Refractory intraoperative hypotension: A case report to keep in mind

Abstract

Refractory intraoperative hypotension can be triggered by a complex interplay of perioperative factors, including anesthetic-induced vasodilation, patient positioning, surgical blood loss, autonomic dysfunction, and the prolonged effects of the patient's daily medications (such as long-acting irbesartan, amlodipine, and concomitant beta-blocker therapy). While the optimal approach to perioperative renin–angiotensin system inhibitor use remains uncertain, these combined agents can severely impair cardiovascular compensatory mechanisms and blunt vasopressor responsiveness under general anesthesia. A 66-year-old male with hypertension and diabetes underwent posterior spinal instrumentation under general anesthesia. Following induction and prone positioning, severe refractory hypotension developed despite aggressive fluid resuscitation guided by Pleth Variability Index, vasopressors, and inotropic support. Progressive lactic acidosis led to surgical termination at the 150th minute. Postoperative cardiac evaluations were normal. Further history revealed the patient had taken a long-acting triple combined antihypertensive regimen (irbesartan/amlodipine/hydrochlorothiazide) the night before surgery. Norepinephrine support was required for 36 hours postoperatively, followed by a full recovery. While diabetic cardiac autonomic neuropathy and prone positioning create a vulnerable baseline for hemodynamic instability, long-acting triple combination antihypertensive therapy acts as the definitive driver for severe, refractory vasoplegic shock. Concomitant use of renin-angiotensin system inhibitors, calcium channel blockers, and thiazide diuretics can severely impair compensatory vasoconstriction and blunt vasopressor responsiveness under general anesthesia. Perioperative antihypertensive management must be strictly individualized according to drug half-life, combination characteristics, and patient comorbidities.