Prone maximal restraint position (PMRP, also known as hogtie or hobble) is often used by law enforcement and prehospital personnel on violent combative individuals in the field setting. Weight force is often applied to the restrained individual's back and torso during the restraint process. We sought to determine the effect of 25 and 50 lbs weight force on respiratory function in human subject volunteers placed in the PMRP. We performed a randomized, cross-over, controlled trial on 10 subjects placed in 4 positions for 5 minutes each: sitting, PRMP, PRMP with 25 lbs weight force (PMRP+25), and PRMP with 50 lbs weight force placed on the back (PMRP+50). We measure pulse oximetry, end-tidal CO2 levels, and forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1). FVC and FEV1 were significantly lower in all restraint positions compared with sitting but not significantly different between restraint positions with and without weight force. Moreover, mean oxygen saturation levels were above 95% and mean end-tidal CO2 levels were below 45 mm Hg for all positions. We conclude that PMRP with and without 25 and 50 lbs of weight force resulted in a restrictive pulmonary function pattern but no evidence of hypoxia or hypoventilation.
From the *Department of Emergency Medicine; the †Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine; and the ‡Department of Pathology, University of California, San Diego School of Medicine and Medical Center, San Diego, California.
Manuscript received November 15, 2003; accepted February 4, 2004.
This study was supported by a grant from the American Academy of Forensic Sciences (AAFS 98-2).
Reprints: Theodore C. Chan, MD, Department of Emergency Medicine, UCSD Medical Center, 200 West Arbor Drive #8676, San Diego, CA 92103. E-mail: email@example.com.