By Bram Duffee, PhD, EMT-P

For EMS providers who respond to a traumatic cardiac arrest, the instinct to initiate CPR is almost automatic. But could this life-saving intervention inadvertently hinder recovery in cases of severe hemorrhagic shock? A recent study, “Effect of Cardiopulmonary Resuscitation on Perfusion in a Porcine Model of Severe Hemorrhagic Shock,” challenges conventional wisdom and offers new insights that could reshape trauma care protocols.

The Study: A Closer Look at CPR in Trauma-Induced PEA

The research, led by Dr. Patrick Greiffenstein, professor of clinical surgery at LSU New Orleans and trauma ICU director at the Norman McSwain Spirit of Charity Trauma Center, addresses a critical gap in trauma care.

While CPR is a cornerstone of resuscitation in cardiac arrest, its application in trauma-induced pulseless electrical activity (PEA) has not been rigorously validated. Trauma PEA, unlike medical cardiac arrest, is a low-flow state caused by severe blood loss (hypovolemia), where the heart shows electrical activity but fails to generate a palpable pulse.

“CPR is a cornerstone of resuscitation and cardiac arrest, but its application in trauma-induced PEA has not really been rigorously evaluated,” explains Dr. Greiffenstein. “Trauma PEA is fundamentally a low-flow state caused by hypovolemia—insufficient blood volume.”

The study aimed to determine how CPR affects tissue perfusion—specifically oxygen delivery to the brain and skin—during severe hemorrhagic shock. Using a porcine model, researchers simulated life-threatening blood loss and compared outcomes between two groups: one receiving automated CPR and the other left untreated during the shock phase.

Key Findings: When CPR May Do More Harm Than Good

The results were both surprising and concerning:

“Knowing now that extreme efforts like lining people up to do CPR can cause turbulence within the system is a significant advancement,” says Dr. Greiffenstein. “It’s possible to have perfusion at these unreadable MAP scores, which is a critical insight for trauma care.”

Implications for Trauma Care

These findings challenge the one-size-fits-all approach to CPR in cardiac arrest scenarios. In cases of hemorrhagic shock, CPR might:

“In military cases, field medics often don’t have the opportunity to perform full chest compressions on the battlefield. Sometimes, all they can do is drag a person to a safe position,” notes Dr. Greiffenstein. This study underscores the importance of prioritizing interventions that address the root cause of trauma PEA—severe blood loss—over traditional resuscitation techniques.

A Call for Updated Guidelines

The American Heart Association’s current guidelines broadly recommend CPR for all pulseless patients. However, this study adds to a growing body of evidence suggesting that trauma-induced PEA requires a different approach. By focusing on restoring blood volume and controlling bleeding, paramedics and EMTs can improve outcomes for patients in hemorrhagic shock.

As Dr. Greiffenstein puts it, “This research is a step toward more tailored and effective trauma care protocols. It’s about understanding the unique physiology of trauma and adapting our interventions accordingly.”

For EMS providers on the front lines, this study serves as a reminder to critically evaluate the tools and techniques we rely on in emergency care. While CPR remains a vital intervention in many scenarios, its role in trauma-induced PEA warrants careful reconsideration by physician medical directors. By staying informed about the latest research, we can continue to improve outcomes for the patients who depend on us most. Click below to watch the full interview

Reference

Greiffenstein, P., Cavalea, A., Smith, A., Sharp, T., Warren, O., Dennis, J., Gatterer, M. C., Danos, D., Byrne, T. C., Scarborough, A., Deville, P., & VanMeter, K. (2025). Effect of cardiopulmonary resuscitation on perfusion in a porcine model of severe hemorrhagic shock. The Journal of Trauma and Acute Care Surgery, 98(2), 251–257.