Measurement of dyspnoea.

Dyspnoea is the term generally applied to unpleasant or uncomfortable respiratory sensations. The measurement of dyspnoea is a critical aspect of patient evaluation and management. Both psychophysical methods and clinical scales have been used to assess breathlessness. Because of dyspnoeic patient is frequently unable to perform the daily activities of life due to discomfort associated with breathing, the clinical methods used to measure dyspnoea have depended primarily on the magnitude of the exertional task that evokes breathlessness. The visual analogue scale is one method that has been used. To improve the clinical rating, two more indices (baseline dyspnoea index and transition dyspnoea index) that include the components of functional impairment and magnitude of effort, in addition to the magnitude of the task, were developed. The category-ratio-10 scale developed by Borg consists of verbal descriptors adjacent to specific numbers, providing a category scale with ratio properties. Measurement instruments may involve a cost for use, may be self-administered or require an interviewer, and will vary in the time required for completion and scoring.