Profile and Stability of Sensorineural Hearing Loss in Persistent Pulmonary Hypertension of the Newborn

Abstract

The purpose of this study was to examine the incidence, profile, and stability of sensorineural hearing loss (SNHL) in infants diagnosed with persistent pulmonary hypertension of the newborn (PPHN). Over a five-year period, 19 of 51 infants (37%) with PPHN were diagnosed with SNHL: 16 with bilateral and 3 with unilateral impairment. This incidence of SNHL is approximately 25 times greater than observed in graduates of our intensive care nursery. The profile of SNHL in the group of 19 children was typically downward sloping. However, there was considerable variation with respect to degree of loss. In addition, progressive SNHL was identified in 5 children whose hearing worsened an average of 55 dB at 2 to 4 kHz. On retrospective analysis, the perinatal variables associated with PPHN were comparable between hearing-impaired and normal-hearing infants. In contrast, the two groups were significantly different when treatment variables, such as the duration of mechanical ventilation or amikacin, were compared. Children with SNHL were treated for longer durations as compared to normal-hearing infants. Children with SNHL were subdivided into two groups, mild and severe, based on degree of loss and treatment variables, and compared again to the normal-hearing group. Two findings emerged from this analysis. First, the duration of hyperventilation was now the only variable significantly different between children with mild SNHL and children with normal hearing. Second, comparison of the mild with the severe SNHL groups showed that the duration of hyperventilation was similar. The pathophysiology and underlying mechanisms resulting in SNHL in PPHN survivors are discussed.