New Biorepository Approach Advances Research on Sudden Cardiac Arrest

University of Cincinnati researchers have demonstrated a new approach to studying sudden cardiac arrest that enables real-time blood collection from patients during emergency treatment, marking a significant advancement in understanding this often-fatal condition.

The study, titled “Cincinnati Biorepository to Enhance the Acute Resuscitation of Cardiac Arrest Patients (Cincy BEARCATS): A Feasibility and Pilot Study,” was recently published in Prehospital Emergency Care, the official journal of the National Association of EMS Physicians. It represents the first-of-its-kind effort to systematically collect biological samples from patients experiencing out-of-hospital cardiac arrest during active resuscitation efforts.

Sudden cardiac arrest occurs when a person collapses outside of a hospital setting. Only about 10% survive. It’s a fast-paced problem. We only have about 30 minutes to try to revive the patient. There’s not even time to get to the hospital. The best thing to do is work on the person at the scene.

Justin Benoit, MD, associate professor of clinical emergency medicine, University of Cincinnati College of Medicine

Traditional clinical research methods are not feasible in the critical minutes following cardiac arrest, when emergency responders must focus solely on life-saving interventions. To overcome this barrier, UC researchers partnered with the Cincinnati Fire Department in 2022 to develop specialized blood collection kits that paramedics could use during routine patient care.

UC researchers began partnering with the Cincinnati Fire Department (CFD) in 2022 for this first-of-its-kind study. Benoit and his collaborators developed kits that allowed CFD paramedics to draw blood from sudden cardiac arrest patients during treatment.

University of Cincinnati news release, April 24, 2026

The blood collection process occurs at two key timepoints: immediately after intravenous access is established and again after return of spontaneous circulation or when resuscitative efforts are terminated on scene. Samples are rapidly transported to the University of Cincinnati Medical Center, where they are centrifuged, frozen, and stored in a dedicated biorepository for later analysis.

Paramedics obtained blood samples using preassembled blood collection kits immediately after intravenous access, and again after return of spontaneous circulation or resuscitative efforts were terminated on scene. Blood samples were rapidly transported, centrifuged, and frozen.

PubMed abstract, February 19, 2026

During the seven-month pilot study period, researchers encountered 27 patient cases with no interference to standard clinical care. From these encounters, they successfully collected initial and repeat blood samples from 10 subjects, demonstrating the feasibility of the approach for larger-scale implementation.

Throughout the 7-month study period, there were no episodes of interference with standard clinical care during 27 patient encounters. Initial and repeat blood samples from 10 subjects had a panel of blood-based biomarker levels measured.

PubMed abstract, February 19, 2026

Preliminary laboratory analysis of the collected samples revealed several significant biological patterns. In the initial samples, researchers observed hyperkalemia in 6 subjects, hypernatremia in 6 subjects, hypocalcemia in 1 subject, complement activation in 7 subjects, hyperreninemia in 2 subjects, and low antithrombin in 1 subject.

In initial samples, we observed 6 subjects with hyperkalemia, 6 with hypernatremia, 1 with hypocalcemia, 7 with complement activation, 2 with hyperreninemia, and 1 with low antithrombin.

PubMed abstract, February 19, 2026

Notably, in repeat samples taken later in the resuscitation process, researchers observed renormalization of potassium levels in 2 subjects despite no pharmacological treatment being administered. Complement activation, fibrin degradation products, and lactate levels increased over time in all but one subject, suggesting dynamic biological changes occurring during the arrest and resuscitation process.

In repeat samples, we observed renormalization of potassium in 2 subjects despite no pharmacological treatment. Complement activation, fibrin degradation products, and lactate levels increased over time in all but 1 subject.

PubMed abstract, February 19, 2026

The research team emphasizes that the biorepository approach creates a valuable resource for investigating the biological pathophysiology of sudden cardiac arrest from the earliest medical contact. By capturing samples during the intra-arrest phase — a period previously inaccessible to systematic study — scientists can now examine molecular changes that occur before hospital arrival.

We created an emergency medical services (EMS) clinical research infrastructure to systematically study its biological pathophysiology from the earliest medical contact in the prehospital setting.

PubMed abstract, February 19, 2026

Sudden cardiac arrest remains a major public health challenge, with approximately 90% of out-of-hospital cases resulting in death. The low survival rate underscores the urgent need for better understanding of the physiological mechanisms involved, particularly during the critical early minutes when intervention is most effective.

Sudden cardiac arrest occurs when a person collapses outside of a hospital setting, said lead author Justin Benoit, MD, an associate professor of clinical emergency medicine. Only about 10% survive.

University of Cincinnati news release, April 24, 2026

The successful demonstration of feasibility in this pilot study paves the way for expanded research collaborations with emergency medical services agencies nationwide. By establishing a scalable model for intra-arrest biological sampling, the Cincy BEARCATS study provides a framework for future investigations into biomarkers, treatment responses, and potential therapeutic targets for sudden cardiac arrest.