Planning the acoustic environment of a neonatal intensive care unit

Excessive sound is an acknowledged problem in neonatal intensive care units (NICUs); however, there is relatively little objective information about the effects of sound on the newborn. The cardiovascular and respiratory systems have been the most extensively studied systems. The patterns of response in these systems may be influenced by a variety of factors, including: the intensity of the sound, the infant's behavioral state, the infant's maturity and postnatal age, and the perinatal history. This article reviews the known cardiovascular, respiratory, and other physiological effects of sound on neonates.

To document low sound levels, the range and pattern of levels, and the relative effects of operational (staff and equipment generated) and facility (building generated) noise on the acoustic environment of a level III nursery. A quasi-experimental, prospective, longitudinal study of one bed space. Operational noise was reduced through staff behavior change while facility noise was reduced through renovation. Initial noise levels were typical of those in the literature and in recently measured nurseries. About 80% of sound levels were between 62 and 70 dBA. The lowest levels (L(min)) were 60 to 65 dBA. After staff behavior change, L(min) was about 56 dBA although the highest levels (L(max)) remained at 78 to 100 dBA. Levels following renovation were reduced to L(min)s of 47 to 51 dBA and L(max)s of 68 to 84 dBA, perceived as three or four times quieter than initially. Staff behavior as well as the acoustical characteristics of the facility determine the levels of noise and quiet in an intensive care nursery.

While concerns regarding the effects of the neonatal intensive care unit (NICU) sound environment have primarily centered on infants, caregivers are exposed to the same auditory stimuli. In a review of the literature on adult responses to sound, behavioral and physiological responses to sound as well as influence on job performance and communication are examined. Hearing damage among caregivers is unlikely given the sound levels of the typical NICU. The effect of the NICU sound environment on caregivers has received little attention in research; however, findings from other research of responses to sound suggest that a variety of physiological and behavioral responses may occur in response to the NICU sound environment, and that the sound intensity of the NICU may interfere with communication and job performance.