Are heart rates useful in determining caloric expenditures/needs for non ambulatory children with cerebral palsy?

PURPOSE: The caloric expenditure of children with non-ambulatory cerebral palsy (NACP) depends on their degree of movement, spasticity, and seizure activity. Many of these children are severely undernourished and many ultimately need gastrostomy tube feedings. The amount of enteral nutrition they require is usually determined by trial and error. The purpose of this study was to test the hypothesis that a continual 72 hour recording of heart rate in non-ambulatory children with spastic quadriplegia cerebral palsy correlates with their basal metabolic rate (BMR). If so, it could serve as an easy non-invasive way to determine their caloric needs. METHODS: Eight children with spastic quadriplegic NACP fed by gastrostomy tubes between the ages of 2-16 years were included in the study. Heart rates were measured with Polar Vantage XL Heart Rate Monitors for three connective 24 hour periods and their heart rates then averaged. Records were kept on the tonicity of their disorder, their activities during monitoring, and caloric intake for the three days they were on the heart monitor. The BMR was measured for 20 minutes by a Quinton ventilated hood metabolic table following 30 minutes of acclimatization. RESULTS: There was no correlation between 72 hour average heart rates recorded from the heart monitors with VO2 uptake and there was no correlation between heart rate averages from the metabolic table and the heart rate monitors. Based on the BMR, caloric requirements varied from 5% to 7% less than the Recommended Daily Allowance. Body surface area (BSA) times Fleisch data revealed caloric requirements of 8% to 10% less than the RDA. CONCLUSIONS: These preliminary findings on a small sample of patients did not support our initial hypothesis. However, it did support a previous report by Kreick, in that body surface area multiplied by tonicity and activity factors can be used to estimate caloric expenditure and needs in this population.