Sudden death during restraint: do some positions affect lung function?

Small but significant numbers of people die during restraint following violent incidents. Current guidance within the NHS states that all restraint positions should be considered to present equal risk. We used a repeated measures design to compare lung function in four restraint positions with a standing control position. Participants restrained flat on the floor, prone or supine, showed non-significant reductions in forced vital capacity (FVC) and forced expiratory volume FEV1 compared with the standing control position. Participants restrained face down with the body weight of the restraining persons pressed on their upper torso and/or in a flexed restraint position showed a significant reduction in lung function (mean reductions in FVC of 23.8% and 27.4% respectively). Recommendations that all restraint positions pose equal risk, or that all prone restraint is dangerous, are not supported by these findings. Some, but not all, prone restraint positions show significant restriction of lung function.