EPIDURAL ANALGESIA DURING MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS (MIDCAB) SURGERY IMPROVES PATIENT OUTCOME

Abstract

Introduction. In MIDCAB surgery there is currently no agreement about the timing of extubation and the use of regional anesthetic techniques. [1] To investigate the effects of epidural analgesia and extubation in the operating room we prospectively analyzed blood gas variables, hemodynamics, pain score, length of hospital stay and myocardial infarction rate in 60 patients after MIDCAB surgery. Methods. Patients were randomized into 3 groups. Group A (n=20) were extubated immediately after the operation. Group B (n=20) had an epidural catheter placed at T3-4 before induction of anesthesia and were extubated immediately after the operation. Group C (n=20) served as controls and were left intubated and mechanically ventilated after the operation. Anesthesia consisted of midazolam, propofol, sufentanil and pancuronium. Epidural analgesia was achieved with bupivacain/sufentanil. A pulmonary artery catheter was inserted. Extubated patients received 40% oxygen by face mask. Pain management consisted of intramuscular opiates. A bupivacain/sufentanil infusion was used in the epidural group. Blood gas analysis and hemodynamic measurements were performed after induction of anesthesia, at end of operation and the morning of the first postoperative day. Results. Patient groups were comparable with respect to age, body surface, ejection fraction, previous infarction and previous PTCA. Main results are shown in Table 1.Table 1: Values are mean +/- SD. *= P<0.05 vs group C; $=P<0.05 vs group B; ANOVA.Discussion. The epidural-based anesthetic technique with direct postoperative extubation in group B resulted in optimal oxygenation and hemodynamics on the first postoperative day. This is probably the combined result of good analgesia allowing for adequate respiration and a sympathetic blockade as seen from a lower mean arterial pressure and lower heart rate with preservation of cardiac output. [2] However, at the end of operation a mild respiratory acidosis was observed in group A and B. This was in the epidural group B not accompanied by an increase in heart rate and mean arterial pressure. We conclude that an epidural-based anesthetic technique with direct postoperative extubation after MIDCAB surgery results in improved patient outcome.