A Traumatic Pulseless Electrical Activity Model: Mortality Increases With Hypovolemia Time

Background: There currently are no well-defined animal models for traumatic pulseless electrical activity (PEA). Our objective was to develop a swine model of traumatic PEA that would be useful for laboratory research where mortality is an outcome of interest. In this pilot study, we hypothesized that animals that remained in PEA without intervention for a longer period would have increased mortality. Materials and methods: Sixteen Yorkshire swine were alternately allocated to either 5 or 10 min of traumatic PEA without intervention. After the nonintervention period, basic life support (BLS) with mechanical cardiopulmonary resuscitation was initiated and performed for 10 min followed by advanced life support (ALS) for an additional 10 min. Hemodynamic and laboratory values are reported for baseline, posthemorrhage, end of BLS, and end of ALS periods. Results: Mortality in the 10-min PEA group (100%) was higher than the 5-min group (38%) (P = 0.03). Animals in the 5-min group had improved aortic diastolic blood pressure, coronary perfusion pressure, and end-tidal CO2 at the end of both the BLS (P = 0.02, 0.002, and 0.02, respectively) and ALS (P = 0.009, 0.005, and 0.008, respectively). The 10-min animals had increased hyperkalemia at the end of the BLS (P = 0.004) and ALS (P = 0.005) periods. All animals in the 10-min group developed ventricular fibrillation (VF) and 38% of the 5-min animals developed VF (P = 0.03). Conclusions: In our pilot study of traumatic PEA in a swine model, a shorter period of nonintervention resulted in increased survival, improved hemodynamics during resuscitation, decreased hyperkalemia, and less incidence of conversion to VF arrest.