Effects of high-dose fentanyl on fluid and vasopressor requirements after cardiac surgery

The effects of two different anesthetic techniques on postoperative cardiopulmonary events, fluid and vasopressor requirements, and overall intensive care unit (ICU) course were studied in patients undergoing elective myocardial revascularization (CABG) (N = 20) or single cardiac valve replacement (N = 20). Patients were randomized to receive either high-dose fentanyl (F, 75 microg/kg followed by 0.3 microg/kg/min) or diazepam-ketamine (0.8 mg/kg D and 2 mg/kg K followed by 0.07 mg/kg/h D and 1 mg/kg/h K). No significant differences in preoperative demographics, prebypass hemodynamics, ischemic crossclamp, or total cardiopulmonary bypass times were noted. Patients receiving F had lower systemic arterial pressures and vascular resistances and required more vasopressors during the first 12 hours postoperatively. They also had a more positive cumulative fluid balance at 24 and 48 hours postoperatively, despite a higher incidence of postoperative diuretic use in CABG patients receiving F. Rectal temperature was significantly higher at four and eight hours postoperatively in F patients. Time until arousal and length of ICU stay were significantly greater with F, although duration of intubation did not differ between anesthetic techniques. Although the data does not provide an explanation for these differences, it indicates that these two techniques produce quite different physiologic responses in the postoperative period following cardiac surgery. In summary, it was found that F for cardiac surgery was accompanied by increased postoperative fluid and vasopressor requirements with increased Qsp/Qt and longer ICU stays compared to diazepam and ketamine. This study suggests that some anesthetic techniques may provide less complicated and less costly postoperative courses than others, with the same outcome after cardiac surgery. Information on the postoperative effects of long-acting anesthetic agents is sparse and more studies of these effects and their mechanisms are necessary because they may affect patient management after cardiac surgery.