Hand-held fans: Physical Properties and Perceptions of Patients with COPD

Patients with chronic obstructive pulmonary disease (COPD) may remain breathless despite optimal medical treatment. Hand-held fans (HHFs) are recommended to relieve breathlessness, but little is known about physical properties of different fans and the impact HHF properties may have on patient perceptions of fans.

To describe the physical properties of HHFs and investigate the relationship of these properties to patient fan preference.

We recruited 33 participants with COPD who were attending a pulmonary rehabilitation program. Participants trialled 5 HHFs in random order. Participants rated perceived airflow, pleasantness of airflow, noisiness, and ease of use of each fan using a 1-10 numerical rating scale (NRS). After trialling all 5 fans, participants ranked each HHF from best (5 arbitrary units; a.u.) to worst (1 a.u.). Rankings for each fan were tallied to produce total HHF scores (T-HHF; maximum=165 a.u.). Objective measurements were made of sound intensity (dB; sound level meter), airflow between 5cm and 30cm from the middle of the fan (anemometer), blade rotation speed, blade size and total fan weight. We assessed the strength of association of T-HHF scores against mean NRS values using Spearman correlation coefficients and used linear regression to compare measured to perceived airflow, and noisiness to sound intensity.

Participants were 68.5 ± 8.9 years (mean ± SD), 63% male, with a median FEV₁ of 0.99L(IQR 0.76-1.31L). There was considerable variability between the 5 fans tested in terms of participant perceptions and physical properties with an almost 5-fold difference in air velocity at 30cm and a 3-fold difference in blade rotation speed. The most preferred fan had a T-HHF score of 140 and had the highest airflow (1.9 m/s) measured at 30cm. T-HHF score positively correlated with pleasantness of airflow (r = 0.46; P < 0.001), perceived airflow (r=0.58; P<0.001) and airflow velocity at 30cm from fan blades (r=1.0; P = 0.02). There were positive linear relationships between fan airflow velocity and perceived air amount, and between measured sound intensity and perceived noisiness(both P<0.001). Women reported significantly higher perceived airflow than men (P < 0.001).

The physical properties of the five included HHFs are quite distinct. Patient preference was related to pleasantness of airflow, perceived airflow, and measured airflow at 30cm. Gender differences in perceived airflow were noted. Future research should explore the relationship between HHF characteristics and relief of breathlessness.