The importance of the feasibility study: Lessons from a study of the hand-held fan used to relieve dyspnea in people who are breathless at rest

Background: The dyspnea accompanying advanced cardiorespiratory disease is often refractory to palliation. It is disabling, distressing and associated with the diseases most common everywhere in the world. The hand-held fan, used to generate a draught across the face, is a simple, cost-effective, safe, and universally applicable palliative breathlessness intervention, consistently described as valuable in qualitative research. A previous crossover trial confirmed its benefit in patients breathless at rest, but the washout period was uncertain.

Aim: To determine the washout period after use of the hand-held fan to inform accurate randomized controlled trial design.

Design: An observational methodological study. Breathlessness intensity was measured using 100 mm visual analog scale and numerical rating scale, and "relief of breathlessness" was measured on a 5-point scale. Those benefitting from the fan provided visual analog scale/numerical rating scale scores until (1) scores returned to baseline values or (2) until response had plateaued. The primary outcome measure was the time (in minutes) to reach either component of the primary study endpoint.

Settings/participants: Four in-/out-patient hospice/hospital units; participants had chronic refractory breathlessness using the fan.

Results: Overall, 31 patients participated (mean age: 74.8 years; range: 49-98 years, standard deviation = 11.5 years); 64% were males. Approximately, half of the sample experienced benefit of moderate effect size. The relative reduction in breathlessness relative to the mean baseline score for the sample was 27% for the visual analog scale and 19% for the numerical rating scale.

Conclusion: Feasibility work is essential, even for simple widely employed interventions.