Patient and intensive care unit organizational factors associated with low tidal volume ventilation in acute lung injury

Abstract

Background: Barriers to evidence-based practice are not well understood. Within the intensive care unit (ICU) setting, low tidal volume ventilation (LTVV) in patients with acute lung injury (ALI) significantly decreases mortality. However, LTVV has not achieved widespread adoption.

Objectives: To evaluate patient demographic and clinical factors, and ICU organizational factors associated with its use.

Design, setting and patients: Prospective cohort study of 250 patients with ALI in 9 ICUs at 3 teaching hospitals in Baltimore, MD.

Measurements: Use of LTVV the day after ALI onset and association of patients' demographic and clinical factors and ICU organizational factors with LTVV using a multivariable logistic regression model adjusted for clustering of patients within ICUs.

Results: On the day after ALI onset, 46% and 81% of patients received a tidal volume < or = 6.5 and < or = 8.5 mL/kg predicted body weight (PBW), respectively, with no significant changes at 3 and 5 days after ALI. Using a strict definition of LTVV (< or = 6.5 mL/kg PBW), no patient demographic factors were independently associated with LTVV; however, two patient clinical and ICU organizational factors (odds ratio, 95% confidence interval) were independently associated: serum HCO3 level (< 22: .3, .1-.9, and > 26: .6, .1-3.5, versus 22-26) and use of a written protocol for LTVV (6.0, 1.3-27.2). In a sensitivity analysis using tidal volume < or = 8.5 mL/kg PBW, use of a written protocol remained significantly associated with LTVV.

Conclusions: Patient demographic factors were not associated with LTVV. Given its strong association with LTVV, ICUs should use a written protocol for ventilation of ALI patients to help translate this evidence-based therapy into practice.