The effect of esmolol-induced controlled hypotension in combination with acute normovolemic hemodilution on cerebral oxygenation

Abstract

Background: It is possible to perform acute normovolemic hemodilution (ANH) in combination with controlled hypotension (CH). In this randomized prospective study, we examined the effect of the combination of ANH and CH on cerebral oxygenation using near-infrared spectroscopy. Methods: Fifty-six patients undergoing major orthopedic surgery were randomly assigned to either group A (ANH only) or group CH (CH in combination with ANH). In group CH, CH was induced with esmolol. The regional cerebral oxygen saturation (rSO(2)) was monitored continuously and was compared between the two groups before and after ANH, 30 min (OP30) and 90 min (OP90) after the beginning of surgery and after the completion of surgery. Results: The value of rSO(2) was the same in both groups in the absence of CH (at baseline: group A, 70.1 +/- 6.0%; group CH, 69.9 +/- 6.7%; after surgery: group A, 64.5 +/- 4.9%; group CH, 64.3 +/- 5.8%). However, in the presence of CH, rSO(2) values were significantly lower in group CH than in group A (at OP30: group A: 60.4 +/- 3.4%; group CH, 55.9 +/- 7.3%; P < 0.01; at OP90: group A, 58.3 +/- 5.2%; group CH, 53.5 +/- 6.5%; P < 0.001). The number of patients with rSO(2) < 50% was significantly higher in group CH (14.3%) than in group A (3.8%). Conclusion: ANH in combination with esmolol-induced CH causes a significant decrease in cerebral oxygen saturation compared with ANH alone.