Toward the prevention of acute lung injury: protocol-guided limitation of large tidal volume ventilation and inappropriate transfusion

Abstract

Objective: We evaluated the effect of two quality improvement interventions (low tidal volume ventilation and restrictive transfusion) on the development of acute lung injury in mechanically ventilated patients.

Design: Observational cohort study.

Setting: Three intensive care units in a tertiary academic center.

Patients: We included patients who were mechanically ventilated for > or =48 hrs excluding those who refused research authorization or had preexisting acute lung injury or pneumonectomy.

Interventions: Multifaceted interdisciplinary intervention consisting of Web-based teaching, respiratory therapy protocol, and decision support within computerized order entry.

Measurements and main results: Of 375 patients who met the inclusion and exclusion criteria, 212 were ventilated before and 163 after the interventions. Baseline characteristics were similar between the two groups except for a lower frequency of sepsis (27% vs. 17%, p = .030), trend toward lower median glucose level (140 mg/dL, interquartile range 118-168 vs. 132 mg/dL, interquartile range 113-156, p = .096), and lower frequency of pneumonia (27% vs. 20%, p = .130) during the second period. We observed a large decrease in tidal volume (10.6-7.7 mL/kg predicted body weight, p < .001), in peak airway pressure (31-25 cm H2O, p < .001), and in the percentage of transfused patients (63% to 38%, p < .001) after the intervention. The frequency of acute lung injury decreased from 28% to 10% (p < .001). The duration of mechanical ventilation decreased from a median of 5 (interquartile range 4-9) to 4 (interquartile range 4-8) days (p = .030). When adjusted for baseline characteristics in a multivariate logistic regression analysis, protocol intervention was associated with a reduction in the frequency of new acute lung injury (odds ratio 0.21, 95% confidence interval 0.10-0.40).

Conclusions: Interdisciplinary intervention effectively decreased large tidal volumes and unnecessary transfusion in mechanically ventilated patients and was associated with a decreased frequency of new acute lung injury.