Hearing Loss Prevalent in Children after Cardiac Surgery as Infants

A new study reveals that children who undergo heart surgery as infants are at risk for hearing loss and a host of other neurodevelopmental outcomes.

Researchers at the Children's Hospital of Philadelphia (CHOP; PA, USA) conducted an audiologic and neurodevelopmental study in 348 children who underwent repair of congenital heart disease (CHD), as part of a prospective study to evaluate neurodevelopmental outcomes at four years of age. A prevalence estimate was calculated based on the presence and type of hearing loss, patient and operative factors associated with the hearing loss, and the relationship of hearing loss to language, attention, cognitive, and other neurodevelopmental outcomes.

The results revealed that the overall prevalence of hearing loss was 21.6%, a rate 20 times higher than that found in the general population. The incidence of conductive hearing loss, sensorineural hearing loss, and indeterminate hearing loss were 12.4%, 6.9%, and 2.3%, respectively. Only 18 of 348 subjects (5.2%) had screened positive for hearing loss before the study, and 10 used a hearing aid. After adjusting for patient and operative covariates, younger gestational age, longer postoperative duration of stay, and a confirmed genetic anomaly were associated with hearing loss.

The researchers found no association with modifiable surgical management factors, but mention that possible contributors to hearing loss, such as high-frequency noises in intensive care units (ICUs) and exposure to medications with side effects that damage hearing could be involved, although the study did not directly examine either potential risk factor. Children with hearing loss also had lower scores on measures of language skills, cognition (IQ testing), and executive function and attention. The study was published in the January 2018 issue of the Journal of Pediatrics.

“Ideally, all newborns should be screened for hearing loss by one month of age, with diagnosis by three months, and intervention services begun by age six months, according to national guidelines issued by the Joint Committee on Infant Hearing,” said study co-author Carol Knightly, AuD, CCC-A, senior director of the CHOP center for childhood communication. “Such newborn screening for hearing loss is already the standard of care at CHOP.”

Hearing loss is a rare but known side effect of surgery. Both the type of anesthesia and surgery being performed may influence the risk of developing hearing loss. Epidural anesthesia may change the circulation of fluid around the brain and spinal cord, and may also affect fluid within the ear. Hearing loss has also been reported after cardiac surgery involving cardiopulmonary bypass, possibly due to microemboli moving into the bloodstream and onto the blood vessels of the ear.

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