Prolonged lateral steep position impairs respiratory mechanics during continuous lateral rotation therapy in respiratory failure.

OBJECTIVE: To establish whether prolonged lateral steep position during continuous rotation therapy leads to improvement on pulmonary gas exchange, respiratory mechanics and hemodynamics.
DESIGN: Prospective observational study.
SETTING: Intensive care unit of a university hospital. PATIENTS: Twelve consecutive patients suffering from acute lung injury or adult respiratory distress syndrome undergoing continuous rotation therapy.
INTERVENTIONS: Blood gas analysis, static lung compliance, blood pressure, cardiac index and pulmonary shunt fraction were measured in supine as well as in left and right lateral steep position at 62 degrees during continuous rotation therapy (phase I). Rotation was then stopped for 30 min with the patients in supine position, left and right lateral steep position, and the same measurements were performed every 10 min (phase II). MEASUREMENTS AND
RESULTS: Phase I and II revealed no significant changes in PaO(2)/FiO(2) ratio, mean arterial blood pressure, pulmonary shunt fraction, or cardiac index. Significantly lower static compliance was observed in lateral steep position than in supine position (p<0.001). Concomitantly, PaCO(2) was significantly lower in supine position than in left and right lateral steep position (p<0.01).
CONCLUSIONS: Lateral steep positioning impairs the compliance of the respiratory system. Prolonged lateral steep position does not lead to benefits with respect to oxygenation or hemodynamics. Individual response to the different positions is unpredictable. The pauses in "extreme" positions should be as short as possible.