Clinical implication of artificial glottic closure for air-stacking exercise in patients with glottis dysfunction

Abstract

[한글]

[영문]Objective: Patients with neuromuscular disease can have severe inspiratory and expiratory muscle weakness that diminishes vital capacity and lung compliance. Atelectasis and inability to effectively cough out airway secretions are the main cause of respiratory failure and mortality. Therefore, air-stacking exercise which insufflates the lung to its maximal capacity is mandatory to maintain pulmonary compliance. However, neuromuscular patients with bulbar musculature weakness or indwelling tracheostomy cannot induce glottic opening and closure. For these patients, we developed a method which enables air stacking exercise by mimicking the glottis function. Method: 40 patients with bulbar muscle weakness or indwelling tracheostomy were recruited. 26 were amyotrophic lateral sclerosis(ALS) patients, and 14 were tetraplegic patients due to cervical spinal cord injury(SCI). T-shaped device is mainly composed of the connection and the control part. One-way valve is installed to the connection part to provide extra volume of air via a manual resuscitator bag, which also prevents air leakage. The control part is designed to artificially modulate glottic opening and closure. In order to confirm the utility of external control device vital capacity(VC), maximum insufflation capacity(MIC), and maximum insufflation capacity with a device(MIC-device) were measured. Results: For the 32 patients, MIC was not measurable initially. However, with help of the method which enables air stacking exercise, MIC-device was successfully measured for all patients. Mean MIC-device value was 1701.9±660.5ml. For the remaining 8 patients, MIC was measurable even without the device, but mean MIC and MIC-device values were 1073.8±242.4ml, 1847.5±233.7ml respectively. MIC-device of the patients was significantly higher than MIC alone. Conclusion: The new method enables air staking, which is mandatory for lung expansion. It also makes it possible to maintain or even improve pulmonary compliance, which eventually prevents lethal pulmonary complications.