Hemodynamic and Catecholamine Responses to a Laparoscopic Adrenalectomy for Pheochromocytoma in a Pediatric Patient

Laparoscopic adrenalectomy for removal of a pheochromocytoma in carefully selected patients has been shown to be relatively safe and effective [1]. A laparoscopic approach offers several advantages compared with an open laparotomy; namely, laparoscopic adrenalectomy decreases fluid shifts that may accompany an open procedure, potentially decreases the surgical stress imposed on the patient, decreases the need for postoperative analgesia, shortens postoperative convalescence-including an intensive care unit stay, and decreases overall hospital stay [2]. We report the hemodynamic response to and anesthetic management of a laparoscopic adrenalectomy for pheochromocytoma in a 12-yr-old boy. Case Report A 12-yr-old boy with a unilateral pheochromocytoma was admitted for laparoscopic adrenalectomy. He presented with a 1-yr history of episodes of palpitations, diaphoresis, and headaches with intermittent hypertension. The cardiologists had performed an initial evaluation with a Holter monitor before referral and evaluation by an endocrinologist. After urine and serum confirmation of excess catecholamine production, the patient was evaluated by a computed tomography (CT) scan. The CT scan revealed a localized 4.0 x 4.0 x 3.0-cm left adrenal mass. The patient's medical history was significant for asthma with only intermittent inhaler use. Family history was negative for familial neuroendocrine syndromes. Physical examination revealed a healthy-appearing boy (59 kg). Vital signs were: blood pressure 153/73, heart rate 101 bpm, and respiratory rate 20 breaths/min. His cardiac, pulmonary, abdominal, and airway examinations were normal. Preoperative hematocrit was initially 40% and decreased to 35%. Electrocardiogram showed a normal sinus rhythm, no preexcitation, and no hypertrophy. The patient had been treated with the alpha-blocker phenoxybenzamine and a 400 mEq/d sodium diet for 12 days before surgery. The patient was premedicated with 2 mg of IV midazolam and 50 [micro sign]g of fentanyl in the holding area, and 1 L of isotonic crystalloid was infused before entry into the operating room. Standard monitors were applied, and general anesthesia was induced with propofol 3.5 mg/kg and sufentanil 1 [micro sign]g/kg. Tracheal intubation was facilitated with vecuronium 0.1 mg/kg, lidocaine 1.5 mg/kg, and esmolol 0.5 mg/kg before direct laryngoscopy. An infusion of nicardipine 2 [micro sign]g [center dot] kg-1 [center dot] min-1 and sufentanil 0.5 [micro sign]g [center dot] kg-1 [center dot] h-1 was started after induction and was maintained at the same rate before and after tracheal intubation. A radial artery catheter and right internal jugular vein catheter were inserted for monitoring purposes. Anesthesia was maintained with isoflurane at 0.5 minimum alveolar anesthetic concentration and sufentanil, nicardipine, and esmolol infusions in 50% oxygen/50% air. The patient was positioned in the right lateral decubitus position. A four-port technique for laparoscopy was used. Ventilation was adjusted to maintain end-tidal CO2 between 33 and 40 mm Hg. The nicardipine infusion was titrated between 1 and 2 [micro sign]g [center dot] kg-1 [center dot] min-1 to maintain systolic blood pressure <150 mm Hg. An intermittent esmolol infusion was used for heart rates >100 bpm. Esmolol infusion rate varied between 50 and 200 [micro sign]g [center dot] kg-1 [center dot] min-1 (Table 1). Blood pressure fluctuations were greatest with tumor manipulation. The nicardipine infusion was stopped immediately after adrenal vein ligation. After adrenal vein ligation, the blood pressure normalized, and an infusion of 3 L of isotonic crystalloid was required to maintain the systolic blood pressure >90 mm Hg. The left adrenal gland was then successfully removed in one piece without complications. The sufentanil infusion was stopped 45 min before the end of surgery. Total IV fluid administered was 135 mL/kg, and estimated blood loss was 70 mL. The patient was tracheally extubated in the operating room, and blood pressure was supported with a fluid infusion to maintain the central venous pressure between 7 and 10 mm Hg. Arterial blood samples for determination of catecholamine levels were drawn at postintubation, postpneumoperitoneum, postadrenal vein ligation, and immediately postoperatively in the recovery room (Table 2).Table 1: Maximal Infusion Rates of Nicardipine and EsmololTable 2: Serum Plasma Catecholamine Levels Drawn During ProcedureThe patient was admitted to the pediatric intensive care unit for overnight monitoring and only required oral analgesics for pain control. The remainder of his hospital course was uneventful. The patient's blood pressure and heart rate normalized within 24 h, and he was discharged on Postoperative Day 2. At his 2-wk postoperative follow-up, he had normal blood pressure and heart rate. Discussion Pheochromocytoma is a rare endocrine tumor with an incidence estimated at 0.8:100, 000 person-years [3]. It occurs in the second part of childhood, more frequently in boys [4]. Surgical management is the definitive therapy for pheochromocytoma. Laparoscopic adrenalectomy has been used successfully for pheochromocytoma resection since 1992 [5] and is a relatively safe procedure despite blood pressure fluctuation [6]. Contraindications for laparoscopic adrenalectomy include invasive adrenal carcinoma, malignant pheochromocytoma, coagulopathy, previous surgery or trauma in the operative area, and a mass >15 cm [6]. Many different anesthetic techniques and pharmacologic drugs have been used successfully to attenuate intraoperative hemodynamic fluctuations during pheochromocytoma resection [7,8]. The anesthetic management for laparoscopic adrenalectomy is different from an open procedure due to the creation of a pneumoperitoneum, which causes an increase in intraabdominal pressure and can induce catecholamine release by the pheochromocytoma. We chose the technique that we felt best controlled the hemodynamic changes and wide fluctuations in blood pressure that accompany the removal of a pheochromocytoma. Our anesthetic technique using sufentanil, nicardipine, and esmolol infusions helped to markedly attenuate the hemodynamic responses associated with maximal catecholamine release in resection of the pheochromocytoma. Despite increases in serum levels of catecholamines, the changes in the hemodynamic status were minimized. In our patient, two events resulted in the greatest release of catecholamines: intubation and induction of pneumoperitoneum. Total plasma catecholamines increased 4-fold and 9.8-fold, respectively, compared with preoperative values. Interestingly, there was no change in heart rate or blood pressure with laryngoscopy, despite the increase in serum catecholamine levels. The one event that caused both serum and hemodynamic changes was the creation of the pneumoperitoneum (Figure 1), which can induce catecholamine release by the tumor and is a critical period in the intraoperative course [9,10]. The continuous infusion of nicardipine allowed us to markedly attenuate the hemodynamic changes secondary to these catecholamine releases. Nicardipine is an IV administered dihydropyridine calcium channel antagonist with selectivity for the coronary and vascular smooth muscle, resulting in vasodilation [11]. Our choice of nicardipine as vasodilator was based on the demonstration of its beneficial effects on the hemodynamic stability during the removal of pheochromocytoma [10,12].Figure 1: Time course changes in systolic blood pressure ([black circle]), heart rate ([up triangle, open]), and total plasma catecholamines ([square]; normal range <550 pg/mL). Systolic blood pressure ranged between 80 and 170 mm Hg. Heart rate varied between 75 and 125 bpm.The blood pressure decrease postadrenal vein ligation and postoperatively may have been caused by desensitization of the sympathetic cardiovascular receptors as the result of decreased density in the presence of prolonged sympathetic stimulation [3]. The decrease in blood pressure in this case was responsive to fluid bolus administration, and no inotropic support was required. In conclusion, this case report suggests the safety and feasibility of laparoscopic removal of pheochromocytoma in the pediatric patient given adequate preoperative medical management. Critical events in the procedure include those that increase tumor catecholamine release; most notably, in the case of laparoscopy, the creation of the pneumoperitoneum. The use of IV infusions of sufentanil, esmolol, and nicardipine could be carefully titrated to attenuate the wide fluctuations in hemodynamic response.