Measurement of respiration in Arnold-Chiari malformation.

Abstract

Respiratory distress occurs in infants with myelomeningocele and Arnold-Chiari malformation. It is difficult to measure it because of the small volume exchanged and the lack of cooperation of infants. Existing equipment had to be modified to do so by decreasing the dead space and reducing the bulkiness of the sensing device. In infants with tracheostomies, a continuous flow of gas was applied to reduce the dead space. In infants without tracheostomies, a continuous flow of gas was applied, but the mask was too bulky to seal around the baby's face. A nose-piece pneumotachograph was developed to alleviate the problem. Respiration was measured in 15 patients with myelomeningocele and hydrocephalus from 1 day to 5 months of age. After gas was administered, they breathed 38.5 times a minute with a tidal volume of 6.25 ml/kg, producing a minute ventilation of 0.2541/min/kg. After administration of 5 per cent CO2-95 per cent O2, respiratory frequency rose to 47 breaths a minute, with a tidal volume of 8.8 ml/kg, producing a minute ventilation of 0.4101/min/kg, comparable to that of normal infants.