Background: Daily clinical observations and a recent study (D Vermeylen et al., 2004) suggest that reflux laryngitis (RL) is involved in apneas/ bradycardias of the newborn. The aim of this study is to develop and tovalidate a unique RL model in newborn lambs to test the assumption that a RL provokesan increase in apneas/ bradycardias/ desaturations observed within thelaryngeal chemoreflexes induced by the contact of a liquid with the larynx.
Methods: A surgical instrumentation was performed on the first day of life, which included the insertion of a transcutaneous esophageal catheter in order to allow instillation of a gastric juice surrogate (HCl +pepsin at pH 2) directly on the larynx. The 2 ml-instillations were made 3 times per day for 6 consecutive days. At day 9-10 laryngeal chemoreflexes were induced during sleep. The larynx was removed at the time of necropsy to grade inflammation by a histological study.
Results: Lambs in which a RL was induced (n = 4) presented characteristic signs of RL: cough, weak bleat, reduction in weight gain. Preliminary histological analyses showed a characteristic laryngeal inflammation. Preliminary results showing that apneas and oxygen desaturations seem more prominent in RL lambs than controls provided further validation ofour RL model.
Conclusion: The ovine model developed in this study presents theclinical and histological characteristics of RL observed in newborns. Preliminary results suggesting that a RL increases apneas/bradycardias/desaturations when a liquid is in contact with laryngealmucosa in the newborn must be confirmed.
Supported by: CIHR, FRSQ, Foundation of stars.
