Cypress Creek Emergency Medical Services (CCEMS) in Houston began a campaign in 2004 to increase sudden cardiac arrest (SCA) survival rates in their region. The EMS team is using hypothermia treatment, a threshold impedance device, an automated chest compression device, ECG upload and wireless communication with the cath lab to improve patient outcomes.
After SCA patients experience a return of spontaneous circulation (ROSC), EMS personnel infuse them with cold saline intravenously. “Hypothermia closes the resuscitation and allows patients to neurologically heal on their own,” says Levon Vartanian, MD, CCEMS medical director.
Previously, the team’s ROSC rate was 10 to 14 percent. The addition of the ResQPOD (Advanced Circulatory Systems), an impedance threshold device, improved their outcomes, “but we wanted to do better,” Vartanian says. At the time, the American Heart Association (AHA) was focusing on cardiopulmonary resuscitation (CPR) perfusion and Vartanian and his team recognized the inefficiency of manual CPR. That’s when they began to use the Lucas automated chest compression device (Physio-Control).
“From August 2007 to September 2008, with 122 uses, we achieved an 11 percent increase in ROSC,” says Kevin Traynor, a clinical supervisor with CCEMS, who oversees staff training and new technology acquisition. “Although the results are not yet statistically significant, we are seeing a nice upward trend,” he says.
One case of cardiac arrest, Traynor recalls, was a woman in her 60s. Rescuers obtained ROSC and performed a 12-lead EKG with the chest compression device still in place. The EKG confirmed that the woman had experienced an MI, and the team alerted the cath lab from the field. The woman survived without any neurologic deficits.
Chest compression fraction
Clinical data support the practical experience. Jim Christenson, MD, and colleagues from the Resuscitation Outcomes Consortium found a linear correlation with uninterrupted chest compressions and survival (Circulation 2009;120:1241-1247).
Researchers noted that the proportion of time rescuers spent giving chest compressions during each minute of CPR—the chest compression fraction (CCF)—is extremely variable. They analyzed data from 78 EMS agencies of more than 500 patients who had a ventricular fibrillation or pulseless ventricular tachycardia cardiac arrest. Automated external defibrillators (AEDs) measured the presence and frequency of chest compressions for each patient. The investigators found that an ROSC was achieved 58 percent of the time when the CCF was 0 to 20 percent, and up to 79 percent when the CCF was 81 to 100 percent.
“There was roughly a 10 percent increase in the chance of survival for every 10 percent increase in the chest compression fraction,” says Christenson, a clinical professor of emergency medicine at the University of British Columbia in Vancouver.”
Consistent chest compressions
Michelle Bird, RN, who works in the medical intensive care unit (MICU) at the Salt Lake City VA Medical Center, Salt Lake City, knows the value of consistent chest compressions. One example is a man in his late 60s who was admitted to the VA’s emergency room with respiratory failure. He was immediately intubated, had a peripheral IV placed and was transferred to the MICU. Shortly after, he suffered a pulseless electrical activity cardiac arrest. Bird and her team began manual compression, but within minutes, an automated chest compression device (AutoPulse; Zoll Medical) was positioned and begun.
Continuous compressions were given for approximately five minutes and the patient regained his pulse with a tachycardia rhythm. He was extubated in two days and discharged five days after admission.
“The automated device was delivering consistent, continuous compressions, resulting in improved blood flow that resulted in normal blood pressures,” Bird says. “Because people were not switching off to administer CPR, there was enough room to hook up IV fluids, administer medications, monitor ventilation and perform other interventions. Additionally, it made the atmosphere less chaotic.”