Meta-analysis of acute lung injury and acute respiratory distress syndrome trials.
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Acute Disease↗
Biomedical subjects
David Schoenfeld
Publications and source records attributed to David Schoenfeld.
Airway pressures and early barotrauma in patients with acute lung injury and acute respiratory distress syndrome.
The determinants of barotrauma in mechanically ventilated patients with acute lung injury or acute respiratory distress syndrome (ALI/ARDS) have not been clearly established. Using data from ARDS Network randomized controlled trials, we retrospectively examined the association between airway pressures and the risk of early barotrauma in a cohort of 718 patients with ALI/ARDS and no baseline barotrauma. We studied airway pressures at three exposure intervals: baseline, one day preceding the barotrauma event (one-day lag), and concurrent with the barotrauma event. During the first four study days, the cumulative incidence of barotrauma was 13% (95% confidence interval [CI] 10.6 to 15.6%). In a forward stepwise Cox proportional hazards analysis using time-dependent variables, higher concurrent positive end-expiratory pressure (PEEP) was associated with an increased risk of early barotrauma (relative hazard [RH] 1.67 per 5-cm H2O increment; 95% CI 1.35-2.07). Once concurrent PEEP was selected into the model, no other airway pressure was related to barotrauma, including plateau pressure. In the multivariate analysis, higher concurrent PEEP was also related to a greater risk of barotrauma (RH 1.93; 95% CI 1.44-2.60), controlling for age, ventilator group (6 versus 12 ml/kg), baseline PEEP, baseline plateau pressure, baseline tidal volume, Acute Physiology and Chronic Health Evaluation score, vasopressor use, serum albumin, hepatic failure, and coagulopathy. When one-day lagged values of PEEP were analyzed, higher PEEP was associated with a greater risk of barotrauma (RH 1.38 per 5-cm H2O increment; 95% CI 1.09-1.76). Controlling for the covariates, higher PEEP was related to an increased risk of barotrauma (RH 1.50; 95% CI 0.98- 2.30). In conclusion, higher PEEP may increase the likelihood of early barotrauma in ALI/ARDS.
Airway Resistance↗
Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome.
BACKGROUND: Traditional approaches to mechanical ventilation use tidal volumes of 10 to 15 ml per kilogram of body weight and may cause stretch-induced lung injury in patients with acute lung injury and the acute respiratory distress syndrome. We therefore conducted a trial to determine whether ventilation with lower tidal volumes would improve the clinical outcomes in these patients. METHODS: Patients with acute lung injury and the acute respiratory distress syndrome were enrolled in a multicenter, randomized trial. The trial compared traditional ventilation treatment, which involved an initial tidal volume of 12 ml per kilogram of predicted body weight and an airway pressure measured after a 0.5-second pause at the end of inspiration (plateau pressure) of 50 cm of water or less, with ventilation with a lower tidal volume, which involved an initial tidal volume of 6 ml per kilogram of predicted body weight and a plateau pressure of 30 cm of water or less. The primary outcomes were death before a patient was discharged home and was breathing without assistance and the number of days without ventilator use from day 1 to day 28. RESULTS: The trial was stopped after the enrollment of 861 patients because mortality was lower in the group treated with lower tidal volumes than in the group treated with traditional tidal volumes (31.0 percent vs. 39.8 percent, P=0.007), and the number of days without ventilator use during the first 28 days after randomization was greater in this group (mean [+/-SD], 12+/-11 vs. 10+/-11; P=0.007). The mean tidal volumes on days 1 to 3 were 6.2+/-0.8 and 11.8+/-0.8 ml per kilogram of predicted body weight (P<0.001), respectively, and the mean plateau pressures were 25+/-6 and 33+/-8 cm of water (P<0.001), respectively. CONCLUSIONS: In patients with acute lung injury and the acute respiratory distress syndrome, mechanical ventilation with a lower tidal volume than is traditionally used results in decreased mortality and increases the number of days without ventilator use.
Barotrauma↗