Large-and small-vessel arterial occlusive disease is the single most important risk factor in the preoperative setting. A careful history and physical examination should be performed to determine the presence or absence of coronary artery or cerebral vascular disease (150). When extended surgery is possible, as with surgery for gynecologic cancer, exercise stress testing or dipyridamole-thallium imaging should be considered to rule out occult coronary artery disease. Perioperative beta-blockade should be continued for patients already on beta-blockers at baseline. For patients with inducible ischemia, coronary artery disease, or multiple clinical risk factors for heart disease, perioperative beta-blockade should be considered, with initiation and careful titration of medication several weeks prior to surgery (154,155). Assessment of end-organ disease in the retina, kidney, and carotid arteries or evidence of peripheral vascular disease by the presence of foot ulcers should alert the clinician to the presence of small-or large-vessel disease. Diabetic nephropathy should be documented carefully preoperatively. Imaging studies using contrast dye should be avoided, and alternative testing should be performed to reduce the incidence of acute tubular necrosis. If a contrast study must be performed, adequate hydration both before and after the procedure is essential, and oral metformin should be withheld for 24 to 48 hours after the procedure.
Diabetes is associated with increased perioperative infections (156). Preoperative evaluation should include examination of the skin and urine sediment to detect asymptomatic infection. Wound infections, skin infections, pneumonia, and urinary tract infections account for two-thirds of the postoperative complications in patients with diabetes (151). There is a known predisposition for patients with DM to have increased colonization by methicillin-resistant Staphylococcus aureus, increased infections by gram-negative and staphylococcal bacteria, and an increased incidence of gram-negative and group B streptococcal sepsis (157–159). Seven percent of individuals with diabetes will have postoperative gram-negative sepsis, a rate approximately seven times higher than that of the nondiabetic population. These complications occur more often in patients with poor glucose control, probably caused by impaired leukocyte function in the presence of hyperglycemia (160,161). Individuals with DM have an increased risk of wound dehiscence and wound infection, possibly related to an impaired immune function, with changes in phagocytosis, cell-mediated immunity, and intracellular bactericidal activity (162). Autonomic neuropathy was documented in patients with DM, and these autonomic impairments can lead to intraoperative hypotension, cardiac arrhythmias, sudden death and abnormal motility of the esophagus, stomach, and small intestine (151). Peripheral sensory and motor neuropathies may or may not be present. The presence of any manifestations of autonomic neuropathy intra-operatively should prompt close monitoring of the affected organ system in the postoperative period.
The traditional goal for glucose control perioperatively is to maintain the glucose level below 200 mg/dL (151,153). Significant debate continues regarding whether strict glycemic control below 110 mg/dL may be beneficial in critically ill patients (163,164). Perioperative hyperglycemia (>250 mg/dL) is associated with increased susceptibility to infection and poor wound healing. Extreme hyperglycemia predisposes type 1 DM patients to metabolic acidosis, and surgery should be canceled until normal acid-base balance is documented. Hyperosmolar hyperglycemic nonketotic states must be recognized before surgery. Electrolyte disturbances, especially those related to sodium and potassium, should be corrected preoperatively. Hypoglycemia should be avoided during the perioperative period.