Objective To investigate the effects of hypobaropathy and hypoxia to the model of rat with spinal cord injury, and discuss the security and protection of the patients in aero medical evacuation. Methods The experiment used 90 rats of female Sprague Dawley that weighed 200~250 g, divided them into 6 groups. We exposed spinal cord of T10 by surgery after anesthesia and made the model of spinal cord injury with NYU (impact height was 25 mm, impact weight was 10 g, contact area was 2 mm2). The control group’s background was of normal environment, not hypobaropathy and hypoxia. In contrast, the experimental group model of rat was put into low pressure oxygen cabin and reducing pressure at a constant speed to the air pressure of 2 500 m. The two groups were kept for 1 h, 2 h and 4 h respectively. Then we could measure the PaCO2 and PaO2 with arterial blood. After 24 h, we could measure hind limbs motor function of the rat (Points-scoring system use Basso-Beattie-Bresnahan and Rivlin Slope method) and the area of spinal cord hematoma. Results The PaCO2 of the groups under hypoxia and hypobaropathy was significantly higher than that in normal environment(P<0.05), while the PaO2 of the groups under hypoxia and hypobaropathy was lower (P<0.05). In the same environment, both PaCO2 and PaO2 were statistically different between the group of 4 h and the group of 1 h (P<0.05). There were no significant differences with regard to BBB method, Rivlin Slope method and the area of spinal cord hematoma (P>0.05). Conclusion The effects of PaCO2 and PaO2 of the model of rat with spinal cord injury are obvious under hypobaropathy and hypoxia with short distance (1 h), medium range (2 h), long distance (4 h) respectively. So we should take care of breath monitor and use oxygen therapy. But the effects of body function early after injury and spinal cord hematoma under hypobaropathy and hypoxia are not obvious.%目的：分析低压低氧环境对大鼠脊髓损伤模型有关行为和病理指标的影响，为脊髓损伤患者航空后送的安全性论证和防护提供实验依据。方法将90只体重为200～250 g的雌性SD大鼠随机分为6组，每组15只，分别为A1（1 h对照组）、B1（2 h对照组）、C1（4 h对照组）、A2（1 h实验组）、B2（2 h实验组）、C2（4 h实验组）。大鼠水合氯醛腹腔注射麻醉后手术暴露T10节段脊髓，使用NYU脊椎冲击损伤仪（撞击高度25 mm，撞击针重10 g，接触面积约2 mm2）制作脊髓挫伤模型。对照组模拟地面环境，不进低压氧舱；实验组放入小动物低压氧舱内，匀速减压至模拟舱内保持2500 m高度的气压值机舱环境。实验组与对照组各组分别维持1 h、2 h、4 h，模拟短程（1 h）、中程（2 h）、远程（4 h）航程。环境干预结束后即刻抽取动脉血，监测血氧分压及二氧化碳分压；于术后24 h分别观测大鼠后肢运动功能[Basso-Beattie-Bresnahan(BBB)评分、Rivlin斜坡法]及脊髓打击处血肿面积。结果分别比较各相应时长，实验组与对照组氧分压及二氧化碳分压差异均有统计学意义（P＜0.05）；正常环境与低压低氧环境下，时长4 h组与时长1 h组氧分压及二氧化碳分压差异均有统计学意义（P＜0.05）。以BBB评分标准评价运动功能：实验组与对照组各时程差异均无统计学意义（P＞0.05）。Rivlin斜坡法评价后肢肌力：实验组与对照组各时程差异均无统计学意义（P＞0.05）。实验组与对照组各时程脊髓撞击处血肿面积差异均无统计学意义（P＞0.05）。结论短程（1 h）、中程（2 h）、远程（4 h）低压低氧环境下，脊髓损伤大鼠血氧分压和二氧化碳分压会受到明显影响，航空后送过程中应当注意呼吸监测与氧疗。
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