September 2019 HSC Section 1 Congenital and Pediatric Problems

Reprinted by permission of Laryngoscope. 2018; 128(8):1952-1957.

The Laryngoscope V C 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Silent Aspiration: Who Is at Risk?

Priatharisiny Velayutham, MBBS, MS; Alexandria L. Irace, BA ; Kosuke Kawai, ScD; Pamela Dodrill, PhD, CCC-SLP; Jennifer Perez, MS, CCC-SLP; Monica Londahl, MPH; Lauren Mundy, BS; Natasha D. Dombrowski, BA; Reza Rahbar, DMD, MD

Objective: To determine the prevalence of silent aspiration in pediatric patients and identify which diagnoses may be associated with this finding. Methods: An institutional review board-approved retrospective review was conducted for all patients under the age of 18 who underwent modified barium swallow (MBS) studies at a tertiary children’s hospital in 2015. Speech-language pathol- ogists reviewed MBS studies to identify aspiration/silent aspiration on each fluid consistency tested. Charts were reviewed to collect demographic information and the otolaryngologic, neurologic, genetic, and syndromic diagnoses of each patient. Results: Among 1,286 patients who underwent MBS, 440 (34%) demonstrated aspiration. Within the aspiration group, 393 (89%) specifically demonstrated silent aspiration. Thin fluids were silently aspirated in 81% of these patients. Of chil- dren aged < 6 months, 41% were found to aspirate and, of those, 95% silently aspirated. Median age at which patients dem- onstrated silent aspiration was 1.1 years. Silent aspiration was documented in 41% of patients with laryngeal cleft, 41% of patients with laryngomalacia, and 54% of patients with unilateral vocal fold paralysis. Laryngeal cleft, laryngomalacia, unilat- eral vocal fold paralysis, developmental delay, epilepsy/seizures, syndrome, and congenital heart disease were all associated with silent aspiration. Conclusion: Silent aspiration may be associated with a number of underlying conditions and is more common than pre- viously described. Caregivers and clinicians should be aware that the absence of cough does not eliminate the possibility of aspiration. Modified barium swallow studies can reveal silent aspiration, which is difficult to detect on clinical feeding evalua- tion. Modified barium swallow findings can guide feeding therapy and the overall management of aspiration. Key Words: Aspiration, silent aspiration, dysphagia, modified barium swallow study. Level of Evidence: 4. Laryngoscope , 00:000–000, 2017 Laryngoscope , 128:1952–1957,

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INTRODUCTION Silent aspiration is the entry of a fluid/food bolus below the true vocal folds in the absence of cough to clear. Normally, the laryngeal cough reflex is stimulated by mechanoreceptors and chemoreceptors in the airway, which served to expel the aspirated material. 1,2 In silent aspiration, however, the cough response is absent. Silent aspiration is commonly associated with central or local weakness/incoordination of the pharyngeal musculature, reduced laryngopharyngeal sensation, and/or impaired ability to cough. 2 If aspirated material is not expelled by a cough response, saliva, food, and/or fluids may enter From the Department of Otolaryngology and Communication Enhancement, Boston Children’s Hospital ( P . V ., A . L . I ., K . K ., P . D ., J . P ., M . L ., L . M ., N . D . D ., R . R .); and the Department of Otolaryngology, Harvard Medi- cal School ( K . K ., R . R .), Boston, Massachusetts, U.S.A. Editor’s Note: This Manuscript was accepted for publication November 18, 2017. Dr. Velayutham and Ms. Irace contributed equally to this work. Presented at the American Society of Pediatric Otolaryngology Annual Meeting, Austin, Texas, U.S.A., May 18–21, 2017. The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Reza Rahbar, DMD, MD, Department of Otolaryngology and Communication Enhancement, Boston Children’s Hospital, 300 Longwood Avenue, Boston, MA 02115. E-mail: reza. rahbar@childrens.harvard.edu

the airway and lead to chronic airway disease, including bronchiectasis. 3 Children are more likely to silently aspirate than adults, 4 which may be due to immature neurologic develop- ment 3,5,6 or the increased survival rate of premature infants and children with complex medical histories. 7 Large studies of children with cerebral palsy or neurologic impairments have reported rates of aspiration ranging from 26% to 38%, with silent aspiration demonstrated in 94% to 97% of the aspiration group. 8,9 One study of a broad pediatric popula- tion reported that 34% of children aspirated, with 81% dis- playing silent aspiration. 3 Normal children may also aspirate, but the incidence of silent aspiration in normal neonates and infants is unknown due to the lack of reliable and easily testable markers needed to make a diagnosis. 10 Despite this prevalence, little is known about whichmedical diagnoses may be associated with silent aspiration in chil- dren. As a result, guidelines on who should be evaluated for this condition have not been well established. Detection and diagnosis of silent aspiration depend on visual confirmation rather than overt signs. 11,12 This typically requires a modified barium swallow (MBS) study or a fiberoptic endoscopic evaluation of swallowing (FEES), both of which may provide visual evidence of impaired pharyngeal/laryngeal function. Although FEES is helpful in the observation of swallowing mechanisms, its use is limited in a pediatric population due to a lack

DOI: 10.1002/lary.27070

Laryngoscope 00: Month 2017 128: August 2018

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