To examine the effects of standardized rest periods on the sleep-wake states of preterm infants who were convalescing.
A randomized experimental study conducted from time of infants' entry into intermediate care until their discharge from the hospital. Because subjects' time in this study varied, data were analyzed cross-sectionally using the observation made between 5-11 days of the study and longitudinally over 3 weeks using a subset of subjects.
The intermediate care nursery of a tertiary care hospital.
Forty-six preterm infants (23 matched pairs). A subset of 12 pairs, in which infants in the experimental and the control groups were in the study for 3 weeks, was analyzed longitudinally.
Four standardized rest periods each day.
Main outcome measures
Infants were observed once a week between noon and 8 p.m. Three sleep-wake states--quiet awake, active, and sleep--were measured as percentages of the naps and total observation.
Within 5 days, infants in the experimental group exhibited more sleep (F[1,44] = 2.37, p < 0.05) and less active states (F[1,44] = 3.06, p < 0.01) during nap time. Infants receiving the intervention for 3 weeks had more sleep (F[1,22] = 4.63, p < 0.05) and less quiet waking states (F[1,22] = 13.85, p < 0.01) during naps. State patterns over the entire observation did not differ between the groups at 5 days, but by 3 weeks, infants in the experimental group had less quiet waking (F[1,22] = 17.44, p < 0.001) and longer uninterrupted sleep bouts (F[1,22] = 5.19, p < 0.05).
A simple modification of nursing care had an impact on the sleeping and waking states of preterm infants.