Short apneas and periodic breathing in preterm infants in the neonatal intensive care unit-Effects of sleep position, sleep state, and age

Abstract

This observational study investigated the effects of sleep position and sleep state on short apneas and periodic breathing in hospitalized preterm infants longitudinally, in relation to postmenstrual age. Preterm infants (25-31 weeks gestation, n = 29) were studied fortnightly after birth until discharge, in prone and supine positions, and in quiet sleep and active sleep. The percentage of time spent in each sleep state (percentage of time in quiet sleep and percentage of time in active sleep), percentage of total sleep time spent in short apneas and periodic breathing, respectively, the percentage of falls from baseline in heart rate, arterial oxygen saturation and cerebral tissue oxygenation index during short apneas and periodic breathing, and the associated percentage of total sleep time with systemic (arterial oxygen saturation < 90%) and cerebral hypoxia (cerebral tissue oxygenation index < 55%) were analysed using a linear mixed model. Results showed that the prone position decreased (improved) the percentage of falls from baseline in arterial oxygen saturation during both short apneas and periodic breathing, decreased the proportion of infants with periodic breathing and the periodic breathing-associated percentage of total sleep time with cerebral hypoxia. The percentage of time in quiet sleep was higher in the prone position. Quiet sleep decreased the percentage of total sleep time spent in short apneas, the short apneas-associated percentage of falls from baseline in heart rate, arterial oxygen saturation, and proportion of infants with systemic hypoxia. Quiet sleep also decreased the proportion of infants with periodic breathing and percentage of total sleep time with cerebral hypoxia. The effects of sleep position and sleep state were not related to postmenstrual age. In summary, when sleep state is controlled for, the prone sleeping position has some benefits during both short apneas and periodic breathing. Quiet sleep improves cardiorespiratory stability and is increased in the prone position at the expense of active sleep, which is critical for brain maturation. This evidence should be considered in positioning preterm infants.

Keywords: NICU; periodic breathing; preterm infants; prone sleep position; short apneas.

FIGURE 1

Effect of sleep position, sleep state and PMA on percentage change from baseline in SpO₂ (ΔSpO₂%), HR (ΔHR%) and cerebral TOI (ΔTOI%) in sAPN (a, b and c, respectively) and PB (d, e and f, respectively). Values are mean ± SEM. *p < 0.05 overall effect of sleep position; **p < 0.01 overall effect of sleep position; ^# p < 0.05 overall effect of sleep state; ^## p < 0.01 overall effect of sleep state; ⁺⁺ p < 0.01 overall effect of PMA; ⁺⁺⁺ p < 0.001 overall effect of PMA. HR, heart rate; PB, periodic breathing; PMA, postmenstrual age; sAPN, short apneas; SpO₂, arterial oxygen saturation; TOI, tissue oxygenation index.

FIGURE 2

Effect of sleep position, sleep state and PMA on %TST spent in sAPN and PB (a, d), and the respective %TST in systemic (b, e) and cerebral hypoxia (c, f). Values are mean ± SEM. **p < 0.01 overall effect of sleep position; ^# p < 0.05 overall effect of sleep state; ^### p < 0.001 ⁺⁺ p < 0.01 overall effect of PMA; ⁺⁺⁺ p < 0.001 overall effect of PMA. PB, periodic breathing; PMA, postmenstrual age; sAPN, short apneas; %TST, percentage of total sleep time.

FIGURE 3

Effect of sleep position and PMA on percentage of time spent in AS (a) and QS (b). Values are mean ± SEM. *p < 0.05 overall effect of sleep position; ⁺⁺ p < 0.01 overall effect of PMA. AS, active sleep; PMA, postmenstrual age; QS, quiet sleep.