York Jiao M.D., Lingesh Sivanesan, M.D. Management of Pheochromocytoma Resection in the Presence of an Unrestricted Intracardiac Shunt York Jiao M.D., Lingesh Sivanesan, M.D. Department of Anesthesiology, University of Connecticut, Farmington CT | Integrated Anesthesia Associates, Hartford CT Background Management Management, cont’d Resection of a pheochromocytoma often presents with hemodynamic challenges as a result of the release of stored catecholamines during stressful stimuli or tumor manipulation. Refractory hypertension is a classic feature of this catecholamine storm. However, in the setting of an intracardiac shunt, hypertension may not be evident as changes in the shunt fraction may compensate for the increased systemic vascular resistance. Despite the absence of hypertension, the cardiac stresses of the catecholamine surge is still present and appropriate treatment is necessary. Induction of anesthesia was uneventful. A radial arterial line and continuous hemodynamic pulmonary artery catheter were placed. During periods of surgical stimulation, the CI transiently increased, with concomitant tachycardia. These episodes were ameliorated with increases in anesthetic depth, cessation of surgical stimulation, or boluses of phentolamine. Hemodynamic parameters during key parts of the procedure are shown in Table 1. Emergence from anesthesia was uneventful and the patient was extubated and transferred to the PACU. His subsequent hospital course was uncomplicated and he was discharged on postoperative day 3. Discussion In a patient with a large intracardiac shunt, catecholamine driven increases in SVR may not always present as hypertension. Left ventricular output is reduced during these catecholamine surges leading to systemic hypoperfusion. The right ventricle conversely sees an acute increase in flow, which can lead to acute right ventricular failure, particularly in a patient with preexisting right ventricular dysfunction. This effect may be exacerbated by an attenuated response of the chronically hypertensive pulmonary vasculature to catecholamines.(1, 2) If the catecholamine surge is large enough, hypertension may still occur as it did in this case during direct tumor manipulation. Table 1: Intraprocedure Hemodynamic Parameters Pre-incision Incision Tumor Dissection Venous Clamping Closing Blood Pressure 100/60 110/70 180/100 130/80 Heart Rate 72 85 101 90 PA Pressure 48/27 71/39 54/38 27/19 Cardiac Index 7.4 9.3 5.3 3.9 Patient A 46-year-old male with a past medical history of congenital rubella, mental retardation, and congenital heart disease presents for robotic resection of a recurrent pheochromocytoma. Preoperative echocardiogram demonstrated an unrestricted ostium secundum ASD, patent ductus arteriosus, mild pulmonic stenosis, severely dilated RV with mild hypokinesis, and moderate pulmonary hypertension. References 1. Dhein, S et al. Changes in α1-adrenergic vascular reactivity in monocrotaline-treated rats. Naunyn-Schmiedeberg’s Arch Pharmacol 2002; 365 :87–95 2. Kwak YL, et al. The effect of phenylephrine and norepinephrine in patients with chronic pulmonary hypertension. Anaesthesia. 2002; 57(1):9-14.