Cardiorespiratory Effects of Derotational Casting during Anesthesia for Children with Early Onset Scoliosis

Study Design: A prospective, observational case series of eighteen children with early onset scoliosis undergo spine manipulation and casting. Objective: Determine if respiratory system compliance decreases during casting warrants tracheal intubation in all Derotational casting procedures. Background: Children with early onset scoliosis with a Cobb angle greater than 25 degrees will have significant progression of their scoliosis. Surgical techniques cannot result in spine fusion as growth retardation will ensue. Serial thoracolumbar casting may correct the scoliosis or delay the need for surgery. The cast, however, is highly restrictive until the cast is appropriately cut. Does respiratory system compliance decrease a significant degree to require tracheal intubation in all Derotational casting procedures? Methods: Eighteen children (mean age: 4.5 years, mean weight: 16.9 kg) undergoing initial scoliosis casting were enrolled. Anesthesia was induced with sevoflurane in oxygen, an intravenous catheter was inserted, intravenous propofol administered and tracheal intubation performed. Baseline measurements of heart rate, blood pressure, SpO2, peak inspiratory pressure (PIP), and pulmonary compliance were made before casting, immediately after casting, and after cast cut-out. Results: PIP increased from 15.8 cm H2O to 42.6 after cast application and decreased to 20.2 after cast cut-out. Compliance decreased from 1.08 ml/cm H2O/kg to 0.21 after cast application and increased to 0.61 after cast cut-out. There were no clinically significant changes in heart rate, blood pressure, or SpO2. Conclusion: The thoracolumbar cast applied for scoliosis treatment causes severe restriction of chest wall movement and subsequent deterioration of pulmonary function. The time of severe restriction of chest wall motion is short and is relieved once cast cut-outs are performed. The marked increase in PIP and decrease in compliance that occurs during the casting process necessitates tracheal intubation.