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目的观察模拟失重条件下心肺循环变化的特点。方法采用超声多谱勒技术对１２ 名健康男性青年，在头低位－ ３０°４５ ｍｉｎ 时，测量了心功能的变化。结果 实验中右心室射血时间显著增加（ Ｐ＜ ０ ．０５） ，肺动脉最大血流速度显著下降（ Ｐ＜ ０ ．０５） ，肺动脉血流加速时间延长，右心室心输出量在１０ ｍｉｎ 、３０ ｍｉｎ 显著下降（ Ｐ＜ ０ ．０５） ，心率、右心室心搏量、肺动脉平均血流速度、肺动脉血流加速度均有下降的趋势，但不具有显著性。左心室输出量、左心室心搏量及血压的变化趋势与国内外报道的相似。结论从右心功能的各个参数的变化，提示在头低位的实验过程中肺循环阻力增高，阻力的增加是肺动脉压增高的直接原因。
Objective To observe the changes of cardiopulmonary circulation under simulated weightlessness. Methods The changes of cardiac function were measured in 12 healthy male youngsters by using ultrasonic Doppler technique at the head low of 30 ° 45 min. Results The right ventricular ejection time was significantly increased (P <0. 05), the maximum pulmonary blood flow velocity was significantly decreased (P <0.05), the pulmonary blood flow acceleration time was prolonged, the right ventricular output was 10 min, 30 min (P <0.05). Heart rate, right ventricular stroke volume, average pulmonary artery blood flow velocity and pulmonary artery blood flow velocity all decreased. However, they were not significant. Left ventricular output, left ventricular stroke volume and blood pressure trends similar to those reported at home and abroad. Conclusions The changes of various parameters of right ventricular function suggest that pulmonary resistance increases and the increase of resistance is the direct cause of pulmonary hypertension.