Reducing Noise in Neonatal Intensive Care Nurseries: Incubator Covers

Abstract

Minimal safe noise levels for premature infants are not definitively known. The American Academy of Pediatrics (1997) set a standard of 50 decibels maximum for hourly noise levels in NICUs to protect the normal growth and development of pre-term infants. Disruption of normal sensorineural development in preterm infants may result from exposure to environmental noise during hospitalization. Concerns emerge from a literature review of noise measurement studies in Neonatal Intensive Care Units. First, few studies have measured high frequency sound within occupied incubators. Second, interventions to reduce noise exposure to preterm infants cared for in incubators focused on transient physiological and/or behavioral states. Third, intervention studies designed to reduce noise within incubators indicated conflicting results. Finally, none of the published studies used acoustical products as the core of an incubator cover. This experiment measured noise levels within the preterm infant's incubator under the treatment and the control condition. It was one of the few studies to perform sound spectral analysis while subjects were cared for within incubators. It was the first study to test the effectiveness of an incubator cover with a Noise Reduction Coefficient of 0;95: Acoustical Incubator Covers©. This study indicated that Acoustical Incubator Covers© significantly reduced high frequency sound(~ 1000 Hz). When examined using ANCOVA procedures, the data indicated a trend toward improved weight gain in the group that received Acoustical Incubator Covers©. There was no difference between the two groups on the variable of pass rate on the hearing screening exam. Length of hospitalization differed between the two groups by 10 days with the treatment group having the lower mean length of hospitalization. Further study with a larger sample size is needed to determine if reduced high frequency noise promotes better weight gain and fewer hospital days in preterm infants.