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Low-Flow NHF Therapy Fizzles in CPAP Non-Compliant Sleep Apnea

— Flow rate possibly 'too low to make a difference'

MedpageToday

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SAN ANTONIO -- Adding nasal high flow therapy (NHF) at low flow in the post-operative setting failed to improve outcomes over oxygen alone in sleep apnea patients who were continuous positive airway pressure (CPAP) non-compliant, a pilot study found.

In the single-blind randomized controlled trial, NHF at 30 LPM was found to be statistically equal to supplemental oxygen alone in reducing oxygen desaturation index (ODI) 4% to under 10 events per hour during the first post-operative night in patients with obstructive sleep apnea (OSA), Bernardo Selim, MD, of the Mayo Clinic in Rochester, Minnesota reported.

The study, presented here at CHEST 2018, the annual meeting of the American College of Chest Physicians, included patients with polysomnography-confirmed moderate to severe OSA who declined to use CPAP at a pre-surgical interview.

Those with an apnea-hypopnea index of ≥5 events per hour were randomly assigned to receive NHF at 30 LPM plus oxygen at 1 LPM or oxygen supplement at 1 LPM via nasal cannula (control) during the first post-surgical night. The primary study outcome was ODI 4% in the first post-operative night.

Baseline demographics, cardiovascular risks, and post-operative recovery room vital signs were collected.

Forty-two of 50 OSA patients who were randomized to the study (84%) completed it, and all were evaluated for ODI 4% in the first post-operative night.

On average, ODI 4% was statistically higher in the group receiving NHF (median 7.4 events per hour, interquartile range [IQR] 3.5-13.3) than in the group receiving oxygen supplementation alone (median 3.1 events per hour, IQR 1.5-6.7, P=0.024).

NHF was as effective as oxygen alone in reducing ODI 4% to under 10 events per hour in the first post-operative night: 19 patients (90.5%) in the NHF group versus 15 patients (71.4%) in the control group (P=0.24).

The researchers concluded that NHF therapy at 30 LPM did not offer any advantage over supplemental oxygen alone in the management of post-operative oxygen desaturation in CPAP non-compliant OSA patients.

Pulmonologist Brian Carlin, MD, of the University of Pittsburgh Medical Center, who was not involved with the study, said it is not surprising that NHF 30 LPM failed to improve first post-operative night outcomes in these patients.

"I think the flow rate was too low to make a difference," he told MedPage Today.

The researchers also suggested that NHF at higher flow rates may be needed to reach increased upper airway patency and decreased dead space in these patients. They also suggested that NHF may be a useful strategy for patients with milder OSA than the patients recruited for the study.

They concluded that more study is needed "to determine the role of NHF in the perioperative management of OSA patients."

Primary Source

CHEST Annual Meeting 2018

Selim B, et al “Nasal high flow therapy vs oxygen supplementation in the postoperative care of OSA patients with CPAP noncompliance: A pilot study” CHEST 2018.