Barnett Richard, Hanson Paul, Stirling Chris, Pandyan Anand D
School of Health and Rehabilitation, Keele University, UK.
Med Sci Law. 2013 Jul;53(3):161-5. doi: 10.1258/msl.2012.012044. Epub 2013 Mar 14.
Deaths occurring during and/or in close proximity to physical restraint have been attributed to positional asphyxia. This study investigated the physiological impact of three recognized prone-restraint positions with participants remaining passive. Position 3 (P3) the supported prone position (SPP) was designed to reduce the extent of pressure on the anterior chest wall (PAC) by bringing the upper limbs underneath the shoulder joint whereas for the other two positions (P1 and P2) the arms were abducted from the torso. Twenty-five adults participated. Forced vital capacity (FVC), expiratory volume in one second (FEV1), heart rate (HR) and oxygen saturations (SpO2) were taken three times in an upright seated position (baseline) and in each prone position. Mean PAC was measured at 102.6 (±24.3) and 101.4 (±24.4) mmHg for P1 and P2, respectively; however, in the SPP (P3) the mean PAC pressure reduced to 72.7 (±16.9) mmHg. All three prone-restraint positions reduced FVC and FEV1 compared with baseline (P < 0.001). P1 and P2 where the arms were abducted reduced respiratory measures equally but differed from the SPP position (P < 0.001) where PAC was significantly lower. Reductions in FVC from baseline were 16% for P1 and P2, and 11% for the SPP (P3) where PAC was ∼28% lower than in P1 and P2. Reductions in FEV1 were similar in all three prone-restraint positions and HR and SpO2 were unaffected. In summary, all prone-restraint positions restrict respiratory function but the risk associated with the position reduces as the PAC reduces.
在身体约束期间和/或紧挨着身体约束发生的死亡被归因于姿势性窒息。本研究调查了三种公认的俯卧约束姿势在参与者保持被动状态下的生理影响。姿势3（P3）即支撑俯卧位（SPP）旨在通过将上肢置于肩关节下方来减少前胸壁（PAC）上的压力程度，而对于其他两种姿势（P1和P2），手臂从躯干外展。25名成年人参与了研究。在直立坐姿（基线）以及每个俯卧姿势下，对用力肺活量（FVC）、一秒用力呼气量（FEV1）、心率（HR）和血氧饱和度（SpO2）进行了三次测量。P1和P2的平均PAC分别为102.6（±24.3）和101.4（±24.4）mmHg；然而，在支撑俯卧位（P3）中，平均PAC压力降至72.7（±16.9）mmHg。与基线相比，所有三种俯卧约束姿势均降低了FVC和FEV1（P＜0.001）。手臂外展的P1和P2对呼吸指标的降低程度相同，但与前胸壁压力显著更低的支撑俯卧位（P3）不同（P＜0.001）。P1和P2的FVC较基线降低了16%，支撑俯卧位（P3）降低了11%，其中前胸壁压力比P1和P2低约28%。在所有三种俯卧约束姿势中，FEV1的降低情况相似，HR和SpO2未受影响。总之，所有俯卧约束姿势均会限制呼吸功能，但随着前胸壁压力降低，与该姿势相关的风险也会降低。
