By Alon Steinberg and Amanda Frugoli 

Sudden and unexpected arrest-related deaths are deeply tragic and have generated widespread concern among the public, medical professionals, and law enforcement agencies. One mechanism that has garnered considerable attention is the use of prone restraint, wherein a subject is placed face-down and controlled in this position. The safety and risks of this technique remain subjects of debate within both scientific literature and legal settings. Supporters of prone restraint’s safety frequently cite prospective epidemiologic studies that report no fatalities associated with its use. However, these studies typically involve small cohorts and are conducted over limited timeframes, potentially underestimating rare but serious outcomes. In contrast, retrospective analyses, which assess larger populations over extended periods, have identified multiple cases of fatal outcomes linked to prone restraint. Notably, some of the most comprehensive data on these fatalities come from investigative journalism, which has uncovered patterns and prevalence rates not fully captured in academic or institutional studies. Based on available evidence, we estimate the mortality rate with use of in-custody prone restraint is at approximately 1 per 4.4 million individuals per year, or 0.023 per 100,000 population annually. These findings underscore the need for more rigorous, large-scale, and transparent epidemiological studies to better inform public policy, law enforcement practices, and clinical guidelines. The potential lethality of prone restraint must be recognized, and its use re-evaluated in light of both fatal risk and ethical responsibility.

By Victor Weedn , Alon Steinberg , Pete Speth 

We postulate that most atraumatic deaths during police restraint of subjects in the prone position are due to prone restraint cardiac arrest (PRCA), rather than from restraint asphyxia or a stress‐induced cardiac condition, such as excited delirium. The prone position restricts ventilation and diminishes pulmonary perfusion. In the setting of a police encounter, metabolic demand will be high from anxiety, stress, excitement, physical struggle, and/or stimulant drugs, leading to metabolic acidosis and requiring significant hyperventilation. Although oxygen levels may be maintained, prolonged restraint in the prone position may result in an inability to adequately blow off CO2, causing blood pCO2 levels to rise rapidly. The uncompensated metabolic acidosis (low pH) will eventually result in loss of myocyte contractility. The initial electrocardiogram rhythm will generally be either pulseless electrical activity (PEA) or asystole, indicating a noncardiac etiology, more consistent with PRCA and inconsistent with a primary role of any underlying cardiac pathology or stress‐induced cardiac etiology. We point to two animal models: in one model rats unable to breathe deeply due to an external restraint die when their metabolic demand is increased, and in the other model, pressure on the chest of rats results in decreased venous return and cardiac arrest rather than death from asphyxia. We present two cases of subjects restrained in the prone position who went into cardiac arrest and had low pHs and initial PEA cardiac rhythms. Our cases demonstrate the danger of prone restraint and serve as examples of PRCA.