Individuals who experience out-of-hospital cardiac arrest (OHCA) with nonshockable presentations have a better chance of survival when first responders use a novel CPR approach that includes gradual head-up positioning combined with basic but effective circulation-enhancing adjuncts, as shown from data from more than 2000 patients.
In a study presented at the American College of Emergency Physicians (ACEP) 2022 Scientific Assembly, Paul Pepe, MD, medical director for Dallas County Emergency Medical Services, in Texas, reviewed data from five EMS systems that had adopted the new approach. Data were collected prospectively over the past 2 years from a national registry of patients who had received what Pepe called a "neuroprotective CPR bundle" (NP-CPR).
The study compared 380 NP-CPR case patients to 1852 control patients who had received conventional CPR. Control data came from high-performance EMS systems that had participated in well-monitored, published OHCA trials funded by the National Institutes of Health. The primary outcome that was used for comparison was successful survival to hospital discharge with neurologically intact status (SURV-NI).
Traditional CPR supine chest compression techniques, if performed early and properly, can be lifesaving, but they are suboptimal, Pepe said. "Current techniques create pressure waves that run up the arterial side, but they also create back-pressure on the venous side, increasing intracranial pressure (ICP), thus compromising optimal cerebral blood flow," he told Medscape.
For that reason, a modified physiologic approach to CPR was designed. It involves an airway adjunct called an impedance threshold device (ITD) and active compression-decompression (ACD) with a device "resembling a toilet plunger," Pepe said.
The devices draw more blood out of the brain and into the thorax in a complementary fashion. The combination of these two adjuncts had dramatically improved SURV-NI by 50% in a clinical trial, Pepe told Medscape.
The new technology uses automated gradual head-up/torso-up positioning (AHUP) after first "priming the pump" with ITD-ACD-enhanced circulation. It was found to markedly augment that effect even further. In the laboratory setting, this synergistic NP-CPR bundle has been shown to help normalize cerebral perfusion pressure, further promoting neuro-intact survival. Normalization of end-tidal CO2 is routinely observed, according to Pepe.
In contrast to patients who present with ventricular fibrillation (shockable cases), patients with nonshockable presentations always have had grim prognoses, Pepe said. Until now, lifesaving advances had not been found, despite the fact that nonshockable presentations (asystole or electrical activity with no pulses) constitute approximately 80% of OHCA cases, or about 250,000 to 300,00 cases a year in the United States, he said.
In the study, approximately 60% of both the NP-CPR patients and control patients had asystole (flatline) presentations. The NP-CPR group had a significant threefold improvement in SURV-NI compared to patients treated with conventional CPR in the high-functioning systems (odds ratio [OR], 3.09). In a propensity-scored analysis matching all variables known to affect outcome, the OR increased to nearly fourfold higher (OR, 3.87; 95% CI, 1.27– 11.78), Pepe said.
The researchers also found that the time from receipt of a 911 call to initiation of AHUP was associated with progressively higher chances of survival. The median time for application was 11 minutes; when the elapsed time was less than 11 minutes, the SURV-NI was nearly 11-fold higher for NP-CPR patients than for control patients (OR, 10.59), with survival chances of 6% vs 0.5%. ORs were even higher when the time to treatment was less than 16 minutes (OR, 13.58), with survival rates of 5% vs 0.4%.
The findings not only demonstrate proof of concept in these most futile cases but also that implementation is feasible for the majority of patients, considering that the median time to the start of any CPR by a first responder was 8 minutes for both NP-CPR patients and control patients, "let alone 11 minutes for the AHUP initiation," Pepe said. "This finally gives some hope for these nonshockable cases," he emphasized.
"All of these devices have now been cleared by the Food and Drug Administration and should be adopted by all first-in responders," said Pepe. "But they should be implemented as a bundle and in the proper sequence and as soon as feasible."
Training and implementation efforts continue to expand, and more lives can be saved as more firefighters and first-in response teams acquire equipment and training, which can cut the time to response, he said.
The registry will continue to monitor outcomes with NP-CPR ― the term was suggested by a patient who survived through this new approach ― and Pepe and colleagues expect the statistics to improve further with wider adoption and faster implementation with the fastest responders.
A recent study by Pepe's team, published in Resuscitation, showed the effectiveness of the neuroprotective bundle in improving survival for OHCA patients overall. The current study confirmed its impact on neuro-intact survival for the subgroup of patients with nonshockable cases.
One other take-home message is that head-up CPR cannot yet be performed by lay bystanders. "Also, do not implement this unless you are going to do it right," Pepe emphasized in an interview.
Advanced CPR Solutions provided some materials and research funding for an independent data collector. No other relevant financial relationshps have been disclosed.
American College of Emergency Physicians (ACEP) 2022 Scientific Assembly: Abstract 3. Presented October 1, 2022.
Heidi Splete is a freelance medical journalist with 20 years of experience.
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Cite this: Novel Head-Up CPR Position Raises Odds of Survival of Out-Of-Hospital Cardiac Arrests - Medscape - Oct 13, 2022.