DENVER – The routine administration of oxygen to terminally ill patients who are near death is unwarranted, according to the results of a randomized, double-blind trial.
"I would suggest that we always use the patient in respiratory distress as their own control in an n-of-1 trial of oxygen. If oxygen does reduce their distress, then that patient should have oxygen, but if it does not – if there’s no change in patient distress – then that oxygen can be discontinued, or certainly not initiated in the first place," Mary L. Campbell, Ph.D., declared at the annual meeting of the American Academy of Hospice and Palliative Care Medicine.
Oxygen has well-established benefits in hypoxemic patients with acute or chronic exacerbations of an underlying pulmonary condition, but without ever having been subjected to scientific scrutiny, oxygen administration has become routine for patients who are near death, asserted Dr. Campbell of Wayne State University, Detroit.
"Oxygen has become almost an iconic intervention at the end of life – as common as golf clubs on a Wednesday afternoon," she said.
And oxygen support is not a benign intervention. It’s expensive, particularly in home care, where it requires additional personnel and materials in the home, including a noisy, intrusive concentrator at the bedside. It also causes nasal drying and nosebleeds as well as feelings of suffocation, Dr. Campbell said.
To assess the value of routine oxygen administration, she conducted a double-blind, randomized, crossover study involving 32 terminally ill patients. None was in respiratory distress at baseline, but all were at high risk for distress because of underlying COPD, heart failure, pneumonia, or lung cancer. All participants had a Palliative Performance Scale score of 30 or less, which is associated with a median 9- to 14-day survival.
Each patient received a capnoline – that is, a nasal cannula with a piece of plastic hanging down over the patient’s mouth to capture exhaled carbon dioxide. Next, randomly alternating 10-minute intervals of oxygen, medical air, and no flow were administered for 90 minutes.
The key finding: 29 of 32 patients experienced no distress during the 90-minute protocol, indicating that they didn’t need the oxygen. Yet, at enrollment, 27 patients had oxygen flowing, reflecting this widespread clinical practice at the end of life, Dr. Campbell said.
The remaining three patients rapidly became hypoxemic and distressed when crossed over from oxygen to no flow. They were returned to baseline oxygen and respiratory comfort.
As many of the study participants were unconscious or cognitively impaired and couldn’t self report their distress, the Respiratory Distress Observation Scale was assessed at baseline and for 10 minutes after every flow change. A score of 4 or less on the 0-16 scale indicates little or no distress; the average baseline score was 1.47, and it didn’t vary significantly during the different flow conditions, she reported.
The average oxygen saturation at baseline was 93.6%, and it didn’t change significantly during the 90-minute protocol.
Dr. Campbell said that she determines the need for oxygen in an end-of-life patient by taking the patient off oxygen for 10 minutes and watching for distress.
Several audience members predicted that the patient’s family is likely to object to this approach because oxygen has become an expected part of end-of-life care. Dr. Campbell responded that the solution to that problem is simply good communication.
"I think if you explain to families that this is a treatment that can be helpful but has side effects, and we always take away the things that aren’t helping when they’re no longer helping, you won’t have pushback from family members," she said.
Dr. Campbell’s study was funded by the Blue Cross/Blue Shield of Michigan Foundation. She reported having no financial conflicts.