1 The American Journal of Forensic Medicine and Pathology: Volume 20(3) September 1999 pp 300-301 Restraint Position and Positional Asphyxia Reay, Donald T. M.D.; Howard, John D. M.D. Seattle, Washington (Reay) Tacoma, Washington (Howard) To the Editor: In the September issue of the Journal, Chan et al. published a review article on restraint position and positional asphyxia (1) . This review resulted from their recent study which assessed ventilatory function in the prone, hog-tied position and its physiologic effects in healthy test subjects. We commend these clinical investigators for their work in giving us a better understanding of respiratory physiology, particularly as it applies to the hog-tied position. Our work in 1988 was an attempt to measure some physiologic effects of position and restraint. The methods employed were less sophisticated and noninvasive compared with those used by Chan et al. We acknowledge that the hog-tied position should be viewed as an inherently neutral position, and although there is a measurable change in ventilatory function, there is no significant physiologic consequence in normal people. We still have concern regarding deaths that occur during restraint. From the work of Chan et al., we now know that the hog-tied position should not produce serious physiologic consequences. However, during street restraint maneuvers, the totality of events must be considered. In the process of rendering a person helpless to handcuff him or her in a prone position, the involved officers may be required to "pile on" the suspect, pinning the person to the ground with the partial or full weight of the officers and thus compressing and restricting ventilatory function. The physical condition of the person and the circumstances of restraint can make a difference, and each case must be evaluated with a careful reconstruction of events to identify respiratory interference during and after the "takedown" and before the person is restrained. One of us (D.T.R.) was witness to a take-down of an obese man whom the police were trying to control. While compressed on the ground, the man repeatedly complained that he was having difficulty breathing. He was handcuffed and sat upright and stopped complaining. We wonder what the outcome would have been if he had been held face down on the ground until he became quiet. We look forward to the planned research by the San Diego group in assessing the respiratory physiologic effects of weighted compression of the chest. Perhaps, this data will establish parameters regarding how much compression of the chest for how long is necessary to cause serious deleterious effects.