Endoscopic evaluation of pharyngeal and laryngeal sensation in patients with chronic obstructive pulmonary disease (COPD): A cross‐sectional study

Abstract

Laryngeal sensation and pharyngeal sensation are crucial for airway protection in swallowing. Previous research suggests that impaired laryngeal sensation and pooled salivary secretions are associated with increased risk of aspiration and post-swallow pharyngeal residue. [1][2][3][4][5][6] Risk factors for impaired sensation include mucosal damage and inflammation secondary to inhaled corticosteroid exposure, 5,7 or acid exposure in gastroesophageal reflux disease (GERD). [8][9][10][11] This study investigated the presence of and risk factors for laryngopharyngeal sensory impairment and its association with secretion pooling in adults with Chronic Obstructive Pulmonary Disease (COPD), given that dysphagia and aspiration can trigger COPD exacerbations. 12 Pharyngeal sensation is commonly assessed in cranial nerve examinations through elicitation of the pharyngeal gag reflex in response to mechanical stimulation of the posterior pharyngeal wall. 13 Laryngeal sensation can be assessed indirectly under laryngoscopy, via mechanical stimulation of the laryngeal mucosa using air puffs or light touch stimulation with the tip of a laryngoscope. 5,[14][15][16][17] Observations of motor responses in the form of pharyngeal contraction 13,18 or the laryngeal adductor reflex (LAR) are interpreted to indicate integrity of the afferent pathway. 14,15,19,20 Impaired LAR mechanosensitivity has been reported in individuals with COPD, 5

Current approaches to reporting pharyngo-laryngeal secretions

“…There is building evidence of the clinical importance of reporting secretions, with a number of recently published articles supporting secretion assessment across patient populations including postextubation [17,18], respiratory diseases [19 ▪ ,20], amyotrophic lateral sclerosis (ALS) [10], minimally conscious patients [21], and head and neck cancer [22]. The relevance of secretions is well established in tracheostomy weaning and decannulation literature.…”

“…Despite the availability of valid reporting tools, there is a lack of use of standardized secretion ratings in existing literature. Many recent studies assess secretions as a dichotomous variable, or use their own choice of categorization, which primarily focus on the location/depth of secretion pooling [7,8 ▪ ,9,19 ▪ ,20,22,26,27]. A number of recently published intervention studies have assessed secretion severity as a primary or secondary outcome measure to determine responses to therapeutic interventions [26,28]; however, only one used a validated tool [28].…”

“…The predictive value of accumulated secretions for swallow impairment and health outcomes is well established and continues to receive attention in recent publications [7,8 ▪ ,9,10,20]. Yet, understanding of its underlying mechanisms is limited.…”

“…All of these recently published studies used stimulation of the LAR using light touch of the arytenoids with the tip of the endoscope to evaluate the sensory integrity of the laryngeal mucosa [7,8 ▪ ,19 ▪ ,20,31 ▪▪ ] and the reliability and diagnostic accuracy of this method has been questioned. The pressure applied when endoscopically tapping the arytenoids has been shown to be highly variable [36] but consistently higher than thresholds established in seminal work by Aviv et al [37], indicating its utility in consistently identifying severe sensory impairments.…”

“…Patients with intact laryngeal sensation were less likely to have secretions in the laryngeal vestibule; however, analyses were limited in terms of secretion severity, as secretions were evaluated using a nonstandardized four-point rating scale. A recent small cross-sectional study in patients with chronic obstructive pulmonary disease (COPD) also indicated a link between diminished pharyngeal and laryngeal sensation and pooled secretions in the pharynx, particularly in the pyriform sinus [20]. Unfortunately, secretions were again crudely rated with a binary measure according to location of secretions only.…”