Pheochromocytoma can be well managed with adequate preoperative adrenergic blockade and intraoperative use of a variety of vasoactive drugs (1). Pediatric laparoscopic procedures result in unstable hemodynamics and intraoperative complications more than in the case of adults (2). We undertook anesthetic management of laparoscopic adrenalectomy for unilateral pheochromocytoma in a 5-yr-old boy and successfully controlled the hemodynamics of this patient with magnesium sulfate (MgSO4).
A 5-yr-old boy (113 cm; 15.8 kg) with von Hippel Lindau disease underwent laparoscopic right adrenalectomy. His medical history included a 1-mo period of weight loss, fever, and abdominal pain after having a meal. Serum adrenaline, noradrenaline, and dopamine levels were 600 pg/mL (normal, <100 pg/mL), 17,900 pg/mL (100–450 pg/mL), and 76 pg/mL (<20 pg/mL), respectively, measured by the method of high-performance liquid chromatography. His mother also had von Hippel Lindau disease and had undergone an operation for pheochromocytoma.
Preoperatively, bunazocin (1 mg/d orally) and fluid (2000 mL/d) had been given for 1 wk to restore the plasma volume. As premedication, 2 mg of diazepam was administered IV. General anesthesia was induced with thiopental (70 mg), fentanyl (25 μg), and vecuronium (2 mg), followed by a bolus injection of MgSO4 (40 mg/kg) and a continuous IV infusion of 15 mg · kg−1 · h−1 of MgSO4. Invasive blood pressure (BP) monitoring was started during mask ventilation. The trachea was intubated without an increase in BP. Anesthesia was maintained with sevoflurane, oxygen, and nitrous oxide, and ventilation was controlled with a peak inspiratory pressure of 15 cm H2O and a respiratory rate of 20 breathes/min. After a central venous route and second peripheral venous route had been established, the laparoscopic operation was performed with the patient in the left lateral position and under 8 mm Hg of pneumoperitoneal pressure.
When the skin incision was made, BP could be kept stable with the continuous infusion of MgSO4. Just after the start of pneumoperitoneum, BP and heart rate (HR) exceeded 180/110 mm Hg and 120 bpm, respectively, so that another bolus injection of MgSO4 40 mg/kg IV was administered, and the infusion rate of MgSO4 was increased to 30 mg · kg−1 · h−1. However, an additional 0.4 mg IV of nicardipine was required to restore systolic BP to its preoperative value. During tumor manipulation, BP and HR again increased to 190/130 mm Hg and 160 bpm, respectively. Hemodynamics could be satisfactorily controlled with a further 0.5 mg IV of nicardipine. After ligation of the left adrenal vein, continuous infusion of MgSO4 was stopped, but systolic BP decreased rapidly to approximately 70 mm Hg, which responded to phenylephrine to produce an increase in BP to 90–100 mm Hg (Fig. 1). The intraoperative concentration of serum magnesium was maintained between 2 and 4 mmol/L. Electrocardiograph abnormalities, such as prolongation of the PQ interval, had not been observed. Fifteen minutes after the end of the operation, the trachea was extubated. Reversal of neuromuscular blockade was not required. Neither decrease of pulse-oximetric saturation nor abnormality in chest radiograph was seen during and after the operation. The total operative time was 1 h 45 min, and the total period of anesthesia was 3 h 49 min. The blood loss was minimal, and the total quantity of fluid administered was 750 mL.
The day after the operation, serum adrenaline, noradrenaline, and dopamine were 221 pg/mL, 2121 pg/mL, and 23 pg/mL, respectively. BP and HR remained stable at approximately 90/50 mm Hg and 110 bpm, respectively. None of the preoperative symptoms have recurred.
MgSO4 inhibits the release of catecholamines from both adrenal medulla and peripheral adrenergic nerve terminals and also blocks catecholamine receptors directly (3). Furthermore, MgSO4 directly exerts a dilating action on vessel walls and has an antiarrhythmic effect on the heart (3). Accordingly, MgSO4 has been used in the anesthetic management of pheochromocytoma in adults (3,4). The major toxic effect of MgSO4 is neuromuscular paralysis (3). Compared with adult cases, pediatric laparoscopic procedures are likely to cause an increase in pulmonary and systemic vascular resistance, sudden bradycardia as a result of stimulation of the vagus nerve, a decrease in total lung capacity and functional residual capacity, an increase in airway pressure, ventilation-perfusion mismatching, bronchospasms, bronchial hypersecretion, and atelectasis (2). Pretorius et al. (5) reported that in a case of laparoscopic adrenalectomy for pheochromocytoma in a pediatric patient, the increase of BP during pneumoperitoneum seemed to be as intense as that during pheochromocytoma manipulation. In our patient, MgSO4 seemed to be effective because BP remained stable during tracheal intubation, and only a small quantity of nicardipine was required while pneumoperitoneum and tumor manipulation were being performed. After pneumoperitoneum, end-tidal CO2 increased, but none of the respiratory complications reported in the earlier study (2) were observed.
In summary, intraoperative use of MgSO4 as an adjunct to the conventional use of nicardipine was effective for managing a pediatric patient with pheochromocytoma who was undergoing a laparoscopic operation.
1. Roizen MF. Anesthetic implication of concurrent diseases. In: Miller RD, ed. Anesthesia. Vol 1. 5th ed. New York: Churchill Livingstone, 2000: 903–1015.
2. Petrat G, Weyandt D, Klein U. Anesthetic considerations in pediatric laparoscopic and thoracoscopic surgery. Eur J Pediatr Surg 1999; 9: 282–5.
3. Pivalizza EG. Magnesium sulfate and epidural anesthesia in pheochromocytoma and severe coronary artery disease. Anesth Analg 1995; 81: 414–6.
4. James MFM. Use of magnesium sulfate in the anaesthetic management of pheochromocytoma: a review of 17 anaesthetics. Br J Anaesth 1989; 62: 619–23.
5. Pretorius M, Rasmussen GE, Holcomb GW. Hemodynamic and catecholamine responses to a laparoscopic adrenalectomy for pheochromocytoma in a pediatric patient. Anesth Analg 1998; 87: 1268–70.