Upper Airway Assessment and Responses During Mechanically Assisted Cough

Abstract

When ability to cough is impaired, secretion clearance may be assisted and augmented by Mechanical Insufflation-Exsufflation (MI-E). In some individuals, the efficacy of MI-E may be hampered by counterproductive upper airway reactions, where the airways close in response to positive pressures. In order to fully utilize the therapeutic potential inherent in the MI-E technology, we need a better understanding of the pathophysiology behind these untoward reactions. There is an increasing interest in monitoring and measuring upper airway responses to MI-E, and how such information can be used to optimize the MI-E settings. The purpose of this narrative review is to increase the theoretical understanding of larynx as a respiratory organ, summarize the current literature in the area, and provide insight into how this knowledge can affect current clinical practice.

From bedside to bench - In vivo and in vitro evaluation of mechanically assisted cough treatment in a patient with bulbar Amyotrophic Lateral Sclerosis

“…Positive pressure from the MI-E device leads to lung insufflation, a subsequent rapid switch to negative pressure leads to lung exsufflation, moving airway secretions proximally. However, MI-E therapy applied non-invasively does not succeed in all patients, as positive airway pressures may cause inappropriate laryngeal responses [ 11 ]. Application of more gentle pressures have been advocated [ 5 ].…”

Adjustments of non-invasive ventilation and mechanically assisted cough by combining ultrasound imaging of the larynx with transnasal fibre-optic laryngoscopy: a protocol for an experimental study

“…The larynx is positioned in the upper airways and has a complex gateway function, protecting the airways from aspiration and controlling both phonation and ventilation 1. The larynx may be divided into supraglottic, glottic and subglottic levels, and consists of airway mucosa, rigid cartilage skeletons, ligaments, and muscles for adduction and abduction.…”

“…These structures together create a dynamic organ which is controlled by reflexes as well as voluntary movements. During quiet breathing, the abduction of the larynx is fundamental to allow free airflow in and out of the lungs at the least possible resistance 1. The larynx widens during inspiration and narrows during expiration2 3 (see figure 1).…”

“…Superior, posterior and medial views of the larynx with anatomical landmarks. Published with permission from Andersen et al 1…”

Value of Peak Expiratory Flow Rate in Evaluating Cough Ability in Patients Undergoing Lung Surgery

“…The secretions cannot be effectively eliminated, which may easily lead to pulmonary infections [ 1 ]. Effective cough could prevent postoperative pulmonary infection and atelectasis by clearing secretions and keeping the airway unobstructed [ 2 ]. At present, only a few indicators were used in evaluating the cough ability after surgery, such as measuring the volume of sputum excreted and observing the occurrence of PPCs.…”