Anesthetic Management Of A Pregnant Patient With HOCM Undergoing Emergency Cesarean Delivery Under General Anesthesia
Abstract Number: T3C-6
Abstract Type: Case Report/Case Series
Introduction: Hypertrophic obstructive cardiomyopathy (HOCM) is associated with hemodynamic abnormalities that can be exacerbated by pregnancy and general anesthesia. We present a case of a parturient with HOCM who underwent an emergency cesarean delivery (CD) under general anesthesia and discuss the relevant hemodynamic and anesthetic considerations.
Case: 36 y/o G2P1 presented at 34 weeks in preterm labor. She previously underwent a CD for non-reassuring fetal heart tones and was scheduled for repeat CD at 38 weeks. Her medical history was notable for asymptomatic HOCM. Anesthetic plan was a combined spinal epidural technique with 25ug fentanyl spinal dose and slow epidural titration of 2% lidocaine with sodium bicarbonate. Following epidural placement, there was a terminal fetal deceleration prior to the patient achieving an anesthetic level. General anesthesia was induced and the fetus was delivered emergently. The patient then became hypotensive and tachycardic. A Focused Cardiac Ultrasound (FoCUS) exam was performed by the anesthesia providers showing an underfilled heart and significant systolic anterior motion (SAM) of the mitral valve with no evidence of right ventricular failure. She was treated with fluid boluses and escalating doses of phenylephrine. Emergence from anesthesia was uneventful, and the patient had an unremarkable postoperative course with discharge on post-operative day #4.
Discussion: HOCM is associated with hemodynamic compromise, partially due to left ventricular outflow tract obstruction. This is exacerbated by decreased preload, reduced afterload, increased inotropy and increased heart rate. Pregnancy can worsen hemodynamics in these patients due to decreased afterload, as well as increased inotropy and baseline heart rate (1). General anesthesia further reduces afterload with a compensatory increase in heart rate. Ideal treatment for acute hypotension in these patients includes phenylephrine and fluid boluses to optimize preload. Echocardiographic findings in HOCM that can be easily evaluated at bedside include left ventricular wall thickness >15mm, evidence of SAM, and the presence and magnitude of a left ventricular outflow gradient (2). This case demonstrates the utility of FoCUS for the anesthesiologist in the operating room.
1) Hall, M.E. The heart during pregnancy. Rev Esp Cardiol,64(11),1045-1050
2) Gersh BJ. 2011 ACCF/AHA guideline for the diagnosis and treatment of HOCM. Circulation 2011;124(24):2761