Ventilator Adjustment Saves Lives

March 18, 1999
News Office: Wallace Ravven (415) 502-6397

A simple adjustment in the way patients receive breathing assistance from a mechanical ventilator has been shown to cut mortality 25 percent among victims of Acute Respiratory Distress Syndrome (ARDS), a devastating, often fatal lung condition that affects about 150,000 Americans annually.

A three-year, nationwide clinical trial of the new ventilator treatment has been so successful that it has been stopped ahead of schedule to alert critical care specialists of the life-saving results, said Dr. Michael Matthay, an anesthesiologist at UCSF Medical Center, a UCSF professor of medicine and a principal investigator in the 10-city study funded by the National Institutes of Health.

"This is the first major breakthrough in treatment of this devastating condition in 32 years," Matthay said. "It is very gratifying to see this progress. More patients die from ARDS each year than from breast cancer."

The successful treatment provided patients with smaller breaths of oxygen-rich air from a mechanical ventilator than had been conventionally used. Laboratory and pre-clinical animal studies had suggested that providing air in smaller volumes might protect the lung from injury.

Matthay directed the ventilator treatment for ARDS patients at UCSF Medical Center. ARDS patients also participated in the study at UCSF-affiliated San Francisco General Hospital Medical Center, under the direction of John Luce, a co-investigator of the study and UCSF professor of medicine and anesthesiology.

"The reason these results are so exciting," Matthay said, "is that 40 to 60 percent of ARDS patients die, yet if we can save so many with this simple treatment, most of them can recover to lead perfectly normal lives."

Matthay, a senior scientist in UCSF's Cardiovascular Research Institute, has focused on mechanisms of lung injury and repair for more than 20 years.

Acute Respiratory Distress Syndrome often results from pneumonia or other life-threatening infections. Patients are often, but not always, already hospitalized for other conditions, Matthay said. Severe trauma and blood loss, such as from a car accident, can also lead to ARDS, as can blood-borne infections, including some that affect AIDS patients.

ARDS patients become severely short of breath, needing intensive care, usually with a mechanical ventilator. Excess fluid in the lungs displaces oxygen and leads to respiratory failure, Matthay said.

"This finding will save thousands of lives each year," said Claude Lenfant, director of the National Heart, Lung and Blood Institute of the NIH, which funded the large-scale study. "It provides us with something that we can implement quickly, at no additional cost, that will improve the treatment of intensive care patients. This is important news."

In an era of tight budgets for medical research it is interesting to note that this simple treatment study required a large-scale, long-term clinical trial which, according to Matthay, "would never have been done if it had to rely on biotech industry support." There is no potential profit in the treatment, no new drug, no new apparatus or appliance to market. "It simply requires a change of setting on the ventilator," Matthay said. "But we couldn't have established its effectiveness without the NIH support for a multi-site study."

The oxygen-rich breaths of air provided to patients in the successful clinical trial were each half the volume of those used in conventional ventilation therapy for ARDS.

At UCSF, Brian Daniel served as the study's clinical coordinator; at San Francisco General, Richard Kallet was clinical coordinator. Both are respiratory therapists.

Other study sites included hospitals associated with the Cleveland Clinic, Duke University, Johns Hopkins University, University of Michigan, University of Washington and Vanderbilt University. The study was coordinated at Massachusetts General Hospital, Boston.

The researchers are eager to share the results with patients and their families, and have already posted the treatment protocol and other treatment-related information on the Internet at: