NICU breast milk warming practices and the physiological effects of breast milk feeding temperatures on preterm infants.

Purpose: No evidence-based standards exist for warming breast milk or determining the optimal milk temperature for preterm infants in the neonatal intensive care unit. In this study, we describe current nursing practices for warming breast milk and examine preterm infants' physiological responses to varying milk temperatures.

Subjects And Design: Randomly selected experienced neonatal nurses (n = 61) were observed as they prepared and administered breast milk gavage feedings.

Methods: We measured the temperature of water baths and breast milk at the beginning and end of the warming period. Physiological responses of the 33 preterm infants cared for by the nurses were observed before feedings and at 5 minutes and 30 minutes after the start of feedings. Gastric residuals were measured 3 hours after the feeds.

Results: Water bath temperatures ranged from 23.3°C to 45.5°C at the start of warming and from 23.8°C to 38.4°C when milk was removed. Refrigerated milk was 3.8°C to 27.1°C and warmed to 21.8°C to 36.2°C at feeding time. Warming times ranged from 133 to 3061 seconds. Infant axillary temperatures increased at 5 and 30 minutes into the feedings (P < .05), while heart rate, respirations, and oxygen saturation showed no significant changes.

Conclusions: Further research is needed to clearly define the risks and benefits of warming infant feedings.