Surgical stimulation during high-dose fentanyl anaesthesia: effects of dehydrobenzperidol on the haemodynamics and myocardial oxygenation.

Twenty-four patients undergoing a coronary artery bypass grafting operation with high-dose fentanyl (100 micrograms/kg)-lorazepam-oxygen anaesthesia were divided into a control group and a group receiving in addition 0.25 mg/kg dehydrobenzperidol (DHBP) before the skin incision (DHBP-group). The changes in the central and coronary haemodynamics and the myocardial oxygenation were studied and compared between the two groups during the skin incision and sternotomy, in order to evaluate the possible effects of the dehydrobenzperidol in preventing the harmful haemodynamic effects of surgical stimulation during high-dose fentanyl anaesthesia. In the control group a marked increase in the systemic vascular resistance and mean arterial pressure was seen during surgery. This haemodynamic stimulation was prevented by dehydrobenzperidol during the skin incision and markedly reduced during the sternotomy. Regardless of whether or not DHBP was given, a significant increase in the myocardial oxygen consumption was observed during the sternotomy; in the control group, the increase was slightly higher and was compensated by a greater increase in the myocardial oxygen extraction. No significant changes were seen in the coronary sinus blood flow or coronary vascular resistance in either group during the study period. The surgery caused no change in the myocardial lactate extraction in either group, although myocardial lactate production was observed in one control patient and the myocardial lactate extraction was markedly reduced in two other control patients and one DHBP patient.