Siegel John H, Smith Joyce A, Siddiqi Shabana Q
Department of Cell Biology and Molecular Medicine, New Jersey Medical School: UMDNJ, Newark, New Jersey 07107-1709, USA.
J Trauma. 2004 Oct;57(4):760-77; discussion 777-8. doi: 10.1097/01.ta.0000147502.50248.c4.
To examine the effect of change in velocity (MV) and energy dissipation (IE) on impact, above and below the test levels for federal motor vehicle crash (MVC) safety standards, on the incidence of aortic injury (AI) and its mortality and associated injury patterns in frontal (F) and lateral (L) MVCs. Comparison of 80 AI and 796 non-AI patients of AIS=3.
Eight hundred seventy-six MVC adult drivers or front-seat passengers (552 F and 324 L) evaluated by 10 Level I CIREN study Trauma Centers together with vehicle and crash scene engineering reconstruction. Patient seatbelt and/or airbag use correlated with clinical or autopsy findings.
In AI, 63% of cases were dead at the scene and only 16% survived to leave hospital. The relation between IE dissipated in the MVC and the DeltaV on impact was exponential as DeltaV increased, but the rise in IE for a given DeltaV was greater in LMVC than in FMVC (p <0.05). A more rapid rise in IE/DeltaV occurred above the mean DeltaV of 48 +/- 19.7 kph (30 mph) in FMVC and above the mean DeltaV of 36 +/- 16.2 kph (23 mph) in LMVC. As DeltaV increased above these means, 65% of 46 FMVC aortic injuries (AIs) and 64% of 34 LMVC AIs occurred. In AI patients there was evidence of focusing of the point of IE impact on the upper chest with a higher incidence of rib1-4 fractures than in non-AI (p <0.01) and more brain, heart, lung and spleen injuries (p <0.01) consequent to lower seatbelt use (p <0.01), but LMVC also had more pelvic fx (p <0.05). Airbags + seatbelts in FMVC and seatbelts in LMVC reduced mortality (p <0.05) Comparison of AI incidence in three successive 4-year vehicle model year periods showed a progressive decrease as new safety devices were introduced (p < 0.05).
The implications for AI of the focused IE at the upper chest suggest a probable mechanism for MVC AI with the pressurized aortic arch acting as the long arm of a lever system with the fulcrum at the subclavian artery, producing maximum torsional strain at the short arm of the isthmus where 75% of the AIs occurred. AI mortality is also influenced by the associated injuries. To develop more effective safety systems to prevent AI, MVC safety testing with airbags and seatbelts should be carried out at DeltaVs of 1 SD above means for FMVC and LMVC.
研究速度变化（MV）和能量耗散（IE）在联邦机动车碰撞（MVC）安全标准测试水平之上和之下对碰撞的影响，以及对主动脉损伤（AI）的发生率、死亡率和相关损伤模式的影响，这些碰撞包括正面（F）和侧面（L）MVC。比较80例AI患者和796例AIS = 3的非AI患者。
10个I级CIREN研究创伤中心对876名成年MVC驾驶员或前排乘客（552例F型和324例L型）进行评估，并结合车辆和碰撞现场工程重建。患者安全带和/或安全气囊的使用情况与临床或尸检结果相关。
在AI患者中，63%的病例在现场死亡，只有16%存活出院。随着DeltaV增加，MVC中耗散的IE与碰撞时的DeltaV之间的关系呈指数关系，但对于给定的DeltaV而言，LMVC中IE的上升幅度大于FMVC（p <0.05）。在FMVC中，当DeltaV高于平均48 +/- 19.7 kph（30 mph），在LMVC中当DeltaV高于平均36 +/- 16.2 kph（23 mph）时，IE/DeltaV出现更快的上升。当DeltaV高于这些平均值时，46例FMVC主动脉损伤（AI）中有65%以及34例LMVC AI中有64%发生。在AI患者中，有证据表明IE撞击点集中在上胸部，与非AI患者相比，第1-4肋骨骨折的发生率更高（p <0.01），并且由于安全带使用较少（p <0.01），导致脑、心、肺和脾损伤更多（p <0.01），但LMVC中骨盆骨折也更多（p <0.05）。FMVC中的安全气囊 + 安全带以及LMVC中的安全带可降低死亡率（p <0.05）。对三个连续的4年车型年期间的AI发生率进行比较，结果显示随着新安全装置的引入，AI发生率逐渐下降（p <0.05）。
上胸部集中的IE对AI的影响表明，MVC导致AI的一种可能机制是，受压的主动脉弓作为杠杆系统的长臂，以锁骨下动脉为支点，在峡部的短臂处产生最大扭转应变，75%的AI发生在此处。AI死亡率也受相关损伤的影响。为开发更有效的预防AI的安全系统，应在高于FMVC和LMVC平均值1个标准差的DeltaV下进行安全气囊和安全带的MVC安全测试。
