Estimating Minute Ventilation and Inspiratory Flow to Trigger Exercise-Induced Laryngeal Obstruction (EILO) in Pediatric Patients

Authors

Rebecca Brovina, University of Texas Health Science Center at Tyler and Cook Children's Healthcare SystemFollow
John M. Robertson, Cook Children's Healthcare SystemFollow
Andreas Kreutzer, Cook Children's Healthcare SystemFollow

Abstract

Exercise-induced respiratory symptoms hinder exercise participation and performance in adolescents. One cause is exercise-induced laryngeal obstruction (EILO). While EILO pathology is poorly understood, high airflow rates through the larynx appear necessary to elicit an episode. Exercise above 75% of peak work capacity reliably triggers EILO; however, the minute ventilation (V̇E) and mean inspiratory flow rates (V_T/T_i) to trigger EILO are unknown. This information could influence diagnostic testing protocols, exercise prescriptions, and training programs. PURPOSE: The purpose of this ongoing study is to estimate the V̇E and V_T/T_i required to trigger laryngeal closure among pediatric patients. METHODS: We screened 39 existing patients with an EILO diagnosis. After excluding patients with missing videos or gas exchange data and those whose diagnosis we could not confirm, we used records from 16 (f = 15, age = 14.6 ± 1.2 years, V̇O₂peak = 39.4 ± 6.6 mL·kg·min^-1) patients in this preliminary analysis. We will add patients until we reach a sample size of 60. We reviewed charts and analyzed videos from a continuous laryngoscopy during exercise with cardiopulmonary exercise test (CLE-CPET), where a flexible laryngoscope records the behavior of the larynx during treadmill running. Obstruction is graded on a 0 to 3 scale at the glottic and supraglottic levels with a score of ≥2 in either category considered pathologic. We estimated the mean V̇E and V_T/T_i to trigger a CLE score of ≥2 among patients with supraglottic, glottic, and mixed-type EILO. We did not perform inferential statistics due to the preliminary nature of this analysis. RESULTS: Ten patients (62.5%) had supraglottic, two (12.5%) had glottic, and four (25%) had mixed-type EILO. Mean V̇E to trigger any type of EILO (n =16) was 60.7 [95% CI: 54.8; 66.3] L·min^-1, which equaled 52.5 [47.8; 57.6] % of Maximal Voluntary Ventilation (MVV), and 80.4 [74.0; 86.5] %V̇Epeak achieved in the test. A supraglottic CLE score of 2 (n = 14) appeared to be triggered at a lower V̇E (60.8 [53.9; 67.8] L·min^-1;53.1 [48.2; 58.4] %MVV; 79.4 [72.8; 86.1]) than a glottic CLE score of 2 (72.2 [52.1; 104.0] L·min^-1;61.0 [47.2; 79.2] %MVV; 92.0 [86.5; 97.0] %V̇Epeak, n = 5). The lowest V̇E to trigger any kind of EILO was 42.0 L·min^-1_, 39.5 %MVV, and 58.2 %V̇Epeak.EILO was triggered at or below a V̇E of 70 L·min^-1and 60 %MVV in most of our patients (81.25%) and at a V̇E of 82.3 L·min^-1and 77 %MVV or below in all patients. Mean V_T/Ti to trigger any type of EILO was 2.63 [2.33; 2.93] L·sec^-1, which equaled 77.8 [70.5; 85.6] %V_T/T_ipeak. Again, V_T/T_i values eliciting a glottic score of 2 (2.87 [2.09; 4.05] L·sec^-1;87.5 [78.1; 96.6] %V_T/T_ipeak) appeared to be higher than those triggering a supraglottic score of 2 (2.66 [2.33; 3.00] L·sec^-1;77.2 [68.9; 85.0] %V_T/T_ipeak). CONCLUSION: A diagnostic exercise test that does not elicit sufficiently high V̇E is not adequate for detecting the presence of EILO. In our preliminary data a VE of 82 L·min^-1 and 77 %MVV was necessary to ensure all patients exhibited EILO. Once confirmed in a larger sample, clinicians and researchers can use these estimates to design exercise protocols that elicit sufficient V̇E.

Recommended Citation

Brovina, Rebecca; Robertson, John M.; and Kreutzer, Andreas (2025) "Estimating Minute Ventilation and Inspiratory Flow to Trigger Exercise-Induced Laryngeal Obstruction (EILO) in Pediatric Patients," International Journal of Exercise Science: Conference Proceedings: Vol. 2: Iss. 17, Article 89.
Available at: https://digitalcommons.wku.edu/ijesab/vol2/iss17/89