AUSTIN, TEX. — Palliative oxygen was no better than air delivered by nasal cannulae for relieving dyspnea or improving quality of life in a study of 239 non- or mildly hypoxemic patients with terminal illness.
During the first 24 hours, patients in the O2 Breathe Trial had an improvement of about 10% in dyspnea symptoms with either treatment, or 1 point on a 10-point self-reported scale. The results were sustained over the 7-day study period, lead investigator Dr. Amy Abernethy and her associates reported at the annual meeting of the American Academy of Hospice and Palliative Medicine.
For the study, patients with intractable dyspnea received ordinary air or palliative oxygen, which combined air with an increased oxygen concentration of up to 28%. Both treatments were given via nasal cannulae from a blinded concentrator at 2 L per minute for at least 15 hours per day.
Regardless of treatment group, patients with worse breathlessness at baseline were more likely to respond, said Dr. Abernethy, an oncologist and co-chair of the Duke Cancer Care Research Program at Duke University Medical Center in Durham, N.C. After 7 days of treatment, the mean change from baseline in dyspnea symptoms was 1 point for patients with moderate dyspnea (baseline 4–6 points), compared with 2.5 for those with severe dyspnea (baseline 7–10 points).
The findings call into question whether it's necessary to prescribe palliative oxygen in these patients, and suggest that giving air via nasal cannulae is just as good, Dr. Abernethy said. Palliative oxygen is widely used to treat breathlessness, which affects up to 70% of patients with cancer and 90% of those with chronic obstructive pulmonary disease (COPD), and tends to worsen as death nears.
Dr. Abernethy noted that her hospice spends $250,000 per month on oxygen and oxygen concentrators in order to provide palliative oxygen.
“The most important piece in translation is focusing on which patients are likely to get the most benefit,” Dr. Abernethy said. “Clearly, it's the patient who is most dyspneic and clearly [the benefits are seen] in the first 24 hours. Whether you should use oxygen or air delivered by nasal cannulae doesn't seem to matter.”
The findings will need to be incorporated into the current evidence base and various guidelines, said Dr. Abernethy, noting that recommendations for palliative oxygen vary by guideline group and country. However, the survival benefit of oxygen therapy is well established for severely hypoxic COPD patients (PaO2 of 55 mm Hg or less).
A trial is underway to evaluate the use of forced-air fans for treating dyspnea, she said. A review of 47 studies in 2,532 patients with breathlessness and advanced stages of malignant and nonmalignant diseases (mostly COPD) concluded that there was low strength of evidence that acupuncture/acupressure is helpful and not enough data to judge the evidence for fans, music, relaxation, counseling, and psychotherapy (Cochrane Database Syst. Rev. 2008. CD005623 [doi:10.1002/14651858]).
The O2 Breathe Trial recruited patients with a baseline PaO2 greater than 55 mm Hg from nine study sites in Australia, the United Kingdom, and the United States. The trial was adequately powered, Dr. Abernethy said, but she noted that it did not have a placebo arm and pulse oximetry was not used. Baseline O2 saturation was 94%–95%. PaO2 was measured only at baseline (mean 77 mm Hg).
The patients' mean age was 73 years, 62% were male, 64% had COPD, and 16% had cancer.
In linear regression analyses, patients receiving oxygen therapy were almost twice as likely to have a morning response as were those receiving air (odds ratio 1.86).
The O2 Breathe Trial was funded by the U.S. National Institute on Aging, Australia's National Health and Medical Research Council, the Doris Duke Charitable Foundation, and the Duke Institute for Care at the End of Life. The authors disclosed no relevant conflicts of interest.
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Giving air via nasal cannulae may be just as good as palliative oxygen. ©