允许性高碳酸血症对急性肺损伤绵羊肺力学及血流动力？…

目的 探讨允许性高碳酸血症（ＰＨＣ）对急性肺损伤（ＡＬＩ）绵羊肺力学及血流动力学的影响。方法 观察不同潮气量（ＶＴ）时，１８只ＡＬＩ绵羊肺气体交换、肺力学和血流动力学的改变。结果 当ＶＴ从１６ｍｌ／ｋｇ降至４～７ｍｌ／ｋｇ时，绵羊均出现ＰＨＣ，动脉血氧分压、氧饱和度和混合静脉血氧饱和度显降低（Ｐ〈０．０５）。ＰＨＣ时气道压力显降低（Ｐ〈０．０５），气道阻力明显增高；体循环和肺循环阻力指数、左心

Effects of permissive hypercapnia on pulmonary mechanics and hemodynamics in sheep with acute lung injury]

OBJECTIVE: To study the effects of permissive hypercapnia (PHC) on pulmonary mechanics and hemodynamics in sheep with acute lung injury (ALI). METHODS: In 18 sheep with LPS induced ALI, gas exchange, pulmonary mechanics and hemodynamics were observed at different tidal volumes (VT). RESULTS: When VT was decreased from 16 ml/kg to 4-7 ml/kg, PHC was induced. Arterial pressure of carbon dioxide increased markedly, arterial oxygen pressure, oxygen saturation and mixed venous oxygen saturation decreased (P < 0.05). Airway pressure decreased significantly (P < 0.05), but the airway resistance increased. Systemic and pulmonary vascular resistance index, right and left ventricular stroke work index increased in PHC, but heart rate decreased (P < 0.05). Compared with VT 16 ml/kg, cardiac index decreased markedly in PHC. In static pressure-volume curve, the pressure of upper inflection point was (21.8 +/- 3.2) cm H2O, volume was (10.7 +/- 1.3) ml/kg. CONCLUSIONS: Alveolar overdistention may be prevented only when airway plateau pressure is less than 20-25 cm H2O, but cardiac index is decreased.