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Titrated Oxygen Better than High Flow for Patients with COPD

SoRelle, Ruth MPH

doi: 10.1097/01.EEM.0000394576.73247.f1


Michael Austin, MD, knows that when a paramedic or a physician sees a patient laboring to breathe, the first impulse is to give them high-dose oxygen.

That well-meaning act could result in more harm than good. “You need to evaluate how much oxygen that patient needs,” said Dr. Austin, who began the trial as a medical student and intern in Australia. He is currently doing a residency in emergency medicine in Ottawa, Canada. “Oxygen is a drug, and we need to titrate it based on what people need,” he said.

A recent study that he led found that patients with chronic obstructive pulmonary disease treated with titrated oxygen had lower mortality when treated with titrated oxygen than those who received standard high-flow oxygen. (BMJ 2010;341:c5462.) The study took place in the prehospital setting. “I hope this is going to open people's eyes,” said Dr. Austin, who is still a researcher with the Menzies Research Institute at the University of Tasmania in Australia. As a former paramedic, he understands the impulse to give high-flow oxygen.

“In an acute situation, you walk in and see someone who cannot breathe. You think that withholding oxygen from that person would be insane,” he said. “[But] oxygen is a drug. You should evaluate the patient and his oxygen saturation. Does this patient need oxygen or medications for his shortness of breath? The patient might need a little oxygen.”

In the study, which was a cluster randomized controlled parallel group trial, the researchers enrolled 405 patients with presumed acute exacerbation of chronic obstructive pulmonary disease. Of these, 214 had a confirmed diagnosis of COPD. Patients received either high-flow oxygen treatment or titrated oxygen in the ambulance.

Overall mortality in the larger group of patients was nine percent, or 21 deaths, in the high-flow oxygen arm compared with four percent (7 deaths) in the full group. In the patients with confirmed chronic pulmonary obstructive disease, the high-flow arm had 11 deaths (9%) compared with two deaths (2%) in the titrated group.

“Titrated oxygen treatment reduced mortality compared with high-flow oxygen for 58 percent of all patients … and by 78 percent for patients with confirmed chronic obstructive pulmonary disease,” the researchers said in their report. Patients in the titrated group also were less likely to have respiratory acidosis or hypercapnia or too much carbon dioxide in the blood.

“This is a small study that is very convincing,” said Kristi Koenig, MD, a professor of emergency medicine and the director of the Center for Disaster Medical Sciences at the University of California-Irvine. Dr. Koenig is an editor for Journal Watch Emergency Medicine, which spotlighted the report for emergency physicians. “You need to focus on the patient, and not blindly use 100 percent oxygen. How is the patient doing?”

Dr. Austin added that oxygen itself is not benign. Although oxygen drives the system in people with chronic obstructive pulmonary disease, giving people with COPD lots to oxygen “tells their breathing mechanism that they have a lot of oxygen and they should slow their breaking,” he said. “They retain CO2. Because they are retaining that, their system gets worse.”

He said he hopes people pay attention to the study. Dr. Koenig agreed, saying the information has to go beyond emergency physicians or the professional societies. The findings also have implications for the emergency department and the intensive care unit. Gaining acceptance in the prehospital setting would be easier because they are protocol-driven, she said, but emergency physicians across the United States practice in various settings.

Getting the information to them poses a challenge, she said, noting that the information should be part of standard teaching rounds with residents, suggesting that they consider how much oxygen to give a patient. “Should we titrate?” she said.

That advice is not restricted to patients with COPD, Dr. Koenig said. Recently, on an airplane, she was asked to help an ill passenger, which she did by starting an IV, but the patient had severe nausea. “Technically, his blood pressure was low, and his heart rate was high,” she said. “Normally, he should have had oxygen, but in this case I felt it would do more harm than good.”

Ron Walls, MD, a professor and the chair of emergency medicine at Brigham and Women's Hospital in Boston, said the findings were as important as the recent findings that changed the approach to cardiopulmonary resuscitation. “And just as EMS systems across the world immediately adopted those changes, they similarly need to adopt this oxygen strategy,” he said. While he agreed that emergency departments need to adopt them as well, he pointed out that there's no national consensus group that is going to look at oxygen therapy in the same way that groups such as the American Heart Association looked at CPR. Dr. Walls is the editor-in-chief of Journal Watch Emergency Medicine.

The need to change practice explains why Dr. Austin pursued the trial as part of an honors study during medical school. Using the highest level of proof should give weight to the need to titrate oxygen in these and all patients, he said.

In an editorial that accompanied his article in the British Medical Journal (2010;341:c5549), B. Ronan O'Driscoll, MD, of Salford Royal University Hospital in the United Kingdom, and Richard Beasley, DSc, of the Medical Research Institute of New Zealand in Wellington, said the study's mortality of only two percent in patients randomized to oxygen titrated to achieve an oxygen saturation of 88-92 percent sets a new “gold standard” for management of this condition. “The priority for future randomized controlled trials will be to define the ideal target oxygen saturation levels; further trials of high concentration oxygen in this condition would not be ethical,” they wrote.

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