[Arterial plasma keton body levels during isoflurane anesthesia and surgery]

The authors measured arterial plasma levels of acetoacetate, 3-hydroxybutyrate, free fatty acid and the blood levels of lactate and glucose to evaluate fat metabolism during isoflurane anesthesia and surgery in twenty patients who ranged in age from 17 to 67 years. They underwent non-abdominal surgery (orthopedic surgery) or abdominal surgery (gastrointestinal or gynecological surgery). The operation started at 9 AM following starvation after 9 PM of the day before surgery. Anesthesia was induced with intravenous thiopental followed by intravenous succinylcholine to facilitate tracheal intubation, and maintained with isoflurane in 50 % nitrous oxide and 50 % oxygen. Vecuronium was given intravenously during surgery. Lactated Ringer's solution at a speed of 5-15 ml.kg-1.h-1 was also administered intravenously throughout the procedures. Patients who had received glucose solution or blood transfusion were excluded. Plasma acetoacetate and 3-hydroxybutyrate levels increased significantly with surgical stimulation in both groups and they were slightly higher in the abdominal group than those in the non-abdominal group. However there was no statistical difference in plasma keton body levels between the groups. Mild increases in plasma free fatty acid and blood lactate levels were detected during surgery in both groups to the same extent. Blood glucose increased significantly during surgery in both groups and the increase was statistically higher in the abdominal group than that in the non-abdominal group. The findings suggest that there is no difference in fat metabolism between non-abdominal and abdominal groups during surgical intervention lasting as long as 3 hours when patients are starved and do not receive any glucose during surgery.