NHF therapy a more tolerable alternative to NIV for hypercapnic COPD

Dr James Fingleton

Nasal high-flow therapy (NHF)  may be an alternative option for hypercapnic COPD patients who cannot tolerate the ‘gold standard’ of non-invasive ventilation (NIV), a study from New Zealand suggests.

In a single blind comparison of NHF and NIV in 24 patients with hypercapnic respiratory failure secondary to COPD, respiratory physicians at the Medical Research Institute of New Zealand in Wellington showed that NHF was almost as effective as NIV, and was better tolerated.

The randomised controlled two-way cross-over single-centre trial was conducted in patients with stable hypercapnic COPD who received NHF at 45 L/min and NIV at 15/4 cm H₂O, each for 60 min with a 15-min washout in between.

In terms of the primary outcome of transcutaneous partial pressure of carbon dioxide (PtCO₂) at 60 min, NIV reduced the PtCO₂ by −5.3 (5.0) compared to −2.5 (3.5) mm Hg with NHF.

The researchers said the difference in PtCO₂ across all time points of −2.5 mm Hg was of uncertain clinical significance.

They also noted that there was no significant difference in the proportion of participants with a reduction of PtCO₂ ≥ 4 or ≥ 8 mm Hg.

Writing in Respirology, the study investigators, led by Dr James Fingleton, reported that patients rated NHF significantly better than NIV for ease of application, comfort and fit.

Dr Fingleton, a respiratory physician at Wellington Regional Hospital, said long-term domiciliary NIV was known to prolong time to readmission or death, reduce exacerbations and potentially improve survival in patients with hypercapnic COPD,

However up to 20% of patients were unable to adhere to NIV treatment.

“The problem is that this treatment [NIV] ] can be complex to administer and is often not well tolerated – [patients] fight the machine and it can’t co-ordinate with them, the mask can give them pressure ulcers on their face and can make them feel claustrophobic,” he said.

“We need other options for treating hypercapnic respiratory failure and one new option is nasal high flow therapy (NHF),” he added.

NHF was already known to be effective for hypoxic (type 1) respiratory failure, but it was not known if it could could help clear CO₂ in hypercapnic respiratory failure, said Dr Fingleton.

“Both treatments lowered CO₂. NIV lowered CO₂ a little more than NHF but the difference between the treatments was not large so both may be effective. NHF was better tolerated than NIV and so may be a good option in people who don’t tolerate NIV,” he concluded.

Randomised controlled trials comparing NIV and NHF administered at home in people with chronic hypercapnic respiratory failure are now warranted, he added.