NEURODEVELOPMENT DISABILITIES Abnormalities in control of ventilation in newborn infants with myelomeningocele Mario C, Petersen, MD, Mark Wolraich, MD, Andrea Sherbondy, MD, and Jeff Wagener, MD From the Division of Developmental Disabilities, Department of Pediatrics, Universityof Iowa, iowa City, the Division of Child Development, Department of Pediatrics, Vanderbilt Univer- sity, Nashville, Tennessee, and the Department of Pediatrics, University of Colorado Med- ical School, Denver Objective: The objective of this study was to assess respiratory responses of new- born infants with myelomeningocele through pneumograms and carbon dioxide challenge, and to evaluate the possibility of predicting which patients with my- elomeningocele acquired respiratory symptoms related to the Arnold-Chiari de- formity and brain-stem dysfunction. Methods: All surviving infants with spina bifida who were born at the University of iowa Hospitals and Clinics (UIHC) or were transferred there on the first day of life between January 1987 and January 1991 were assessed with a pneumogram and CO2 challenge once they were medically stable, and were followed for a mean of 30 months (10 to 53 months). Results: Thirty patients met the inclusion criteria for this study; four died before be- ing studied. Of the 26 remaining patients, 12 were born at the UIHC and 14 were transferred to the UIHC on the first day of life. Of the 26 infants studied, 12 (46%) had abnormalities on the pneumogram, including 2 with significant periodic breathing and 10 with episodes of desaturation below 87%. Of the 26 infants studied, 4 had no detectable response to an increasing fraction of CO2 in inspired air on the CO2 challenge and 12 had an increase in exhaled minute venfilafion per increase in the alveolar fraction of CO2 in exhaled air more than 2 SD below the mean. Only 10 patients (38.5%) had normal venfilatory responses to the increasing fraction of CO2 in inspired air. On follow-up, only one study patient had symptoms related to Arnold- Chiari deformity and brain-stem dysfunction (bilateral vocal cord paralysis). His neo- natal CO2 challenge results and his pneumogram were normal. Conclusion: We conclude that these two tests are not useful in predicting which pa- tients will have symptoms related to Arnold-Chiari deformity. Specificity for the pneu- mogram and the CO2 challenge was 0.52 and 0.36, respectively. SensiHvity was zero for both tests, although this result is limited by the low incidence of symptomatic Ar- nold-Chiari deformity in this sample. As previous investigators have found, a signifi- cant number of patients with meningomyelocele had abnormal venfilatory patterns. These ventilatory abnormalities indicate that even in the absence of severe symp- toms, the control of the ventilatory response is somewhat impaired in many patients with meningomyelocele. This alteration in ventilatory control is probably related to abnormalities in the development of the brain stem. (J PEDIATR 1995; 126:101125) Submitted for publication Feb. 19, 1994; accepted Dec. 20, 1994. Reprint requests: Mark Wolraich, MD, Child Development Direc- tor, Vanderbitt University, Nashville, TN 37232. Copyright © 1995 by Mosby-Year Book, Inc. 0022-3476/95/$3.00 + 0 9/73/62886 The Amold-Chiari malformation is present in 95% of patients with myelomeningocele. 1 The Amold-Chiari II de- formity is characterized by an abnormal position of the cer- ebellum and the brain stem. The cerebellum is caudally dis- placed, extending into the foramen magnum. In some cases 1011