Preoperative evaluation: A time-saving algorithm

Perioperative medication management

One aspect of the preoperative evaluation that should not be overlooked is a thorough medication reconciliation. Primary care providers can support the operative team by recommending medication adjustments prior to surgery. Several classes of medications have specific perioperative recommendations, which are summarized here.

Hypertension medications

• Beta-blockers. A patient who regularly takes a beta-blocker should continue the medication on the day of surgery and restart after surgery.^2,20
• Calcium channel blockers. Calcium channel blockers can be continued through the day of surgery.^2,20
• Renin-angiotensin system antagonists. Given the increased risk of hypotension following anesthesia induction, have patients refrain from taking angiotensin-converting enzyme inhibitors and angiotensin receptor blocker medications for at least 10 hours prior to surgery.²⁰
• Diuretics. Diuretics can be given on the day of surgery, although they increase the risk of hypovolemia and electrolyte disturbances.²⁰

Diabetes medications

• Insulin. For patients with type I diabetes, recommend basal insulin of 0.2 to 0.3 units/kg/day of long-acting insulin.²¹ If the patient is using an insulin pump, basal rate should be continued. For patients with type 2 diabetes, the simplest method is to use one-half the normal long-acting insulin dose on the morning of surgery.²²
• Metformin. Discontinue metformin 24 hours prior to surgery because of the risk for lactic acidosis.^21,22 While the risk of lactic acidosis from metformin is low, mortality rates as high as 50% have been documented after lactic acidosis occurred with similar medications.²²
• Sulfonylureas. Sulfonylureas should be held on the day of surgery due to the risk of hypoglycemia and a possible increased risk of ischemia.^21,22
• Thiazolidinediones, dipeptidyl peptidase-4 inhibitors, and glucagon-like peptide-1 agonists. All should be held on the day of surgery.²¹