Effect of acute normovolemic hemodilution on anesthetic effect, plasma concentration, and recovery quality in elderly patients undergoing spinal surgery

Objective To explore the effect of acute normovolemic hemodilution (ANH) on the anesthetic effect, plasma concentration, and postoperative recovery quality in elderly patients undergoing spinal surgery. Methods A total of 60 cases of elderly patients aged 65 to 75 years who underwent elective multilevel spinal surgery were assigned randomly into the ANH group (n = 30) and control group (n = 30). Hemodynamic and blood gas analysis indexes were observed and recorded before ANH (T.sub.1), after ANH (T.sub.2), immediately after postoperative autologous blood transfusion (T.sub.3), 10 min (T.sub.4), 20 min (T.sub.5), 30 min (T.sub.6), 40 min (T.sub.7), and 50 min (T.sub.8) after the transfusion, and at the end of the transfusion (i.e., 60 min; T.sub.9). At T.sub.3 ~ 9, bispectral index (BIS) and train-of-four (TOF) stimulation were recorded and the plasma propofol/cisatracurium concentration was determined. The extubation time and recovery quality were recorded. Results The ANH group presented a lower MAP value and a higher SVV value at T.sub.2, and shorter extubation and orientation recovery time (P < 0.05) compared with the control group. BIS values at T.sub.8 and T.sub.9 were lower in the ANH group than those in the control group (P < 0.05). TOF values at T.sub.7 ~ 9 were lower in the ANH group than those in the control group (P < 0.05). There were no statistically significant differences in the postoperative plasma concentrations of propofol and cisatracurium between the groups (P > 0.05). Conclusion During orthopedic surgery, the plasma concentration of elderly patients is increased after autologous blood transfusion of ANH, and the depth of anesthesia and muscle relaxant effect are strengthened, thus leading to delayed recovery of respiratory function and extubation. Keywords: Acute normovolemic hemodilution, Anesthetic effect, Elderly, Plasma concentration, Spinal Surgery