The problem of police-related cardiac arrest

In pursuit of inter-specialty consensus on excited delirium syndrome: a scoping literature review

Excited delirium syndrome (ExDS) is a controversial and disputed diagnosis involving altered mentation, agitation, and, frequently, substance abuse. Recently, it has become a common pre-hospital diagnosis, serving as justification for use of force, restraint, and/or medication administration. To conduct a scoping review across three databases to describe the most frequently reported diagnostic criteria for ExDS, as well as to explore its use as a diagnosis for deaths of individuals in the custody of law enforcement. In 2021, three literature databases were searched: Ovid Medline, PsycInfo, and Scopus. Studies were included if they were peer-reviewed, English articles describing (1) ExDS symptoms, (2) substance intoxication with at least 2 ExDS symptoms present, or (3) centering on deaths occurring in the custody of law enforcement and attributed to ExDS. Key study data were extracted and the current literature was described qualitatively. Analysis took place between March and December 2021. A total of 97 studies were identified through initial abstract and secondary full-text review, with noted discrepancies in the definition of ExDS itself. After review, differences in ExDS diagnosis among organizations were explored, along with subsequent clinical impact, particularly in the pre-hospital setting. Resulting impact on patients, particularly those of minoritized ethnic and racial groups, was also noted. Prone aggressive restraint, in particular, is noted as an established risk factor for fatalities in ExDS cases. At this time, ExDS should not be utilized as a diagnosis; major medical organizations have an urgent responsibility to convene to formalize consensus-based diagnostic criteria or to propose alternate management guidelines for agitated and altered persons.

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

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.

Thoracic weighting of restrained subjects during exhaustion recovery causes loss of lung reserve volume in a model of police arrest

Restraint asphyxia has been proposed as a mechanism for some arrest-related deaths that occur during or shortly after a suspect is taken into custody. Our analysis of the literature found that prone positioning, weight applied to the back, recovery after simulated pursuit, and restraint position have led to restrictive, but non life-threatening respiratory changes when tested in subsets. However, the combined effects of all four parameters have not been tested together in a single study. We hypothesized that a complete protocol with high-sensitivity instrumentation could improve our understanding of breathing physiology during weighted restraint. We designed an electrical impedance tomography (EIT)-based protocol for this purpose and measured the 3D distribution of ventilation within the thorax. Here, we present the results from a study on 17 human subjects that revealed FRC declines during weighted restrained recovery from exercise for subjects in the restraint postures, but not the control posture. These prolonged FRC declines were consistent with abdominal muscle recruitment to assist the inspiratory muscles, suggesting that subjects in restraint postures have increased work of breathing compared to controls. Upon removal of the weighted load, lung reserve volumes gradually increased for the hands-behind-the-head restraint posture but continued to decrease for subjects in the hands-behind-the-back restraint posture. We discuss the possible role this increased work of breathing may play in restraint asphyxia.

The relationship between positional asphyxia and increasing body mass index

Review of the files of the Pathology section of Forensic Science SA over 17 yrs (January 2003-December 2019) revealed 32 adult cases of positional asphyxia (age range 18-87 years; average 49 years - m:f ratio 3:1). Predisposing/causative conditions were accidents, N = 8, alcohol intoxication N = 7, neurological disease N = 7, drug intoxication N = 5, morbid obesity N = 2, combinations of factors N = 2, and a single homicide N = 1. There was one case with below normal weight (BMI 17.9), with 6 cases having normal weights (BMI range 18.9-24.6, average 22.3), 9 being overweight (BMI range 25.3-29.5, average 27.9), and 16 being obese (BMI range 30-66.2, average 40.9). Only 7 cases (22%) had either under/normal weight compared to 25 (78%) who were overweight/obese (p < 0.05). Increasing body mass appears to be a risk factor to be considered in all forms of positional asphyxia; BMI should, therefore, be routinely taken into account in the forensic evaluation of such cases.

Second opinion system for sudden cardiac death cases in forensic practice

Sudden cardiac death (SCD) represents a considerable percentage of cardiovascular deaths worldwide. The most frequent pathological substrate of SCD is atherosclerotic coronary artery disease (CAD). The other, less common, pathologies which can cause SCD include cardiomyopathies, congenital diseases (including abnormal anatomy), and arrhythmias such as channelopathies, many of which are genetically determined. Autopsies of SCD victims are generally performed by forensic pathologists. In some cases, a third person responsibility could be invoked. While CAD diagnosis at post-mortem examination is not a major challenge for the forensic pathologist, the other rarer diseases may be. In such instances, referral of the hearts to specialized centers with recognized expertise is recommended, and this is particularly important in cases of SCDs of young people. Moreover, in order to avoid the frequent overdiagnosis of a pathological heart, an expert opinion should be sought for even in the presence of a morphologically normal heart. In cases where retention of the heart is not feasible, it is essential to provide an extensive photographic documentation, with the indication of the sampling sites for histological examination. However, some practical aspects, as the criteria for case selection in routine forensic practice are missing. In this paper, we present the recommendations for heart retention for a second expert opinion and the alternative of documentation and sampling for cases where retention is not possible.

Restraint in mental health settings: is it time to declare a position?

The emergence of a drive to reduce restrictive interventions has been accompanied particularly in the UK by a debate focussing on restraint positions. Any restraint intervention delivered poorly can potentially lead to serious negative outcomes. More research is required to reliably state the risk attached to a particular position in a particular clinical circumstance.Declaration of interestF.S. is a consultant psychiatrist in Psychiatric Intensive Care at the Maudsley Hospital, London. He is on the Executive Committee of the National Association of Psychiatric Intensive Care and Low Secure Units, and was a member of the National Institute for Health and Care Excellence Guideline Development Group for the Short-Term Management of Aggression and Violence (2015). J.P. is a senior lecturer at the Faculty of Health and Life Sciences, Coventry University. E.B. is a consultant and expert witness in violence reduction and the use of physical interventions, independent expert to the High Secure Hospitals Violence Reduction Manual Steering Group and a member of the College of Policing Guideline Committee Steering Group and Mental Health Restraint Expert Reference Group. B.P. is the clinical director for Crisis and Aggression Limitation and Management (CALM) Training and formerly a senior lecturer for the Faculty of Health, University of Stirling. He is a nurse and psychotherapist and presently chairs the European Network for Training in the Management of Aggression. A.O'B. is a consultant psychiatrist, the Director of Educational Programmes for the National Association of Psychiatric Intensive Care and Low Secure Units, and the Dean for Students at St George's University of London.

The Promise of Molecular Autopsy in Forensic Pathology Practice

Molecular autopsy is changing the practice of forensic pathology. Under some circumstances, one must contemplate the involvement of genetic factors to help explain why someone has died unexpectedly. Such considerations most commonly occur when a young person dies by natural means. However, there are deaths that occur by nonnatural means that the forensic pathologist will be asked to investigate, which could involve natural disease that has a significant genetic underpinning. Elucidation of genetic mutations may not only further an understanding of the pathophysiology at hand, but also speak to underlying susceptibilities in an individual who dies that may not have been recognized. In addition, one may occasionally identify pathological findings that are confused for trauma that may actually be better explained by an underlying disease process. Using molecular medicine as a tool to explore such possibilities can improve the quality of death investigations and provide a new lens to probe challenging and contentious forensic cases that have proved resistant to traditional methods.