Anesthetic management of laparoscopic pheochromocytoma excision in a patient with a Fontan circulation: a case report
An 18-year-old 170-cm-tall male weighing 51 kg was admitted via the emergency room complaining of palpitations, dyspnea, and cyanosis. The patient was born with complex congenital cardiac anomalies, consisting of a single ventricle (right ventricle type), a complete endocardial cushion defect, corrected transposition of the great arteries, right isomerism, and a supracardiac type total anomalous pulmonary venous return. The patient underwent correction of the total anomalous pulmonary venous return and bidirectional cavo-pulmonary shunt when he was 11 months old, and a Fontan procedure at age 3 years. The patient was taking aspirin (200 mg), digoxin (0.25 mg), enalapril (5 mg) and, atenolol (12.5 mg) daily. The initial vital signs were a systolic blood pressure (SBP) of 126 mmHg and heart rate (HR) of 116 beats/min. Arterial blood sampling was obtained on room air, and showed hypoxemia (PaO2 58 mmHg). The patient also had compensatory polycythemia (hemoglobin 15.8 g/dl) secondary to chronic hypoxemia. The last cardiac catheterization was performed when the patient was 12 years old, and it showed only mild atrio-ventricular valve regurgitation (AVVR). The mean pressure of the Fontan pathway was 13 mmHg. Laboratory testing revealed increased serum (3,533 pg/ml; normal < 1,050 pg/ml) and urine (768.2 µg/day; normal < 97 µg/day) norepinephrine and urine vanillylmandelic acid (8.8 mg/day; normal 2-7 mg/day) levels. Computed tomography showed a 4 cm mass in the left para-aortic area above the left kidney. With an impression of pheochromocytoma, the patient was scheduled for laparoscopic excision of the tumor. Phenoxybenzamine (10 mg) was administered daily for 2 weeks before the surgery. Preoperative electrocardiography showed supraventricular tachycardia and 24 h Holter monitoring showed no significant cardiac arrhythmia except intermittent junctional rhythm. Echocardiography revealed mild AVVR. The estimated ejection fraction of the ventricle was approximately 50% and the ventricular wall motion was normal. There was no obvious stenosis within the Fontan pathway or the scanned parts of pulmonary vessels.\nAfter being administered intravenous midazolam (1.5 mg), the patient was brought to the operating room. The initial SBP and HR there were 144 mmHg and 94 beats/min, respectively. Anesthesia was induced with intravenous midazolam (2.5 mg), etomidate (10 mg), remifentanil (40 µg), and rocuronium (50 mg). The trachea was intubated and anesthesia was maintained with sevoflurane and 50% oxygen in 2 L/min fresh gas. In addition, intravenous remifentanil was infused continuously during the surgery. The right radial artery was cannulated for continuous arterial blood pressure monitoring. A central venous catheter was placed in the right internal jugular vein, and continuous central venous pressure (CVP) monitoring was started. The initial CVP was 15 mmHg. A transesophageal echocardiography (TEE) probe was inserted smoothly and the echocardiographic evaluation revealed normal ventricular function with mild AVVR. After achieving hemodynamic stability, a continuous infusion of milrinone (0.5 µg/kg/min) and magnesium sulfate (MgSO4) (1 g/h) was started after a 1-g loading dose of MgSO4 to prevent severe pulmonary hypertension and maintain a stable blood pressure during the surgery.\nSurgery was started, and intra-abdominal CO2 insufflation was begun for the laparoscopic procedure. After insufflation, the CVP was increased to 28 mmHg and the SBP rose from 90 to 128 mmHg (). Simultaneously, the peak inspiratory pressure increased from 17 to 24 cmH2O. The arterial oxygen saturation decreased from 100 to 97%, and the arterial oxygen partial pressure dropped from 196 to 93 mmHg. The intra-abdominal pressure (IAP) was maintained between 13 and 15 mmHg. The inspired oxygen fraction was transiently set to 1.0, and an immediate TEE evaluation showed preserved ventricular contractility without aggravation of the mild AVVR. To prevent abrupt arterial hypertension, a continuous infusion of sodium nitroprusside (SNP) was started (0.5 µg/kg/min) and titrated up to 1.5 µg/kg/min. However, four further sudden increases in SBP over 160 mmHg, up to 194 mmHg, occurred during the dissection and approach to the tumor; these were controlled by intravenous bolus injections of SNP (30 or 40 µg) and remifentanil (40 or 50 µg). No significant cardiac arrhythmias were detected, except sinus tachycardia during the dissection.\nApproximately 2 h after establishing pneumoperitoneum, the surgeon decided to convert from laparoscopic surgery to a laparotomy, suspecting aortic invasion of the tumor. After exsufflation, the CVP decreased from 18 to 10 mmHg and the SBP dropped from 120 to 70 mmHg. Subsequent TEE showed decreased ventricular volume with preserved contractility. After fluid resuscitation and continuous infusion of dopamine (5 µg/kg/min) and norepinephrine (0.02 µg/kg/min) for approximately 7 min, the SBP recovered and was maintained at 100-120 mmHg. Arterial blood gas analysis showed that the oxygen partial pressure had increased to 157 mmHg. Subsequently, there were several abrupt increases in SBP up to 190 mmHg until the tumor was excised; these were well controlled with bolus injections of SNP and remifentanil.\nThe tumor was removed approximately 260 min after beginning the surgery. After removing the tumor, the MgSO4 was discontinued and the milrinone was tapered (0.25 µg/kg/min). Continuous infusion of dopamine (5 µg/kg/min) and norepinephrine (0.04 µg/kg/min) was initiated. The infusion rates were tapered to 3 and 0.02 µg/kg/min, respectively, before the end of surgery. The duration of the surgery and anesthesia was 490 min. The patient was transferred to the surgical intensive care unit and extubated 12 h later. Intravenous patient-controlled analgesia with fentanyl was used to manage postoperative pain, which was relatively well controlled. All inotropics were discontinued on the third postoperative day. Subsequently, the patient was moved to a general ward and discharged uneventfully on the 13th postoperative day.