Agitated delirium versus positional asphyxia.

To the Editor." The recent article by Stratton et al [May 1995;25:710-712] describes two violent and combative patients who were placed, prone, in hobble restraints and died while being transported and monitored by paramedical personnel. The authors are to be commended for bringing this problem to the attention of emergency physicians. Unfortunately, they appear to have confused agitated delirium and positional asphyxia, without making a good case for the occurrence of either condition. The deaths remain unexplained, and any causal relationship between these deaths and the hobble restraints remains unproved. Because both individuals were being monitored during transport, it is difficult to see how they could have died as a result of positional asphyxia: Had respiratory difficulty become apparent, the paramedics would certainly have changed the patients' positions! Most reported cases of positional asphyxia have been associated with the use of alcohol and depressant drugs, not stimulants 1, and then only in individuals who had been hog tied. 2 The authors repeatedly used the term "nonlethal" with regard to levels of cocaine and methamphetamine. No scientific basis exists for the designation of lethal and nonlethal blood cocaine levels; this practice was abandoned some years ago. 3 In the last 4 years, the San Francisco medical examiner has certified cocaine toxicity as the cause of death in more than 75 cases in which no other drug was involved. Blood cocaine levels in these individuals ranged from near zero to more than 15,000 ng/mL. Drug reaction may certainly have been the sole cause of the deaths of the restrained patients described by Stratten et el, particularly in the victim with myocardial fibrosis and measurable levels of cocaethylene. More information is, however, needed. Long-term cocaine users are hyperadrenergic, with high circulating levels of catecholamines. 4,5 As a consequence of chronic catecholamine stimulation, and probably also of immediate early gene activation, alterations occur in the hearts 6 and brains 7 of cocaine abusers. Myocardial hypertrophy and fibrosis are common a,9, and both favor the occurrence of arrhythmic sudden death. 1° Such anatomic alterations are sufficient to cause death even in the face of negligible blood cocaine levels. Another problem with trying to assign "lethal" and "nonlethal" levels is that tolerance rapidly emerges. Extraordinarily high levels (more than 10,000 ng)are sometimes seen as incidental findings in cases in which trauma, not cocaine, is the cause of death. 11 Blood cocaine levels in most cases of agitated delirium are on the order of 1,000 ng 12,13, similar to the levels found in crack smokers. 14 However, just knowing the blood cocaine level is not enough to rule in, or rule out, cocaine as the cause of death, is Similar considerations apply to amphetamine-related deaths as well. The two victims described by Stratton et al might have been experiencing agitated delirium, but if this had been the case, certain other findings would also be expected. Benzoylecgonine levels are generally much higher and hyperthermia is inevitably present, as are the other behavior changes typical of that condition. Positional asphyxia and agitated delirium are not two names for the same disease. Not all deaths from positional asphyxia involve drugs, and many individuals with agitated delirium die without ever being restrained. Deaths from agitated delirium tend to occur in summer, especially when the weather is warm and humid. Two thirds of the victims die at the scene or during transport by paramedics to the hospital. The few victims who live long enough to be hospitalized succumb to disseminated intravascular coagulation, rhabdomyolysis, and kidney failure. In the Miami patients, the average body temperature at the time of first medical encounter of 48 patients with agitated delirium was 40.2°F. In Miami, most drug-related deaths are caused by cocaine, and 1 of every 10 cocaine-related deaths is due to agitated delirium. 13 In San Francisco, agitated delirum is much less frequent, but then, so is the number of cocaine-related deaths. When victims of agitated delirium die, litigation is inevitable, with allegations of police brutality or medical mismanagement. However, some steps can be taken that will improve the patient's chances of survival and decrease the chance of litigation. Sometimes an individual with agitated delirium must simply be restrained. But if the patient is restrained, he or she should never be taken directly to jail for booking. Body temperature should be documented at the scene and aggressive cooling measures undertaken when the patient arrives at the hospital. If the individual must be transported in a police van, every effort should be made to ensure that someone can see the patient. If the patient does die, accusations of police brutality can be ruled out only if the postmortem examination includes a meticulous, well-documented neck dissection. Some medical examiners have gone so far as to ask the family of the decedent to retain their own pathologist to witness the autopsy. This may sound extreme, but in our experience, settlements in cases of this type have not been insubstantial.