- Email: [email protected]
Hearing loss in congenital diaphragmatic hernia (CDH) survivors: Is it as prevalent as we think?
Journal of Pediatric Surgery (2013) 48, 942–945
www.elsevier.com/locate/jpedsurg
Hearing loss in congenital diaphragmatic hernia (CDH) survivors: Is it as prevalent as we think? Marnie Goodwin Wilson a , Patricia Riley b , Anne-Marie Hurteau c , Robert Baird a , Pramod S. Puligandla a,⁎ a
Division of Pediatric General Surgery, The Montreal Children's Hospital, Montreal, QC, Canada H3H 1P3 Division of Neonatology, The Montreal Children's Hospital, Montreal, QC, Canada H3H 1P3 c Division of Audiology, The Montreal Children's Hospital, Montreal, QC, Canada H3H 1P3 b
Received 21 January 2013; accepted 3 February 2013
Key words: Sensorineural hearing loss; Congenital diaphragmatic hernia; Long-term follow-up; Audiological outcomes
Abstract Purpose: The incidence of sensorineural hearing loss (SNHL;N20 dB loss) in CDH survivors is debated. We evaluated long-term audiological outcomes at a single tertiary care center with ECMO capability and an established neonatal follow-up program. Methods: With REB approval, records of CDH survivors from 2000 to 2010 were retrospectively analyzed. Demographic, postnatal, and audiometric information was gathered. All underwent auditory brainstem response (ABR) or otoacoustic emissions screening before discharge and complete audiological surveillance. Thirty-three patients were evaluated to age 4 + years with others continuing follow-up. Results: Forty-three patient records were reviewed with 1 excluded (transferred to another institution). Median GA and BW were 39 weeks (35–41) and 3.1 kg (2–4), respectively. Median ventilation days were 10 (2–189) with 34 infants ventilated 5 + days. Sixteen (36%) received HFOV, 21 (49%) iNO, and 5 (12%) ECMO. The median time to CDH repair was 3 days (1–23), and 11 (26%) required patch repair. Nine infants (21%) received diuretics and oxygen after discharge. Audiological surveillance identified only one patient with SNHL (received HFO, iNO, and patch repair). Conclusion: Neonatal screening identifies CDH survivors at risk for hearing difficulties but must be followed with comprehensive testing until school age. The incidence of SNHL may be less than previously reported in this population. © 2013 Elsevier Inc. All rights reserved.
Despite more infants surviving to discharge, many CDH survivors experience long-term morbidity [1,2]. For example, in a cohort of 90 infants from the Canadian Pediatric Surgery Network (CAPSNet), 55 had active, ongoing cardiorespiratory, feeding and/or motor problems that ⁎ Corresponding author. Tel.: + 1 514 412 4438; fax: + 1 514 412 4289. E-mail address: [email protected] (P.S. Puligandla). 0022-3468/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jpedsurg.2013.02.007
required specialized treatment, 30 had detectable psychomotor or neurodevelopmental disability by age 1 year, and 48 had detectable disability by age 3 years [3]. Although some of the risk factors leading to these morbidities were perinatal in origin, a portion of the morbidity experienced by these patients was likely related to the therapies instituted in the perinatal period. As a result of the significant morbidities experienced by CDH survivors,
Hearing loss in CDH survivors
943
The American Academy of Pediatrics has provided followup recommendations to guide clinicians who care for these infants after hospital discharge [4]. Sensorineural hearing loss in CDH survivors is an important long term morbidity that can have significant consequences if not detected in a timely fashion, and the need for proper audiological screening into childhood has been well established [5]. However, the true incidence and natural history of SNHL among CDH survivors are debated. Some studies indicate an incidence as high as 60%, particularly in ECMO patients, with a significant proportion of these patients presenting late at 2 to 5 years [6–8]. However, others have shown a significantly lower incidence of SNHL [9,10] (including unpublished data from our centre). At the Montreal Children's Hospital (MCH), CDH survivors receive comprehensive care by the Neonatal Follow-up Program until school age. All patients with CDH undergo standardized hearing screening, as close to term as possible, prior to hospital discharge and subsequent comprehensive audiological surveillance. The purpose of this study was to review our single institution experience regarding the frequency and presentation of SNHL in a continuous cohort of CDH survivors in a tertiary pediatric centre with ECMO capabilities.
1. Materials and Methods With institutional REB approval, the records of CDH survivors treated at the MCH from 2000 to 2010 were retrospectively analyzed. Late presenters with CDH were excluded from the study. In addition to basic demographic data, perinatal (Apgar scores, ventilation, nitric oxide, need for ECMO) and peri-operative (timing of surgery, need for patch repair) information was gathered from medical dossiers to assess the acuity and severity of disease. Audiological data were obtained from standardized audiological reports. A certified audiologist reviewed all abnormal audiological test results. The protocol for screening and auditory surveillance is presented in Table 1. Descriptive statistical analyses (mean, median, range and standard deviations of various data fields) were performed as indicated using SPSS Version 20 (Armonk NY).
2. Results Forty-three patient records were reviewed with 1 excluded due to transfer to another institution. Follow-up data were available for 42 (95%). The demographic data are presented in Table 2. Most infants were born at term, with just over half having an antenatal diagnosis. Median Apgar scores were 6 and 7 at 1 and 5 min, respectively. All patients were intubated in the immediate post-natal period. The median period of ventilation was 10 days for the entire cohort with 34 patients requiring mechanical ventilation for more than 5 days. Sixteen infants required high frequency oscillatory ventilation (HFOV) while 21 received inhaled nitric oxide (iNO). Five infants were physiologically so unstable as to require ECMO. The management strategy for infants during the study period was to minimize neuromuscular blockade and to avoid severe alkalosis from overventilation or the overzealous use of diuretics. The median time to CDH repair was 3 days after birth (1–23) and 11 infants (26%) required patch repairs. The median length of stay in the NICU was 21 days. Nine infants (21%) received diuretics and oxygen after discharge as they were deemed to have chronic lung disease. Sixteen infants (36.4%) were also discharged on bronchodilators. All infants underwent auditory brainstem response (ABR) or automated auditory brainstem response (AABR) screening before hospital discharge and complete audiological assessments thereafter (Table 1). Twenty-nine (70%) patients have completed the 3-year follow-up program with another 11 still in progress. Only two patients in this series had incomplete surveillance. Of the 42 patients who had long-term follow-up, only one patient (2.5%) sustained a late onset, progressive sensorineural hearing loss (Table 3). This patient had a complicated hospital stay, requiring a patch repair of a right-sided CDH as well as surgical closure of a patent ductus arteriosus that was complicated by chylothorax. This patient did not require ECMO, but was treated with HFOV for 5 days after surgery as well as iNO. The total NICU stay for this patient was 40 days. The patient was ultimately discharged on home oxygen and diuretics. Other medical co-morbidities in this child included a right dysplastic kidney and a recurrence of his CDH at 4 years of age that required an emergency operation due to a small bowel obstruction. Neonatal hearing screening prior to discharge was normal. Testing at 9 months
Table 1 Montreal Children's Hospital hearing screening and surveillance protocol for children presenting with high risk of hearing loss (2000 to 2011). Risk factors
Prior to hospital discharge
8 months
18 months
3 years
CDH ± ECMO
AABR or ABR
-Age-appropriate audiogram -Impedence -Otoacoustic emissions
Age-appropriate audiogram -Impedence -Otoacoustic emissions
Age-appropriate audiogram -Impedence -Otoacoustic emissions
CDH = congenital diaphragmatic hernia; ABR = auditory brainstem response (screening and diagnostic test); AABR = automated auditory brainstem response (screening test only).
944
M.G. Wilson et al.
Table 2 Demographic, perinatal and surgical data for study population (n = 44).
Gestational Age (weeks) Birthweight (g) Apgar scores at (1, 5) min NICU Stay (days) Days on ventilator Highest ventilator pressure (mm Hg) Timing of Surgical Repair (day of life)
Median
Range
39 3070 (6, 7) 21.5 10.5 22 3
35–41 1840–4350 1–10 7–189 2–189 15–35 1–23
Value (%) Unknown Antenatal diagnosis High Frequency Oscillatory Ventilation Nitric Oxide ECMO Side of Hernia (Left noted) Patch repair Chylothorax Use of supplemental oxygen after discharge Use of inhaled bronchodilators after discharge Use of inhaled steroids after discharge Use of diuretics after discharge Use of anticonvulsants after discharge Use of anti-reflux medication after discharge
23 (52) 16 (36) 21 (48) 5 (11) 36 (82) 11 (25) 5 (11) 9 (21)
– – – – – – – 1 (2)
16 (36)
2 (5)
15 (34) 10 (23) 0 (0) 27 (61)
2 (5) 1 (2) 2 (5) –
of age revealed a bilateral high frequency SNHL. Subsequent testing confirmed a diagnosis of sloping hearing loss in the high frequencies, which appeared to worsen over time. One other patient failed his neonatal hearing screening test and had a mild unilateral hearing loss that was most probably conductive in nature when last tested at 9 months of age. The child's language development at age 5 was normal. This patient did not require patch repair, was not treated with HFOV, and did not require oxygen or diuretics on discharge. Information on the results for both patients with hearing loss is summarized in Table 3.
3. Discussion Although advances in perinatal care have significantly increased CDH survival over the last several years, multi-
Table 3
Abnormal audiological outcomes in CDH survivors.
Total number (N) = 42 a
Late onset progressive SNHL (sloping high frequency loss) Possible mild unilateral deficit (follow-up pending) a
system morbidity still exists in CDH survivors [11–13]. Emphasis is now being placed on reducing this burden with structured surveillance and the early identification of problems [4]. While some older studies have documented SNHL rates as high as 60% in CDH survivors and infants with severe cardio-respiratory illnesses [6,7,14], other studies, including our own unpublished data, have indicated a much lower incidence [9,10]. The present study identified only one CDH survivor with SNHL in a continuous cohort of 42 children. Thus, our results would suggest that the incidence of SNHL could be less than previously reported. The etiology of SNHL in CDH has been linked to the use of neuromuscular blockers (e.g. pancuronium bromide), certain ototoxic medications (e.g. vancomycin; loop diuretics), as well as pulmonary hypertension of the newborn [15,16], prolonged mechanical ventilation, severe alkalosis and high oxygen requirements [17,18]. ECMO and the use of HFOV have also been implicated [14,19]. However, a true causal effect remains to be identified and it is unclear if there is a single pathophysiologic mechanism, if the insults are cumulative, or if these interventions have a synergistic effect leading to SNHL. Furthermore, there is likely an underestimation of the impact of associated genetic syndromes [20]. Indeed, in our only patient with SNHL, an unknown genetic syndrome could not be ruled out as part of the etiology. The discrepancy between our results and those published in earlier years [6,7] may be related to a few issues. First, the management strategies for infants in our contemporary cohort of CDH survivors were likely much different than for the patients enrolled in the studies by Cheung [7] and Robertson [6], whose patients were born in the late 1980's and mid 1990's. The philosophy of care for CDH infants in our institution during the period of study attempted to minimize the use of neuromuscular blockade and significant hyperventilation and alkalosis, thereby potentially limiting the negative impact on the auditory system. The NICU at the Montreal Children's Hospital is also a 'hearing friendly environment', whereby noise levels are controlled for the benefit of the patients. We acknowledge the limitations inherent in our study, including its retrospective nature and the lack of analysis related to medication use or other proposed risk factors for the development of SNHL. This information will be requested from the Canadian Neonatal Network for further analysis. In addition, all infants with CDH are followed in
N (%)
ECMO
HFOV
Patch repair
Oxygen at discharge
Diuretics at discharge
1(2.5%)
No
Yes
Yes
Yes
Yes
1(2.5%)
No
No
No
No
No
Defined as onset after the neonatal period.
Hearing loss in CDH survivors our hearing surveillance program until age 3. Therefore we cannot state categorically that no hearing loss appeared after this age. However, the development of all of these children, including appropriate speech and language, is closely followed until school age and no additional cases of clinically suspected hearing loss have been detected. Nonetheless, the effectiveness of the early identification of hearing loss is undeniable and our results do demonstrate the need for consistent neonatal hearing screening and structured long term follow-up for this population. Although our results do not support some previous studies on the subject, this discrepancy needs to be resolved by studying prospective, contemporary multi-site patient populations that better reflect the current management strategies involving patients with CDH.
945
[8]
[9]
[10]
[11]
[12]
[13]
References [1] Chiu PP, Hendrick H. Postnatal management and long-term outcome for survivors with congenital diaphragmatic hernia. Prenat Diagn 2008;28:592-603. [2] Danzer E, Hedrick HL. Neurodevelopmental and neurofunctional outcomes in children with congenital diaphragmatic hernia. Early Hum Dev 2011;87:625-32. [3] Canadian Association of Pediatric Surgery Network annual report. 2010. www.capsnet.org. [4] Lally KP, Engle W. Postdischarge follow-up of infants with congenital diaphragmatic hernia. Pediatrics 2008;121:627-32. [5] Yoshinaga-Itano C. From screening to early identification and intervention: discovering predictors to successful outcomes for children with significant hearing loss. J Deaf Stud Deaf Educ 2003;8:11-30. [6] Robertson CM, Tyebkhan JM, Hagler ME, et al. Late-onset, progressive sensorineural hearing loss after severe neonatal respiratory failure. Otol Neurotol 2002;23:353-6. [7] Cheung PY, Tyebkhan JM, Peliowski A, et al. Prolonged use of pancuronium bromide and sensorineural hearing loss in childhood
[14]
[15]
[16]
[17]
[18]
[19]
[20]
survivors of congenital diaphragmatic hernia. J Pediatr 1999;135: 233-9. Robertson CM, Cheung PY, Haluschak MM, et al. High prevalence of sensorineural hearing loss among survivors of neonatal congenital diaphragmatic hernia. Western Canadian ECMO Follow-up Group. Am J Otol 1998;19:730-6. Morando C, Midrio P, Gamba P, et al. Hearing assessment in high-risk congenital diaphragmatic hernia survivors. Int J Pediatr Otorhinolaryngol 2010;74:1176-9. Safavi A, Synnes AR, O'Brien K, et al. Multi-institutional follow-up of patients with congenital diaphragmatic hernia reveals severe disability and variations in practice. J Pediatr Surg 2012;47:836-41. Muratore CS, Utter S, Jaksic T, et al. Nutritional morbidity in survivors of congenital diaphragmatic hernia. J Pediatr Surg 2001; 36:1171-6. Chiu PP, Sauer C, Mihailovic A, et al. The price of success in the management of congenital diaphragmatic hernia: is improved survival accompanied by an increase in long-term morbidity? J Pediatr Surg 2006;41:888-92. Chen C, Jeruss S, Chapman JS, et al. Long-term functional impact of congenital diaphragmatic hernia repair on children. J Pediatr Surg 2007;42:657-65. Inhaled nitric oxide in term and near-term infants: neurodevelopmental follow-up of the neonatal inhaled nitric oxide study group (NINOS). J Pediatr 2000;136:611-7. Graziani LJ, Gringlas M, Baumgart S. Cerebrovascular complications and neurodevelopmental sequelae of neonatal ECMO. Clin Perinatol 1997;24:655-75. Graziani LJ, Baumgart S, Desai S, et al. Clinical antecedents of neurologic and audiologic abnormalities in survivors of neonatal extracorporeal membrane oxygenation. J Child Neurol 1997;12: 415-22. Robertson CM, Tyebkhan JM, Peliowski A, et al. Ototoxic drugs and sensorineural hearing loss following severe neonatal respiratory failure. Acta Paediatr 2006;95:214-23. Masumoto K, Nagata K, Uesugi T, et al. Risk factors for sensorineural hearing loss in survivors with severe congenital diaphragmatic hernia. Eur J Pediatr 2007;166:607-12. Fligor BJ, Neault MW, Mullen CH, et al. Factors associated with sensorineural hearing loss among survivors of extracorporeal membrane oxygenation therapy. Pediatrics 2005;115:1519-28. Tovar JA. Congenital diaphragmatic hernia. Orphanet J Rare Dis 2012;7:1.
www.elsevier.com/locate/jpedsurg
Hearing loss in congenital diaphragmatic hernia (CDH) survivors: Is it as prevalent as we think? Marnie Goodwin Wilson a , Patricia Riley b , Anne-Marie Hurteau c , Robert Baird a , Pramod S. Puligandla a,⁎ a
Division of Pediatric General Surgery, The Montreal Children's Hospital, Montreal, QC, Canada H3H 1P3 Division of Neonatology, The Montreal Children's Hospital, Montreal, QC, Canada H3H 1P3 c Division of Audiology, The Montreal Children's Hospital, Montreal, QC, Canada H3H 1P3 b
Received 21 January 2013; accepted 3 February 2013
Key words: Sensorineural hearing loss; Congenital diaphragmatic hernia; Long-term follow-up; Audiological outcomes
Abstract Purpose: The incidence of sensorineural hearing loss (SNHL;N20 dB loss) in CDH survivors is debated. We evaluated long-term audiological outcomes at a single tertiary care center with ECMO capability and an established neonatal follow-up program. Methods: With REB approval, records of CDH survivors from 2000 to 2010 were retrospectively analyzed. Demographic, postnatal, and audiometric information was gathered. All underwent auditory brainstem response (ABR) or otoacoustic emissions screening before discharge and complete audiological surveillance. Thirty-three patients were evaluated to age 4 + years with others continuing follow-up. Results: Forty-three patient records were reviewed with 1 excluded (transferred to another institution). Median GA and BW were 39 weeks (35–41) and 3.1 kg (2–4), respectively. Median ventilation days were 10 (2–189) with 34 infants ventilated 5 + days. Sixteen (36%) received HFOV, 21 (49%) iNO, and 5 (12%) ECMO. The median time to CDH repair was 3 days (1–23), and 11 (26%) required patch repair. Nine infants (21%) received diuretics and oxygen after discharge. Audiological surveillance identified only one patient with SNHL (received HFO, iNO, and patch repair). Conclusion: Neonatal screening identifies CDH survivors at risk for hearing difficulties but must be followed with comprehensive testing until school age. The incidence of SNHL may be less than previously reported in this population. © 2013 Elsevier Inc. All rights reserved.
Despite more infants surviving to discharge, many CDH survivors experience long-term morbidity [1,2]. For example, in a cohort of 90 infants from the Canadian Pediatric Surgery Network (CAPSNet), 55 had active, ongoing cardiorespiratory, feeding and/or motor problems that ⁎ Corresponding author. Tel.: + 1 514 412 4438; fax: + 1 514 412 4289. E-mail address: [email protected] (P.S. Puligandla). 0022-3468/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jpedsurg.2013.02.007
required specialized treatment, 30 had detectable psychomotor or neurodevelopmental disability by age 1 year, and 48 had detectable disability by age 3 years [3]. Although some of the risk factors leading to these morbidities were perinatal in origin, a portion of the morbidity experienced by these patients was likely related to the therapies instituted in the perinatal period. As a result of the significant morbidities experienced by CDH survivors,
Hearing loss in CDH survivors
943
The American Academy of Pediatrics has provided followup recommendations to guide clinicians who care for these infants after hospital discharge [4]. Sensorineural hearing loss in CDH survivors is an important long term morbidity that can have significant consequences if not detected in a timely fashion, and the need for proper audiological screening into childhood has been well established [5]. However, the true incidence and natural history of SNHL among CDH survivors are debated. Some studies indicate an incidence as high as 60%, particularly in ECMO patients, with a significant proportion of these patients presenting late at 2 to 5 years [6–8]. However, others have shown a significantly lower incidence of SNHL [9,10] (including unpublished data from our centre). At the Montreal Children's Hospital (MCH), CDH survivors receive comprehensive care by the Neonatal Follow-up Program until school age. All patients with CDH undergo standardized hearing screening, as close to term as possible, prior to hospital discharge and subsequent comprehensive audiological surveillance. The purpose of this study was to review our single institution experience regarding the frequency and presentation of SNHL in a continuous cohort of CDH survivors in a tertiary pediatric centre with ECMO capabilities.
1. Materials and Methods With institutional REB approval, the records of CDH survivors treated at the MCH from 2000 to 2010 were retrospectively analyzed. Late presenters with CDH were excluded from the study. In addition to basic demographic data, perinatal (Apgar scores, ventilation, nitric oxide, need for ECMO) and peri-operative (timing of surgery, need for patch repair) information was gathered from medical dossiers to assess the acuity and severity of disease. Audiological data were obtained from standardized audiological reports. A certified audiologist reviewed all abnormal audiological test results. The protocol for screening and auditory surveillance is presented in Table 1. Descriptive statistical analyses (mean, median, range and standard deviations of various data fields) were performed as indicated using SPSS Version 20 (Armonk NY).
2. Results Forty-three patient records were reviewed with 1 excluded due to transfer to another institution. Follow-up data were available for 42 (95%). The demographic data are presented in Table 2. Most infants were born at term, with just over half having an antenatal diagnosis. Median Apgar scores were 6 and 7 at 1 and 5 min, respectively. All patients were intubated in the immediate post-natal period. The median period of ventilation was 10 days for the entire cohort with 34 patients requiring mechanical ventilation for more than 5 days. Sixteen infants required high frequency oscillatory ventilation (HFOV) while 21 received inhaled nitric oxide (iNO). Five infants were physiologically so unstable as to require ECMO. The management strategy for infants during the study period was to minimize neuromuscular blockade and to avoid severe alkalosis from overventilation or the overzealous use of diuretics. The median time to CDH repair was 3 days after birth (1–23) and 11 infants (26%) required patch repairs. The median length of stay in the NICU was 21 days. Nine infants (21%) received diuretics and oxygen after discharge as they were deemed to have chronic lung disease. Sixteen infants (36.4%) were also discharged on bronchodilators. All infants underwent auditory brainstem response (ABR) or automated auditory brainstem response (AABR) screening before hospital discharge and complete audiological assessments thereafter (Table 1). Twenty-nine (70%) patients have completed the 3-year follow-up program with another 11 still in progress. Only two patients in this series had incomplete surveillance. Of the 42 patients who had long-term follow-up, only one patient (2.5%) sustained a late onset, progressive sensorineural hearing loss (Table 3). This patient had a complicated hospital stay, requiring a patch repair of a right-sided CDH as well as surgical closure of a patent ductus arteriosus that was complicated by chylothorax. This patient did not require ECMO, but was treated with HFOV for 5 days after surgery as well as iNO. The total NICU stay for this patient was 40 days. The patient was ultimately discharged on home oxygen and diuretics. Other medical co-morbidities in this child included a right dysplastic kidney and a recurrence of his CDH at 4 years of age that required an emergency operation due to a small bowel obstruction. Neonatal hearing screening prior to discharge was normal. Testing at 9 months
Table 1 Montreal Children's Hospital hearing screening and surveillance protocol for children presenting with high risk of hearing loss (2000 to 2011). Risk factors
Prior to hospital discharge
8 months
18 months
3 years
CDH ± ECMO
AABR or ABR
-Age-appropriate audiogram -Impedence -Otoacoustic emissions
Age-appropriate audiogram -Impedence -Otoacoustic emissions
Age-appropriate audiogram -Impedence -Otoacoustic emissions
CDH = congenital diaphragmatic hernia; ABR = auditory brainstem response (screening and diagnostic test); AABR = automated auditory brainstem response (screening test only).
944
M.G. Wilson et al.
Table 2 Demographic, perinatal and surgical data for study population (n = 44).
Gestational Age (weeks) Birthweight (g) Apgar scores at (1, 5) min NICU Stay (days) Days on ventilator Highest ventilator pressure (mm Hg) Timing of Surgical Repair (day of life)
Median
Range
39 3070 (6, 7) 21.5 10.5 22 3
35–41 1840–4350 1–10 7–189 2–189 15–35 1–23
Value (%) Unknown Antenatal diagnosis High Frequency Oscillatory Ventilation Nitric Oxide ECMO Side of Hernia (Left noted) Patch repair Chylothorax Use of supplemental oxygen after discharge Use of inhaled bronchodilators after discharge Use of inhaled steroids after discharge Use of diuretics after discharge Use of anticonvulsants after discharge Use of anti-reflux medication after discharge
23 (52) 16 (36) 21 (48) 5 (11) 36 (82) 11 (25) 5 (11) 9 (21)
– – – – – – – 1 (2)
16 (36)
2 (5)
15 (34) 10 (23) 0 (0) 27 (61)
2 (5) 1 (2) 2 (5) –
of age revealed a bilateral high frequency SNHL. Subsequent testing confirmed a diagnosis of sloping hearing loss in the high frequencies, which appeared to worsen over time. One other patient failed his neonatal hearing screening test and had a mild unilateral hearing loss that was most probably conductive in nature when last tested at 9 months of age. The child's language development at age 5 was normal. This patient did not require patch repair, was not treated with HFOV, and did not require oxygen or diuretics on discharge. Information on the results for both patients with hearing loss is summarized in Table 3.
3. Discussion Although advances in perinatal care have significantly increased CDH survival over the last several years, multi-
Table 3
Abnormal audiological outcomes in CDH survivors.
Total number (N) = 42 a
Late onset progressive SNHL (sloping high frequency loss) Possible mild unilateral deficit (follow-up pending) a
system morbidity still exists in CDH survivors [11–13]. Emphasis is now being placed on reducing this burden with structured surveillance and the early identification of problems [4]. While some older studies have documented SNHL rates as high as 60% in CDH survivors and infants with severe cardio-respiratory illnesses [6,7,14], other studies, including our own unpublished data, have indicated a much lower incidence [9,10]. The present study identified only one CDH survivor with SNHL in a continuous cohort of 42 children. Thus, our results would suggest that the incidence of SNHL could be less than previously reported. The etiology of SNHL in CDH has been linked to the use of neuromuscular blockers (e.g. pancuronium bromide), certain ototoxic medications (e.g. vancomycin; loop diuretics), as well as pulmonary hypertension of the newborn [15,16], prolonged mechanical ventilation, severe alkalosis and high oxygen requirements [17,18]. ECMO and the use of HFOV have also been implicated [14,19]. However, a true causal effect remains to be identified and it is unclear if there is a single pathophysiologic mechanism, if the insults are cumulative, or if these interventions have a synergistic effect leading to SNHL. Furthermore, there is likely an underestimation of the impact of associated genetic syndromes [20]. Indeed, in our only patient with SNHL, an unknown genetic syndrome could not be ruled out as part of the etiology. The discrepancy between our results and those published in earlier years [6,7] may be related to a few issues. First, the management strategies for infants in our contemporary cohort of CDH survivors were likely much different than for the patients enrolled in the studies by Cheung [7] and Robertson [6], whose patients were born in the late 1980's and mid 1990's. The philosophy of care for CDH infants in our institution during the period of study attempted to minimize the use of neuromuscular blockade and significant hyperventilation and alkalosis, thereby potentially limiting the negative impact on the auditory system. The NICU at the Montreal Children's Hospital is also a 'hearing friendly environment', whereby noise levels are controlled for the benefit of the patients. We acknowledge the limitations inherent in our study, including its retrospective nature and the lack of analysis related to medication use or other proposed risk factors for the development of SNHL. This information will be requested from the Canadian Neonatal Network for further analysis. In addition, all infants with CDH are followed in
N (%)
ECMO
HFOV
Patch repair
Oxygen at discharge
Diuretics at discharge
1(2.5%)
No
Yes
Yes
Yes
Yes
1(2.5%)
No
No
No
No
No
Defined as onset after the neonatal period.
Hearing loss in CDH survivors our hearing surveillance program until age 3. Therefore we cannot state categorically that no hearing loss appeared after this age. However, the development of all of these children, including appropriate speech and language, is closely followed until school age and no additional cases of clinically suspected hearing loss have been detected. Nonetheless, the effectiveness of the early identification of hearing loss is undeniable and our results do demonstrate the need for consistent neonatal hearing screening and structured long term follow-up for this population. Although our results do not support some previous studies on the subject, this discrepancy needs to be resolved by studying prospective, contemporary multi-site patient populations that better reflect the current management strategies involving patients with CDH.
945
[8]
[9]
[10]
[11]
[12]
[13]
References [1] Chiu PP, Hendrick H. Postnatal management and long-term outcome for survivors with congenital diaphragmatic hernia. Prenat Diagn 2008;28:592-603. [2] Danzer E, Hedrick HL. Neurodevelopmental and neurofunctional outcomes in children with congenital diaphragmatic hernia. Early Hum Dev 2011;87:625-32. [3] Canadian Association of Pediatric Surgery Network annual report. 2010. www.capsnet.org. [4] Lally KP, Engle W. Postdischarge follow-up of infants with congenital diaphragmatic hernia. Pediatrics 2008;121:627-32. [5] Yoshinaga-Itano C. From screening to early identification and intervention: discovering predictors to successful outcomes for children with significant hearing loss. J Deaf Stud Deaf Educ 2003;8:11-30. [6] Robertson CM, Tyebkhan JM, Hagler ME, et al. Late-onset, progressive sensorineural hearing loss after severe neonatal respiratory failure. Otol Neurotol 2002;23:353-6. [7] Cheung PY, Tyebkhan JM, Peliowski A, et al. Prolonged use of pancuronium bromide and sensorineural hearing loss in childhood
[14]
[15]
[16]
[17]
[18]
[19]
[20]
survivors of congenital diaphragmatic hernia. J Pediatr 1999;135: 233-9. Robertson CM, Cheung PY, Haluschak MM, et al. High prevalence of sensorineural hearing loss among survivors of neonatal congenital diaphragmatic hernia. Western Canadian ECMO Follow-up Group. Am J Otol 1998;19:730-6. Morando C, Midrio P, Gamba P, et al. Hearing assessment in high-risk congenital diaphragmatic hernia survivors. Int J Pediatr Otorhinolaryngol 2010;74:1176-9. Safavi A, Synnes AR, O'Brien K, et al. Multi-institutional follow-up of patients with congenital diaphragmatic hernia reveals severe disability and variations in practice. J Pediatr Surg 2012;47:836-41. Muratore CS, Utter S, Jaksic T, et al. Nutritional morbidity in survivors of congenital diaphragmatic hernia. J Pediatr Surg 2001; 36:1171-6. Chiu PP, Sauer C, Mihailovic A, et al. The price of success in the management of congenital diaphragmatic hernia: is improved survival accompanied by an increase in long-term morbidity? J Pediatr Surg 2006;41:888-92. Chen C, Jeruss S, Chapman JS, et al. Long-term functional impact of congenital diaphragmatic hernia repair on children. J Pediatr Surg 2007;42:657-65. Inhaled nitric oxide in term and near-term infants: neurodevelopmental follow-up of the neonatal inhaled nitric oxide study group (NINOS). J Pediatr 2000;136:611-7. Graziani LJ, Gringlas M, Baumgart S. Cerebrovascular complications and neurodevelopmental sequelae of neonatal ECMO. Clin Perinatol 1997;24:655-75. Graziani LJ, Baumgart S, Desai S, et al. Clinical antecedents of neurologic and audiologic abnormalities in survivors of neonatal extracorporeal membrane oxygenation. J Child Neurol 1997;12: 415-22. Robertson CM, Tyebkhan JM, Peliowski A, et al. Ototoxic drugs and sensorineural hearing loss following severe neonatal respiratory failure. Acta Paediatr 2006;95:214-23. Masumoto K, Nagata K, Uesugi T, et al. Risk factors for sensorineural hearing loss in survivors with severe congenital diaphragmatic hernia. Eur J Pediatr 2007;166:607-12. Fligor BJ, Neault MW, Mullen CH, et al. Factors associated with sensorineural hearing loss among survivors of extracorporeal membrane oxygenation therapy. Pediatrics 2005;115:1519-28. Tovar JA. Congenital diaphragmatic hernia. Orphanet J Rare Dis 2012;7:1.