Anesth Analg 2004;98:334-335
© 2004 International Anesthesia Research Society
doi: 10.1213/01.ANE.0000096187.58714.B6
PEDIATRIC ANESTHESIA
Severe Hypotension in the Prone Position in a Child with Neurofibromatosis, Scoliosis and Pectus Excavatum Presenting for Posterior Spinal Fusion
Daniela Alexianu, MD,
Eric T. Skolnick, MD,
Annie C. Pinto, MD,
Susumu Ohkawa, MD,
David P. Roye, Jr., MD,
David E. Solowiejczyk, MD,
Joshua E. Hyman, MD, and
Lena S. Sun, MD
From the Departments of Anesthesiology, Pediatrics, Orthopaedic Surgery and Division of Pediatric Cardiology, Columbia University College of Physicians & Surgeons and The Children’s Hospital of the New York-Presbyterian, New York, New York
Address correspondence and reprint requests to: Eric T. Skolnick, MD, Division of Pediatric Anesthesia, Children’s Hospital of NY-Presbyterian, 440N, 622 West 168th Street, New York, NY 10032. Address email to ets1{at}columbia.edu
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Abstract
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A 34-mo-old boy with neurofibromatosis, scoliosis, and pectus excavatum developed severe hypotension when positioned prone. A magnetic resonance image study revealed neurofibromas encircling the great vessels. During the next anesthetic the patient was placed in the prone position on transverse bolsters and hypotension ensued again. A transesophageal echocardiogram (TEE) revealed compression of the right ventricle by the sternum. When the child was turned supine, the blood pressure returned to baseline. The patient was returned to the prone position, this time with bolsters placed longitudinally, without problem. This case supports a cardiac evaluation, possible intraoperative TEE, and avoidance of sternal pressure in patients with chest wall deformities requiring prone positioning.
IMPLICATIONS: A child with neurofibromatosis, scoliosis, and a chest wall deformity presenting for spinal fusion developed severe hypotension while prone. This was due to compression of the heart by the sternum, not compression of the great vessels by neurofibromas. Sternal pressure in prone patients with chest wall deformities should be avoided. Unique management included the use of transesophageal echocardiography to determine the cause of the hypotension.
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Introduction
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Scoliosis is the most common skeletal abnormality in neurofibromatosis, or VonRecklinghausen’s disease (1). The association of scoliosis with anterior chest wall deformities has been reported to be as frequent as 21% (2). We report a case of a child with neurofibromatosis, pectus excavatum, and rapidly progressive scoliosis who developed unanticipated, severe hypotension after placement in the prone position during elective posterior spinal fusion.
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Case Report
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A 10.4-kg, 34-mo-old boy with neurofibromatosis who had a history of failure to thrive, severe progressive scoliosis, pectus excavatum, and impaired pulmonary function was scheduled for posterior spinal fusion. His previous general anesthetic for a gastric feeding tube 3 mo before the present procedure was uneventful. A thoracic magnetic resonance image (MRI) done three and one-half months before this procedure revealed numerous paraspinal neurofibromas without involvement of the great vessels.
The patient received midazolam (10 mg) orally (PO) for premedication. General anesthesia was induced via mask with sevoflurane in oxygen. Fentanyl (50 µg) in incremental doses and cisatracurium (1 mg) IV were administered. The patient was monitored with a radial arterial line and standard noninvasive monitors. The induction was well tolerated.
After being positioned prone, the patient developed severe hypotension. The systolic blood pressures decreased from the high 80s to 90s after induction when supine to the 20s almost immediately upon turning prone. The patient received IV crystalloid (40 mL/kg total), ephedrine (3 mg total), and phenylephrine (40 µg total), and was returned to the supine position. His blood pressure then returned to baseline. The surgery was aborted and the patient was transferred to the pediatric intensive care unit.
Subsequently, a MRI was obtained that revealed large paraspinal, posterior mediastinal, and retroperitoneal confluent masses that increased substantially from the previous MRI. The masses were displacing and encircling the great vessels in the upper abdomen and the aorta at the level of the arch. Transthoracic echocardiography showed a dilated inferior vena cava that was displaced to the right. The typical appearance of mild compression of the right ventricle seen with pectus excavatum was also evident.
During an interdisciplinary meeting including pediatric anesthesiologists, pediatric surgeons, and pediatric orthopedic surgeons, the consensus was that surgical removal of the masses before spinal fusion was not feasible because of the risk of hemorrhage and the likelihood of recurrence. However, to improve the patient’s rapidly progressive scoliosis, the consensus was that the only option was posterior spinal fusion.
For the planned procedure, management strategies included intraoperative transesophageal echocardiography (TEE), monitoring of central venous and radial artery pressures, and fluid loading before prone positioning.
On the day of the surgery, the patient received premedication with midazolam (7 mg) PO. The patient underwent inhaled induction of anesthesia with nitrous oxide (6 L/min), oxygen (3 L/min), and sevoflurane, followed by tracheal intubation after the administration of fentanyl (25 µg) IV and cisatracurium (1 mg) IV. Transthoracic echocardiography and TEE were performed in the supine position. Cardiac function was normal. The right ventricle had the same appearance of mild compression seen previously. The patient received 30 mL/kg of lactated Ringer’s solution to achieve a central venous pressure of 8–9 mm Hg before prone positioning.
Under continuous TEE monitoring, the patient was gradually turned to the lateral decubitus position. The blood pressure remained stable and the patient was then positioned prone on transverse bolsters. At this point his systolic blood pressure rapidly declined from 88–90 to the low 50s together with bony compression of the right ventricle seen on TEE (Fig. 1). The blood pressure rapidly normalized when the patient was lifted off the bolsters and returned to the supine position (Fig. 2). The same degree of hypotension and bony compression of the right ventricle could be reproduced by gentle finger compression on the sternum while the patient was supine.
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Figure 1. Transesophageal echocardiography long axis view showing the right ventricular outflow tract obstructed by the sternum when the patient was in the prone position on the transverse bolsters.
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Figure 2. Transesophageal echocardiography long axis view showing the right ventricle unobstructed when lifting the patient off the transverse bolsters.
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The patient was again placed in the prone position on longitudinal bolsters situated along the sides of his body, rather than across his chest and hips, so that there would be no pressure on the sternum. After repositioning the bolsters, the patient remained hemodynamically stable. No compression of the right ventricle was seen on TEE. The case proceeded uneventfully. The child had a good postoperative course and was discharged home on the third postoperative day.
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Discussion
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The prevalence of spinal deformity in an otherwise unselected cross section of neurofibromatosis patients is 10% (3,4). In the case of our patient, the urgency of the surgical correction was dictated by the rapid substantial progression of the spinal curvature (Cobb’s angle progression by 50 degrees in <6 months).
A MRI examination was negative for tumor involving the great vessels approximately three months before the initial planned spinal fusion. The patient was asymptomatic; therefore, no further testing was ordered before the first surgery. After discovering the massive growth and invasion of the abdominal neurofibromas after the initial hypotensive episode, we assumed that compression by neurofibromatous tissue on the vena cava and/or the aorta was responsible for the hemodynamic compromise in the prone position. However, it was clearly demonstrated by TEE that when positioning the patient prone on the transverse bolsters, right ventricular compression by the sternum, rather than compression by the neurofibromas, was the etiology of the hypotension.
Our case strongly supports a cardiac evaluation and possibly intraoperative TEE in patients with chest wall deformities requiring prone positioning for surgery such as posterior spinal fusion. Sternal compression of the heart may cause severe hypotension in these patients. We recommend that care be taken to avoid pressure on the sternum by using longitudinal rather than transverse bolsters when positioning such a patient.
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References
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- Winter RB, Moe JH, Bradford DS, et al. Spine deformity in neurofibromatosis: a review of one hundred and two patients. J Bone Joint Surg Am 1979; 61: 677–94.[Abstract/Free Full Text]
- Waters P, Welch K, Micheli LJ, et al. Scoliosis in children with pectus excavatum and pectus carinatum. J Pediatr Orthop 1989; 9: 551–6.[ISI][Medline]
- Overweg-Plandsoen WC, Weersink RG, Sillevis Smitt JH, et al. Neurofibromatosis type 1: a survey of 195 patients [in Dutch]. Ned Tijdschr Geneeskd 1997; 141: 624–9.[Medline]
- Akbarnia BA, Gabriel KR, Beckman E, Chalk D. Prevalence of scoliosis in neurofibromatosis. Spine 1992; 17 (8 Suppl): S244–8.[ISI][Medline]
Accepted for publication August 26, 2003.
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Abstract
Introduction
