Association between use of lung-protective ventilation with lower tidal volumes and clinical outcomes among patients without acute respiratory distress syndrome: a meta-analysis.

CONTEXT: Lung-protective mechanical ventilation with the use of lower tidal volumes has been found to improve outcomes of patients with acute respiratory distress syndrome (ARDS). It has been suggested that use of lower tidal volumes also benefits patients who do not have ARDS. OBJECTIVE: To determine whether use of lower tidal volumes is associated with improved outcomes of patients receiving ventilation who do not have ARDS. DATA SOURCES: MEDLINE, CINAHL, Web of Science, and Cochrane Central Register of Controlled Trials up to August 2012. STUDY SELECTION: Eligible studies evaluated use of lower vs higher tidal volumes in patients without ARDS at onset of mechanical ventilation and reported lung injury development, overall mortality, pulmonary infection, atelectasis, and biochemical alterations. DATA EXTRACTION: Three reviewers extracted data on study characteristics, methods, and outcomes. Disagreement was resolved by consensus. DATA SYNTHESIS: Twenty articles (2822 participants) were included. Meta-analysis using a fixed-effects model showed a decrease in lung injury development (risk ratio [RR], 0.33; 95% CI, 0.23 to 0.47; I2, 0%; number needed to treat [NNT], 11), and mortality (RR, 0.64; 95% CI, 0.46 to 0.89; I2, 0%; NNT, 23) in patients receiving ventilation with lower tidal volumes. The results of lung injury development were similar when stratified by the type of study (randomized vs nonrandomized) and were significant only in randomized trials for pulmonary infection and only in nonrandomized trials for mortality. Meta-analysis using a random-effects model showed, in protective ventilation groups, a lower incidence of pulmonary infection (RR, 0.45; 95% CI, 0.22 to 0.92; I2, 32%; NNT, 26), lower mean (SD) hospital length of stay (6.91 [2.36] vs 8.87 [2.93] days, respectively; standardized mean difference [SMD], 0.51; 95% CI, 0.20 to 0.82; I2, 75%), higher mean (SD) PaCO2 levels (41.05 [3.79] vs 37.90 [4.19] mm Hg, respectively; SMD, -0.51; 95% CI, -0.70 to -0.32; I2, 54%), and lower mean (SD) pH values (7.37 [0.03] vs 7.40 [0.04], respectively; SMD, 1.16; 95% CI, 0.31 to 2.02; I2, 96%) but similar mean (SD) ratios of PaO2 to fraction of inspired oxygen (304.40 [65.7] vs 312.97 [68.13], respectively; SMD, 0.11; 95% CI, -0.06 to 0.27; I2, 60%). Tidal volume gradients between the 2 groups did not influence significantly the final results. CONCLUSIONS: Among patients without ARDS, protective ventilation with lower tidal volumes was associated with better clinical outcomes. Some of the limitations of the meta-analysis were the mixed setting of mechanical ventilation (intensive care unit or operating room) and the duration of mechanical ventilation.

Association between static and dynamic thenar near-infrared spectroscopy and mortality in patients with sepsis: a systematic review and meta-analysis.

BACKGROUND: Oxygen delivery and consumption disturbances are frequently seen with critically illness, potentially leading to pathologic changes in tissue oxygenation (StO2). Near-infrared spectroscopy (NIRS) is a potentially useful method to monitor StO2, but the role of NIRS in prognostication of septic patients is uncertain. The aim of this study was to systematically review the literature and evaluate static and dynamic NIRS in patients with sepsis. METHODS: This is a systematic review and meta-analysis of publications between 1966 and 2013. The MEDLINE and EMBASE databases were searched for studies on StO2 in patients with severe sepsis or septic shock. Meta-analysis was limited to studies about static and dynamic variables derived from NIRS in patients with sepsis. The association between StO2, reperfusion slope (Rres), occlusion slope, and maximum StO2 minus basal StO2 (ΔStO2) and prognosis in septic patients was evaluated. RESULTS: The search identified 20 articles (962 participants; 717 with severe sepsis or septic shock, and 245 healthy controls). Compared with healthy controls, septic patients had lower levels of StO2 (78.27% [4.91%] vs. 82.02% [3.57%], p = 0.012), Rres (2.75% [0.63%] vs. 5.19% [2.86%] per second, p = 0.003), and ΔStO2 (7.86% [0.11%] vs. 12.53% [2.65%], p = 0.011). Survivors from sepsis presents higher levels of StO2 (81.68% [4.68%] vs. 74.54% [5.31%], p = 0.02) and Rres (3.37% [0.44%] vs. 2.16% [0.51%] per second, p = 0.016). CONCLUSION: Septic patients have lower levels of StO2, Rres and ΔStO2, and survivors from sepsis present higher levels of StO2 and Rres compared with nonsurvivors. LEVEL OF EVIDENCE: Systematic review/meta-analysis, level III.

Fluid resuscitation with hydroxyethyl starches in patients with sepsis is associated with an increased incidence of acute kidney injury and use of renal replacement therapy: a systematic review and meta-analysis of the literature.

PURPOSE: Fluid resuscitation is a key intervention in sepsis, but the type of fluids used varies widely. The aim of this meta-analysis is to determine whether resuscitation with hydroxyethyl starches (HES) compared with crystalloids affects outcomes in patients with sepsis. MATERIALS AND METHODS: Search of MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials up to February 2013. Studies that compared resuscitation with HES versus crystalloids in septic patients, and reported incidence of acute kidney injury (AKI), renal replacement therapy (RRT), transfusion of red blood cell (RBC) or fresh frozen plasma and/or mortality. Three investigators independently extracted data into uniform risk ratio measures. The Grading of Recommendations Assessment, Development and Evaluation framework was used to determine the quality of the evidence. RESULTS: Ten trials (4624 patients) were included. An increased incidence of AKI (risk ratio [RR], 1.24 [95% Confidence Interval {CI}, 1.13-1.36], and need of RRT (RR, 1.36 [95% CI, 1.17-1.57]) was found in patients who received resuscitation with HES. Resuscitation with HES was also associated with increased transfusion of RBC (RR, 1.14 [95% CI, 1.01-1.93]), but not fresh frozen plasma (RR, 1.47 [95% CI, 0.97-2.24]). Furthermore, while intensive care unit mortality (RR, 0.74 [95% CI, 0.43-1.26]), and 28-day mortality (RR, 1.11 [95% CI, 0.96-1.28]) was not different, resuscitation with HES was associated with higher 90-day mortality (RR, 1.14 [95% CI, 1.04-1.26]). CONCLUSIONS: Fluid resuscitation practice with HES as in the meta-analyzed studies is associated with increased an increase in AKI incidence, need of RRT, RBC transfusion, and 90-day mortality in patients with sepsis. Therefore, we favor the use of crystalloids over HES for resuscitation in patients with sepsis.

Neuromuscular blocking agents in patients with acute respiratory distress syndrome: a summary of the current evidence from three randomized controlled trials.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a potentially fatal disease with high mortality. Our aim was to summarize the current evidence for use of neuromuscular blocking agents (NMBA) in the early phase of ARDS. METHODS: Systematic review and meta-analysis of publications between 1966 and 2012. The Medline and CENTRAL databases were searched for studies on NMBA in patients with ARDS. The meta-analysis was limited to: 1) randomized controlled trials; 02) adult human patients with ARDS or acute lung injury; and 03) use of any NMBA in one arm of the study compared with another arm without NMBA. The outcomes assessed were: overall mortality, ventilator-free days, time of mechanical ventilation, adverse events, changes in gas exchange, in ventilator settings, and in respiratory mechanics. RESULTS: Three randomized controlled trials covering 431 participants were included. Patients treated with NMBA showed less mortality (Risk ratio, 0.71 [95 % CI, 0.55 - 0.90]; number needed to treat, 1 - 7), more ventilator free days at day 28 (p = 0.020), higher PaO2 to FiO2 ratios (p = 0.004), and less barotraumas (p = 0.030). The incidence of critical illness neuromyopathy was similar (p = 0.540). CONCLUSIONS: The use of NMBA in the early phase of ARDS improves outcome.