过度通气对严重颅脑伤手术患者脑氧供需平衡的影响

目的：探讨过度通气对严重颅脑伤手术患者颈内静脉球血氧饱和度(SjvO2)、脑动静脉氧含量差(A-VDO2)和脑静动脉血乳酸差(V-ADL)的影响及其临床意义。方法：16例严重颅脑损伤急诊手术患者全身麻醉后，通过改变控制通气呼吸频率和吸入气氧分压调节过度通气水平，使每种通气水平维持稳定15min后，均测定SjvO2、A-VDO2以及V-ADL。结果：当动脉血氧分压(PaO2)为100～150mmHg(1mmHg-0．133kPa)和200-250mmHg、动脉血二氧化碳分压(PaCO2)从30mmHg降至25mmHg时，可使SjvO2明显降低，A-VDO2明显升高，但PaO2200～250mmHg与PaO2100～150mmHg相比，SjvO2的绝对值均明显较高，A-VDO2绝对值明显较低。与基础值相比，PaO2100～150mmHg、PaCO230mmHg及25mmHg和PaO2200～250mmHg、PaCO225mmHg时V—ADL均明显升高。结论：较高氧合(PaO2200-250mmHg)和中度过度通气(PaCO230mmHg)对脑氧供需平衡无明显影响，是严重颅脑损伤手术患者过度通气的最佳匹配方式。

Effects of hyperventilation on cerebral oxygen supply and consumption in perioperative patients with severe head injury and their significance

Objective: To investigate the effects of hyperventilation on jugular venous oxygen saturation (SjvO 2), arteriovenous oxygen content difference(A-VDO 2) and lactate concentration difference(V-ADL) perioperative patients with severe head injury and their significance. Methods: Sixteen patients with severe head injury for operation were studied. The changes of SjvO 2, A-VDO 2 and V-ADL in response to changes in partial pressure of oxygen in artery(PaO 2) and partial pressure of carbon dioxide in artery(PaCO 2) were studied through adjusting respiratory rate and fraction of inspired oxygen. Results: SjvO 2 decreased significantly and A-VDO 2 increased significantly when PaCO 2 deceased from 30 mm Hg to 25 mm Hg ( 1 mm Hg = 0 133 kPa ) at a PaO 2 of 100-150 mm Hg or 200-250 mm Hg. The absolute value of SjvO 2 was greater and the absolute value of A-VDO 2 was lower at a PaO 2 of 200-250 mm Hg for any given PaO 2. V-ADL did not change significantly only at a PaO 2 200-250 mm Hg and PaCO 2 30 mm Hg. Conclusion: Moderate hyperventilation to a PaCO 2 of 30 mm Hg in combination with higher PaO 2 (200-250 mm Hg) may be beneficial for patients with severe head injury.