Perioperative changes in cardiac autonomic control in patients receiving either general or local anesthesia for ophthalmic surgery.

Abstract

To investigate whether local (LA) or general anesthesia (GA) provides more perioperative stability in cardiac autonomic tone, we analyzed heart rate variability (HRV) by means of spectral analysis, intraoperatively and up to 3 h postoperatively, in otherwise healthy patients scheduled for cataract surgery. Fourteen patients received GA (premedication: clorazepate; anesthetic induction: propofol, alfentanil, atracurium; anesthetic maintainance: isoflurane, alfentanil; airway management: laryngeal mask airway), and 14 patients received LA (retrobulbar block with bupivacaine/mepivacaine). In the GA group, total power, as an indicator of cardiac autonomic activity, was significantly reduced intraoperatively and increased slowly during the postoperative period. The ratio of low frequency/high frequency (LF/HF) power, indicating cardiac sympathovagal balance, did not change significantly intraoperatively and remained stable in the postoperative period. The LA group showed no significant changes in total power intraoperatively. Postoperatively, heart rate and the LF/HF power ratio were significantly increased in the LA group compared to the GA group. GA as described above was associated with intra- or postoperative stability of the cardiac sympathovagal balance. Thus GA had no disadvantageous effects on the perioperative cardiac autonomic tone during ophthalmic surgical procedures compared to LA in otherwise healthy patients.