Anesthetic management of a patient with undiagnosed paraganglioma -a case report-
A 55-year-old female patient (weight 52 kg, height 155 cm) with multiple myoma was admitted for transabdominal hysterectomy (TAH). She suffered from severe dysmenorrhea and menorrhagia for several years. The patient had reported intermittent chest tightness, feeling of palpitations and a headache prior to admission. She had no history of diabetes, hypertension or any other systemic disease. At admission she had vital signs of blood pressure 130/75 mmHg, pulse rate 81 beats/min, respiratory rate 20 times/min and body temperature 36.3℃. Preoperative laboratory tests were within normal limit with the exception of severe anemia (hemoglobin = 5.1 g/dl, hematocrit = 19.5%). An abdominal magnetic resonance imaging (MRI) showed multiple and variable sized myomas and two simple hepatic cysts (). She received 4 pints of packed red cells (PRC) for over three days to correct the anemia in preparation for surgery.\nUpon arrival to the operating room, she seemed to be anxious. Standard monitoring with electrocardiogram, pulse oximetry, and noninvasive blood pressure were applied before the induction of anesthesia. The initial vital signs were a blood pressure (BP) of 180/105 mmHg, pulse 77 beats/min, normal sinus rhythm on electrocardiogram (ECG) and arterial saturation of 99%. To reduce anxiety, 3 mg of midazolam was injected and general anesthesia was induced with propofol and remifentanil using a target-controlled infusion (TCI) system. After lidocaine administration, the target effect-site concentration (Ce) of propofol 4 µg/ml and remifentanil 4 ng/ml were started with 100% O2 and rocuronium 0.6 mg/kg was administered and used to facilitate tracheal intubation. Total intravenous anesthesia (TIVA) with propofol-remifentanil-50% N2O in O2 was used for anesthetic maintenance. The target Ce of propofol was 2.5-3.5 µg/ml and of remifentanil 2.5-3.0 ng/ml, respectively. The value of bispectral index (BIS) was maintained in the 35-45.\nDuring the surgical exploration for TAH, a retroperitoneal encapsulated hard mass measuring 5.5 × 4.5 × 5 cm sized was found incidentally with huge uterine myomas (20 × 18 cm). It lay at the para-arotic space along L3 vertebra with adhesion to the aorta. The operation for TAH began and the patient stayed hemodynamically stable as surgery proceeded. Approximately 135 min after abdominal hysterectomy started, a surgical excision for a retroperitoneal mass was continued a general surgery team. When the surgeon manipulated the retroperitoneal mass, the patient's BP suddenly increased to 220/130 mmHg with a pulse rate of 140 (beats/min). The patient showed with frequent bigeminy on the ECG. The depth of anesthesia was deepened by increasing the Ce of propofol from 2.5-3.5 µg/ml to 4.5-6.0 µg/ml and remifentanil from 2.5-3.0 ng/ml to 4.5-5.0 ng/ml, respectively. The value of BIS decreased from 40-50 to the range of 25-30. But the blood pressure continued to rise reaching 180 mmHg for systolic and 100 mmHg for diastolic. To control the increased BP and pulse rates, a continuous infusion of nicardipine (2.0 mg/hr) was started and an intermittent bolus of labetalol (15 mg of labetalol in three doses of 5 mg each) with additional esmolol (total 30 mg) also used. However these treatments were not effective and the BP still remained at 170-180 mmHg for systolic and 95-100 mmHg for diastolic with increased heart rates in the range of 115-125 (beats/min) whenever the surgeon directly manipulated the mass. Radial arterial line was inserted after a modified Allen's test to monitor the labile BP and arrhythmia and to draw arterial blood gas (ABG) analysis sample. The ABG analysis revealed pH of 7.46, PaCO2 33 mmHg, PaO2 246 mmHg, and oxygen saturation 98% on FiO2 0.5. Despite the increased anesthetic depth and anti-hypertensive therapy, the BP remained a wide range BP of 170-100 mmHg/60-80 mmHg. It was difficult to control due to the frequent swing between hypertension and hypotension. Therefore we highly suspected an unrecognized ectopic pheochromocytoma.\nThe retroperitoneal mass was completely removed approximately 60 min. Following the tumor removal, the BP decreased to as low as 75-85 mmHg/45-50 mmHg and there was a slight increased heart rate 90 (beats/min) but it remained as low state despite fluid administration. When 2100 ml of fluid was administered during the whole period of anesthesia (300 min), 420 ml of crystalloid was administered at the time of retroperitoneal paraganglioma removal. After the removal of retroperitoneal mass, we administrated 500 ml of volume expander and 2 pints of PRC and started a continuous dopamine infusion (5 mcg/kg/min) with intermittent phenylephrine 50-100 mcg bolus injection to improve the patient's hemodynamic status. The estimated blood loss during the TAH was about 250 ml and 200 ml for the retroperitoneal mass. The mean urine output was 140 ml/hr and the total was 700 ml. After surgery, the patient showed BP 80-85 mmHg for systolic and 50-60 mmHg for diastolic and pulse 90 beats/min and the patient sent to the intensive care unit for close monitoring. The mass confirmed histopatholgically as an extra-adrenal paraganglioma a week later ().