Background: The pharmacokinetic properties of the short-acting micro opioid receptor-agonist remifentanil makes it possible to give cardiac surgical patients a deep intraoperative anesthesia without experiencing postoperative respiratory depression and a prolonged stay in the intensive care unit (ICU). However, previous investigations have shown that patients who received remifentanil required additional analgesia during the early postoperative period as compared to patients who received fentanyl. The aim of the present study therefore was to investigate the effects of supplementing remifentanil to a standard fentanyl-based anesthesia in coronary artery bypass grafting (CABG).
Methods: The study was prospective, randomized, double-blind, and placebo-controlled. Twenty male patients aged 55-70 years were included. All patients received a standard fentanyl and isoflurane-based anesthesia. In addition, the patients were randomized to receive either remifentanil 0.5 micro g kg(-1) min(-1) or placebo during surgery. Hemodynamic recordings and measurements of blood glucose and plasma adrenaline and noradrenaline were performed intra- and postoperatively.
Results: Remifentanil reduced the hemodynamic and metabolic response to surgical stress compared to the standard fentanyl-based anesthetic regimen. However, the patients in the remifentanil group had a lower cardiac output (CO), left ventricular stroke work index (LVSWI), and mixed venous oxygen saturation (SvO(2)), and a higher central venous pressure (CVP) than the patients in the placebo group during the early postoperative phase, indicating a postoperative cardiac depression in the remifentanil group.
Conclusion: In CABG, remifentanil reduces the hemodynamic and metabolic responses during surgery but seems to give a cardiac depression in the early postoperative phase.