[The effect of sufentanil in high doses on hemodynamics and electroencephalography activity in coronary patients]

Sufentanil, a synthetic opioid that is 5-10 times as potent as fentanyl, has been suggested by some authors to prevent hypertensive responses to noxious stimuli in patients undergoing coronary artery bypass surgery much better than fentanyl, while in other studies it has failed to maintain cardiovascular stability during surgical stimulation. This study was designed to investigate the cardiovascular and electroencephalographic effects of high-dose sufentanil/O2/pancuronium anesthesia in patients undergoing coronary artery bypass surgery. METHODS. Two different doses of sufentanil were administered to two groups including a total of 20 male patients. Patients in group 1 (n = 10) received 10 micrograms.kg-1 sufentanil as an induction dose plus 0.15 microgram.kg-1.min-1 as a continuous infusion, while 10 micrograms.kg-1 plus 0.3 microgram.kg-1.min-1 were administered to the patients in group 2 (n = 10). Hemodynamic measurements were performed with the patients awake (I), 15 min following the induction of anesthesia with sufentanil and pancuronium at rest (II), and during sternotomy and sternal spreading (III). Patients were ventilated with oxygen in air (FiO2 = 0.5). Cerebral electrical activity was recorded by periodic analysis of the EEG, and plasma concentrations of sufentanil were measured throughout the entire study period. RESULTS AND DISCUSSION. The dosage scheme used in this study, which consisted of a sufentanil bolus followed by a continuous infusion, prevented plasma concentrations of sufentanil from declining in both groups during the entire study period. Following induction there was a significant decrease in systolic arterial pressure by 12% in group 1 and 20% in group 2 accompanied by a reduction in cardiac index by 25% and 21%, respectively, and in stroke volume index by 19% in group 1 and 24% in group 2, while systemic vascular resistance increased by 27% and 10%, respectively. Sternotomy led to a rise in systolic arterial pressure that did not exceed the awake values in both groups, while diastolic and mean arterial pressures (MAP) increased by 17% and 14% and by 15%, respectively, due to further increases in systemic vascular resistance by 57% and 41% above the control values. Cardiac and stroke volume indexes stayed significantly lower than the awake values, whereas heart rate remained essentially unchanged during the course of the study. There were no statistically significant differences between the groups during all measurements. In the EEG, sufentanil anesthesia was characterized by a decrease in the number of higher frequency waves and an increase in lower frequency (delta) waves, which did not change during sternotomy in 17 of the 20 patients.