Could reflex cough induced through nebulized capsaicin achieve airway clearance in patients with acute retention of lung secretions?

摘要

Nasotracheal suctioning (NTS) is a procedure commonly performed by respiratory physiotherapists and nurses to remove excess respiratory secretions from the tracheobronchial tree in a self-ventilating, non-intubated and non-tracheotomized patient. NTS is an important treatment modality for patients with acute secretion retention who are at high risk of progressive respiratory deterioration and arrest. However, NTS is a blind invasive procedure with risk of serious adverse events, and the patient experience of NTS is often extremely negative.Capsaicin, a substance extracted from cayenne pepper, elicits reflex coughs when inhaled. It is hypothesized that capsaicin-induced reflex cough may offer an alternative treatment option to NTS. It is suggested that repeated reflex cough bouts, elicited through inhalation of nebulized capsaicin via a facemask, could achieve clearance of retained secretions from the tracheobronchial tree to the oropharynx, thereby avoiding the need for NTS.This hypothesis is supported by preliminary cough flow data from a stroke trial. Stroke patients underwent assessments of peak cough flow (PCF, a measure of cough effectiveness) of both maximal volitional cough and capsaicin-induced reflex cough. In a sub-group of 20 stroke patients with weak volitional cough (mean PCF 220?L/min, SD 80), PCF of capsaicin-induced reflex cough was on average 184?L/min (SD 130) higher than PCF of subjects’ maximal volitional cough effort. Cough flow traces indicate a pattern of cough augmentation during consecutive reflex cough bouts.It is suggested that the hypothesis may best be tested in a pragmatic applied clinical study,i.e.through the application of nebulized capsaicin in relevant clinical situations, as opposed to observational or experimental physiological studies.