Randomised controlled trial of rhinothermy for treatment of the common cold: a feasibility study.

Objective To determine the feasibility of a randomised controlled trial (ACT) of rhinothermy for the common cold. Design Open label, randomised, controlled feasibility study. Setting Single-centre research institute in New Zealand recruiting participants from the community. Participants 30 adult participants with symptoms of a common cold, presenting within 48 hours of the onset of symptoms. Interventions Participants were randomly assigned 2:1 to receive either 35 L/min of 100% humidified air at 41 degrees C via high flow nasal cannulae, 2 hours per day for up to 5 days (rhinothermy), or vitamin C 250 rug daily for 5 days (control). Primary and secondary outcome measures The primary outcome was the proportion of screened candidates who were randomised. Secondary outcomes included: proportion of randomised participants who completed the study; modified Jackson scores from randomisation to 10 days after initiation of randomised regimen; time until feeling a lot better' compared with study entry; time until resolution of symptoms or symptom score at 10 days postrandomisation; proportion of organisms identified by PCR analysis of nasal swabs taken at baseline; the patterns of use of the rhinothermy device; estimated adherence of the control group; and rhinothermy device tolerability. Results In all 30/79 (38%, 95% CI 27% to 50%) of potential participants screened for eligibility were randomised. Rhinothermy was well tolerated, and all randomised participants completed the study (100%, 95%, CI 88% to 100%). The reduction from baseline in the modified Jackson score was greater with rhinothermy compared with control at days 2, 3, 4, 5 and 6, with the maximum difference at day 4 (-6.4, 95% CI -9.4 to -3.3). The substantial clinical benefit threshold for modified Jackson score was a 5-unit change. Conclusions This study shows that an ACT of rhinothermy compared with low-dose vitarnin C in the treatment of the common cold is feasible.