Attenuation of the hemodynamic responses to chest physical therapy.

Chest physiotherapy (CPT) is a commonly used technique in mechanically ventilated critically ill patients. This study examines the hemodynamic and metabolic changes associated with CPT and measures the attenuation by two doses of intravenous fentanyl (1.5 micrograms/kg and 3.0 micrograms/kg) on these changes. Heart rate, systolic and mean blood pressures, cardiac output, oxygen consumption (VO2), and carbon dioxide production (VCO2) all increased during CPT. Decreases in arterial pH and VE and increases in PaCO2 were also observed. The higher, but not lower dose, of fentanyl significantly attenuated increases in blood pressure and heart rate during CPT and no substantial hemodynamic changes occurred once CPT had stopped. The increases in VO2 and VCO2 were not attenuated. Short acting narcotics attenuate the hemodynamic responses to stressful stimuli such as CPT.