RESUMO
INTRODUCTION: A prospective study was performed of a cohort of extremely low-birth-weight (ELBW) premature neonates (birth weight 500 to 1,000 g) consecutively admitted to the neonatal intensive care unit. The aim of this study was to examine the thermal changes that occur during all the hygiene-related interventions in ELBW infants in the first 2 weeks of life. PATIENTS AND METHODS: The study was carried out for 10 consecutive months in the Neonatology Service of La Paz University Hospital. We studied all consecutively admitted ELBW infants who satisfied the following criteria: a) adequate weight for gestational age; b) survival for at least 1 week, and c) no major congenital malformations or dysmorphic features. The infants included in the study were managed according to a standard care protocol for maintaining thermal stability and preventing cold-induced stress. Central temperature (Tc) was measured in the axilla and peripheral temperature (Tp) was measured on the sole of the foot. Both temperatures were continuously monitored for a) a period of scheduled non-handling--baseline period--and b) during and after a series of "hygiene interventions". In each of these periods, Tc and Tp were continuously monitored and recorded at 10 min intervals for the first 30 minutes and then at 30 min intervals until completing a 180 min period. RESULTS: Although incubator temperature was raised by a mean of 3 degrees C during hygiene interventions, hygiene was accompanied by a change in body temperature that remained fairly constant throughout the study period; Tc and Tp decreased by a mean of 1 degrees C with respect to baseline temperature. A fall in axillary temperature to less than 36.5 degrees C was observed in 87.4 % of recordings and a fall to less than 36 degrees C was observed in 45.5 %; axillary temperature remained below 36.5 degrees C for a mean duration of almost 1 hour. The differential temperature (Td 5 Tc - Tp), an indicator of thermal stress, was more than 1 degrees C for a mean duration of more than 80 min and > 2 degrees C for more than 20 minutes in both the first and second weeks of life. CONCLUSIONS: During hygiene interventions, ELBW infants experienced a sharp fall in central and peripheral body temperature. After hygiene interventions, these neonates had a Td suggestive of prolonged thermal stress, despite the use of standardized care protocols designed to avoid or minimize the potential effects of hygiene interventions on neonatal temperature.
