Prone restraint cardiac arrest in in‐custody and arrest‐related deaths

Abstract

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 CO 2 , causing blood pCO 2 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. K E Y W O R D Sprone restraint, in-custody deaths, arrest-related deaths (ARDs), police-involved deaths, restraint asphyxia, positional asphyxia, excited delirium, sudden cardiac death, metabolic acidosis, George Floyd, forensic pathology, autopsy Highlights• Prone restraint deaths result from metabolic acidosis, not hypoxic asphyxia.• Metabolic demand is increased by stimulant drugs, physical exertion, and stress.• Metabolic acidosis requires hyperventilation to "blow off" carbon dioxide (CO 2 ).• Prolonged restraint in the prone position may prevent adequate elimination of CO 2 .• An initial ECG rhythm of PEA or asystole after a cardiac arrest is generally inconsistent with a primary cardiac etiology.How to cite this article: Weedn V, Steinberg A, Speth P. Prone restraint cardiac arrest in in-custody and arrest-related deaths.

Prone restraint death: Possible role of the Valsalva maneuver

“…In the two case reports of prone restraint death described by Weedn et al, 8 the loss of consciousness may also have been precipitated by a Valsalva maneuver. By raising forcefully his head and shoulders once prone restrained, the individual in case #1 (BMI; 39.7 kg/m 2 ) was possibly performing repetitive Valsalva maneuvers.…”

“…8 Indeed, the case series reported by Hick et al 9 suggests that severe metabolic acidosis may be a major factor precipitating cardiac arrest in handcuffed individuals with acute psychosis who are continually struggling against restraints. However, George Floyd was not struggling against restraints and the struggle was not significant in the two cases described by Weedn et al 8…”

Scrutinizing the causal link between excited delirium syndrome and restraint: a commentary on ‘The role of restraint in fatal excited delirium: a research synthesis and pooled analysis’ by E.M.F. Strömmer, W. Leith, M.P. Zeegers, and M.D. Freeman

“…The paper has been cited multiple times in peer-reviewed journals covering forensic pathology [2][3][4], emergency care [5], psychiatry [6], and general medicine [7]. It is furthermore cited in commentaries [8,9] and in an influential report of Physicians for Human Rights [10].…”

Commentary on: Prone restraint cardiac arrest in in‐custody and arrest‐related deaths. J Forensic Sci. 2022;67(5):1899–914. doi: 10.1111/1556‐4029.15101

“…First, the authors cite and mischaracterize two small animal studies. In Pudiak and Bozarth [2] cited as evidence of "restricted ventilation," Weedn et al [1] contend the rats in cylinders "allowed some movement, but generally not the ability to turn around" and "confinement restricted chest expansion preventing deep breaths". In actuality, the animals in the primary comparison "typically reversed their positions one or more times" and no comment was made regarding chest expansion or deep breaths.…”

“…We read with interest the recent report of two cases and literature review by Weedn et al [1] titled "Prone restraint cardiac arrest in in-custody and arrest-related deaths." We agree with the authors' conclusion that the cause of death in these types of cases is not positional nor restraint asphyxiation, but rather cardiac arrest.…”