An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea

Abstract

Background: Dyspnea is a common, distressing symptom of cardiopulmonary and neuromuscular diseases. Since the ATS published a consensus statement on dyspnea in 1999, there has been enormous growth in knowledge about the neurophysiology of dyspnea and increasing interest in dyspnea as a patient-reported outcome.

Purpose: The purpose of this document is to update the 1999 ATS Consensus Statement on dyspnea.

Methods: An interdisciplinary committee of experts representing ATS assemblies on Nursing, Clinical Problems, Sleep and Respiratory Neurobiology, Pulmonary Rehabilitation, and Behavioral Science determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant expertise. The final content of this statement was agreed upon by all members.

Results: Progress has been made in clarifying mechanisms underlying several qualitatively and mechanistically distinct breathing sensations. Brain imaging studies have consistently shown dyspnea stimuli to be correlated with activation of cortico-limbic areas involved with interoception and nociception. Endogenous and exogenous opioids may modulate perception of dyspnea. Instruments for measuring dyspnea are often poorly characterized; a framework is proposed for more consistent identification of measurement domains.

Conclusions: Progress in treatment of dyspnea has not matched progress in elucidating underlying mechanisms. There is a critical need for interdisciplinary translational research to connect dyspnea mechanisms with clinical treatment and to validate dyspnea measures as patient-reported outcomes for clinical trials.

Figure 1.

Functional magnetic resonance images showing cerebral activations correlated with the experience of strong air hunger in healthy subjects. The test condition consisted of low tidal volume controlled ventilation during mild hypercapnia; the baseline comparison condition used the same level of hypercapnia but with high tidal volume (subjects reported little or no discomfort at baseline). The strongest activation is in the right anterior insula, indicated by the blue crosshairs; this activation has been shown in a number of studies. Other activations can be seen in the left anterior insula, anterior cingulate, supplementary motor area, prefrontal cortex, and cerebellum. Not visible in this figure, but reported in the same study was activation of the amygdala. Most of these regions fall in the category of limbic/paralimbic, and overlap with activations seen during pain, thirst, fear, and hunger. Reproduced and adapted with permission from Reference 137.