Moderate acoustic changes can disrupt the sleep of very preterm infants in their incubators

Aim To evaluate the impact of moderate noise on the sleep of very early preterm infants (VPI). Methods Observational study of 26 VPI of 26-31weeks' gestation, with prospective measurements of sound pressure level and concomitant video records. Sound peaks were identified and classified according to their signal-to-noise ratio (SNR) above background noise. Prechtl's arousal states during sound peaks were assessed by two observers blinded to the purpose of the study. Changes in sleep/arousal states following sound peaks were compared with spontaneous changes during randomly selected periods without sound peaks. Results We identified 598 isolated sound peaks (5SNR<10 decibel slow response A (dBA), n=518; 10SNR<15dBA, n=80) during sleep. Awakenings were observed during 33.8% (95% CI, 24-43.7%) of exposures to sound peaks of 5-10dBA SNR and 39.7% (95% CI, 26-53.3%) of exposures to sound peaks of SNR 10-15dBA, but only 11.7% (95% CI, 6.2-17.1%) of control periods. The proportions of awakenings following sound peaks were higher than the proportions of arousals during control periods (p<0.005). Conclusions Moderate acoustic changes can disrupt the sleep of VPI, and efficient sound abatement measures are needed.