Controlling deliberate hypotension in hypertensive patients undergoing spinal surgery: a comparison between remifentanil and sodium nitroprusside

ABSTRACT

BACKGROUND:This study was designed to determine whether remifentanil or sodium nitroprusside (SNP) with sevoflurane anesthesia can induce safe deliberate hypotension (DH) to a target mean arterial pressure (MAP) of 55-65 mmHg in patients with controlled hypertension. METHODS:Thirty patients with controlled hypertension and who were scheduled for posterior lumbar interbody fusion were randomly assigned to receive remifentanil (n = 15, group R) or SNP (n = 15, group S).All the patients received a balanced anesthetic technique including 1.5-2 vol% sevoflurane.Group R received remifentanil by target-controlled infusion.The infusion was initiated with a target concentration at 4 ng/ml and this was adjusted every 1 min by 1 ng/ml to maintain the MAP to the target level of 55-65 mmHg.In group S, the infusion of SNP was initiated at 1 ug/kg/min and this was increased by 0.5 ug/kg/min.Cerebral oximetry was done and the cardiac index was measured with esophageal Doppler. RESULTS:DH was achieved at a MAP = 60 mmHg within 5.7 min for group R and 3.7 min for group S.The intraoperative blood loss was lower in Group R than that in Group S (304 +/- 103 vs 650 +/- 141 ml, P < 0.05).The frequency of added ephedrine injection to control the MAP and discontinuation of the study drug due to a MAP < 60 mmHg were higher in group S than in group R (46% vs 13%, P < 0.05 and 62% vs 20%, P < 0.05, respectively). CONCLUSIONS:Compared to SNP, remifentanil with sevoflurane anesthesia induced safer DH for patients with controlled hypertension.