Risk factors associated with sensorineural hearing loss in infants at the neonatal intensive care unit: 15-year experience at the National Institute of Perinatology (Mexico City).

BACKGROUND: Infants from neonatal intensive care units (NICU) are at high risk for sensorineural hearing loss (SNHL); however, risk factors may change from NICU to NICU and from country to country. Our objective was to describe the main causes associated with SNHL in infants from a tertiary level NICU in Mexico City and to show the associated audiometric profiles.
METHODS: We performed a comparison of follow-up of infants from NICU with SNHL and a control group with the same history but with normal hearing. Infants were examined at birth by brainstem auditory evoked potentials (BAEP) and followed by audiometric tests. Hearing loss was associated with clinical variables.
RESULTS: SNHL group had 146 children and the control group had 272 children. Mean weight at birth in the SNHL group was 1530+/-581 g and in the control group, 1723+/-805 g (p<0.01). Days spent at the NICU and under mechanical ventilation were higher in the SNHL group (p<0.001). In addition, serum bilirubin levels were higher in the SNHL group than in the control group (p<0.001). Blood exchange, intraventricular hemorrhage, and neonatal meningitis comprised the main SNHL-associated variables. Use of prenatal steroids and pulmonary surfactant demonstrates protection against SNHL. Audiometric profiles disclosed mainly severe SNHL.
CONCLUSIONS: Low birth weight, longer stay in NICU and under mechanical ventilation, higher serum bilirubin levels, prevalence of blood exchange, intraventricular hemorrhage, and meningitis in high-risk newborns were the main risk factors associated with SNHL and merit hearing screening and early intervention in high-risk infants.