背景:长途飞行与航空相关血栓形成(ART)的风险增加2至4倍有关。几项研究调查了低氧低压暴露的程度,航空旅行期间的脱水和长时间固定会引起止血变化。
目的:探讨高海拔作为ART危险因素的作用。
方法:年龄≥18岁(N=40)的健康志愿者,没有静脉血栓栓塞的危险因素,暴露在18000英尺(5486米)的高度下1小时。在飞行过程中,参与者的氧气(O2)水平,接受补充O2的患者通过脉搏血氧饱和度进行测量,并维持在>92%。在出发前和在未加压的双引擎飞机上飞行后立即收集静脉血和尿液样本。D-二聚体水平,血栓弹力图(TEG)参数,测定血管性血友病因子(VWF)活性和尿渗透压。
结果:参与者是19名男性和21名女性,平均(标准差)年龄为46(14)岁。D-二聚体水平有显著差异,VWF活动,尿渗透压和TEG参数(反应(R)时间,在1小时飞行之前和之后观察到动力学(K)时间和最大振幅(MA))(p<0.001)。尿渗透压与VWF活性水平呈正相关(r=0.469;p<0.002)。
结论:在高海拔地区的航空旅行引起健康志愿者的高凝状态。未来的研究应集中在血栓预防是否可以显着消除响应高海拔的凝血激活。
BACKGROUND: Long-haul flights have been associated with a two- to four-fold increased risk of aviation-related thrombosis (ART). Several studies have investigated the extent to which hypoxic hypobaric exposure, dehydration and prolonged immobilisation during air travel induce changes in haemostasis.
OBJECTIVE: To investigate the role of high altitude as a risk factor for ART.
METHODS: Healthy volunteers aged ≥18 years (N=40), without risk factors for venous thromboembolism, were exposed to an exacerbated altitude of 18 000 feet (5 486 m) for 1 hour. During the flight, the oxygen (O2) levels of the participants, who received supplemental O2, were measured by pulse oximetry and maintained at >92%. Venous blood and urine samples were collected prior to departure and immediately after flying in an unpressurised twin-engine airplane. D-dimer levels, thromboelastography (TEG) parameters, von Willebrand factor (VWF) activity and urine osmolality were measured.
RESULTS: The participants were 19 men and 21 women, with a mean (standard deviation) age of 46 (14) years. A significant difference in D-dimer levels, VWF activity, urine osmolality and TEG parameters (reaction (R) time, kinetic (K) time and maximum amplitude (MA)) before and after the 1-hour flight was observed (p<0.001). Urine osmolality correlated positively with VWF activity levels (r=0.469; p<0.002).
CONCLUSIONS: Air travel at high altitude induced a hypercoagulable state in healthy volunteers. Future research should focus on whether thromboprophylaxis can significantly obviate the activation of coagulation in response to high altitude.