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INTRODUCTION

CASE DISCUSSION

A 72-year-old, 96-kg, 179-cm male is scheduled for a transperineal repair of a 6-cm suprarenal abdominal aortic aneurysm repair. His past medical history is significant for coronary artery disease, hypertension, gastroesophageal reflux, smoking, and chronic obstructive pulmonary disease. His current medical management includes metoprolol, losartan, atorvastatin, and omeprazole. He has not taken any medications this morning. His ­current vital signs are: pulse 95/min, blood pressure 165/96 mm Hg, oxygen saturation 92%, and respiratory rate 19/min.

PREMEDICATION

  • Anxiolytic: Intravenous midazolam

  • β blocker: Intravenous metoprolol, esmolol infusion, or propranolol

  • Antihypertensive: Intravenous labetalol, hydralazine, or nicardipine

  • Statin: Oral atorvastatin, simvastatin, pravastatin, or fluvastatin

  • Thoracic epidural: Preoperative placement

Sample Dosing Regimen

  • Anxiolytic: Intravenous midazolam 1 to 2 mg, 15 to 30 minutes prior to induction

  • a blocker: Consider slowly titrating intravenous metoprolol 1 to 10 mg (0.1 mg/kg) to a heart rate of < 65 beats/min, 30 minutes prior to induction.

  • Antihypertensive: Consider intravenous labetalol 5 to 50 mg titrated to blood pressure within 20% above baseline blood pressure if not achieved with anxiolysis 10 minutes prior to induction.

  • Statin: Oral atorvastatin 20 to 40 mg, 30 minutes prior to induction

  • Thoracic epidural: Placement of an epidural catheter in the T10–11 interspace 30 minutes preoperatively, with administration of 3 mL of 1.5% lidocaine with 1:200,000 epinephrine as a test dose

Clinical Pharmacology

Anxiolysis prior to major vascular surgery can have the additional benefit of reducing adrenergic tone. Anxiolysis may be sufficient to return this patient's heart rate and blood pressure to baseline. Midazolam is frequently chosen due to its rapid onset, but the slower offset of midazolam can be a source of sedation into the postoperative period. Prolonged sedation is of more concern in the elderly and those with preexisting cognitive dysfunction.

β Blockers should not be acutely discontinued, because this can result in rebound tachycardia, hypertension, and angina. Evidence supports the continuation of chronic β-blocker therapy.1 Initiation of perioperative β blockade has been questioned based on the PeriOperative Ischemic Evaluation (POISE) trial. The POISE trial demonstrated that perioperative β blockade decreased the incidence of myocardial infarction but increased overall mortality and stroke.2 There are several limitations to the POISE trial; the 2 major limitations are (1) the fixed high dose of metoprolol (100 mg) and (2) the revised cardiac risk index (RCRI) of 1 or 2 in most of the patients (Table 32–1). Therefore, there may still be overall benefit in patients with high cardiac risk (RCRI ≥ 3).

Table 32–1Revised cardiac risk index (rcri) predictors of perioperative cardiac risk.3

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