soft-tissue changes and cellular swelling affect airway anatomy, which may result in difficult glottic visualization due to stiff tissue and joints. Even accounting for equal degrees of obesity, the airway in patients with diabetes is more likely to be difficult compared to those without DM (2). Furthermore, diabetic autonomic neuropathy delays gastric emptying and can increase aspiration risk.
for Ambulatory Anesthesia (SAMBA) Consensus statement states that patients with preoperative hyperglycemia who have adequate long-term glycemic control may proceed to surgery. For patients with chronically poor glycemic control, SAMBA recommends a joint decision with the surgeon considering other comorbidities and risks of surgical complications. SAMBA also recommends postponing surgery if there are complications of hyperglycemia such as dehydration, diabetic ketoacidosis (DKA), or hyperosmolar nonketotic states (9). Some clinicians and institutions routinely specify that the HbA1c must be below a specific level (e.g., HbA1c <7 to 8) for some specific interventions (e.g., elective total joint replacement or spine surgery).
TABLE 8.1 History and Physical Examination
TABLE 8.2 Who Should Be Tested?
practice are renal impairment (defined as eGFR <60 mL/min/1.73 m2) and the anticipated use of IV iodinated radiographic contrast. Recently, in two important trials, the GLP-1 agonist liraglutide and the SGLT-2 inhibitor empagliflozin have been shown to reduce MACE, cardiovascular death, and all-cause mortality (13,14). These can also be given perioperatively provided the fasting period is brief (i.e., only one meal missed) (12).
the commencement of fasting with some specific exceptions (see Table 8.3). For insulin instructions, see Chapter 18.3, noting that patients with type 1 DM require constant exogenous insulin to prevent ketoacidosis.
TABLE 8.4 Systemic Manifestations of Thyrotoxicosis
TABLE 8.5 Systemic Manifestation of Hypothyroidism and Myxedema Coma
leads to accumulation of glycosaminoglycans in the interstitial tissues resulting in coarse hair, dry skin, nonpitting edema, macroglossia, periorbital edema, and hoarseness (7,8). The history explores risk factors, including autoimmune disease, prior thyroid surgery, or pituitary insufficiency. If undergoing treatment, symptoms of excess thyroid hormone (see Chapter 8.2 on Hyperthyroidism) are monitored.
TABLE 8.6 Preoperative Testing
can include fatigue, loss of appetite, weight loss, nausea, vomiting, myalgias, and arthralgias. Signs can include orthostatic hypotension and, in the case of primary adrenal insufficiency, hyperpigmentation from increased concentrations of ACTH (2). Examination of the patient includes recording of vital signs, particularly the blood pressure with orthostatic measurements.
Patients continue their glucocorticoid or mineralocorticoid replacement therapy on the day of surgery.
Steroid supplementation is advisable for major procedures in patients taking >20 mg/day of prednisone or its equivalent. See Chapter 18.6.
The risk of adrenal insufficiency remains for up to 1 year after the cessation of highdose steroid therapy.
and adrenal carcinomas can lead to inappropriately high plasma levels of glucocorticoids (1). Cushing disease refers specifically to Cushing syndrome caused by pituitary secretion of excessive ACTH.
TABLE 8.7 Clinical Features of Cushing Syndrome
TABLE 8.8 Preoperative Evaluation of Patients With Cushing Syndrome