But it doesn't improve death rates, study finds
WEDNESDAY, July 9 (HealthDay News) -- Assisted breathing improves the symptoms of patients whose lungs fill with water because of a weak heartbeat, but it doesn't reduce death rates, a new British study shows.
The study found no significant difference between two forms of assisted breathing -- continuous positive airway pressure (CPAP) and noninvasive intermittent positive-pressure ventilation (NIPPV). Both deliver more air to the lungs through face masks -- CPAP continuously, NIVVP in an on-and-off fashion.
The study, led by physicians at the University of Edinburgh, included 1,069 people, average age 77, hospitalized with what is formally called cardiogenic pulmonary edema -- accumulation of fluid in the lungs due to a weak heartbeat.
Standard treatment in such cases concentrates on improving heart function, said Dr. Arnold Baas, a cardiovascular disease specialist at the University of California, Los Angeles. Many patients also get oxygen through nose tubes.
"Lots of small studies suggested that a noninvasive breathing support mechanism might be of benefit," Baas said. "This is the largest randomized trial showing whether pushing air into the lungs might help."
In the British study, reported in the July 10 issue of the New England Journal of Medicine, one-third of the participants got conventional oxygen therapy, one-third were given CPAP, and one-third received NIVVP.
"The long and short of it is that they showed these interventions improved symptoms and blood chemistry but didn't help patients live longer," Baas said.
People getting either of the assisted breathing treatments reported less shortness of breath and had better heartbeats and fewer blood abnormalities than those getting conventional oxygen therapy. But deaths during the seven days of treatment were about the same for those getting conventional oxygen therapy (9.8 percent of patients) and those with assisted breathing (9.5 percent).
The percentage of those getting assisted breathing who died or required more serious intervention in those seven days was about the same for CPAP (11.7 percent) and NIVVP (11.1 percent).
The improvement in symptoms means that assisted breathing is worth using for pulmonary edema, Baas said. "It did make people feel more comfortable," he noted.
Both methods are readily available in hospitals, Baas said, but CPAP probably is preferable because it is in wider use by people with sleep apnea, who can do it at home, he explained.
Pulmonary edema and its treatment are described by the U.S. Library of Medicine.
SOURCES: Arnold Baas, M.D., assistant professor, medicine, University of California, Los Angeles; July 10, 2008, New England Journal of Medicine
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