Case Report: Vocal cord collapse during phrenic nerve-paced respiration in congenital central hypoventilation syndrome

Mark C Domanski,Diego A Preciado

doi:10.12688/f1000research.1-42.v1

Abstract

Objective: Phrenic nerve pacing can be used to treat congenital central hypoventilation syndrome (CCHS). We report how the lack of normal vocal cord tone during phrenic paced respiration can result in passive vocal cord collapse and produce obstructive symptoms. Methods: We describe a case of passive vocal cord collapse during phrenic nerve paced respiration in a patient with CCHS. As far as we know, this is the first report of this etiology of airway obstruction. The patient, a 7-year-old with CCHS and normal waking vocal cord movement, continued to require nightly continuous positive airway pressure (CPAP) despite successful utilization of phrenic nerve pacers. On direct laryngoscopy, the patient’s larynx was observed while the diaphragmatic pacers were sequentially engaged. Results: No abnormal vocal cord stimulation was witnessed during engaging of either phrenic nerve stimulator. However, the lack of normal inspiratory vocal cord abduction during phrenic nerve-paced respiration resulted in vocal cord collapse and partial obstruction due to passive adduction of the vocal cords through the Bernoulli effect. Bilateral phrenic nerve stimulation resulted in more vocal cord collapse than unilateral stimulation. Conclusions: The lack of vocal cord abduction on inspiration presents a limit to phrenic nerve pacers.

Highlights

Congenital central hypoventilation syndrome (CCHS) is a rare disorder typified by the lack of ventilatory responsiveness to hypoxemia and hypercarbia
Tumors of neural crest origin such as ganglioneuromas, neuroblastomas and ganglioneuroblastomas are associated with CCHS1
Case Description A seven year-old female presented with a history of CCHS and a current complaint of obstructive sleep apnea requiring continuous positive airway pressure (CPAP)

Summary

Introduction

Introduction Congenital central hypoventilation syndrome (CCHS) is a rare disorder typified by the lack of ventilatory responsiveness to hypoxemia and hypercarbia. Patients with CCHS may have other disorders of the autonomic nervous system such as Hirschsprung’s disease, lack of heart rate variability, poor temperature regulation, and diminished pupillary light response. A mouse model of CCHS showed that Phox2B -/- mice fail to develop the normal neuronal connections of several structures including the solitary tract[4,5]. Case Description A seven year-old female presented with a history of CCHS and a current complaint of obstructive sleep apnea requiring continuous positive airway pressure (CPAP).

Results

Conclusion