Clinical trial of esmolol-induced controlled hypotension with or without acute normovolemic hemodilution in spinal surgery

Abstract

Background: Drug-induced controlled hypotension (CH) combined with acute normovolemic hemodilution (ANH) is being widely used for blood conservation in surgical patients. The purpose of this study was to investigate the efficacy and safety of esmolol-induced CH combined with ANH (hematocrit down to 28%). Methods: Thirty patients who were scheduled to receive spinal surgery were randomly divided into two groups: an esmolol-induced CH alone group (esmolol group, n=15) and a CH-ANH combined group (E-ANH group, n=15). Controlled hypotension was induced with esmolol 500 μg/kg, followed by a continuous infusion of 0-300 μg/kg/min to maintain mean arterial pressure at 55-65 mmHg. Results: The mean infusion rate of esmolol in the esmolol-ANH group was 46±6 μg/kg/min (mean±SD), which was significantly lower than the 77±9 μg/kg/min used in the esmolol group (P<0.05). The number of units of homologous blood (packed RBC) transfused perioperatively was 2.2±0.6 units in the esmolol-ANH group, which was significantly less than 4.3±0.4 units used in the esmolol group (P<0.01). While O2 delivery decreased significantly during CH, O2 consumption remained unchanged in both groups. No complications resulted from CH or ANH in any of the groups. Conclusion: Our data suggest that ANH of moderate degree can be combined with esmolol-induced CH to improve blood conservation in surgical patients. © Acta Anaesthesiologica Scandinavica 47 (2003).