The National Heart, Lung, and Blood Institute of the National Institutes of Health today announced that a large clinical trial of mechanical ventilator use for intensive care patients with Acute Respiratory Distress Syndrome (ARDS) has been stopped early. The decision was recommended by the study's Data Safety and Monitoring Board (DSMB) on March 10, 1999, based on data on the first 800 patients which showed approximately 25 percent fewer deaths among patients receiving small, rather than large, breaths of air from a mechanical ventilator.
The ARDS Network Study of Ventilator Management in ARDS, scheduled to end late in 1999, was stopped early so that critical care specialists could be alerted to the results.
According to NHLBI Director Dr. Claude Lenfant, "This is the first large clinical trial to demonstrate a more effective treatment for ARDS patients. The findings will improve the care of these patients and save thousands of lives each year."
ARDS is a devastating, often fatal, inflammatory lung condition that usually occurs in conjunction with catastrophic medical conditions, such as pneumonia, shock, sepsis, and trauma. Approximately 150,000 Americans are affected each year, and more than 40 percent die.
No specific therapies currently exist for these patients. Treatment involves supportive care in an intensive care unit (ICU), including use of a mechanical ventilator and supplemental oxygen to help patients breathe.
The ARDS study was designed to compare the safety and efficacy of two different methods of setting the ventilator. After informed consent was obtained, patients were randomly assigned to receive either relatively large (12 ml/kg) or small (6 ml/kg) breaths of air from the ventilator. The initial plan for the study, which began in 1996, was to enroll 1,000 patients, ages 18 and older.
Mechanical ventilators deliver breaths of oxygen-enriched air to the body and remove breaths of carbon-dioxide produced by the body. Earlier laboratory studies had suggested that small breaths from the ventilator might not remove sufficient carbon-dioxide and that large breaths might damage lung tissue. Several small clinical trials had failed to show clearly which approach was superior.
The NHLBI ARDS Clinical Network, a consortium of 10 clinical centers including 24 hospitals, developed and performed the study. The network was formed in 1994 to ensure that multiple large treatment studies on ARDS could be designed and conducted quickly. The ARDS Network is currently conducting several other studies, including two trials of anti-inflammatory drugs for ARDS.
The results of the ARDS study will be presented at the annual meeting of the American Thoracic Society in San Diego, CA on April 26, 1999.
Participating centers and affiliated hospitals in the ARDS Network are: The Cleveland Clinic Foundation and MetroHealth Medical Center, Cleveland; Duke University Hospital and Veterans Affairs Hospital, Durham, NC; LDS Hospital and University of Utah Hospital, Salt Lake City; McKay-Dee Hospital, Ogden, UT; University of California Medical Center, Moffitt-Long Hospital, and San Francisco General Hospital, San Francisco; University of Colorado Health Sciences Center, Denver Health and Hospitals, Veterans Affairs Hospital, and Rose Medical Center, Denver; University of Maryland Hospital, Veterans Affairs Medical Center, Johns Hopkins-Bayview Medical Center, and Johns Hopkins Hospital, Baltimore; University of Michigan Medical Center, Ann Arbor; Hospital of the University of Pennsylvania and Thomas Jefferson University Hospital, Philadelphia; University of Washington/Harborview Medical Center, Seattle; and Vanderbilt University Hospital, Nashville. The Coordinating Center is at Massachusetts General Hospital, Boston.
For additional information, please contact the NHLBI Communications Office, 301-496-4236. Steering Committee Chairman Dr. Gordon Bernard and Dr. Taylor Thompson of the ARDS Network Coordinating Center also are available for interviews. Dr. Bernard can be reached through John Howser at the Vanderbilt University Medical School Public Affairs Office at 615-322-4747 and Dr. Thompson through the Massachusetts General Hospital Public Affairs Office at 617-726-2206.
NHLBI press releases, fact sheets, and other materials, including information about ARDS can be found online at http://www.nhlbi.nih.gov.
Additional information on the ARDS Network and the Ventilator Management Study can be found at http://hedwig.mgh.harvard.edu/ardsnet.