P2.H148: Novel Earmuff Management for Noise Reduction of Auditory Stimuli in Preterm Infants

Background: Approximately 70% of premature infants require Neonatal Intensive Care Unit (NICU) hospitalization, exposing infants to excessive noise levels. Noise pollution has been studied to increase risk for hearing loss, vital sign instability, apnea, increased metabolism, and decreased sleep. There is an additional risk for intraventricular hemorrhage in neonates < 30 weeks gestational age. At our institution, we utilize the marketed Minimuffs® earmuffs with downsides including minimal noise attenuation, improper fit and adherence problems. We conducted a Proof-of-Concept noise reduction study on term infants to assess noise reduction utilizing novel earmuffs created by one of our nurses. Results demonstrated the novel earmuffs attenuated sound by adjusted mean decreases in value by 12.8dBA-25 dBA, as compared to 7dBA in marketed earmuffs. The purpose of this study is to evaluate premature neonates before and after the application of novel earmuffs via Newborn Individualized Developmental Care and Assessment Program (NIDCAP) scoring and vital sign assessment. The hypothesis is that the novel noise-reducing earmuffs will demonstrate improved physiologic stability in the neonate, as compared with no earmuffs.

Methods: Thirty infants >30 weeks gestational age in our NICU, per eligibility, were consented. A NIDCAP certified nurse scored each infant on an observational NIDCAP sheet for baseline measurements over 10 minutes, before and after cares/feeds without earmuffs. If the patient was NPO, the “cares” included vital signs assessment, diaper changing, and moving positions. Three hours later, the same scorer placed the earmuffs on the infant and scored the child pre- and post-feeding/cares. We obtained ambient noise level in the patient's room utilizing Decibel X-dB Sound Level Meter application. We analyzed the data comparing calm versus stress cues extrapolated from NIDCAP scoring tool, and vital sign changes, to assess for neurobehavioral improvement with or without earmuffs. The average scores were controlled for values clustered in subjects with a confidence interval of 97.5%.

Results: There was significant reduction of stress cues from baseline pre/post earmuff placement; -2 (97.5% CI: -9,6). There was no significant improvement in calm cues from baseline pre/post earmuff placement; 1 (97.5% CI: -4,7). There was no difference between baseline vs cares conditional on earmuff status (no multiplicative effect of earmuffs). There was no difference in vital signs pre/post earmuff placement. Average sound level in our NICU was 55 dBA.

Conclusion: The novel earmuffs demonstrated reduction in stress cues extrapolated from NIDCAP scoring tool behavioral assessment. There can be further research to assess use of novel earmuffs in high stress/loud environments i.e. neonatal transport, MRI or clinically unstable infants on oscillator/jet ventilators. Additionally, we would like to further assess improvement in feeding with earmuffs as this was anecdotally observed during this trial.