Effects of glucose-free maintenance solution on plasma glucose during anesthesia in patients undergoing long neurologic surgery

Background. Using glucose-free solution as fluid maintenance is widely advocated during neurosurgery because of concerns about hyperglycemia aggravating cerebral ischemia. This study evaluated the alterations in plasma glucose concentrations in both adult and pediatric patients undergoing lengthy neurologic surgery, during which they were given glucose-free solutions. Methods. This study included 154 patients (ASA class II, aged 3 months-75 years) undergoing elective neurosurgical procedures. They were divided into two groups: group A (15-75 years-of-age) and group P (3 months- 14 years-of-age). Groups A (n=126) and P (n=28) were further divided into five subgroups, respectively, based on the duration of surgery: 5, 6, 7, 8 and 9 hours. Anesthesia was maintained with isoflurane, fentanyl and vecuronium. Blood sampling was undertaken every hour throughout surgery. Results. Adult patients differed significantly in body weight (61.5 ± 10.9 vs 25.6 ± 14.9 kg), age (58.9 ± 15.7 vs 7.5 ± 4.3 years), use of preoperative β-blocking agents (33/126 vs 1/28) and the need for blood transfusion (58/126 vs 24/28). Neither group had elevated glucose levels. Compared with pediatric patients, the incidence of intraoperative hypoglycemia was statistically higher in adult patients, with a rate that peaked in the eighth (25.9%, group A vs 0% group P) and ninth hours (27.3%, group A vs 0% group P) of surgery. There were no differences in glucose concentrations at other points in time. Conclusions. In contrast to pediatric patients, intraoperative hypoglycemia occurred more often in adult patients during prolonged neurosurgical procedures when glucose-free solution was used for fluid maintenance. Therefore, frequent determination of plasma glucose concentrations is mandatory, especially in patients undergoing long-lasting neurosurgical anesthesia.