University of Pittsburgh Researchers Find a Marker for Blood Clotting in Patients Who Suffer Cardiac Arrest Outside the Hospital
SEATTLE, October 8, 2002 — When a patient's heart stops and goes into cardiac arrest, the patient's blood begins to clot, a process that begins as early as six minutes after cardiac arrest and may hamper resuscitation efforts. Even after resuscitation, it is possible that blood clots that form within blood vessels can lead to organ failure and ultimately death.
Researchers in the department of emergency medicine at the University of Pittsburgh School of Medicine tried to determine the extent to which increased blood clotting occurs in patients who suffer cardiac arrest outside the hospital. Using blood samples collected from 28 patients, the researchers found that all but one patient showed evidence of clot formation within the veins and that clotting increased the longer the patient was in cardiac arrest.
Their results were reported today at the American College of Emergency Physicians Scientific Assembly 2002, Research Forum at the Washington State Convention and Trade Center in Seattle.
"These findings will add to our understanding of the changes that occur during cardiac arrest outside the hospital so that we can design strategies to improve survival," stated Clifton Callaway, M.D., assistant professor of emergency medicine at the University of Pittsburgh School of Medicine.
The researchers conducted their study by collaborating with municipal paramedics who were called to the scene of cardiac arrest. Blood samples were taken from those 28 patients who were between 30 and 80 years of age (with a mean age of 55). Seventy-five percent of the patients were male.
"It is worth noting that the one patient with no sign of clotting went into cardiac arrest in the presence of paramedics and was immediately resuscitated with an external defibrillator. The patient responded quickly with no impaired mental or neurological complications," explained Dr. Callaway.
The researchers also determined from the blood tests that the longer a patient was in cardiac arrest, the more the patient's blood clotted. More than 400,000 people die each day in the United States from sudden cardiac arrest and most of these events occur outside the hospital. Resuscitation efforts are often unsuccessful when started more than five minutes from collapse, and less than 10 percent of patients survive sudden cardiac arrest.
"When you look at those numbers, the need for resuscitation research is significant," added Dr. Callaway.
In addition to Dr. Callaway, other authors were David Newman M.D., an emergency medical services research fellow, and David Hostler, Ph.D., visiting research instructor, both with the department of emergency medicine at the University of Pittsburgh.
This study was funded in part by the Pittsburgh Emergency Medicine Foundation.