Hearing loss associated with neonatal ECMO: a clinical investigation

Personally Modifiable Risk Factors Associated with Pediatric Hearing Loss: A Systematic Review

BACKGROUND

Pediatric hearing loss is an increasingly recognized problem with significant implications. Increasing our quantitative understanding of potentially modifiable environmental risk factors for hearing loss may form the foundation for prevention and screening programs.

OBJECTIVE

To determine whether specific threshold exposure levels of personally modifiable risk factors for hearing loss have been defined, with the overarching goal of providing actionable guidance for the prevention of pediatric hearing loss.

DATA SOURCES

A systematic review was performed. Computerized searches of PubMed, EMBASE, and the Cochrane Library were completed and supplemented with manual searches.

REVIEW METHODS

Inclusion/exclusion criteria were designed to determine specific threshold values of personally modifiable risk factors on hearing loss in the pediatric population. Searches and data extraction were performed by independent reviewers.

RESULTS

There were 38 criterion-meeting studies, including a total of 50,651 subjects. Threshold noise exposures significantly associated with hearing loss in youth included: (1) more than 4 hours per week or more than 5 years of personal headphone usage, (2) more than 4 visits per month to a discotheque, and (3) working on a mechanized farm. Quantified tobacco levels of concern included any level of in utero smoke exposure as well as secondhand exposure sufficient to elevate serum cotinine.

CONCLUSIONS

Specific thresholds analyses are limited. Future studies would ideally focus on stratifying risk according to clearly defined levels of exposure, in order to provide actionable guidance for children and families.

Long-term outcome of children treated with neonatal extracorporeal membrane oxygenation: increasing problems with increasing age

As more and more critically ill neonates survive, it becomes important to evaluate long-term morbidity. This review aims to provide an up-to-date overview of medical and neurodevelopmental outcomes in children who as neonates received treatment with extracorporeal membrane oxygenation (ECMO). Most patients-except those with congenital diaphragmatic hernia-have normal lung function and normal growth at older age. Maximal exercise capacity is below normal and seems to deteriorate over time in the CDH population. Gross motor function problems have been reported until school age. Although mental development is usually favorable within the first years and cognition is normal at school age, many children experience problems with working speed, spatial ability tasks, and memory. In conclusion, children who survived neonatal treatment with ECMO often encounter neurodevelopmental problems at school age. Long-term follow-up is needed to recognize problems early and to offer appropriate intervention.

Sensorineural hearing loss and language development following neonatal extracorporeal membrane oxygenation

OBJECTIVES

To determine the prevalence of hearing loss in school-age children who have undergone neonatal extracorporeal membrane oxygenation treatment and to identify any effects of hearing loss on speech- and language development [corrected] .

DESIGN

Prospective longitudinal follow-up study within the framework of a structured post-extracorporeal membrane oxygenation follow-up program.

SETTING

Outpatient clinic of a level III university hospital.

RESULTS

Tone audiometry was performed by standardized protocol in 136 children aged 5-12 yrs. Hearing loss was considered clinically significant when >20 dB. Hearing was normal in 75.7% of children. Five children (3.7%) had bilateral sensorineural or combined hearing loss; three of them received special audiological care (2.2% of total sample). Of the 24 children with congenital diaphragmatic hernia, 19 (79.2%) had normal hearing and only two (8.3%) had mild sensorineural hearing loss, unilateral in one of them. Follow-up at 24 months of age had shown normal verbal and nonverbal developmental scores. Language development and intelligence median (range) scores at 5 yrs of age were also normal: receptive language development 104 (55-133), syntactical development 104 (68-132), and lexical development 101 (50-141) for 89 children; intelligence quotient 104 (68-132) for 106 children. Scores did not differ among those with normal hearing, mild hearing loss, and moderate-to-severe hearing loss (p = 0.800, p = 0.639, p = 0.876, and p = 0.886, for the respective developmental tests).

CONCLUSIONS

We found normal language development and intelligence in a cohort of neonatal extracorporeal membrane oxygenation survivors. The prevalence of bilateral sensorineural hearing loss was in accordance with that of a larger series in the United States-which exceeds the prevalence in the normal population.

Factors associated with sensorineural hearing loss among survivors of extracorporeal membrane oxygenation therapy

OBJECTIVES

To endeavor to explain why some graduates of extracorporeal membrane oxygenation (ECMO) therapy develop sensorineural hearing loss (SNHL) whereas others do not, to study the variability seen in the degree of SNHL, to attempt to explain why some graduates with SNHL experience progressive worsening whereas others do not, and to describe the time course of the onset of SNHL on the basis of identified risk factors.

DESIGN

A retrospective chart review with proportional-hazards regression analysis to identify specific risk factors for SNHL from a list of patient and treatment variables.

SETTING

Children's Hospital Boston, a pediatric tertiary-care facility and ECMO center.

PATIENTS

Neonatal ECMO graduates born in 1986-1994 who survived to discharge and underwent audiologic evaluations (n = 111) and a random sample of ECMO graduates who survived to discharge and did not undergo audiologic evaluations (n = 30).

OUTCOME MEASURES

Audiologic data, including the presence or absence of SNHL, the severity of SNHL at the most recent evaluation, the stability or progressive worsening of hearing (with the first evaluation compared with the most recent evaluation), and the occurrence of delayed-onset SNHL.

RESULTS

Twenty-nine (26%) of 111 ECMO graduates who underwent audiologic testing had SNHL at the last evaluation. Of these 29 subjects with SNHL, 21 (72%) had progressive SNHL, of whom 14 (48%) had delayed-onset SNHL. The age of identification of SNHL ranged from 4 months to 8 years 11 months. Factors identified with proportional-hazards regression analyses as being associated significantly with the time to onset of SNHL were a primary diagnosis of congenital diaphragmatic hernia (hazard ratio: 2.60), length of ECMO therapy (hazard ratio: 7.18), and number of days children received aminoglycoside antibiotics (hazard ratio: 5.56). Kaplan-Meier "time-to-event" curves were constructed to illustrate the time course of onset of SNHL, as affected by each of the variables identified as significant risk factors.

CONCLUSIONS

These findings illustrate the need for early, routine, audiologic evaluations throughout childhood for all ECMO graduates. Children at even greater risk for developing SNHL because of a history of congenital diaphragmatic hernia, prolonged ECMO therapy, and/or a lengthy course of aminoglycoside antibiotic therapy should be monitored even more closely throughout childhood, depending on the child's individual risk indicators, as suggested here. On the basis of these risk indicators, efforts can be made to minimize the risk of hearing loss while a child is being treated with ECMO. In addition, these risk indicators can assist with counseling families of ECMO graduates regarding the child's specific risk of developing SNHL and how it can be managed should it occur.

Neurodevelopmental outcome after congenital diaphragmatic hernia: Extracorporeal membrane oxygenation before and after surgery

BACKGROUND/PURPOSE

Extracorporeal membrane oxygenation (ECMO) as a treatment of last resort for neonates with persistent pulmonary hypertension of the newborn (PPHN) caused by congenital diaphragmatic hernia (CDH) may be used for preoperative stabilization or postoperative rescue. The aim of this study was to examine the acute and long-term morbidity associated with pre- and postoperative ECMO.

METHODS

Neonates born with CDH and needing ECMO were classified into 2 groups. Group 1 consisted of neonates placed on ECMO after CDH surgery. Patients in group 2 underwent preoperative ECMO stabilization. Medical records after birth were evaluated. Growth, neuromotor and cognitive development, hearing, and behavior were evaluated. Student t test and chi(2) were used to determine statistical significance between groups.

RESULTS

Subjects in group 2 had significantly more days on ECMO and loop diuretics. Alkalosis was induced for a longer duration in group 2. At follow-up 3 to 9 years later, no differences were found between the 2 groups in growth parameters, neuromotor outcome, or behavior. However, in group 1, 2 of 9 children had significant hearing impairment necessitating amplification compared with 6 of 6 subjects in group 2.

CONCLUSIONS

Neonates with CDH first stabilized on ECMO (group 2) had a higher incidence of hearing loss compared with those needing ECMO postrepair (group 1). The etiology of this finding is not clear. This may be secondary to the prolonged period of hyperventilation or general intensive care that is part of the protocol for neonates who are electively stabilized on ECMO preoperatively. J Pediatr Surg 36:539-544.

Clinical evaluation of the hearing-impaired infant

Early identification of hearing loss and rapid rehabilitative intervention are the two key elements that will give an infant the best chance to develop normal speech and allow the family members to make appropriate adjustments that will enhance communication in the home environment. Hearing loss in an infant may be only one feature of a syndromic disorder, and the physician must aspire to diagnose and treat the entire dysfunction. While a limited laboratory evaluation and appropriate referrals to related specialties are helpful, a comprehensive history and a complete physical examination are the most effective means to identify syndromic hearing loss and to direct future evaluation and therapy.