If the patient who is on lisinopril develops hypotension intraoperatively, how would you manage it?
Answer:
The more common causes of intraoperative hypotension, such as hypovolemia, deep anesthesia, and surgical manipulation, should be corrected first. Vasoplegic syndrome is most commonly observed in cardiac surgery. It is characterized by severe refractory hypotension in the absence of other identifiable causes of hypotension. Persistent hypotension increases perioperative mortality.
BP is maintained by three systems: the sympathetic system, the renin-angiotensin system (RAS), and the vasopressinergic system. Most anesthetic medications reduced the influence of the sympathetic system, and, as a result, the body relies more on the RAS and vasopressinergic systems. ACE inhibitors and angiotensin receptor blockers are RAS antagonists. ACE inhibitors specifically prevent the conversion of angiotensin I to angiotensin II. This results in a lower arterial resistance and increased vascular capacitance.
There is no specific antagonist for ACE-inhibitors. Treatment may be challenging. Conventional therapies such as volume expansion and vasopressors may be tried. When these conventional therapies are not effective, exogenous vasopressin may improve hypotension. Refractory hypotension may be treated with methylene blue, which interferes with the nitric oxide-cyclic guanylate monophosphate (cGMP) pathway. Methylene blue is contraindicated in patients with renal impairment because it is primarily eliminated by the kidneys.
Reference(s):
- Ertmer C, Rehberg S, Westphal M. Vasopressin analogues in the treatment of shock states: potential pitfalls. Best Pract Res Clin Anaesthesiol. 2008;22:393-406.
- Fischer GW, Levin MA. Vasoplegia during cardiac surgery: current concepts and management. Semin Thorac Cardiovasc Surg. 2010;22:140-144.
- Gomes WJ, Carvalho AC, Palma JH, et al. Vasoplegic syndrome after open heart surgery. J Cardiovasc Surg (Torino). 1998;39:619-623.
- Lange M, Aken HV, Westphal M, et al. Role of vasopressinergic V1 receptor agonists in the treatment of perioperative catecholamine-refractory arterial hypotension. Best Pract Res Clin Anaesthesiol. 2008;22:369-381.
- Turan A, You J, Shiba A, et al. Angiotensin converting enzyme inhibitors are not associated with respiratory complications or mortality after noncardiac surgery. Anesth Analg. 2012;114(3):552-660.