PubMedDate not supplied
OBJECTIVE: To assess the hypotensive and antiarrhythmic effect of adenosine triphosphate (ATP) and its impact on hypertensive crises and heart rhythm abnormalities resulting from surgery to remove pheochromocytoma. PATIENTS AND METHODS: A prospective study of 7 patients with pheocromocytoma who were scheduled for unilateral (4) or bilateral (3) suprarenalectomy prior to treatment with phenoxybenzamine and propranolol. The anesthetic procedure was the same for all patients, as was monitoring: ECG, digital pulse oximetry, capnography, direct recording of arterial pressure by a catheter in the left radial artery and a Swan-Ganz fiber optic catheter in the pulmonary artery to measure pulmonary pressures and mixed venous oxygen saturation. Minute volume was measured by thermodilution. Blood glucose levels and urine excreted through a catheter were recorded hourly during surgery. During surgery, when arterial pressure had risen 20% above baseline level, i.v. infusion of ATP 0.5 mg/kg/min was begun and adjusted up or down depending on patient response. Infusion was stopped when the suprarenal vein had been tied. Hemodynamic analysis was performed during 4 phases: 1) start of surgery; 2) during manipulation of the tumor; 3) after excision, and 4) after surgery. Hemodynamic and metabolic variables were recorded, as were ATP doses and requirements for vasopressors and antiarrhythmic drugs. RESULTS: We found the following changes between phase 1 and phase 2, coinciding with ATP infusion: systemic arterial pressure increased 22.2%, heart rate increased 28.04% (with no cardiac arrhythmia observed in any patient), pulmonary artery pressure rose 25.35%, pulmonary capillary pressure rose 22.17%, cardiac index rose 108% while systemic vascular resistance decreased 55.82% and pulmonary vascular resistance decreased 33.96%.(ABSTRACT TRUNCATED AT 250 WORDS)