P8. Humidification and nasal high flow (NHF) therapy

Several trials have shown that nasal high flow (NHF) humidified air in stable COPD patients reduces transcutaneous CO₂ (PtCO₂) and respiratory rate (Fraser 2016, Biselli 2017, McKinstry 2018, 2019).

A randomised trial by Rea et al (Rea 2010) found that NHF for up to 2 hours daily reduced annual exacerbation days and days to first exacerbation but not hospital admission compared with usual care in a group of 108 patients, with COPD/ bronchiectasis. Quality of life and lung function also improved. No sham treatment was given.

In a 12 month study by Storgaard et al (Storgaard 2018), 200 Danish patients with stable hypoxaemic COPD who had commenced long term oxygen therapy (LTOT) within the preceding 3 months were randomised to LTOT alone or LTOT plus high flow nasal cannula (HFNC)  at 20 litres/minute with oxygen flow unchanged (mean 1.75 (0.8) L) for at least 6 hours per day. 67 patients in the HFNC group completed the trial and 71 in LTOT group. Analysis was by intention to treat. Exacerbation rate was decreased in the HFNC group but not hospitalisations. In a small study crossover by Nagata et al (Nagata 2018), use of nocturnal HFNC in addition to LTOT also demonstrated  significant  benefit in quality of life (St George’s Respiratory Questionnaire COPD (SGRQ-C)) score improved by 7.8 points; (95% CI, 3.7 to 11.9; p<0.01) and measured PCO₂ (-4.1 95% CI  -6.5 to -1.7) .

The role of long term domiciliary HFNC is as yet still unclear.  Prospective randomised controlled trials in the appropriate COPD patient population with meaningful clinical endpoints are required before long term domiciliary NHF can be recommended.

In the acute setting, high flow nasal oxygen has a role in hypoxic respiratory failure where hypercapnia has been excluded (Stephan 2015, Frat 2015).