Global Physiology and Pathophysiology of Cough: Part 1: Cough Phenomenology - CHEST Guideline and Expert Panel Report

Abstract

The purpose of this state-of-the-art review is to update the American College of Chest Physicians 2006 guideline on global physiology and pathophysiology of cough. A review of the literature was conducted using PubMed and MEDLINE databases from 1951 to 2019 and using prespecified search terms. We describe the basic phenomenology of cough patterns, behaviors, and morphological features. We update the understanding of mechanical and physiological 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 patient cough hypersensitivity phenotype are explored. Lastly, because the clinical assessment of patients largely focuses on the duration rather than morphological features of cough, we review the morphological features of cough that can be measured in the clinic. This is the first of a two-part update to the American College of Chest Physicians 2006 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.

Keywords: cough; pathophysiology; phenomenology; physiology.

Figure 1

Bouts of coughs, characterized by multiple expulsive efforts occurring close together.

Figure 2

A, The three-phase flow pattern of a classical cough is characterized by an initial inspiratory phase followed by cessation of flow during the compression phase (glottis closure) and then rapid expulsion of air during the expiratory phase. B, Expiration reflexes and classical cough. Flow trace depicting a series of three expiration reflexes (characterized by lack of preceding inspiration) followed by a single classical cough and two expiration reflexes.

Figure 3

Example of diminishing cough strength during cough reaccelerations within a bout. An initial inspiratory effort is followed by multiple expiratory events efforts that have sequentially less flow as the bout progresses.

Figure 4

A typical three-phase cough sound shown in the time domain. The first phase, explosive, relates to the expulsion of air through the glottis and is followed in most cases by a voiced phase, with a gradually diminishing sound signal; a quiet intermediate phase occurs between the two.