PC1097: Duration of Respiratory Mode Exposures Is Associated with Bilateral Hearing Screen Failure in Single Family Room (SFR) NICU

Background: Despite efforts to limit excessive sound exposures in the NICU environment, preterm infants remain at risk for hearing screen failure (HSF) and sensorineural hearing loss. Our group previously reported that the < 45dB noise limit recommended by the AAP was frequently exceeded in our modern level IV SFR NICU, and identified modifiable environmental factors such as respiratory support devices as contributors (Capriolo, C. et al. Am J Perinatol 2020). In a subsequent retrospective cohort study of inborn infants < 33 wks gestation, exposure to high frequency oscillator ventilation, IMV, and HFNC> 2LPM were each associated with higher combined unilateral (UHSF) and bilateral hearing screen failure (BHSF) rates. To test the hypothesis that duration of exposure to these respiratory modes increases the risk for HSF, we analyzed the effect of cumulative exposure to specific respiratory modes on HS outcomes. Since BHSF has greater association with later confirmed sensorineural hearing loss than UHSF, we compared the duration of exposures in infants who passed the HS with those who had UHSF or BHSF.

Methods: We conducted a retrospective cohort study of infants < 33wks GA admitted to the UMMC SFR NICU from 1/1/2016-12/31/2018 who survived to discharge and had automated auditory brainstem response results available. Demographics, antenatal and postnatal factors, and respiratory support modes and their duration were collected by EMR review. Continuous variables were compared with ANOVA with Bonferroni correction and categorical variables were compared by Chi-square.

Results: 425 of 428 eligible infants (99%) had documented HS results; 353(83%) passed and 72(16.9%) failed [unilateral 44(10.4%); bilateral 28(6.6%)]. HS were performed at later chronologic ages [84.1d±80d and 67.5d±57.4d vs 49.6d±39.5d, p< 0.001] and PMA [40.3wk±11.1wk vs 36.7wk±4.1wk, p< 0.001] in HSF groups compared to HS pass group. As shown in Table 1, BHSF, but not UHSF was associated with lower GA and lower 1 and 5 minute Apgar scores. Infants with BHSF experienced higher rates of hypotension within the first 4 days of life, supplemental oxygen >28d, and chronic lung disease compared to infants who passed the hearing screen or had UHSF. Respiratory modes associated with HSF included mechanical ventilation >7days, HFNC>2LPM, and HFOV. HFOV duration was higher in infants with BHSF [4.2d±9.6d vs 1.2d±4d; p=0.0065], but not UHSF. HFNC>2LPM duration was significantly higher in infants with BHSF (18.4d±18.4d) compared to duration in infants who passed HS [7.4d±12.8d] and those with UHSF [9d±13d].

Conclusion: Despite efforts to reduce excessive sound exposures in SFR NICUs, preterm infants remain at risk for sensorineural hearing loss. Factors specifically associated with BHSF include extreme prematurity, low APGAR scores, hypotension, and CLD. Since duration of exposure to specific respiratory modes increases the risk for BHSF, attention to hearing protection in at-risk infants during these exposures may mitigate risk of hearing loss.