“神舟”7号飞行前后呼吸和应激测试中航天员血流动力学反应(英文)

Hemodynamic Responses to Respiratory and Stress Tests before and after "Shenzhou" 7 Spaceflight

目的本研究旨在探明3 d航天飞行是否会导致航天员的心脏-压力反射功能及血流动力学参数发生变化。方法在飞行前14 d及返回后第2天,采用SEVE系统以非介入式的逐搏测量技术连续监测航天员做呼吸动作及应激测试时的心电、血压和呼吸信号。通过分析这些生理信号,对航天员自发性压力反射敏感性(SBRs)、心输出量(CO)、每搏量(SV)及总外周血管阻力(TPR)变化进行评价。结果飞行后,航天员的立位耐力评分轻微下降;在基础状态下,飞行导致SBRs和TPR下降,SV和CO升高。在做呼吸动作及应激测试中发现,航天飞行导致收缩压、舒张压、心率(HR)、SV及CO对应激的反应能力下降,而SBRs对应激的反应能力却没有受到影响。结论短期航天飞行导致了基础状态下航天员的SBRs和TPR下降,SV和CO升高,抑制了应激状态下心血管系统的调节功能。

Objective To clarify if the cardiac-baroreflex loop and the hemodynamics parameters were changed after the 3 d spaceflight mission. Methods Electrocardiogram（ECG）, blood pressure wave and breath signals were recorded through a non-invasive beat-by-beat measurements based on cardio-vascular experimentation system（SEVE） during breath maneuvers and stress test 14 d before launch （L-14） and 2 d after landing （R ＋ 2）. Then the spontaneous baroreflex sensitivity （SBRs）, cardiac output （CO）, stroke volume （SV） and total peripheral resistance （TPR） were evaluated. Results After 3 d spaceflight, the orthostatic tolerance eval- uation scores of astronauts slightly decreased. Moreover, spaceflight decreased the SBRs and TPR, but in- creased the SV and CO. During the test of controlled breath and stress, we found that spaceflight had inhibited the responsiveness of systolic blood pressure （ SBP）, diastolic blood pressure （ DBP）, heart rate （ HR）, SV and CO to stress stimulation, but had no effect on SBRs. Conclusion Short-term spaceflight induces the de- crease of SBRs and TPR and the increase of SV and CO in basic condition, however, it also induces a global inhibition of cardiovascular regulation in stress condition.