06/06/2007

Easing breath-robbing disease with slow leaks

By Lauran Neergaard
The Associated Press

Poking holes in a lung is usually a bad idea. But dozens of people suffocating from a disease that traps stale air in their lungs are volunteering to try it.

The idea: Spark a slow leak in lungs so overinflated that there's not enough room left to take a deep breath, and do so without open surgery.

It's called airway bypass, one of a trio of innovative experiments — including squirting a kind of glue into the lungs — designed not to cure the lung destroyer that is the nation's No. 4 killer, but to ease breathing during its victims' last years.

And it comes amid a major government push to get more of the estimated 24 million Americans with breath-robbing COPD, or chronic obstructive pulmonary disease, diagnosed and treated sooner, to stall the need for such last-ditch care.

"This is a huge public health problem,” says Dr. James Kiley, lung chief at the National Institutes of Health. "It's not going to get better unless we do something very aggressively.”

Yet half of COPD sufferers don't know they have it. Aside from the eye-glazing name — a term for diseases once called emphysema and chronic bronchitis — people tend to shrug off the main symptom, shortness of breath, as poor fitness or mere aging until their lungs are ravaged.

Healthy lungs inflate and deflate like balloons as they take in oxygen and remove carbon dioxide. The windpipe feeds air into bronchial tubes that resemble an upside down tree with ever-smaller branches. Between these airways are tiny air sacs, elastic bubbles that stretch as they fill with air and then spring back into shape as used air rushes back out.

COPD destroys that elasticity. Airways collapse, blocking the way out. Air sacs distend with stale air, enlarging lungs and leading to COPD's distinctive barrel chest. Eventually, it becomes physically impossible to inhale deeply enough to get air to the lungs' remaining working spots.

Those lungs need emergency exits, decided Dr. Joel Cooper of the University of Pennsylvania.

Cooper helped pioneer an arduous surgery that cuts out portions of COPD patients' dead lung to make more space for the remaining working lung. But few patients qualify; most have such widespread lung damage that there's no logical spot to remove, or couldn't survive the operation.

With airway bypass, Cooper invented a different approach: He threads a tiny needle through a tube inserted in the windpipe, down to airways about the diameter of a pencil. Smaller airways downstream are completely blocked. To route trapped air around them, he pokes up to a dozen holes through the bigger airway's wall and into surrounding air sacs. He wedges those holes open with stents, the same kind of metal scaffolding that cardiologists use to prop open clogged heart arteries.