Tan Y, Qiu H, Guo F
Department of Critical Care Medicine, Zhongda Hospital, Southeast University, Nanjing 210009, China.
Zhonghua Jie He He Hu Xi Za Zhi. 2000 Nov;23(11):683-5.
To study the effects of permissive hypercapnia (PHC) on pulmonary mechanics and hemodynamics in sheep with acute lung injury (ALI).
In 18 sheep with LPS induced ALI, gas exchange, pulmonary mechanics and hemodynamics were observed at different tidal volumes (VT).
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.
Alveolar overdistention may be prevented only when airway plateau pressure is less than 20-25 cm H2O, but cardiac index is decreased.
研究允许性高碳酸血症（PHC）对急性肺损伤（ALI）绵羊肺力学和血流动力学的影响。
对18只脂多糖诱导ALI的绵羊，在不同潮气量（VT）下观察气体交换、肺力学和血流动力学。
当VT从16 ml/kg降至4 - 7 ml/kg时，诱导产生PHC。动脉血二氧化碳分压显著升高，动脉血氧分压、血氧饱和度和混合静脉血氧饱和度降低（P < 0.05）。气道压力显著降低（P < 0.05），但气道阻力增加。PHC时全身和肺血管阻力指数、左右心室每搏功指数升高，但心率降低（P < 0.05）。与VT 16 ml/kg相比，PHC时心脏指数显著降低。在静态压力-容积曲线中，上拐点压力为（21.8±3.2）cm H2O，容积为（10.7±1.3）ml/kg。
仅当气道平台压小于20 - 25 cm H2O时可防止肺泡过度扩张，但心脏指数降低。
