The reviewed literature documents serious complications, particularly sudden death, as being associated with physical restraint use on acutely behaviourally disturbed individuals. The exact casual mechanisms that lead to these complications are complex as many risk factors are seen as being contributory to death and remain a challenge to medical examiners in determining the cause of death. From the evidence reviewed it was difficult to assign an independent association of 22 physical restraint use and method to these deaths. Restraint methods involving the prone position with hog-tie restraint appear to be a risk factor contributing to these deaths. The descriptions of these deaths in the literature have identified the cause of death as restraint or positional asphyxia. Despite the highly controversial and newsworthy profile of these deaths they remain a rare event compared with the overall prevalence of restraint use in health settings or in law enforcement. The experimental literature reviewed did not adequately establish a direct relationship between prone restraint and compromised cardio-pulmonary or ventilatory functioning.
The quality of the evidence that is presented here was relatively low with only one systematic review graded above Level IV according to the NHMRC hierarchy of evidence. The lack of relevant published literature from New Zealand health and law enforcement settings was a major limitation of this Tech Brief. The focus of the published literature was on deaths associated with the physical restraint of behaviourally disturbed individuals. There was a lack of material examining non-fatal adverse effects and also the benefits of physical restraint use.
The overall evidence for the safety of physical restraint use indicates that its use may be contributory to serious adverse effects in behaviourally disturbed individuals. Formal staff training in restraint use, alternatives to physical restraint and evidence-based protocols may help minimise the risk of harm. More appropriate empirical research on the safety as well as the efficacy of physical restraint is required.