The effect of the prone maximal restraint position with and without weight force on cardiac output and other hemodynamic measures

Alcohol use, civilian interference, and other possible risk factors for death during restraint

Physical restraint is usually used when trying to control and terminate a violent episode. Many causes are possible behind aggressive, agitated, and violent behavior. Some of these are such factors that can either be detected in forensic autopsies or can be evident from the person's medical records. Various causes for deaths during physical restraint have been suggested. In this study, we wanted to review all incidents in which physical restraint was employed, ending in death of the restrained person, whether the restraint was applied by police officers, security guards, police custody personnel, health care personnel or ordinary civilians. The main aim was to see if this new kind of study design would increase our knowledge in circumstances and causes leading to death in restraint situations. Data was collected retrospectively from all forensic autopsies performed in the Southern Finland area during 2010-2015. We went through 21,036 forensic autopsy cases and found 12 cases (0.06 %) in which a physical restraint was employed before death. Police officers were involved in the physical restraint in 7/12 of the cases: in two of these cases, police alone; in three cases, police and guards; and in two cases, police and health care personnel. Civilians carried out the restraint in 5/12 cases. With civilians responsible for the restraint, the cause of death was more likely considered to be a result of the restraint itself than in cases where police and other authorities were responsible for the restraint. This could be because civilians aren't educated about safe restraint methods, and they might themselves be intoxicated. Alcohol was the most common psychoactive substance found in this study and could be a risk factor for not only aggressive behavior but also death, since alcohol use can provoke cardiac arrhythmias and even sudden death. Based on this study, and previously published studies, we see restraint deaths as a varying spectrum of deaths, in which the death is often possibly a result of many factors, including the effects of agitation and restraint, intoxication, and cardiac and other illnesses.

Prone restraint death: Possible role of the Valsalva maneuver

There is an on-going debate about the safety of prone restraint and the exact role of the prone position in physical restraint death. Cardiac arrest in prone restraint death is essentially the end-result of a violent physical altercation wherein a combative individual suddenly loses consciousness while trying to counteract an opposing force. The direct correlations of increased static weight force with decreased inferior vena cava diameter, decreased cardiac output, and decreased stroke volume in prone restraint studies suggest that decreased venous return and decreased cardiac output could have a significant role to play in prone restraint death. Although the degree of changes observed in those studies might not be sufficient to cause cardiac arrest, they could predispose people who instinctively try to free themselves of the restraints to severe complications. The Valsalva maneuver, or forceful expiration against a closed airway, is frequently performed spontaneously in daily activities involving straining and resistance exercise, but has never been considered in restraint death. Pre-existing diminished venous return could increase the risk of major complications in individuals performing the Valsalva maneuver. A substantial decrease in venous return and cardiac output could increase the risk of cerebral hypoperfusion, loss of consciousness, hypoventilation, and sudden death. By increasing the risk of increased intra-abdominal pressure and its negative effect on venous return, high body mass index may be a significant risk factor in prone restraint death. The Valsalva maneuver may have different roles in prone restraint cardiac arrest and might be overlooked in prone restraint death.

Physical restraint within the prehospital Emergency Medical Care Environment: A scoping review

Background

Psychomotor agitation and aggressive behaviour (AAB) have the potential to occur in any healthcare setting, including those in which Emergency Medical Services (EMS) operate. This scoping review aimed to examine the available literature on physical restraint of patients within the prehospital setting and to identify guidelines and their effectiveness, safety to patients and health care practitioners and strategies relating to physical restraint when used by EMS.

Methods

We performed our scoping review using the methodological framework described by Arksey and O'Malley augmented by that of Sucharew and Macaluso. Several steps guided the review process: identification of the research question, eligibility criteria, information sources (CINAHL, Medline, Cochrane and Scopus), search, selection and data collection, ethical approval, collation, summarizing and reporting on the results.

Results

The population of interest, in this scoping review was prehospital physically restrained patients, however, there was a reduced research focus on this population in comparison to the larger emergency department.

Conclusion

The limitation of informed consent from incapacitated patients may relate to the lack of prospective real-world research from previous and future studies. Future research should focus on patient management, adverse events, practitioner risk, policy, and education within the prehospital setting.

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.

Acute effects of postural changes and lower body positive and negative pressure on the eye

Introduction: Entry into weightlessness results in a fluid shift and a loss of hydrostatic gradients. These factors are believed to affect the eye and contribute to the ocular changes that occur in space. We measured eye parameters during fluid shifts produced by lower body negative pressure (LBNP) and lower body positive pressure (LBPP) and changes in hydrostatic gradient direction (supine-prone) in normal subjects to assess the relative effects of fluid shifts and hydrostatic gradient changes on the eye.

Methods: Ocular parameters (intraocular pressure (IOP), ocular geometry, and optical coherence tomography measures) were measured in the seated, supine, and prone positions. To create a fluid shift in the supine and prone positions, the lower body chamber pressure ranged from -40 mmHg to +40 mmHg. Subjects maintained each posture and LBNP/LBPP combination for 15 min prior to data collection. A linear mixed-effects model was used to determine the effects of fluid shifts (as reflected by LBNP/LBPP) and hydrostatic gradient changes (as reflected by the change from seated to supine and from seated to prone) on eye parameters.

Results: Chamber pressure was positively correlated with both increased choroidal thickness (β = 0.11 ,p = 0.01) and IOP (β = 0.06 p < 0.001). The change in posture increased IOP compared to seated IOP (supine β = 2.1, p = 0.01, prone β = 9.5, p < 0.001 prone) but not choroidal thickness. IOP changes correlated with axial length (R = 0.72, p < 0.001).

Discussion: The effects of hydrostatic gradients and fluids shifts on the eye were investigated by inducing a fluid shift in both the supine and prone postures. Both hydrostatic gradients (posture) and fluid shifts (chamber pressure) affected IOP, but only hydrostatic gradients affected axial length and aqueous depth. Changes in choroidal thickness were only significant for the fluid shifts. Changes in hydrostatic gradients can produce significant changes in both IOP and axial length. Fluid shifts are often cited as important factors in the pathophysiology of SANS, but the local loss of hydrostatic gradients in the head may also play an important role in these ocular findings.

Evaluation of the ventilatory effects on human subjects in prolonged hip-flexed/head-down restraint position

BACKGROUND

The restraint chair is a tool used by law enforcement and correction personnel to control aggressive, agitated individuals. When initiating its use, subjects are often placed in a hip-flexed/head-down (HFHD) position to remove handcuffs. Usually, this period of time is less than two minutes but can become more prolonged in particularly agitated patients. Some have proposed this positioning limits ventilation and can result in asphyxia. The aim of this study is to evaluate if a prolonged HFHD restraint position causes significant ventilatory compromise.

METHODS

Subjects exercised on a stationary bicycle until they reached 85% of their predicted maximal heart rate. They were then handcuffed with their hands behind their back and placed into a HFHD seated position for five minutes. The primary outcome measurement was maximal voluntary ventilation (MVV). This was measured at baseline, after initial placement into the HFHD position, and after five minutes of being in the position while still maintaining the HFHD position. Baseline measurements were compared with final measurements for statistically significant differences.

RESULTS

We analyzed data for 15 subjects. Subjects had a mean MVV of 165.3 L/min at baseline, 157.8 L/min after initially being placed into the HFHD position, and a mean of 138.7 L/min after 5 min in the position. The mean baseline % predicted MVV was 115%; after 5 min in the HFHD position the mean was 96%. This 19% absolute difference was statistically significant (p = 0.001).

CONCLUSIONS

In healthy seated male subjects with recent exertion, up to five minutes in a HFHD position results in a small decrease in MVV compared with baseline MVV levels. Even with this decrease, mean MVV levels were still 96% of predicted after five minutes. Though a measurable decrease was found, there was no clinically significant change that would support that this positioning would lead to asphyxia over a five-minute time period.

Prone restraint cardiac arrest: A comprehensive review of the scientific literature and an explanation of the physiology

Deaths occurring among agitated or violent individuals subjected to physical restraint have been attributed to positional asphyxia. Restraint in the prone position has been shown to alter respiratory and cardiac physiology, although this is thought not to be to the degree that would cause asphyxia in a healthy, adult individual. This comprehensive review identifies and summarizes the current scientific literature on prone position and restraint, including experiments that assess physiology on individuals restrained in a prone position. Some of these experimental approaches have attempted to replicate situations in which prone restraint would be used. Overall, most findings revealed that individuals subjected to physical prone restraint experienced a decrease in ventilation and/or cardiac output (CO) in prone restraint. Metabolic acidosis is noted with increased physical activity, in restraint-associated cardiac arrest and simulated encounters. A decrease in ventilation and CO can significantly worsen acidosis and hemodynamics. Given these findings, deaths associated with prone physical restraint are not the direct result of asphyxia but are due to cardiac arrest secondary to metabolic acidosis compounded by inadequate ventilation and reduced CO. As such, the cause of death in these circumstances would be more aptly referred to as "prone restraint cardiac arrest" as opposed to "restraint asphyxia" or "positional asphyxia."

The role of restraint in fatal excited delirium: a research synthesis and pooled analysis

The purpose of the present study was to perform a comprehensive scientific literature review and pooled data risk factor analysis of excited delirium syndrome (ExDS) and agitated delirium (AgDS). All cases of ExDS or AgDS described individually in the literature published before April 23, 2020 were used to create a database of cases, including demographics, use of force, drug intoxication, mental illness, and survival outcome. Odds ratios were used to quantify the association between death and diagnosis (ExDS vs. AgDS) across the covariates. There were 61 articles describing 168 cases of ExDS or AgDS, of which 104 (62%) were fatal. ExDS was diagnosed in 120 (71%) cases, and AgDS in 48 (29%). Fatalities were more likely to be diagnosed as ExDS (OR: 9.9, p < 0.0001). Aggressive restraint (i.e. manhandling, handcuffs, and hobble ties) was more common in ExDS (ORs: 4.7, 14, 29.2, respectively, p < 0.0001) and fatal cases (ORs: 7.4, 10.7, 50, respectively, p < 0.0001). Sedation was more common in AgDS and survived cases (OR:11, 25, respectively, p < 0.0001). The results of the study indicate that a diagnosis of ExDS is far more likely to be associated with both aggressive restraint and death, in comparison with AgDS. There is no evidence to support ExDS as a cause of death in the absence of restraint. These findings are at odds with previously published theories indicating that ExDS-related death is due to an occult pathophysiologic process. When death has occurred in an aggressively restrained individual who fits the profile of either ExDS or AgDS, restraint-related asphyxia must be considered a likely cause of the death.

Arrest-related death on the basis of a drug-induced excited delirium syndrome

AIMS

In typical arrest-related death (ARD) scenarios, the victims often show signs of excited delirium syndrome (ExDS), intoxication, exhaustion and/or suffered from a preexisting physical or psychiatrical condition, all of which could have caused or at least triggered the person's death. Since autopsy findings are very rare in such cases, a clear clinicopathologic diagnosis and thus mechanism of death is rarely found.

METHODS

We present a case of a 25-year old woman, who died while being arrested by the police. Based on the patient's medical history, autopsy findings, contradicting witness testimonies, and reliable clinical and toxicological blood parameters, the most probable diagnosis is discussed.

RESULTS

The cause of death was determined as cardiac arrest subsequent to a combination of excited delirium syndrome, physical exhaustion and respiratory impairment. The manner of death was unnatural and juridically, the charges were dropped.

CONCLUSIONS

In cases, where the cause and mechanism of death can only be diagnosed by exclusion, police collaboration, detailed clinical history (past and present) as well as clinical blood parameter analyses are necessary to help evaluating possible contributing factors and the most probable cause of death in ARD.

Restraint physiology: A review of the literature

Law-enforcement often uses forensic restraints to control individuals and often these individuals are placed in positions and with various amounts of weight used to hold them in place. There has been a moderate amount of research performed on humans in this field of study to assess the physiologic impact of the positions and weight on ventilatory and cardiovascular parameters. This review discusses the scientific medical literature on the use of restraints and restraint position including the use of weight force and aggregates the findings in specific physiologic areas, such as impact on blood pressure, heart rate, and ventilatory parameters.

Sudden death during physical restraint by the Dutch police

BACKGROUND

and goal: The Police is sometimes confronted with the death of a subject during physical restraint. In most of these cases a clear Cause of Death (COD) cannot be determined by the Pathologist. The goal of this research is to find and clarify a pattern and pinpoint a clearer COD.

METHOD

The research group is compiled of 38 closed police case files from the NPIID (National Police Internal Investigation Department) between 2005 and 2016. The control group is compiled of cases involving excitation and restraint, without leading to death. 148 cases were included from the NPIID between 2005 and 2016 and the Violence Registration Database of the Dutch National Police between 2014 and 2015. Case files of both the research and the control group were systematically analyzed and compared.

RESULTS AND CONCLUSION

The observed patter shows that subjects dying during Physical Restraint are mostly males between 30 and 40 years old with a BMI above 30 kg/m². Both BMI and age are remarkably lower in the control group. Subjects were encountered in a state of excitation mostly attributed to (multiple) drugs (cocaine, MDMA or cannabis). The physical restraint portrayed a pattern of escalation with restraint being mostly face-down, hands cuffed to the back, receiving thoracic pressure, resulting in a high total amount of force used. In the research group 44.7% (17/38) of subjects were encountered (partially) unclothed versus 4.1% (6/148) in the control group. Cause of death in these cases seems to be multifactorial and is comprised of both personal factors and factors during and after the struggle. The different factors are comingled and augment each other. The end effect is that the subjects end up in a fatal spiral.

EXCITATION study: Unexplained in-custody deaths: Evaluating biomarkers of stress and agitation

BACKGROUND

Law enforcement personnel often confront violent and dangerous individuals suffering from Excited Delirium Syndrome (ExDS) who need emergent medical evaluation and treatment to optimize the best outcomes for this potentially lethal medical emergency. These subjects typically require physical restraint and use of force measures to control them. We sought to determine if stress-related biomarkers can differentiate ExDS subjects when compared with agitation and stress under other circumstances, including agitation and extreme physical exhaustion and restraint coupled with emotional stressors.

METHODS

This was a prospective multi-center study enrolling a convenience sample of patients who presented with agitation or ExDS. Patients were enrolled from three academic emergency departments (ED), two in the United States and one in Canada. Three study groups (SG) included: SG1) patients brought to the ED with ExDS based on the use of standardized clinical criteria; SG2) ED patients with acute agitation who were not in a clinical state of ExDS but required sedation; SG3) a laboratory control group of subjects exercised to physical exhaustion, restrained, and psychologically stressed with threat of Conducted Energy Device (CED) activation. We examined a panel of stress-related biomarkers, including norepinephrine (NE), cortisol, copeptin, orexin A, and dynorphin (Dyn) from the blood of enrolled subjects.

RESULTS

A total of 82 subjects were enrolled: 31 in the agitation group, 21 in the ExDS group, and 30 in the laboratory control group. Data were analyzed, comparing the findings between ExDS and the two other groups to determine if specific stress-related biomarkers are associated with ExDS. Biomarker comparisons between subjects identified with ExDS, agitation, and control groups demonstrated that cortisol levels were more elevated in the ExDS group compared with the other groups. Orexin was only significant in ExDs (with Agitated tendency but lot of variability in the group). NE and Dyn increased as response to stress in Agitated and ExDS.

CONCLUSIONS

Cortisol levels were more elevated in subjects in the ExDS group compared with the other comparison groups and orexin was elevated in ExDS compared to controls, a trend that did not reach statistical significance in the agitated group. The clinical or diagnostic significance of these difference have yet to be defined and warrants further study.

Excited Delirium: A Systematic Review

OBJECTIVE

We aimed to clarify the definition, epidemiology, and pathophysiology of excited delirium syndrome (ExDS) and to summarize evidence-based treatment recommendations.

METHODS

We conducted a systematic literature search of MEDLINE, Ovid, Web of Knowledge, and Cochrane Library for articles published to March 18, 2017. We also searched the gray literature (Google Scholar) and official police or medical expert reports to complete specific epidemiologic data. Search results and full-text articles were independently assessed by two investigators and agreements between reviewers assessed with K statistics. We classified articles by study type, setting, and evidence level.

RESULTS

After reviewing the title and abstract of 3,604 references, we fully reviewed 284 potentially relevant references, from which 66 were selected for final review. Six contributed to the definition of ExDS, 24 to its epidemiology, 38 to its pathophysiology, and 27 to its management. The incidence of ExDS varies widely with medical or medicolegal context. Mortality is estimated to be as much as 8.3% to 16.5%. Patients are predominantly male. Male sex, young age, African-American race, and being overweight are independent risk factors. Pathophysiology hypotheses mostly implicate dopaminergic pathways. Most cases occur with psychostimulant use or among psychiatric patients or both. Proposed treatments are symptomatic, often with rapid sedation with benzodiazepines or antipsychotic agents. Ketamine is suggested as an alternative.

CONCLUSION

The overall quality of studies was poor. A universally recognized definition is lacking, remaining mostly syndromic and based on clinical subjective criteria. High mortality rate may be due to definition inconsistency and reporting bias. Our results suggest that ExDS is a real clinical entity that still kills people and that has probably specific mechanisms and risk factors. No comparative study has been performed to conclude whether one treatment approach is preferable to another in the case of ExDS.

Is LSD toxic?

LSD (lysergic acid diethylamide) was discovered almost 75 years ago, and has been the object of episodic controversy since then. While initially explored as an adjunctive psychiatric treatment, its recreational use by the general public has persisted and on occasion has been associated with adverse outcomes, particularly when the drug is taken under suboptimal conditions. LSD's potential to cause psychological disturbance (bad trips) has been long understood, and has rarely been associated with accidental deaths and suicide. From a physiological perspective, however, LSD is known to be non-toxic and medically safe when taken at standard dosages (50-200μg). The scientific literature, along with recent media reports, have unfortunately implicated "LSD toxicity" in five cases of sudden death. On close examination, however, two of these fatalities were associated with ingestion of massive overdoses, two were evidently in individuals with psychological agitation after taking standard doses of LSD who were then placed in maximal physical restraint positions (hogtied) by police, following which they suffered fatal cardiovascular collapse, and one case of extreme hyperthermia leading to death that was likely caused by a drug substituted for LSD with strong effects on central nervous system temperature regulation (e.g. 25i-NBOMe). Given the renewed interest in the therapeutic potential of LSD and other psychedelic drugs, it is important that an accurate understanding be established of the true causes of such fatalities that had been erroneously attributed to LSD toxicity, including massive overdoses, excessive physical restraints, and psychoactive drugs other than LSD.

Acute effects of changes to the gravitational vector on the eye

Intraocular pressure (IOP) initially increases when an individual enters microgravity compared with baseline values when an individual is in a seated position. This has been attributed to a headward fluid shift that increases venous pressures in the head. The change in IOP exceeds changes measured immediately after moving from seated to supine postures on Earth, when a similar fluid shift is produced. Furthermore, central venous and cerebrospinal fluid pressures are at or below supine position levels when measured initially upon entering microgravity, unlike when moving from seated to supine postures on Earth, when these pressures increase. To investigate the effects of altering gravitational forces on the eye, we made ocular measurements on 24 subjects (13 men, 11 women) in the seated, supine, and prone positions in the laboratory, and upon entering microgravity during parabolic flight. IOP in microgravity (16.3 ± 2.7 mmHg) was significantly elevated above values in the seated (11.5 ± 2.0 mmHg) and supine (13.7 ± 3.0 mmHg) positions, and was significantly less than pressure in the prone position (20.3 ± 2.6 mmHg). In all measurements, P < 0.001. Choroidal area was significantly increased in subjects in a microgravity environment ( P < 0.007) compared with values from subjects in seated (increase of 0.09 ± 0.1 mm2) and supine (increase of 0.06 ± 0.09 mm2) positions. IOP results are consistent with the hypothesis that hydrostatic gradients affect IOP, and may explain how IOP can increase beyond supine values in microgravity when central venous and intracranial pressure do not. Understanding gravitational effects on the eye may help develop hypotheses for how microgravity-induced visual changes develop.

The problem of police-related cardiac arrest

The term "positional asphyxia" was originally used to describe the situation in which the upper airways becomes compromised by sharp angulation of the head or neck, or where the chest wall is splinted and the diaphragm is prevented from moving because of an unusual position of the body. The term was redefined in the early 1980s to describe sudden death during physical restraint of an individual who is in a prone position. A large percent of reported victims were overweight males. Most were in early middle age and manifesting psychotic behavior at the time of death. Most were reported to have unremarkable autopsies, save for the finding, in many cases, of cocaine or methamphetamine (more recently synthetic cannabinoids and cathinones as well). As no cause of death was apparent (other than non-specific signs such as pulmonary edema), it became common practice to attribute death to force exerted on the decedent's back. When experimental studies with human volunteers disproved this notion, the term "restraint asphyxia" was substituted for positional asphyxia, but with nearly the exact same meaning. No experimental study has ever determined the actual amount of force necessary to cause asphyxia by force applied to the back (although the range of required static force is known), nor the duration for which it must be applied. This review discusses the epidemiology and the evidence for and against the theory of "restraint/positional" asphyxia. It also considers alternative theories of causation, including the findings of studies suggesting that cardiac channelopathies/cardiomyopathies may explain many cases of ARD.

Sudden death during struggle in the setting of heterozygosity for a mutation in calsequesterin 2

Instances of sudden and unexpected death while in police custody remain complex and controversial cases in forensic pathology, and provide unique diagnostic challenges. In general, the circumstances of these cases have resulted in two major theories to account for these deaths: "excited delirium syndrome", and positional (restraint) asphyxia. However, some cases that are not easily explained by one of these theories may be best explained by a theory from another emergent area in forensic pathology, non-structural genetic heart disease. We present one such case, a sudden arrhythmic death during struggle/restraint. A 45 year old man with developmental delay was walking outdoors as part of his daily routine. He was misidentified as a criminal suspect by police officers, who attempted to take him into custody. He resisted this arrest violently. He was taken to the ground, and restrained in a face-down position. Both police and civilian witness state that he was pushing his chest off the ground with his arms, when he suddenly collapsed and died. The interaction with police lasted approximately 3 min. There was no prior excited delirium. At autopsy, minor external blunt force injuries were observed. The heart showed mild cardiomegaly with concentric left ventricular hypertrophy, and sub-occlusive coronary atherosclerosis. Toxicological testing was negative for common drugs, including cocaine and its metabolites. Post-mortem molecular testing demonstrated this man to be heterozygous for a catecholaminergic polymorphic ventricular tachycardia (CPVT) associated mutation (Phe189Leu) in the calsequestrin 2 (CASQ2) gene. This mutation was classified as a class I mutation (deleterious), that may cause disease in a heterozygous state. The cause of death was given as cardiac arrhythmia precipitated by struggle/restraint in a man with CPVT. This case illustrates the difficulty assigning a scientific cause of death in rare and controversial cases, and the value of the molecular autopsy in identifying disease causing mutations.

Investigation of Deaths Temporally Associated with Law Enforcement Apprehension

The investigation of a death that occurs in custody requires a careful and methodical approach since concerns of police or institutional misconduct may be raised. The medicolegal official charged with the investigation and ultimate certification of death bears heavy responsibility to the decedent's family, the public, law enforcement and other institutions. A wide variety of causes of death and manners of death are seen in these deaths. This paper reviews causes, mechanisms, manners, findings, and evaluation of persons who have died in temporal relation to legal apprehension.