Coordination between respiration and swallowing in patients with dysphagia after cervical spinal cord injury: an observational case-control study

Background: Patients with cervical spinal cord injury are commonly associated with respiratory impairment, but swallowing dysfunction is usually overlooked. Respiratory system and swallowing function are highly coordinated during feeding, play a vital role in airway protection and reduce the risk of aspiration. However, the pathophysiological changes underlying dysphagia and its development remain largely unknown. The purpose of the present study was to observe the changes between respiration and swallowing in patients with cervical spinal cord injury with dysphagia and to explore the underlying mechanism. Methods Ninety participants were recruited for Bedside Swallowing Evaluation and surface electromyography with thermocouple nasal airflow sensor examination: 60 with spinal cord injury (30 with dysphagia and 30 without dysphagia) and 30 healthy controls. Results Compared with the healthy controls and patients without dysphagia, the post-swallow respiratory pattern was an inspiratory pattern, and the duration of swallowing apnea duration was significantly lower in patients with dysphagia( P  < 0.05). The index of swallowing apnea duration was statistically significant for predicting the development of dysphagia in patients with cervical spinal cord injury ( P  < 0.05). The expiratory time in patients with dysphagia was significantly shorter than the inspiratory time, and the swallowing efficiency was reduced, requiring multiple swallows. Conclusion Incoordination between respiration and swallowing may be the cause of dysphagia in patients with cervical spinal cord injury. Swallowing apnea duration can be used as a predictor of dysphagia in patients.