Accurate determination of cast weight for neonates with clubfoot.

The purpose of this study was to determine changes in cast weight during the first 48 hours after application so that the true weight of a neonate can be estimated without the need for removing the cast. Five types of cast materials were compared. Cast weight measurements were obtained before and after application and at intervals during 48 hours. Final cast weight averaged 107.5% of dry weight for plaster and 99% of dry weight for synthetic cast materials. For very low birth weight infants, the difference between the initial wet weight of plaster of Paris and its final dry weight may be significant for calculating drug and fluid dosages. The weight of an infant can now be calculated without the necessity of cast removal.