Postoperative insulin secretion is decreased in patients with preoperative insulin resistance

Postoperative hyperglycemia is associated with increased rate of surgical site infection, renal failure, and cardiovascular events. The study of insulin sensitivity state before surgery could help in treating postoperative hyperglycemia and preventing iatrogenic hypoglycemia. We studied the postoperative insulin secretion in patients who have a low insulin sensitivity (IR) before surgery compared to patients with normal preoperative insulin sensitivity (IS).

Forty-two consecutive patients, undergoing abdominal surgery, underwent preoperative sequential hyperglycemic-euglycemic clamp (SHEC) in order to measure insulin secretion and to screen patients with low insulin sensitivity (IR) or with normal insulin sensitivity (IS). Patients had been randomized to receive either general anesthesia with epidural or PCA.

Postoperative insulin secretion in IR patients is decreased compared to IS (P = 0.059) and to IR before surgery regardless to the type of analgesia (P < 0.001). In the IS group, postoperative insulin secretion depends on type of analgesia. It is increased when using PCA and decreased when using epidural (P < 0.05). Blood glucose increased after surgery in both IS an IR (P < 0.001). Patients with preoperative insulin resistance had a higher glycemia before and after surgery (P < 0.001). Blood glucose levels were comparable between PCA and epidural patients (P = 0.450).

Insulin secretion is reduced in IR regardless the type of anesthesia. PCA increases insulin secretion, whereas epidural decreases it in patients with normal insulin sensitivity. These findings implicate that after surgery insulin administration is advisable in patients with preoperative insulin resistance while it should be given cautiously in those with normal preoperative insulin sensitivity.