Potential Reasons Why Physicians Underuse Lung-Protective Ventilation: A Retrospective Cohort Study Using Physician Documentation

BACKGROUND: Physicians often fail to use lung-protective ventilation (LPV) in patients with acute lung injury.

OBJECTIVE: To use physician documentation to identify why physicians did not initiate or continue LPV in patients with acute lung injury.

METHODS: This was a retrospective cohort study in a university hospital. The study period was September 2000 through November 2002. In our primary analysis, LPV was defined as use of a tidal volume ≤ 7.5 mL/kg predicted body weight (PBW). We also conducted a sensitivity analysis in which we defined LPV as use of a tidal volume ≤ 6.0 mL/kg PBW.

RESULTS: In our primary analysis, in 42 (56%) of 75 cases, physicians used or intended to use LPV. Of these 42 subjects, 12 received LPV transiently, and 6 never received LPV, despite the fact that the physician ordered or documented LPV use. In 21 of the 33 remaining cases the physicians documented concerns or clinical criteria that may explain why LPV was not used: relative contraindications to LPV (n = 2), change of care goal to comfort care only (n = 1), rapid resolution of hypoxemia (n = 4), and consideration of alternative diagnoses for which LPV was not indicated (n = 14). Of the 12 cases where LPV was used transiently, diagnostic uncertainty (n = 6) was a common finding. The sensitivity analysis yielded explanations in similar proportions.

CONCLUSIONS: LPV, once initiated, is often discontinued. Uncertainty in the diagnosis of acute lung injury appears to be an important barrier to initiating and continuing LPV, whereas concerns regarding metabolic acidosis and clinical changes (hypoxemia improved) may prevent the initiation of LPV. Even when physicians believe they are using LPV, they may not be, which suggests that protocol-implementation failure is an important barrier to use of LPV.