expensive, and thus a body of research has focused on strategies to reduce its costs. However, efforts to reduce the total cost of intensive care have met with limited success, partly because of the challenges of calculating how much a day in the ICU actually costs. We discuss these challenges and introduce the concept of total cost savings as an outcome of critical care trials, assuming statistically negative effects on mortality and quality of life.

Association of Intensive Care Unit Patient-to-Intensivist Ratios With Hospital Mortality

Importance The patient-to-intensivist ratio (PIR) across intensive care units (ICUs) is not standardized and the association of PIR with patient outcome is not well established. Understanding the impact of PIR on outcomes is necessary to optimize senior medical staffing and deliver high-quality care. Objective To test the hypotheses that: (1) there is significant variation in the PIR across ICUs and (2) higher PIRs are associated with higher hospital mortality for ICU patients. Design, Setting, and Participants Retrospective cohort analysis of patients (≥16 years) admitted to ICUs staffed by a single intensivist during daytime hours in the United Kingdom from 2010 to 2013. Exposures Patient-to-intensivist ratios, which we defined for each patient as the number of patients cared for by the intensivist each day averaged over the patient’s stay. Main Outcomes and Measures Using standard summary statistics, we evaluated PIR variation across ICUs. We used multivariable, mixed-effect, logistic regression analysis to evaluate the association between PIR and hospital mortality at ultimate discharge from acute hospital (primary outcome) and at ICU discharge. Finding Among 49u2009686 adults in 94 ICUs, median age was 66 (interquartile range [IQR], 52-76) years, and 45.1% were women. The ultimate hospital mortality was 25.7%. The median PIR for patients was 8.5 (IQR, 6.9-10.8; full range, 1.0-23.5), and varied substantially among individual ICUs. The association between PIR and ultimate hospital mortality was U-shaped; there was a reduction in the odds of mortality associated with an increasing PIR up to 7.5 after which the odds of mortality increased again significantly (average patient mortality for lowest PIR, 22%; PIR of 7.5, 15%; highest PIR, 19%; Pu2009=u2009.003). A similar U-shaped association was seen for PIR and mortality in the ICU (nadir of mortality at a PIR of 7.8, Pu2009<u2009.001). Conclusions and Relevance PIR varied across UK ICUs. The optimal PIR in this cohort of UK ICU patients was 7.5, with significantly increased ICU and hospital mortality above and below this ratio. The number of patients cared for by 1 intensivist may impact patient outcomes.

An Official American Thoracic Society Systematic Review: The Effect of Nighttime Intensivist Staffing on Mortality and Length of Stay among Intensive Care Unit Patients

Background: Studies of nighttime intensivist staffing have yielded mixed results. Goals: To review the association of nighttime intensivist staffing with outcomes of intensive care unit (ICU) patients. Methods: We searched five databases (2000‐2016) for studies comparing in‐hospital nighttime intensivist staffing with other nighttime staffing models in adult ICUs and reporting mortality or length of stay. We abstracted data on staffing models, outcomes, and study characteristics and assessed study quality, using standardized tools. Meta‐analyses used random effects models. Results: Eighteen studies met inclusion criteria: one randomized controlled trial and 17 observational studies. Overall methodologic quality was high. Studies included academic hospitals (n = 10), community hospitals (n = 2), or both (n = 6). Baseline clinician staffing included residents (n = 9), fellows (n = 4), and nurse practitioners or physician assistants (n = 2). Studies included both general and specialty ICUs and were geographically diverse. Meta‐analysis (one randomized controlled trial; three nonrandomized studies with exposure limited to nighttime intensivist staffing with adjusted estimates of effect) demonstrated no association with mortality (odds ratio, 0.99; 95% confidence interval, 0.75‐1.29). Secondary analyses including studies without risk adjustment, with a composite exposure of organizational factors, stratified by intensity of daytime staffing and by ICU type, yielded similar results. Minimal or no differences were observed in ICU and hospital length of stay and several other secondary outcomes. Conclusions: Notwithstanding limitations of the predominantly observational evidence, our systematic review and meta‐analysis suggests nighttime intensivist staffing is not associated with reduced ICU patient mortality. Other outcomes and alternative staffing models should be evaluated to further guide staffing decisions.