Asphyxial Death During Prone Restraint Revisited, O'Halloran and Frank, 2000
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The American J ournal of Forensic Medicine and Pathology ©2000 Lippincott W illiams & Wilkins , Inc., Philadelphia 21(1):39- 52, 2000. Asp:Q.yxial Death During Prone Restraint Revisited A Report of 21 Cases Ronald L. O'Halloran. M.D .• and Janice G. Frank, Determining the cause of death when a restrained p erson suddenly dies Is a problem for death investigators. Twenty-one cases of death during prone restraint a re reported as examples of the common elements and range of variation in these apparently asphyxial events. A reasonable diagnosis of restraint asphyxia can usually be made after ruling out other causes and collec ting supportive participant and witness statements in a timely fashion. Common elements in this syndrome include prone restraint with pressure on the upper torso; handcuffing, leg restraint, or hogtying; acute psychosis and agitation, often stimulant drug induced; physical exertion· and struggle; and obesity. Establis hing a temporal association between the restraint and the sudden loss of consciousness/death is critical to making a correct d etermination of cause of death. Key W ord s: Restraint asphyxia- Positional asphyxiation--Prone restraint- Hogtying-Sudden death in custody- Agitated delirium-Excited delirium-Cocaine-Methamphetamine-Baton- Pepper spray- Taser--Stun gun. M .D. The sudden, unexpected death of an individual while in police custody is always a matter of public concern and frequently leads to litigation. Such high-profile deaths often are a diagnostic dilemma for medical examiners or coroners and the forensic p athologists who work with them . T he autopsy findings are frequently nonspecific, detailed witness descriptions of the circumstances of the terminal event are often not initially obtained, and accurate accounts are difficult to collect later because of potential litigation. Reports of sudden death of individuals who were restrained prone, many of whom were also hogtied, appeared in the 1990s (1 - 5). The tenn hogtying is used in this paper to refer to the restraint of a person in a prone position with their wrists and ankles bound together behind the back. Based on such reports, many members of the law enforcement community have discussed the problem of sudden death during restrain t procedures, and many have attempted to modify or eliminate the use of the hogtied prone position; however, sudden deaths during prone restraint continue to occur. We present the previously unreported sudden deaths of 2 1 individuals who died while being restrained in a prone position and discuss the factors that seem to put these persons at risk. METHODS The case hi stories and autopsy findings of 21 m en who died suddenly while being restrained prone during the years 1992 to 1996 were reviewed, analyzed, and summarized. In all cases, the records included interviews with the restrainers and other witnesses, if any. In most cases, transcripts of statements or testimony were also reviewed. Four of the autopsies were done by the authors, and the case histories were reviewed as an adjunct. The other cases were seen in consultative review related to potential litigation. Manuscript received May I 0, 1999; accepted August 25, 1999. From the Office of the Medical Examiner, Ventura County, Ventura, California, U.S.A. Address correspondence and reprint requests to Ronald L. O'Halloran, 3291 Lorna Vista Roac' Ventura, CA 93003, U.S.A. 39 ··~ 40 ) R. L. 0 'HALLORA N AND J. G. FRANK CASE RE,PORTS Case 1 Police responded . to a domestic violence situation. A man in his early thirties was holding his w ife against her will. He was physically violent and irrational and did not respond to verbal commands. Four police officers used control holds and a baton to force him into a prone position on the floor, hogtied . He seemed to calm down and stop wrestling shortly before the hogtying was complete d. He was canied from the residence and laid prone on the grass in the yard, still hogtied, awaiting transportation to jail. Officers soon noticed that he was unconscious, was not breathing, and had no pulse. They started cardiopulmonary resuscitation (CPR) and called' 'paramedics. Paramedics found him asystolic and not breathing. They intubated him and administered advanced cardiac life suppmi (ACLS), eventually obtaining an idioventricular rhythm. Marginal cardiac function was restored, but he remained unconscious without spontaneou s respiration. He was transported to a hospital where he was maintained on a respirator for 24 hours b efore he died, having sustained extensive ischemic brain damage. H is temperature on admission was 36. 1oc (97°F). He was known to have abused methamphetamine in the recent past and had associated paranoid ideation. It was not clear from the investigation how long the officers stmggled with the man prior to his effo tis subsiding, what pressure was applied to the prone p erson while restraints were appli ed, or how long he was prone on the grass before his unconscious state was recognized. An autopsy disclosed a 175-cm (70-inch), 88.6kg (I 95-lb) man with abrasions and contusions on his shoulders, anns, and abdomen and n o internal injuries. The eyes were not described. His heart weighed 420 g and was normal microscopically. Blood drawn in the emergency depmiment tested positive for cocaine and methamphetamine but the levels were not quantitated. Postmortem blood was negative for cocaine and contained benzoylecgonine 1.7 mg/L, methamphetamine 0.85 mg/L, and amphe tamine 0 .08 mg/L. The cause of death was listed as acute intoxication due to the combined effects of cocaine/methamphetamine/amphetamine, and the manner of death was listed as accident. Case 2 A man in his mid-thirties appeared to be intoxicated in public. When approached by police, he was described as delirious, ai'ated, and sweaty._He fled on foot and after a long :ursuit was cornered, Am J Forensic Med Pathol. Vol. 21. No. I. March 2000 and electrical darts (i.e., tasers) were used with little effect. He was eventually hogtied by many police officers and carried to a police car, where he was placed prone in the back seat. After a few minutes, he was found not breathing. Paramedics transported him while asystolic to the hospital, w here he was pronou nced dead on arrival. A n autopsy disclosed a 182.5-cm (73-inch), 145.5-kg (320-lb) man w ith many superficial injuries and several da1is in the skin of the trunk. No petechial hemorrhages were described. No interna l injuries were found. The heart weighed 480 g, was di lated, and had microscopic foci of fibrosis. Toxicology blood test results disclosed cocaine 1.9 mg/L and benzolecgonine 2.7 m g/L. The death was certified as due to cocaine intoxication and asphyxia from restraint, and the m anner of death was listed as homicide. Case 3 Police responded to reports of a man in his midforties walking the street, yelling, and hitting obj ects. When officers approached the man , h e appeared to be under the influence, delusional, and incoherent. He fled and was pursued on foot. When caught, he was delirious and combative. Pepper spray and baton strikes had no apparent effect. Three to five officers eventually forced him in the prone position on the ground w ith weight applied to h is back and legs, and his arms were handcuffed behind his back. Minutes later, police noticed that he was not moving or breathing. They statied CPR and called for an ambulance. Paramedics found no vital signs and were unable to resuscitate him. They noted that he was sweaty. He was transported to a hospital, where he was declared dead on arrival. An autopsy disclosed a 185-cm (74-inch), 86.4kg (190-lb) man with many external bruises but no internal injuries. No petechial hemorrhages were described. He had a history of paranoid schizophrenia. The death was certified as due to excited delirium due to paranoid schizophrenia, and the manner of death was listed as natural. Case 4 Police responded to a man in his early thirties babbling incoherently on the street. He was arrested for public intoxication and was transported to j ail in handcuffs. At the jail he became combative an d was hobbled (i.e., ankles bound) and transported to another jail. At the second jail he was screaming and stmggling, clearly agitated but not delirious. He was dragged into a safety cell stmggling and sweating. Several officers held him prone on the floor, applying body weight to the back, arms , and RESTRAIN T ASPHYXIA legs as they switched handcuffs. After a few minu tes of stmggling, he became limp and made s noring sounds. Officers soon noticed the prisoner was not breathing. CPR was starte d, and paramedics were called. He w as transported to an em ergency depa rtment and s hortly thereafter was pronounced dead. No vita l signs w ere detected at any point after the arrival of the ambulance. An autopsy disclosed a 182.5-cm (73 -inch), 11 3. 6-kg (250-lb) man with many superficia l abrasions and contusions of the h ead, trunk, and extre mities. Intrathoracic petechial hemorrhages were noted. The h eart w eighed 500 g but was microscopically nonnal. Toxicology blood tests results revealed cocai ne 1.2 mg/L, benzolecgonine 6..4 m g/ L , cocaethy lene 0.4 mg/L, and alcohol 0.02%. The death w as certified as due to alcohol and cocaine toxicity, and the manner was listed as accident. Case 5 A man in his early forties, with a history of alcohol and cocaine abuse, was arres ted for burglary a nd booke d into j ail. He had a his tory of alcohol withdrawa l, and a nurse ordered that he be s tarted on Dilantin 2 days prior to his death. On the day of death h e became violent in his cell, was kicking the door, and was delirious and s w eating. He w as then handcu ffed and moved to a safety cell. He was pl aced prone on the floor and held down by two officers on his back and legs while they attempted to remove his clothing and cuffs. After an estimated 2- to 5-minute stmggle, he became limp and turned blue. Chest compressions were s tarted, and an ambulance was called. H e was transp orted to a hospital in full cardiopulmonary arrest. After epi nephrine administration and electric shock, the heart started beating again, but he never regained consciou sness and died about 18 hours after the incident. N o temperature was recorded. An autopsy disclosed a 175-cm (70-inch), 77.3kg (1 70-lb) man with many abrasions and contusions . Intrathorac ic petechial hemorrhages w ere noted. The heart weighed 480 g and had septal contrac tion bands. The liver w a s fatty and cirrhotic. T ox icology tests di sclosed only therapeutic levels of phenytoin and very low levels of chlordiazep oxide. The d eath was certified as due to hy poxic encephalopathy following a cardiac arrest due to p ositional asphyxia. Complications of chronic a lcoholism were considered contributing conditions, and the manner of death was lis ted as accident. Case 6 A man in his mid-thirties v- :; seen by security guards wandering suspiciously between cars in a 41 park ing Jot. Three guards c hased him 400 m be fo re catching him. He was reported to be combative and talking gibberish and was w restled to the ground. The guards held him prone, with on e guard s traddling his back, as they handcuffed him. He was he ld prone for an estima ted 2 minutes, and then h e stoppe d stmggling. T wo guards went searching for a weapon, and when th ey came back they discovered h e was not breathing. They started CPR and called for an ambulance. Paramedi cs adminis tered A CL S and transported him to a hospital, where he was pronounced dead on arrival. H e was asystolic from the time the paramedics arrive d . The autopsy disclosed a 170-cm ( 68-inch), 81.8kg ( 180-lb) man with cutaneous a brasions and small contusions. N o p etechiae were seen . The postmortem blood cocaine level was 1.1 mg/L. The death w as certified as due to cocaine intoxication, and the manner was listed as accident. Case 7 A man in his early thirties was driving a tmck erratically and was follo wed by a police officer until the tmck broke down. He fled on foot, and the officer chased him hundreds of m eters and finally caught him, pitming him to the ground. Two other office rs arrived, and pepper spray was u sed with no apparent effect. After a 10- to 15-minu te stmggle on the ground, he w as fina lly controlled by hogtying him in a prone position. With in a few minutes after the officers got off the man th ey noticed he was not breathing. They s tarte d CPR , and he v omited . Within 10 minutes an ambulance atTived. Paramedics removed the wrist and ankle res traints and continued resuscitation attemp ts, and the man was transported to a hospital, w here he was pronounced dead on arri val. He had a his tory of previous paranoid and psychotic behavior after methamphetamine use. An autopsy disclosed a 1<?2.5-cm (65-inch), 63.6-kg (140-lb), muscular man. Only injuries of the wris ts and ankles w ere no ted . Internal organs were n ot weighed. Toxico logy tests disclosed methamph etamine 0.1 mg/L in postmortem blood. The cause of death was listed as due to methamphetam ine tox icity, and the m anner of death w as mled an accident by a coroner inquest jury. Case 8 A man in his mid-th irties drove hi s speeding vehicle into a restaurant parking lot, followed by police. Civilians and police observed him acting agitated and talking to God. He asked for a knife to kill himself, and later bolted to a police car and went for a gun. A police officer pulled him from Am J For e11sic M ed Pathol. Vol. 2 1, No. 1. March 2000 42 R. L. 0 'HALLORAN A ND J. G. FRANK the car before he could get the gun, but he began chasing the officer. Several bursts of pepper sprayed were used, and the man was stmck with a baton with little effect. Eventua lly, seven police officers wrestled him to the ground, and after a 5- to 10-minute prone struggle, he was controlled with handcuffs behind his back and his ankles bound. One officer w as straddling his lower back area, one held a foreann on his upper back, and more officers were holding down his upper torso when he lost consciousness. Officers administered CPR u ntil paramedics arrived minutes later. Th e man was without vital signs during tran sport to a hospital, where he was pronounced dead on arrival. He had a h istory of a bipolar or chronic schizophrenic psychotic disorder. An autopsy disclosed a 182.5-cm (73-inch), 127kg (280-lb) man w ith abrasions and contusions of the head, back, and extremities. Laryngeal mucosal petechial hemorrhages were seen, along ·w ith faint neck strap muscle contusions. The h eart was estimated to weigh 450 g. Minimal patchy areas of subendocardial fibrosis were note d. Postmortem toxicology drug screens were negative. The cause of death was listed as stress induced cardiopulmonary fai lure due to restraint and acute psychotic episode. Schizophrenia, blunt force injuries, and cardiac hypertrophy were listed as contributing factors. The manner of death was listed as accident. Case 9 A severely mentally retarded teenaged boy was being disruptive and damag ing property at a public residential care facility. Two custodial officers cuffed his hands behind his back as they held him prone on the floor for an estimated 3 to 10 minutes. One officer placed a knee on his back and pulled upward on his wrists while the o ther put pressure on his upper back or neck area w ith a forearm and body weight. Some witnesses said a n eck hold may have been applied. A third officer held his legs. Several wi tnesses heard a wheezing sound before he stopped struggling. H e was soon noted to be unconscious and to have stopped breathing. CPR attempts by staff and later by paramedics were unsuccessful, and h e was pronounced dead on arrival at a hospital. An autopsy disclosed a 167 .5-cm (67-inch), 104.5-kg (230-lb) teenaged boy with abrasions and contusions of the head, back, arms, and legs. A neck muscle contus ion and h emorrhage beside the thyroid cartilage were noted, but no pe techial hemorrhages were seen. Postmortem blood toxicology tests detected therapeutic · ·vels of doxepin and thioridazine. The cause of ..eath was listed a s asAm J Forensic Mt•d Pathol. Vol. 21. No. I . March 2000 phyxiation due to restraint, and the m anner of death was listed as undetennined. Case 10 A teenaged boy w as arrested for suspected intoxication. H e was combative and appeared delirious. After a stmggle, police transported him to jail in the hogtied prone p osition in the back of a police car. At the jail he was placed on the concrete floor, reportedly lying on his side, still hogtied, stmggling, swearing, sweating, and spitting. Six officers held him down, and a towel was placed around his face and neck area to prevent spitting or biting and control head movement. After approximately 3 to 5 minutes on the fl oor, he stopped mov ing, and - 1 minute later, officers realized he was not conscious and summoned help. Resuscitation attempts by jail staff and later by paramedics were unsuccessful , and he was pronounced dead after 50 minutes in a hospital emergency department. He had a 3-year history of psychosis. An autopsy disclosed a 190-cm (76-inch), 109kg (240-lb) teenaged boy w ith palpebral conjuncti val petechiae. Scattered contusions and abrasions of the head, extremities, and tmnk were observed. The heart weighed 450 g. A haloperidol level within the therap eutic range was found in the blood. The cause of death was certified as dysrhythmia due to positional hypoxia due to excited delirium while restrained. The manner of death was recorded as natural. Case 11 Police were dispatched to a minor traffic accident where they found a man in his mid-thirties acting bizarre and sweating profusely. He appeared to be delirious and under the influence of "PCP" and was arrested afte r a stmggle. He was transported to j a il in the hogtied prone position in the back seat of a police car. He continued to b e combative and incoherent at the jail and was placed in a safety cell. While police attempted to remove his restraints and clothing, he was held prone by six detention officers. Two officers had their knees on his back and one was holding his shoulders when he suddenly relaxed. He was soon noticed to have stopped breathing. Paramedics were summoned, but resuscitation attempts were unsuccessful, and he was pronounced dead at the jail. T he struggle in the safety cell lasted about 5 minutes. An autopsy disclosed a 170-cm (68 inch), 8 1.8kg ( 180-lb) man with conjunctival petechial hemorrhages, intramuscular hemorrhages in the neck, a large contusion on the back, and many contusions and abrasions of the head, arms, and legs. The heart RESTRAINT ASPHYXIA appeared normal and :weighed 4 10 g. P ostmortem blood contained methamphetamine 1.7 mg/L, and the urine level of methamphetamine was 34 mg/L. The cause of death was listed as traumatic asphyxia with neck compress ion and positional asphyxia. The manner of death was listed as accident. Case 12 A severely menta lly retarded boy in his midteens was damaging property in a private residential care facility. Attempts at verbal control were unsuccessful , and he was wrestled to the floor by three adu lt male attendants. He was he ld prone with a pillow under his head for about 10 minutes, with attendants holding down each arm/shoulder and one holding his legs, when they noticed he had stopped struggling and was not breathing. CPR was initiated. When paramedics arrived, they detected no vital signs and an idi ovcntricular cardiac rhythm. At the emergency department only pulseless electrical cardiac activity was present, and he was pronounced dead within 30 minutes. He had a history of mental retardation, cerebral palsy, epilepsy, autism, and attention deficit disorder. An autopsy disclosed a 177 .5 -cm (71-inch), 113.6-kg (250-lb) teenaged boy w ith petechial hemorrhages of the eyes, pleura, and epicardium. The heart weighed 410 g. Microscopic foci of fibrosis were seen in the he art. Fluoxetine and its metaboli te, thioridazine, and mesoridazine were identified in postm ortem blood in therapeutic concentrations. The cause of death was certified as asphyxia due to restraint and suffocation, w ith cardiom yopathy listed as a contributing condition. The manner of death was ruled as accident. Case 13 A man in his early thirties was in a hospital for 2 days while being treated for hypertension and ren al failure. Because of verbal ab use and physical threats against the staff, he was physically escorted by two hospital security s taff to the emergency area, where a struggle developed. He was he ld prone on the floor for an estimated 2 or 3 minutes with weight on his back, his anns pulled upward behind his back, and his legs held down. He said that he could not breath several times. His breathing became s hallow before he lost consciousness. Resusc itation and ACLS measures were initiated promptly. Sinus bradycardia was detected initially but deteriorated quickly to pulseless electrical activity and death. No pulse was ever palpated. An autopsy indicated no xtemal or internal injuries in this 167.5-cm (67- .,Jch), 81.8-kg (180-lb) 43 man. The heart weighed 750 g and sho'?!'ed severe left ventricular hypertrophy. The lungs had emphysematous changes. The kidneys had vascular and glomerular sclerosis. Toxicology tests w ere negative. The case was submi tted to the grand jury. The cause of death was lis ted as sudden cardiac death during restraint due to positional asphyxia and the manner of death was called hom icide. Case 14 Police responded to a residentia l domestic abuse call. A man in his middle f01ties was escorted out of his residence, at which point he resisted arrest. A struggle ens ued, p epper spray was used, and he was eventually hogtied and transported to j ail in the prone position in the back seat of a police car. At the j ail he continued to be combative, yelling obscenities and spitting, so a dust mask was put on his face. He was caiTied to a holding cell, w here he was placed in the prone position and s tripsearched. He was held prone for severa l minutes by several officers, with a disputed amount of weight placed on the upper torso. While handcuffs were removed and others applied, he suddenly stopped resisting, was noted to be not moving, and was found to have absent vita l signs. Resuscitation attempts were initiated by a j ail nurse, and paramedics were s ummoned. When they arrived, he was in ventricular fibri llation which progressed to asystole during transport to the hospital, where he was pronounced dead. He had a history of illicit drug use. Officers stated that during the encounter he seemed paranoid about his wife and called to God. An autopsy of this 170-cm (68-inch), 72. 7-kg (160-lb) man disclosed eye and oral petechial hemorrhages, a bite on the tongue, lip lacerations, and scattered abrasions and contusions of the extremities and tmnk. The heart weighed 450 g and was microscopically normal. Toxicology testing disclosed a postmortem blood cocaine level of 1.2 mg/L and a benzoylecgonine level of 3.2 mg/L. The cause of death was listed as cardiac arrhythm ia due to exertion and cocaine toxicity, wi th restraint asphyxia listed as a contributing factor. The manner of death was ruled accidental. Case 15 Police responded to a domestic violence report at a residence. T hey confronted a m an in his midforti es who would not respond to verbal commands and assaulted the officers. Pepper spray was used with no effect. He was wrestled _to the floor, hit several times with a flashlight, and eventually controlled in a prone position by officers pinning and Am J Forensic Mc:d Parhol. Vol. 21. No. 1, March 2000 44 R. L. 0 'HALLORAN AND J. G. FRANK shackling his legs, cuffing his wrists behind his back, and holding his chest down· with feet and knees on his back and near the base of his neck. About I 0 m inutes later, he was discovered to be nonresponsive. Resuscitation efforts were initiated and an ambu lance was called . When paramedics arrived, he had no vital signs. ACLS m easures were unsuccessful , and he was pronounced dea d on arrival at a hospita l. He had a psychiatric history of paranoid schizophrenia fo r several yea rs, associated w ith poor impulse control , delusions, and homic idal threats. The initial call for po lice assistance involved delusions about spousa l infidelity. The autopsy of this 162.5-cm (65-inch), 8 1.8-kg (180-lb) man disclosed many abrasions and contusions of the face, anns, legs, and trunk. Two linear lacerations were found on the scalp. Bilateral sc leral hemorrhages, a cutaneous neck contusion and abrasion, and a hemorrhage in the sternocleidomastoid muscle were seen. Postmortem toxicol ogy tests of blood identified chlorpromazine and diphenhydramine in therapeutic concentrations. The cause of death was listed as asphyxia by com pression of the neck and chest due to restraint. The manner was listed as homicide. nonexistent beings . Officers fo und and confro nted him. He became physically a ggressive toward the o fficers, and a 5-minute str ugg le ensued. Pepper spray was used with no effect, and he was wrestled to the ground. After being he ld prone by several officers fo r an estimated 2 or 3 minutes while being handcuffed w ith pressure on his waist and upper body and with his legs held down, officers noticed he was not m oving. Restraints were immediately removed, and ambulance p ersonnel at the scene were summoned. Agonal respiratory efforts quickly ceased, and the man was transported asystolic to the hospital, where death was pronounced. Ninety minutes after death, the rec ta l temperature was 36 .8°C (98.3°F) . He h ad a cocaine delusional disorder 2 years prior to death. An autopsy of this 180-cm (72-inch), 140.9-kg (31 0-lb) m an revealed ocu lar petechial hemorrh ages along with abras ions and contusions of hi s face and extremiti es. The heart weighed 430 g. Autopsy blood contained 5 .4 mg/L of coca ine and 1.3 mg/L of benzoylecgonine. The cause of death w as certified as anhythmi a/asphyxia while restrained clue to cocaine toxici ty. The manner was listed as accident. Case 16 A man in his mid-twenties wh o had used crack cocaine began ye lling incoherently about God and the devil while banging on walls and windows. His male companion tri ed to quiet him, which led to a st ruggle. The companion told investigators that he pinned the man prone on the floor by sitting on his back , pulling his arms upward behind his back, and applying pressure to his shoulders. After several minutes, the man stopped struggling, and his companion got off hi s back. He heard a few short gasps but never saw the m an move again. The companion eventually decided the man was dead and hours later told friends w ho then called police. An autopsy of th is I 70-cm (68-inch), 63 .6-cm (1 40-lb) man disclosed bilateral ocular petechiae, contusions of the lips, and several areas of intem al neck soft ti ssue hemorrhage with intact laryngeal stmctures. Other abrasions and contusions of the trunk and extremi ties were seen. The postmortem blood levels were cocaine 0.02 mg/L , benzoylecgonine 0.4 mg!L, and ecgonine methyl ester 0.4 mg/ L. The cause of death was listed as manual strangulation, and the manner was listed as homicide. Case 18 A man in his mid-twenties was seen walking down the street, talking and gesturing to nonexistent persons . He broke into a house and stole a k.Jiife . P olice were summoned and found the man c ra wling on his hands and knees near a p ark where he had assaul ted someone. Poli ce confronted him, a struggle occur red, and h e was w restled to the g round and held supine. Fire personnel noted a rapid pulse and incoherent sp eech. An ambu lance ani ved, he was given oxygen, and he eventually quieted. He suddenly jumpe d up, ran, and was tackled again by pol ice. This time he was held prone w ith officers ' body weight on his back and legs. Handcuffs were attache d w ith his anns behind his back, and hobble restraints were wrapped around his ankles. He was held down an estimated 2 minutes by three officers until he became quiet and officers removed their weight. Officials were discussing w hat to do with him when a paramedic noticed he was not breathing and had no pulse. Handcuffs were removed, and resuscitation attempts were started. Pulseless electrical activity (idioventric ular rhytlm1) was initially detected. Despite ACLS measures during transport to the hospital, he became asystolic. He was. pronounced dead after 30 minutes in the emergency department. Twenty minutes later, the rectal temperature was 42.2°C (108°F). He had a history of drug use. Case 17 Police were called because a man in his early forties had snorted cocai1 and left his home, running, stumbling, and screaming incoherently to Am J Forensic Mer/ Parhol. Yo/. Zl, No. I . March 2000 RESTRAINT ASPHYXIA An autopsy disclosed a 180-cm (72-inch), 100kg (220-lb) man with conjunctival- and epicardial petechial hemorrhages. Multiple contusions and abras ions were found on the head, extremities, and trunk. A contus ion was found in a sternocleidomastoid muscle. The heart weighed 430 g and was microscopically nom1al. Postmortem blood contained cocaine 0.23 mg/L and benzoylecgonine 2.3 mg/L. The cause of death was lis ted as asphyxia/ arrhythmia during prone restraint du e to cocaine induced agitated delirium. Coca ine-induced hyperthem1ia was listed as a contr ibuting conditi on, and the manner of death was listed as accident. Case 19 Police were called because of complaints of a man in his late twenties dam aging property. Heappeared agitated and said he was having a heart attack. Police called for an ambulance, but w hile waiting the man became verbally aggressive, spoke inappropriately in religious and sexual te1ms, failed to respond to commands, and appeared to feign a seizure. Pepper spray was used without effect. The man was restrained in the prone position for an estimated 1 to 5 minutes on a lawn with an officer straddling his buttocks and another with a knee on his back while handcuffs were attached a nd his legs were he ld. Paramedics arrived during the s truggle, and it was decided to transport the man to the h ospital on a gurney in leather restraints. Shortly before or during the transfer to the gumey, he stopped breathing. Despite ACLS meas ures, only intermitte nt pulseless electrical activity was detected. He was pronounced dead in the e mergency department. He had a history of bipolar disorder with episodes of mania as well a s drug abuse. An au topsy disclosed a 180-cm (72- inch), 13 1.8kg (290-lb) man with ocular and facial petechial hemorrhages and contu sions and abrasions of the face, extremities, and tnmk. The h eart weighed 430 g and was microscopically nonnal. Autopsy blood contained the following concentrations of drugs: delta-9-THC 0.028 mg/L , free codeine 0.18 mg!L, tota l codeine 0.40 mg/L, fenflurami ne 0.05 mg/L, doxylamine 0.068 mg/L, and trace amounts of dextromethorphan. The cause of death was listed as card iac anhythmia due to asphyxia during prone res trai nt. Acute and chronic psychosis, THC intoxication, struggle, obesity and a m a lpositioned endotracheal tube were listed as contributory factors. Th e manner of death was lis te d a s accident. Case 20 An obese man in his late t e nties with a history of epilepsy had a grand mal seizure at the home of 45 a friend . While one friend c rad led hi s head during the seizure, another fri end called 9 11 . After- the seizure, the man jumped up, beca me combative, and seemed confused. A third friend arrived, and the three restrained the m an in the prone position on the floor by applying a " full ne lson" and lying across his legs. When the fire depm1ment arrived, three firefighters assisted in holding the man down while another called for police assis tan·c e. When the first police officer arrived, he rested a knee on the man' s back when applying handcuffs w hil e the man was held by firefighters and his friends. One person stated he h eard the m an say ' ' Get off, I can 't breathe.'' Approxim ately I 2 minutes after the s tart of the restraint process, more police arrived and saw the man still stm ggling. Straps were wrapped around his a nkles, and the man was placed prone on a s tretcher, where he appeared to lose strength and had a pulse rate of 120 beats per minute. Within seconds of being held prone on the stretcher he became calm, s topped breathing, and had no pulse. Restraints were removed and CPR commenced while a call for paramedics went out. Four minutes later, p aramedics started full ACLS measures. He was defibrillated several times at the scene and en route to the hospital without ever regaining life signs and was pronounced dead in the hospital. He had epilepsy since birth, was having several seizures per m onth, and was taking Dilantin. An autopsy disclosed a 175-cm (70-inch), 118kg (260-lb) man w ith abras ions on the wrists and hip but no petechial hemorrhages or other injuries. The heart weighed 510 g and was microscopically normal. Toxicologic tests of p ostmortem blood revealed phenytoin 0.2 mg/L and carboxy-THC 0.007 mg/L. The death was certified as cardiac arrhythmia due to agitated de lirium with restra int. Hypertrophic hea11 disease was listed as a contributing factor. The manner of death was listed as accident. Case 21 Police were called because a man in his early f011ies, said to be mentally ill, hysteri ca l, violent, and having a gun, was dancing in street traffic, s houting incomprehensibly. When two officers arrived, the man grabbed one officer by the clothing; the other officer joined in the stmggk, and all three fell to the pavement. Three more officers ani ved. Pepper spray was used w ith no effect. Several officers wrestled the man to the ground and held him in the prone position. One officer had both knees on his back while handcuffs and ankle cuffs were applied. Firemen arrived and suggested using a backboard for control. Multiple officers moved the man and placed him prone on the backboard. Straps Am J Forensic /\.fed Parhol. Vol. 2 1, No. I. March 2000 R. L. 0 'HALLORAN AND J. G. FRANK 46 were secured across his pack and legs. They soon noticed he had ceased struggling ar\d had no pulse. Paramedics were called. The total prone restraint time was approximately 8 minutes. When paramedics arrived 4 minutes later, the man was in full cardiac arrest. They started ACLS but were imable to restore cardiac function, and he was pronounced dead at the hospital. He had a history of crack cocaine use with periods of delirious hyperactive behavior. He stopped taking his prescription Thorazine 2 weeks prior to death. An autopsy disclosed a 167 .5-cm (67-inch), 86.4-kg (190-lb) man with conjunctival petechial hemorrhages and scattered contusions, abrasions, and lacerations of his extremities and face. The heart weighed 340 g and was described as having a 1-cm-long myocardial band over the left anterior descending coronary artery. Postmortem blood contained cocaine 0.2 mg/L and benztropine (Cogentin) 3 ng/ml. The cause of death was listed as agitated delirium with restraint. Recent cocaine use and tunnel coronary artery were listed as contributing conditions. The manner was listed as accident. ANALYSIS These 21 case reports represent a nonrandom sample of sudden deaths that occurred during restraint from 1992 to 1996 in the United States, mostly in California. Except for the 4 deaths that we autopsied, all cases came to our attention because of litigation. In many of the cases the details of the circumstance and timing of the sudden Joss of consciousness were developed during investigation subsequent to death certification. All of the decedents were male, ranging in age from 17 to 45 years. All were involuntarily held in a prone position when they lost consciousness except for case I 0, who was reportedly held on his side but had earlier been prone. Four were hogtied at the time they were noticed to be unconscious; the remainder had body weight applied to the upper torso at the time they lost consciousness. All who lost consciousness while hogtied had weight placed on their upper torso during the hogtying process. Eighteen persons were handcuffed behind the back; the other 3 had their arms restrained manually. Eleven had ankle or lower leg restraints; the remainder had body weight applied to the legs. Two were reported to have said that they could not breathe prior to dying. The number of persons applying restraint ranged from one to seven. Best estimates of the time held pror- ~ ranged from 2 to 12 minutes. Fifteen of the 21 in~ H.lents involved police Am J Forensic Med ?athol. Vol. 21. No. I. March 2000 only; 3 involved private security or custodial officers; 2 involved lay persons, and 1 involved both police and firefighters. Five of the incidents occurred in a jail or detention center; 2 occurred in health care facilities. Seven of the restraint episodes were preceded by the use of pepper spray alone, 3 by use of pepper spray and a baton, I by baton use alone, and I by use of a taser. In 2 instances a towel or a mask was on the persons face during restraint. In all but 1 case extensive resuscitation efforts were made, with initial cardiopulmonary resuscitation followed by advanced life-support measures, including intubation. All but 2 persons were taken to hospitals, where they were pronounced dead. Eight of the decedents had a history of chronic mental illness excluding substance abuse. Eight had a history of substance abuse. Seventeen appeared to be acutely delirious. Eleven had stimulant drugs found in their blood at autopsy (8 cocaine, 2 methamphetamine, 1 both cocaine and methamphetamine). In the 8 who had cocaine found in postmortem blood, concentrations ranged from 0.02 to 5.4 mg/L (mean, 1.4 mg/L). Postmortem temperatures were taken in only 3 cases, and in only 1 was hyperthem1ia detected. Six were noted to be sweaty prior to death. Six decedents could be considered obese, having a body mass index (BMI) > 30; 9 were overweight (BMI = 25- 30), and 6 were of normal weight (BMI < 25). In 5 autopsies, heart abnom1alities were described. In 2 cases the heart weight was more than 2 standard deviations above the predicted mean for males, adjusted for body weight (6). In 4 cases the heart weight was between 1 and 2 standard deviations above the mean. In 3 cases the heart was not weighed but was reported as normal. Petechial hemorrhages were described in the eyes in 10 cases and were noted in the thorax in 2 additional cases. Evidence of soft tissue injury (hemonhage) in the neck was noted in 5 cases, 4 of which also had ocular petechiae. Death certificates listed asphyxia or a similar tem1 in the cause of death section in 13 cases, and 8 listed dmgs of some so1i. The manner of death was listed as accident in 14 cases, homicide in 4 cases, natural in 2 cases, and undetermined in 1 case. Selected circumstances of the deaths and the causes and manners of deaths as reported by the medical examiner or coroner are summarized in Table 1. DISCUSSION The concept that the sudden death of individuals held prone during police restraint might be due to RESTRAINT ASPHYXIA TABLE 1. Case history summary Prone restraint Behavior 1 2 3 4 5 6 7 8 9 10 Hogtied Hogtied Body weighVcuffs Body weighVcuffs Body weighVcuffs Body weighVcuffs Hogtied Body weight/cuffs Body weight/cuffs Hogtied on side Paranoid/irrational Delirium Delusional/paranoid Delirium Delirium/withdrawal Delirium Irrational Delusions T emper tant ru m Delirium Cocaine/methamphetamine Cocaine Schizophrenia Cocaine Alcohol Cocaine Methamphetamine Schizophrenia Mental retardation Psychosis 11 12 13 14 15 Body weight/cuffs Body weight Body weight Body weight/culls Body weight/cuffs Delirium Temper tantrum Anger/obnoxious Paranoid delusions Delirium Methamphetamine Mental retardation Personality trait Cocaine Schizophrenia 16 17 18 19 20 21 Body Body Body Body Body Body Delirium Delirium Delirium Delirium Combative/confused Delirium Cocaine Cocaine Cocaine Psychosis/marijuana Epileptic seizure Cocaine weight weight/cuffs weight/cuffs weight/cuffs weight/cuffs weighVcuffs 47 Cause of behavior Cause of death Manner of death Drug toxicity Drugs/asphyxia Excited delirium/Schizophrenia Drug toxicity Positional asphyxia Drug toxicity Drug toxicity Restraint/psychosis Restraint asphyxia Positional hypoxia/rest raint/ delirium Choking/positional asphyxia Asphyxia/restraint Positional restraint Drug toxicity Asphyxia/chesVneck compression Strangulation Cocaine/restraint Cocaine/restraint Restraint asphyxia Delirium/restraint Delirium/restraint Accident Homicide Natural Accident Accident Accident Accident Accident Undetermined Natural asphyxia, even though neck holds were not applied, is relatively recent. In 1985, W etli and Fishbain reported 7 sudden deaths during cocaine-induced p sychosis, some of which occurred while the persons were restrained in police custody (7). The manner of restraint was not specified, and the deaths were attributed to cocaine. In 1992, Reay et al. reported the deaths of 3 men who died while restrained hogticd in the prone position in the back seat of police cars and attributed their deaths to positional asphyxia (1 ). In the same year, the San Di ego Police Department c irculated a task force report on 7 in-custody deaths; 3 of these persons were hogtied (2). In 1993, O 'Hallora n and Lewm an reported 11 delirious m en who died while they were restrained in a prone position; 9 were hogtied (3). In 1995, Stratton et al. reported 2 deaths in hogtied prone patients in ambulances (4). In 1998, Pollanen et al. rep01ted 21 excited delirium- re lated restraint deaths betwee n 1988 and 1995 in Ontario, Canada (5 ); 18 were prone and the other 3 had neck compression. A lso in I 998, Ross reporte d on factors associated with excited delirium deaths in p olice custody from rep01ts of 61 deaths in various police agencies in the United States (8) . Based on concerns raised by reports like these and kn owledge of other unpublished incidents of sudden death in custody during prone restraint, articles discussing the "sudden in-custody death syndrome," " hogtying," "positional asphyxia," and "excited delirium" deaths appeared in the law enforcement literature (2,9, 1 0). P vate companies began promoting and providing products and training Accident Accident Homicide Accident Homicide Homicide Accident Accident Accident Accident Accident to law enforcement agencies addressing the risks of hogtying, positional asphyxia, and sudden in-custody deaths in the mid- I 990s (1 1). It is not a new concept that a person can die from the application of body weight to the thorax. " Burking," a form of m echanical asphyxia combined w ith smothering which involved sitting on a person 's chest, was used by the nineteenth century murderers-for-profit Burke and Hare. D eaths from asphyxia in individuals knocked down and pinned by the weight of people on top of them during crowd stampedes and "huma n pile" situations are w idely recognized (12) . That homicide can occur by knee ling or sitting on the back of a prone victim or suspect, or by hogtying, has been acknowledged in a m ajor forensic pathology text ( 13). The term ''restraint asphyxia'' has been suggested for asphyxial deaths that occur through ·interference with the mechanical bellows action of the chest, such as in the prone hogtied position or in the prone p osition with arms and legs restrained and weig ht applied to the back (3, 14). However, alternative explanations for sudden death are frequently offered when prone restraint while in custody is involved. These include b lun t force head injury, cardiac an·est from drug toxicity, acute exhaustive mania/excited delir. ium, e lectrical shock from stun guns, respiratory arrest from pepper spray, and cardiomyopathy. One or more of these factors was present in most of the 2 I cases currently reported. Four of the 21 currently reported cases received baton blows. Two involved blows to the head with discernible skin lesions but no skull fractures or Am J Forensic Med Pa1hol. Vol. 21. No. 1. March 2000 48 R. L. 0 'HALLORAN AND J. G. FRANK brain injuries at autopsy. In all cases there was a several-minute period of purposeful activity and voca lization between the delivery of the baton s trikes and the later loss of consciousness while held prone. It seems reasonable to exclude brain injury as a cause of death when loss of consciousness does not follow the blows to the head within seconds, when the autopsy discloses no skull fractures or brain injuries, and w h en there are other reasonable explanations for the death. In 1994, M irchandani et al. emphasized this point with 4 case reporis of sudden death during poli ce restraint following a stmggle in men with cocaine-induced agitated deli riu m who had sustained minor head injuries (15). They suggested cocaine-induced cardiac arrest or mental s tress- related "stress cardiomyopathy" may have caused the deaths. They may not have considered mechanical asphyxia by chest compression during the restraint process (restraint asphyxia) as a possible cause for th e deaths. Karch has recently summarized the pathologic effects of cocaine and emphasizes the importance of considering the physical findings, history, and scene investigation before attributing a death to cocaine effect ( 16). Cocaine can cause sudden death and can cause delirium. Blood concentrations in individuals w hose death was attributed to cocaine overlap those in which cocaine was an incidental finding and have a wide range (17). Some of the postulated mechanisms by which cocaine could cause s udden death without leaving les ions vis ibl e at autopsy include cardiac arrhythmia or coronary spasm with myocardial ischemia from catecholamine excess, nonspecific myocardial disease from chronic ischemia, cardiac electrical conduction slowing from anesthetic effect in high doses, hyperthennia, and seizures. Methamphetamine is postulated to have similar effects ( 18). Eight of the cases reported herein had cocaine in their blood at the time that they lost consciousness while being restrained, and 3 had m ethamphetam ine, and 1 had both methamphetamine and cocaine. So-called ''cocaine delirium '' deaths have been reported to occur w hile in police custody much more commonly than other cocaine toxicity deaths (7,15,16, 19,20). The stress of the struggle has been hypothesized to be a critical factor precipitating a lethal cardiac arrhythmia in these police encounters, but considerations of the timing of the lethal event coincident w ith restraint a nd resp iratory compromise were not addressed. Although it is reasonable to attribute the disturbed mental state of excited delirium to cocaine or methamphetamine toxicity in this subset, it WC' ld seem that asphyxia Am J Fon.:n.<ic A/ed Pa thol. Vol. 2 1. No. I , March 2000 wou ld be the likely immediate cause of death, because the sudden collapse that resulted in death occurred while the person was held in a position that wo.uld compromise breathing. Stimulant drug toxicity could be considered a contributory cause, because the dmg probably precipitated the abenant behavior that lead to th e encounter that resulted in death, and may also have sensitized the heart to an anhythmia. "Excited (agitated) d e lirium," loosely defined as a condition of extreme mental and motor excitem ent w ith confused and unconn ected thoughts, could be interpreted as present in all but 3 of the 21 cases based on reports of behavior during the incident and knowledge of prior drug-induced or psychosis-associated deliri~us or delusional s tates. Others have postulated that s udden deaths in delirious individuals w ho u sed cocaine chronically are due to a cocaine-induced brain disord er similar to neuroleptic malignant syndrome (NMS), with abnormalities in the synaptic concentration and metabolism of the neurotransmitter dopamine proposed as mechanism s ( 19-22). Similarly, in hospitalized, agitated p sychiatric patients who may or may not be taking phenothiazine m edications, sudden deaths have been reported without significant autopsy findings to explain the cause (23). Various ly known as acute exhaustive mania, Bell's mania, lethal catatonia, or acute exhaustive psychosis, some postulate that such patient deaths are related to cardiac arrhythmias from catecholamine-mediated emotional stress, but the relation to restraint is unclear. NMS is defined as neuroleptic drug- induced hyperthem1ia with muscle rigidity and is thought to be produced by disruption of the dopamine-dependent them10regulatory centers in the hypothalamus and basal ganglia. D eath rates attributed to NMS have dropped from an estimated 30% of diagnosed cases to nearly zero with treatment. Autopsy findings are often minimal (24). Two of the cases reported here had neuroleptic drugs present in thei r b lood. Eight had medical histories of major psychoses. In 3 cases, the postmortem temperature was re corded, and in 1 case it was elevated. In 6 of the cases, sweating was noted. Interestingly, sweating was not noted in the 1 case with documented hyperthem1ia. Of course, perspiration is a normal physiologic response to vigorous physical ac tivity, psychologic stresses, and wam1 e nvironments; the firs t two factors were present in all 21 cases. Sweating does not equate with hyperthermia. Medical examiners and coroners could help c larify the role, if any, of hyperthermia in prone restraint deaths by promptly obtaining a post- RESTRAINT ASPHYXIA mortem temperature. None of the 2 1 death investigations indicated muscle rigidity. Given the temporal association of the restra int process to the terminal loss of consciousness in all 2 1 of the repoiied cases, it would seem reasonable to attribute these deaths to asphyxia during restraint rather than to agitated de lirium . The agitated delirium and its associated s tresses, whethe r or not drug induced, could reasonably be considered predisp osing or contributing to death. Chronic mental illness was present in 8 of the 2 I deaths reported and was the probable explanation for these persons' agitated behavior. Three were schizophrenic, 1 had bipolar disorder, 1 had both diagnoses, I had undifferentiated psychosis, I was mentally retarded, and I h ad cerebral palsy with autism. Two of these persons also had cocaine in their blood a t autopsy. Obviously, not all cases of agitation and delirium are cocaine induced. Pepper spray conta ining oleoresin capsicum has been implicated in deaths in Califomia by the American Civil Liberties Union (25). However, reviews of deaths where pepper spray was u sed fail to reveal convincing evidence of lethality (14,26). One case report of a custody death attributed to pepper spray indicated that the victim stopped struggling while handcuffed and being held prone (27), suggesting restraint asphyxia. Pepper spray was used in 7 of the 2 I cases reported herein. In all cases, witnesses reported n o significant effect caused by the s pray. In all cases, the spraying was followed by minutes of voluntary physical acti~ity and verba lization before loss of consciousness during restra int. In no cases were symptoms of respiratory difficulty following the spraying described, and in no cases were inflammatory changes of the respiratory mucosa noted a t autopsy. Electrical shocking devices (s tun guns and tasers) intended to immobilize people are frequently used by law enforcement officers, and stun guns are legally available to the public for self-defense in many areas. They are generally not considered lethal weapons, and the fe w reports of fatalities associated with their use have identified other more likely causes o f death (3 ,28-31 ). A tascr was u sed in 1 of our reported cases. Several minutes of purposeful activity and verbaliz ation followed the shocks and preceded the death during restrai nt. Significant physical exertion was present in most cases before restraint and in all cases during restraint. Officials involved in res training these people often described the persons as unusually strong and persis tent in their struggle. Increased oxygen demand from such physical . ::tivity could increase 49 susceptibility to asphyxiation during resH:aint with pressure on the chest. Asys tole was the presenting cardiac arrhythmia found in 15 of the 20 cases reported that had parame dic response. Five others presented w ith agonal rhythms, described as pulseless e lectrical activity in 3, and idioventricular rhythm and fine ventricular fibrillation in the other 2 cases. Pree~isting heart disease was considered by the certifier of death as a contributory factor in 4 of the 2 1 cases. Microscopic fibrosis was seen in 3 hearts, and 1 heart was listed as having hypertrophic cardi om yopathy. In both cases that had hearts more than 2 standard deviations above the body weight- and gender-adjusted mean (6), the cardiomegaly was not mentioned on the death certificate. Obesity has been m entioned as a possible risk factor for death from positional asphyxia during hogtying (I ,9). Obesity could contribute to asphyxia when excessive body w eight makes chest wall movement more difficult wh ile prone and w hen excessive abdominal fat limits diaphragmatic motion (14). Similarly, obesity has been thought to be a possible risk factor for death during cocaineinduced excited delirium by contributing to body insulation and predisposing to hyperthermia (19). Fifteen of the 21 cases reported were overweight or obese, defined as having a BMI (body weight in kilograms/height in meters squared) greater than 25 (32), supporting an association between obesity and these deaths. Other p ossible mechanisms of asphyxia in addition to res tricted breathing from chest/abdominal com pression were present in several cases. Pathologis ts described the presence of soft tissue hemorrhage in the neck musculature in 5 cases, suggesting the possibility of neck compression during the restraint process. In 2 of those 5 cases, the e vidence was compelling enough for " neck compress ion" or " strangulation " to be mentioned on the death certificate. However, in no case did the participants or w itnesses describe neck holds. In 1 case w ith neck hemorrhage, a towel was held around the face, and in another case, a mask was placed over the nose and mouth. All but 1 p erson received extensi ve resuscitation efforts, including intubation, possibly expl aining some of the injuries noted. In a series of 50 patients intubated in the field by paramedics, 14% had incidenta l hemorrha ges in the strap muscles of the neck found at autopsy (33). Ten of the 21 cases had ocular petechial hemorrhages described at autopsy, and 2 more had intrathoracic petechial hemorrhages which were con- Am J For£>usic Med Pathol. Vo l. 2 1. No. I. March 2000 R. L. 0 'HALLORAN AND J. G. FRANK 50 sidered inconsistent and donspecific indicators of asphyxia (34). Two other persons ptoclaimed that they could not breathe shortly before they lost conscious ness and died. These observations support an asphyxial mechanism of death. Asphyxia or a similar term was used on the death certificate in only 13 of the 21 cases, indicating the difficulty in recognizing restraint-associated deaths and the difficulty in diagnosing asphyx ia through autopsy findings alone. In many cases the m edical examiner or coroner did not have detailed statements from witnesses or dispatch logs that established the association between the restraint and the loss of consciousness that lead to death. In all· cases in which the persons were not fully hogtied when they lost consciousness, weight was being applied to the chest area when movement ceased and loss of consciousness was noticed. In the 4 cases that were hogticd when loss of consciousness was noticed and in the I person who was restrained lying on his side, the persons had been restrained with weight on their backs while held prone moments before. No statements by witnesses indicated conscious activity by any of the persons following completion of the hogtying, suggesting that loss of consciousness may have occuned during the application of restra ints. Table 1 indicates the wide range of cause of death designations given for these remarkably similar deaths. The tenn "restraint asphyxia (asphyxiation) " was first proposed in 1993 to refer to the sudden deaths of people who were hogtied or restrained in the prone position with weight on their backs in which the evidence suggests an asphyxial death (3). Previously, in cases involving deaths di scovered during h ogtying by police , the tem1 "positional asphyxia" had been used (1). "Mechanical asphyxia" or "traumatic asphyxia " are other accepted terms that could have been used. In the field of forensic pathology, positional asphyxia has usually referred to deaths in which a victim, often compromised by alcohol or drugs, cannot escape from a p osition that inhibits pulmonary gas exchange and in which other causes of death have been excluded by a thorough autopsy (35). Use of the tenn ''positional asphyxia'' has lead to som e confus ion when applied to deaths that occur in hogtied p ersons, because positional asphyxia has usually implied accidental, passive entrapment. The same confusion applies to deaths that occur from asphyxia produced by other people restricting a person's ability to breathe during restraint. When the nose and mouth are blocked, "suffocation" or "smothering " are accepte. tem1s. When the neck is compressed, "choking" or "strangulation" are Am J Forensic M~d Pathol. Vol. 21. No. I, March 2000 commonly used. Reay has discussed hogtying and prone restraint deaths wi th chest compression in the context of law enforcement take-downs, refening to them as restraint asphyxia, and has also discussed the biomechanics of such deaths (1 4) . A recent court decision rested, in part, on a confusing interplay .between the terms " hog tie" and "positional asphyxia" (36) . We suggest that the tenn "restraint asphyxia" be used to describe deaths during restraint that appear to be the result of chest compression or hogtying. Alternatively, more descriptive tenns such as ''asphyx ia by chest compression" or "asphyx ia during hogtying" could be used. The major advantage of using a sing le term for death certification is the increased accuracy in death certificate coding and vital statistics-based research. The manner of death designati ons in these 2 1 cases included 14 accident, 4 homicide, 2 natural, and 1 undetennined. Given the variation in tem1s used to describe the causes of these deaths, it is not surprising to see variation in th e manner of death also. Because restraint asphyxia deaths are "deaths at the hands of another,'' it has been argued that they should be considered homicides (37). Conversely, it has been argued that because death by res traint asphyxia was not recognized until recently and information regarding its potential lethality has not b een circulated widely, it is reasonable to classify them as accidental deaths (3,38). Considering the amount of discussion during the past decade in th e forensic pathology, emergency medicine, and law enforcement literature regarding the risks of death during hogtying, the argument for class ification as accident becomes weaker. Little has been written in first-responder literature regarding the danger of death in delirious persons restrained in the prone position w ithout the use of arms or legs for support and with sustained pressure applied to the back- the circumstance in most of the cases reported herein. Finally, i( one believes sudden death dnring agitated delirium is a natural consequence of endogenous psychiatric illness, and if no res traint asphyxial component of the death is recognized, then a determination of death by natural causes is understandable. The magnitude of the problem of sudden death during prone restraint in the United States remains unclear. In Ventura C ounty, California, which has a mostly suburban population averaging 720,000 persons, 8 deaths from restraint asphyxia have occuned during the last 14 years. This translates to a rate of 0.8 deaths/million/year. This would extrapolate to > 200 deathsllt'!illistJyear in the United States, but the numbers are too low and the popu- r RESTRAINT ASPHYXIA lation too restricted for more than .a crude projection. A s tudy from the province of Ontario, Canada (5), which had an average population of 11 million during the years 1988 to 1995, identified 18 cases of sudden death during prone restraint in excited delirious p ersons, producing a rate of 0.2 deaths/ million/year. We know of no reports regarding the frequency of death during prone maximal restraint, with or without actual hogtying, in any law enforcement population. CONCLUSIONS Despite efforts by law enforcement agencies to limit hogtying, asphyxial deaths still occur when suspects are held prone w ith their arms and legs restrained and weight applied to their backs for minutes. The tem1 "restraint asphyxia" is proposed for such asphyxial deaths involving prone restraint and/or hogtying. Such deaths are not unique to Jaw enforcement. Persons with mental disorders, especially drug-induced or psychotic illness- induced agitated delirious states, seem to be at greater risk. It is not clear whether the delirious state itself or its tendency to precipitate violent encounters with police put them at risk. P hysical exhaustion, preexisting heart disease, and obesity may also increase risk of death in this situation . As is the case with many other fom1s of asphyxial death, the autopsy findings in restraint asphyxia can be subtle and nonspecific. Each case must be evaluated on its own merits and altemative explanatio ns for the death considered. Accurate diagnosis depends on both a thorough autopsy and a thorough investigation of the circumstances of the death. Pointed interviews with witnesses and participants in the restraint, focus ing on the mechanics of the restraint, the length of time involved, and the moment when loss of consciousness occurred, should be conducted soon after the event while memories are still fresh. Identifying the timing of the sudden loss of consciousness whil e the p erson was restrained in a position that compromises the ability to breathe is essential for establishing a cause-and-effect relation between restraint and death. REFERENCES I . Reay DT, Fligner CL, Stilwell AD, Amold J . Positional asphyxia during law enforcement transport. Am J Forensic Med Pathol 1992; 13:90. 2. Burgreen B, Krosch C, Binkerd V, B1ackboume B . Final report of the custody death task force. San Diego: San Diego Police Department, 1992 . 3. O'Halloran RL, Lewman LV. Restraint asphyxiation in excited delirium. Am J Forensic Med Patho/1993; 14:289. 51 4. Stratton SJ, Rodgers C, Green K. 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