Wake County paramedics saved 100 lives over a seven-year period because they worked longer than expected to resuscitate people whose heart had stopped, according to an analysis by the SAS Advanced Analytics Lab.
Paramedics are traditionally trained to stop trying to resuscitate cardiac arrest victims after 20 to 25 minutes and declare them dead.
Wake County EMS responders occasionally continued chest compressions for longer than 20 minutes. Even if the monitor showed a flatline, a victim’s eyebrows might involuntarily twitch, their hand would move or their chest would heave as if gasping for unattainable air, giving paramedics the impetus to keep trying.
“We would be getting way past the 25-minute mark, and lo and behold we would have a pulse back,” said Jeffrey Hammerstein, Wake County EMS chief of community outreach.
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Wake County EMS responders such as Hammerstein, who worked in an ambulance for 18 years, wanted to know not only whether longer chest compressions could bring back a pulse, but whether patients would walk out of the hospital fully functioning. Sometimes people are revived after their heart has stopped for long periods, only to languish in a vegetative or impaired state because their brain has been deprived of oxygen.
“Are we doing good for people or are we not doing good for people?” Hammerstein said. “That’s the bottom line.”
To test their hunches, Wake EMS hired SAS Advanced Analytics Lab, a division of the giant Cary-based SAS software firm that analzes large amounts of data, to calculate the time spent resuscitating patients compared with their outcomes in the hospital and beyond.
SAS researchers studied 2,900 patient outcomes from 2005 through 2012. They discovered that 100 people survived, leaving the hospital with little to no brain damage, because responders continued resuscitation beyond the recommended time.
The longer someone undergoes cardiac arrest, the less likely he or she is to survive. But if a person survives, he or she is just as likely to be “neurologically intact” regardless of the duration of CPR, the study found.
One patient walked out of the hospital after responders spent 70 minutes on resuscitation.
Wake County EMS responds to about 500 cardiac arrest calls a year and has made it a priority to find how to best perform CPR on cardiac arrest patients.
For example, responders changed to continuous chest compressions – instead of interrupted or staggered compressions – and found they got better results. In 2006, the county’s paramedics discovered that cooling patients assisted in survival rates and prevented brain damage.
Survival rates rise
Wake County already has doubled cardiac arrest survival rates to 16 percent, double the national rate. SAS reports that former improvements such as cooling and continued compressions had already improved cardiac arrest survival among Wake EMS patients by 48 percent.
Michael Bachman, deputy director of medical affairs for Wake County EMS, helped present the study’s findings at the National Association of EMS Physicians conference in January.
“It was very well received,” Bachman said, adding that the study won the best pre-hospital research award at the conference.
Other EMS agencies have taken note of the SAS study.
“It has opened up dialogue with our medical staff, and it is easy to do,” said Kim Woodward, EMS operations manager for Orange County. “We collectively at the EMS are always looking for improved cardiac arrest survival. We get pretty jazzed about it.”
Wake County EMS is continuing projects with SAS to predict survival during CPR. They will examine factors such as carbon dioxide levels and other measurements used during resuscitation to determine more definitively whether a patient will survive, Hammerstein said.