Title: Results of an Acoustic Incubator Cover among Preterm Infants: Incubators and Modes of Respiratory Therapy

Abstract

We previously described high frequency (HF) sound spectra (SSA) within unoccupied incubators using acoustic foam in an incubator cover. This acoustical product incubator cover was made from Sonexwet Baffles™ a melamine foam designed to designed to absorb sound in frequencies above 500 Hz with a noise reduction coefficient of 0.95.

The current two-group study describes HF sound within occupied incubators of 33 premature infants (M = 28 weeks G.A.) using the Acoustic Incubator Cover© (AIC). Each subject received seven HF noise assessments. Every subject was on one of three respiratory therapy modes. Sound spectra were analyzed by a Larson Davis SLM 824 with SSA functions. A total of 230 hours of sound spectral analysis were recorded. RM-ANCOVA with mixed models was used to analyze the linearly transformed data. Results indicated that HF sound was reduced at 1000, 2000, 4000, and 8000 Hz (p < 0.001) in the treatment group when compared to the control group. The AIC was most effective in HF sound reduction by Incubator model covariate at 1000 Hz (F = 11.37, p = 0.0023). The AIC was most effective in HF sound reduction by respiratory mode covariate at 8000 Hz (F =22.57, p < 0.0001). Nasal cannula mode of respiratory therapy produced the most intense HF sounds. Based on these findings we recommend that SSA be part of Level III NICU noise assessments.