CPAP/BP study info from Doug

Tuesday, May 23, 2006 9:42 PM

 

Hey JC,

Thought this would interest you.

Hope all is well.

Doug

 

CPAP, but not supplemental oxygen alone, decreases BP in sleep apnea

News Story:
By Megan Rauscher


NEW YORK (Reuters Health) 

 

Nighttime CPAP (continuous positive airway pressure) therapy significantly lowers both daytime and nighttime blood pressure in patients with obstructive sleep apnea, whereas supplemental oxygen does not.

That's according to a randomized, controlled study presented at the American Thoracic Society International Conference by Dr. Daniel Norman of the University of California San Diego Medical Center.

In an interview with Reuters Health, Dr. Norman noted that "many patients have a difficult time tolerating CPAP therapy for sleep apnea, and many times doctors will place people on supplemental oxygen as 'second best' therapy. Our study suggests that supplemental oxygen may not work as well in terms of improvements in blood pressure as traditional CPAP therapy."

Dr. Norman and colleagues obtained 24-hour ambulatory blood pressure measurements in 46 patients with moderate to severe obstructive sleep apnea. The patients were then randomized to two weeks of traditional CPAP, sham CPAP therapy, or supplemental oxygen alone.

"After two weeks of therapy in their assigned group, we again examined their 24-hour ambulatory blood pressure," Dr. Norman explained, "and found that patients in the traditional CPAP group had significant improvements in their 24-hour ambulatory blood pressure but patients in the placebo CPAP and supplemental oxygen groups did not."

The results of the current study, Dr. Norman said, mirror those of other studies in showing improvements in blood pressure following CPAP therapy.

"However, the results create a little bit of discussion about what the mechanisms are about how obstructive sleep apnea may cause elevated in blood pressure," he told Reuters Health.

"Sleep apnea causes both disruption in sleep and arousals in sleep and also intermittent drops in oxygen levels during the night and many people think that drops in oxygen level at night are the prime force that are responsible for the increased blood pressure," the investigator explained. "However, we did not see improvement in blood pressure by treating the oxygenation issue alone."


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