Global Physiology and Pathophysiology of Cough

Abstract

Background:The purpose of this state-of-the-art review is to update the American College of Chest Physicians (CHEST) 2006 guideline on global physiology and pathophysiology of cough.Methods: A review of the literature was conducted using PubMed and Medline databases from 1951 to 2019 using pre-specified search terms. Results:We describe the basic phenomenology of cough patterns, behaviors and morphologic features. We update the understanding of mechanical and physiologic characteristics of cough, adding a contemporary view of the types of cough and their associated behaviors and sensations. New information about acoustic characteristics is presented, and recent insights into cough triggers and the cough hypersensitivity patient phenotype are explored. Lastly, because the clinical assessment of patients largely focuses on the duration rather than morphologic features of cough, we review the morphological features of cough that can be measured in the clinic. Conclusions: This is the first of a two-part update to the 2006 CHEST Cough Guideline; it provides a more global consideration of cough phenomenology, beyond simply the mechanical aspects of a cough. A greater understanding of the typical features of cough, and their variations, may allow a more informed interpretation of cough measurements and the clinical relevance for patients. Information presented was obtained from both animal and human experimental work. Abbreviations: CHS (cough hypersensitivity syndrome) COPD (chronic obstructive pulmonary disease) CPD (compression phase duration) EMG (electromyography) ER (expiratory reflex) ERS (European Respiratory Society) FRC (functional residual capacity) OEP (optoelectronic plethysmography) TRPV1 (transient receptor potential vanilloid 1)

The Acoustic Dissection of Cough: Diving into Machine Listening-based COVID-19 Analysis and Detection

“…This process allows the compression of the thorax and the increase of subglottic pressure. The next phase of a cough constitutes the rapid opening of the glottis resulting in a high-velocity airflow (peak expiratory airflow phase), followed by a steady-state airflow (plateau phase) for a variable -voluntarily controllable -duration (Kelemen et al, 1987;Lee et al, 2021). The optional final phase is the interruption of the airflow due to the closure of the glottis (Lee et al, 2017).…”

Cough hypersensitivity and chronic cough

“…• A typical cough consists of three respiratory phases: (1) a brief inspiratory phase to prime the lungs with a volume of air; (2) a compression phase characterized by expiratory muscle contraction against a closed glottis, needed to ramp up intrapulmonary pressure; and finally (3) the expiratory phase during which the glottis opens, and high velocity expiratory airflow occurs 234 .…”

“…The identification of an expiration reflex requires assessment of airflow with a pneumotachograph in the laboratory. The clinical relevance of the expiration reflex has therefore been difficult to study 234 .…”

Sensitive Skins May Be Neuropathic Disorders: Lessons from Studies on Skin and Other Organs

“…Especially, the triggering of cough by relatively innocuous stimuli suggests heightened sensitivity of the sensory nerve pathways alluded to earlier that normally serve to detect and respond to harmful airway irritants. In these circumstances, the chronic cough should not be considered as a symptom but rather as a disease entity caused by a disordered nervous system in which the concept of hypersensitivity cough is emerging [50].…”