Effects of combined use of droperidol with pentazocine and with fentanyl on pulmonary hemodynamics.

The effects of droperidol combined with pentazocine and with fentanyl on the pulmonary hemodynamics were investigated in intact dogs anesthetized with urethanechloralose, and the results were compared with those of each analgesic alone. Mean pulmonary arterial pressure and pulmonary driving pressure remained almost unchanged after droperidol and pentazocine. Pulmonary vascular resistance decreased significantly, and pulmonary vascular compliance and its radium tended to increase. These results indicate that droperidol counteracts the vasoconstrictive action of pentazocine on the pulmonary hemodynamics. On the contrary, almost all the parameters of the pulmonary hemodynamics after droperidol and fentanyl changed to similar directions to those after fentanyl alone. Droperidol seemed not to modify but to exaggerate the pulmonary circulatory effects of fentanyl.