Nerve stimulation in patients undergoing hysterectomy under general anaesthesia

The possible impact of transcutaneous electrical nerve stimulation (TENS) on cardiovascular responses associated with tracheal intubation, surgery and postoperative period was evaluated in patients undergoing hysterectomy. Thirty-eight patients undergoing abdominal hysterectomy were randomly allocated either to the TENS group (n = 19), with electrical stimulation applied preoperatively and continued postoperatively for six hours on the stellate ganglion (SG), or to the control group (n = 19), with the stimulator turned off. Systolic arterial pressure (SAP) and heart rate (HR) were recorded before induction of anaesthesia, after cuff inflation, one minute, three minutes and five minutes later, every 15 minutes intraoperatively and every two hours postoperatively for eight hours. TENS of SG failed to prevent the cardiovascular responses associated with intubation of the trachea and surgery. HR, but not SAP, mean values were significantly lower in the TENS-treated group four and six hours postoperatively (p < 0.02, p < 0.01, respectively) when compared with the control group. These differences disappeared when TENS was discontinued.