P043: MANAGEMENT OF AN END STAGE RENAL DISEASE PATIENT WITH MULTIPLE ACCOUNTS OF LOSARTAN INDUCED VASOPLEGIC SYNDROME, IS THERE A BETTER APPROACH? : A CASE REPORT
Taylor Brown, MD, Matthew Gunst, MD, R Victor Zhang, MD, PhD; University of Florida
Introduction: Hypotension during anesthesia is a known issue, especially in patients taking inhibitors of the renin-angiotensin-aldosterone system (RAAS) such as angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs).1 Understanding the role of the RAAS in blood pressure regulation can help with management in refractory hypotension in the patient under general anesthesia. This case report describes accounts of refractory hypotension in a patient with end stage renal disease (ESRD) on hemodialysis (HD) and taking an ARB despite receiving different levels of anesthesia.
Case Presentation: A 44 year old 162 kg male with an extensive past medical history notable for hypertension on losartan, furosemide, and carvedilol, hyperlipidemia, type 2 diabetes mellitus on insulin, ESRD on HD, and a history of difficult intubation presented for revision of his HD access. Previously he was taken for HD access creation under general anesthesia when he had severe hypotension leading to cardiac arrest requiring 23 shocks to obtain return of spontaneous circulation. In addition, previous vascular surgeries with either general anesthesia, regional anesthesia with minimal sedation or solely sedation with ketamine have all resulted in profound hypotension.
The surgeon requested general anesthesia for required revision of HD access. Induction of anesthesia was achieved with fentanyl, lidocaine, rocuronium, as well as propofol in divided doses to a total of 200 mg. Following successful intubation with video laryngoscopy, his blood pressure fell to 60/38 mmHg. Vasopressin was given in 1 unit increments for a total of 3 units.
Discussion: RAAS is one mechanism for maintaining normal blood pressure, along with the sympathetic nervous system and the arginine vasopressin (AVP) system. With induction of anesthesia acting as a sympatholytic, it is not uncommon for profound hypotension to occur in patients who take RAAS antagonists.2 Although inhibitors of RAAS are vital for cardiorenal protection in hypertensive patients, there is evidence to hold for 24 hours prior to surgery to prevent hypotension and increases in mortality. Severe hypotension refractory to catecholamine therapy is referred to as vasoplegic syndrome.3 Vasoplegic syndrome can be treated with vasopressin by focusing on the third, often overlooked, AVP system.
It is important to investigate the potentially increased effects losartan has on blood pressure for patients with ESRD on HD experiencing vasoplegia. Losartan is metabolized by the CYP450 pathway to a more pharmacologically active metabolite, E3174, that is 10 to 40 fold more potent than its parent compound.4 Interestingly, E3174 is not removed during hemodialysis. This case presents a unique challenge in further preoperative considerations for losartan in patients with ESRD on HD.
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3. Shear T, Greenberg S. “Vasoplegic Syndrome and Renin-Angiontensin System Antagonists.” Anesthesia Safety Patient Foundation Newsletter (2012) 27:1 18-19
4Sica D, Gehr T, Ghosh S. “Clinical Pharmacokinectics of Losartan.” Clin Pharmacokinet (2005) 44:8 797-814