Chapter 29 - Diabetes mellitus

Summary

Surgery has major effects on carbohydrate metabolism and thus presents special risks for patients with diabetes. Surgical mortality rates for patients with diabetes have declined but the successful perioperative care of these patients requires close cooperation between surgeons, anesthesiologists, and primary physicians to prevent complications. There are 25.8 million children and adults in the USA with diabetes – 8.3% of the population [1]. Diabetes is listed as a diagnosis on 23% of hospital discharges [2]. At least half of these patients will require surgery at some point in their lives. In addition to surgical conditions typical of the general population, patients with diabetes have an increased incidence of occlusive vascular disease; cholelithiasis; ophthalmic disease (i.e., cataract extraction, vitrectomy); renal disease; and infection. Three of four patients with diabetes are older than 40 years and are approaching a time of life when surgical indications increase. The presence of diabetes typically is known prior to surgery, although a new diagnosis of diabetes is made in the perioperative period in as many as 12% of cases [3].

Hyperglycemia in the hospital is common and may result from stress, infection, effect of procedures, or is iatrogenic [4]. Previously, glucose levels between 100 and 200 mg/dL were not treated in the perioperative period. This practice was challenged by studies suggesting that more aggressive treatment of elevated glucose levels with insulin reduces infectious complications, decreases mortality, and decreases length of hospital stay [5–7]. Many hospitals developed programs, and started treating both medical and surgical patients with intensive insulin therapy to maintain blood glucose at or below 110 mg/dL, particularly in ICU settings. But, following studies performed in other ICUs, particularly medical ones, failed to reproduce the beneficial effects of intensive insulin therapy. In fact, intensive insulin therapy increased the risk of death [8–11]. One study demonstrated a 2.6% absolute increase in 90-day mortality in patients randomized to tight glucose control [10]. This may have been related to the increased risk for hypoglycemia in the intensive insulin group [12].