Glucose management in patients undergoing operation for insulinoma removal

Medical records of 38 patients undergoing anesthesia and surgery for removal of an insulinoma were reviewed to determine 1) the safety of avoiding intraoperative glucose, 2) the appropriate frequency of plasma glucose analysis, and 3) the accuracy of using rebound hyperglycemia as an indication of tumor removal. Plasma glucose was determined approximately every 15 min during operative and recovery-room periods. The changes in plasma glucose concentrations before tumor removal were compared with those occurring after the resection in each patient by separate linear regressions of glucose concentration versus time. The slopes of the preresection regression lines averaged +0.196 (+/- SD 0.577) mg X dl-1 X min-1. The mean of the postresection slopes was +0.624 (+/- SD 0.339) mg X dl-1 X min-1. The mean difference in slope (post- minus pre-) was +0.426 (+/- SD 0.748) mg X dl-1 X min-1, indicating that a significant (P less than 0.02) increase in post-resection slope had occurred. In no case did a preresection plasma glucose concentration decrease to less than 50 mg X dl-1 if the previous value had been 60 mg X dl-1 or greater. Nonetheless, there were nine patients whose plasma glucose did decrease to less than 50 mg X dl-1 at some time during the operative course. Only 39% of patients showed a rebound of 20 mg X dl-1 or more in the first 30 min after resection. The authors conclude that intermittent sampling is safe as long as plasma glucose is kept above 60 mg X dl-1 by infusing glucose.(ABSTRACT TRUNCATED AT 250 WORDS)