目的研究模拟失重对心脏形态的影响及其用四肢加压套带和下体负压的拮抗作用. 方法自愿接受试验的健康男性青年18名，年龄19～25（平均22.6）岁，随机分为对照组，套带组和下体负压组，进行21 d 6°头低位卧床试验. 对照组卧床中不用任何对抗措施；套带组卧床期间每日08∶30～20∶30，四肢戴加压套带，压力维持在5.3 kPa；下体负压组卧床期间第1 wk和最后1 wk每日15:00使用1 h下体负压裤，压力维持在-4 kPa. 所有组均分别于卧床前1 d和卧床结束后1 d摄取X线胸片各1张，测量胸廊横径、心脏横径、长径和宽径，并计算反映心脏形态大小的心胸比和心脏面积. 结果对照组心脏横径减少0.54 cm, 心胸比减少0.024,心脏面积减少9 cm2，前后比较均有明显差异(P<0.05);套带组分别减少0.50 cm, 0.021和1.9 cm2，前后比较无显著性差异(P>0.05);下体负压组各指标变化不明显(P>0.05). 结论头低位卧床模拟失重对心脏形态有明显的影响，而四肢加压套带和下体负压均可拮抗失重对心脏形态的作用.%AIM To investigated the effects of simulated weightlessness on cardiac morphology and counteracting effects of cuffs and low body negative pressure (LBNP) on them. METHODS The 21d -6° head down bed rest was used to simulate weightlessness. Eighteen young healthy volunteers were divided into 3 groups randomizedly: cuffs group, LBNP group and control group. In cuffs group, cuffs on the upper part of thighs and arms were inflated from 8:30 am to 20:30 pm during bed rest with pressure 5.3 kPa. In LBNP group, low body pressure was maintained at -4 kPa for one hour from 15:00 pm to 16:00 pm during the first and last week of bed rest. X-ray examination was used to study the cardiac morphology changes during simulated weightlessness. All groups were taken X-ray examination one day before and after bed rest and the alongside of thoracic cage and cardiac transverse diameter were measured. Also, the cardiac-thoracic ratio and area of heart were calculated. RESULTS The alongside of thoracic cage, cardiac-thoracic ratio and area of heart were significantly decreased after bed rest in control group. However, there were no significant differences in cuffs and LBNP groups after bed rest. CONCLUSION It is suggested that simulated weightlessness, conducted by head down bed rest has great influences on cardiac morphology and cuffs and LBNP can counteract the effects of simulated weightlessness.
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