ACCURACY OF URINE OUTPUT MEASUREMENT WITH REGULAR DISPOSABLE NAPPIES

Evaporation of urine from four types of disposable absorbent infant na ppies (A, B, C, D) was assessed under a radiant warmer or in an incuba tor, with or without phototherapy. Each nappy was weighed dry and then 5, 10, 15 or 30 ml of urine were added. The nappy was immediately rew eighed, placed in its study environment and then weighed 5, 15, 30, 60 and 120 min later. Unter all conditions, the percentage evaporation f rom each type of nappy increased during the 120 min and was inversely correlated with urine volume. Without phototherapy, the maximum evapor ation at 120 min with a 5-ml urine sample was 15.9% +/- 6.1% for nappy B in the incubator and 20.8% +/- 4.0% for nappy A in the radiant warm er. Phototherapy was associated with slight but significant changes in evaporation in the incubator and the radiant warmer. Nappy D allowed the lowest percentage evaporation in the incubator with or without pho totherapy and in the radiant warmer with phototherapy (8.8% +/- 4.4%, 2.4% +/- 1.8% and 16.0% +/- 10%, respectively for a 5-ml urine sample) .