Risks Seen in Therapy for Breathing Failure

Death rate of noninvasive intervention nearly doubled

WEDNESDAY, June 9, 2004 (HealthDayNews) -- Standard medical therapy is a better option than assisted breathing devices when people who had respiratory failure come off an invasive ventilator.

That's the conclusion of a global trial that was cut short when findings showed the death rate following noninvasive ventilation, an assisted breathing method, was almost double that following standard therapy. The research appears in the June 10 issue of the New England Journal of Medicine.

Researchers from hospitals all over the world participated in the study, which compared noninvasive positive pressure ventilation, by face mask, to standard medical therapy, such as medication and respiratory physiotherapy.

Noninvasive positive pressure ventilation is similar to invasive ventilation because, in both cases, a machine is helping you breathe. In the invasive form, you are "intubated," which means a tube is placed down your throat and the machine takes over your breathing. In the noninvasive form, a mask is placed over your mouth, or over your mouth and nose, and the machine helps you breathe.

Machines to help you breathe become necessary if you experience respiratory failure, a life-threatening situation. Respiratory failure occurs when your respiratory system stops functioning properly, and no longer circulates enough oxygen through your body. Excess amounts of carbon dioxide can build up also because your respiratory system normally removes carbon dioxide from your body.

Disorders that may cause respiratory failure include chronic obstructive pulmonary disease, severe asthma, heart failure, pneumonia, or another lung infection.

If you have to be placed on an invasive ventilator, doctors want to get you off the ventilator and breathing on your own again as soon as possible. One reason is that the breathing tube increases the risk of hospital-acquired pneumonia, according to Dr. Jonathon Truwit, author of an accompanying editorial in the same issue of the journal and chief of pulmonary and critical care medicine at the University of Virginia in Charlottesville.

A major problem that occurs in 13 to 19 percent of all patients taken off invasive ventilation (extubation), however, is that they need to be reintubated, according to the study.

The researchers hoped that noninvasive ventilation would reduce the need for reintubation and reduce the rate of death following extubation. To test their theory, they recruited 221 intubated respiratory failure patients from 37 centers in eight countries.

One hundred and fourteen people were randomly assigned to noninvasive ventilation, while the other 107 were placed on standard medical therapy after extubation. Standard medical therapy includes medications called bronchodilators, supplemental oxygen, and respiratory physiotherapy, according to the study.

The researchers found no difference in the rate of reintubation. Both groups had a 48 percent reintubation rate.

The rate of death, however, was significantly higher in the noninvasive ventilation group -- so much so that the trial was stopped early. Twenty-five percent of those in the noninvasive group died, while 14 percent in the standard medical therapy group did.

"Doctors are learning that there are benefits, but real limitations to noninvasive positive pressure ventilation," said Truwit. In the editorial, Truwit said that if noninvasive ventilation is going to be successful, it's usually apparent soon after the therapy begins.

Dr. Keith Stevens, chairman of pulmonary medicine at Beaumont Hospital in Troy, Mich., agreed and said, "You can usually tell in the first couple of hours if they're benefiting from it."

Both Stevens and Truwit said that while noninvasive ventilation may not be effective for people in respiratory failure, it is useful for people who have chronic obstructive pulmonary disease, such as emphysema, or who have fluid in the lungs due to heart failure.

Stevens said it's important for people to realize that there are ways besides intubation to help people breathe. He said this may be especially important for people who sign "Do Not Resuscitate" orders, because they need to let their families know if noninvasive ventilation is something that would be acceptable or not.

More information

To learn more about different methods of assisted breathing, visit the American Medical Association.

SOURCES: Jonathon Truwit, M.D., senior associate dean for clinical affairs and chief of pulmonary and critical care medicine, University of Virginia, Charlottesville; Keith Stevens, D.O., chairman, pulmonary medicine, Beaumont Hospital, Troy, Mich.; June 10, 2004, New England Journal of Medicine
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