Definition, categorization, and terminology of episodic breathlessness: consensus by an international Delphi survey

Abstract

Context: Episodic breathlessness is a common and distressing symptom in patients with advanced disease. Still, it is not yet clearly defined.

Objectives: The aim of this work was to develop an international definition, categorization, and terminology of episodic breathlessness.

Methods: An online Delphi survey was conducted with international breathlessness experts. We used a structured questionnaire to identify specific aspects and reach agreement on a definition, categorization, and terminology (five-point Likert scale). Consensus was defined in advance as ≥70% agreement.

Results: Thirty-one of 68 (45.6%), 29 of 67 (43.3%), and 33 of 67 (49.3%) experts responded in the first, second, and third rounds, respectively. Participants were 20-79 years old, about 60% male, and more than 75% rated their own breathlessness expertise as moderate to high. After three rounds, consensus was reached on a definition, categorization, and terminology (84.4%, 96.3%, and 92.9% agreement). The final definition includes general and qualitative aspects of the symptom, for example, time-limited severe worsening of intensity or unpleasantness of breathlessness in the patient's perception. Categories are predictable or unpredictable, depending on whether any triggers can be identified.

Conclusion: There is high agreement on clinical and operational aspects of episodic breathlessness in advanced disease among international experts. The consented definition and categorization may serve as a catalyst for clinical and basic research to improve symptom control and patients' quality of life.

Keywords: Delphi method; dyspnea; episodic breathlessness; palliative medicine; respiratory symptoms.