Airflow relieves chronic breathlessness in people with advanced disease : An exploratory systematic review and meta-analyses

BACKGROUND:: Chronic breathlessness is a neglected symptom of advanced diseases. AIM:: To examine the effect of airflow for chronic breathlessness relief. DESIGN:: Exploratory systematic review and meta-analysis. DATA SOURCES:: Medline, CINAHL, AMED and Cochrane databases were searched (1985-2018) for observational studies or randomised controlled trials of airflow as intervention or comparator. Selection against predefined inclusion criteria, quality appraisal and data extraction was conducted by two independent reviewers with access to a third for unresolved differences. 'Before and after' breathlessness measures from airflow arms were analysed. Meta-analysis was carried out where possible. RESULTS:: In all, 16 of 78 studies (n = 929) were included: 11 randomised controlled trials of oxygen versus medical air, 4 randomised controlled trials and 1 fan cohort study. Three meta-analyses were possible: (1) Fan at rest in three studies (n = 111) offered significant benefit for breathlessness intensity (0-100 mm visual analogue scale and 0-10 numerical rating scale), mean difference -11.17 (95% confidence intervals (CI) -16.60 to -5.74), p = 0.06 I2 64%. (2) Medical air via nasal cannulae at rest in two studies (n = 89) improved breathlessness intensity (visual analogue scale), mean difference -12.0 mm, 95% CI -7.4 to -16.6, p < 0.0001 I2 = 0%. (3) Medical airflow during a constant load exercise test before and after rehabilitation (n = 29) in two studies improved breathlessness intensity (modified Borg scale, 0-10), mean difference -2.9, 95% CI -3.2 to -2.7, p < 0.0001 I2 = 0%. CONCLUSION:: Airflow appears to offer meaningful relief of chronic breathlessness and should be considered as an adjunct treatment in the management of breathlessness.