High-Flow Oxygen and High-Flow Air for Dyspnea in Hospitalized Patients with Cancer: A Pilot Crossover Randomized Clinical Trial

Abstract

Abstract Background The effect of high-flow oxygen (HFOx) and high-flow air (HFAir) on dyspnea in nonhypoxemic patients is not known. We assessed the effect of HFOx, HFAir, low-flow oxygen (LFOx), and low-flow air (LFAir) on dyspnea. Subjects, Materials, and Methods This double-blind, 4×4 crossover clinical trial enrolled hospitalized patients with cancer who were dyspneic at rest and nonhypoxemic (oxygen saturation >90% on room air). Patients were randomized to 10 minutes of HFOx, HFAir, LFOx, and LFAir in different orders. The flow rate was titrated between 20–60 L/minute in the high-flow interventions and 2 L/minute in the low-flow interventions. The primary outcome was dyspnea numeric rating scale (NRS) “now” where 0 = none and 10 = worst. Results Seventeen patients (mean age 51 years, 58% female) completed 55 interventions in a random order. The absolute change of dyspnea NRS between 0 and 10 minutes was −1.8 (SD 1.7) for HFOx, −1.8 (2.0) for HFAir, −0.5 (0.8) for LFOx, and − 0.6 (1.2) for LFAir. In mixed model analysis, HFOx provided greater dyspnea relief than LFOx (mean difference [95% confidence interval] −0.80 [−1.45, −0.15]; p = .02) and LFAir (−1.24 [−1.90, −0.57]; p < .001). HFAir also provided significantly greater dyspnea relief than LFOx (−0.95 [−1.61, −0.30]; p = .005) and LFAir (−1.39 [−2.05, −0.73]; p < .001). HFOx was well tolerated. Seven (54%) patients who tried all interventions blindly preferred HFOx and four (31%) preferred HFAir. Conclusion We found that HFOx and HFAir provided a rapid and clinically significant reduction of dyspnea at rest in hospitalized nonhypoxemic patients with cancer. Larger studies are needed to confirm these findings (Clinicaltrials.gov: NCT02932332). Implications for Practice This double-blind, 4×4 crossover trial examined the effect of oxygen or air delivered at high- or low-flow rates on dyspnea in hospitalized nonhypoxemic patients with cancer. High-flow oxygen and high-flow air were significantly better at reducing dyspnea than low-flow oxygen/air, supporting a role for palliation beyond oxygenation.