颅脑损伤后颈、股动脉间PaO_2差监测的临床意义

Monitoring of the difference of pressure of arterial oxygen between the carotid artery and the femoral artery and clinical significance in patients with head injury

目的 :研究颈、股动脉之间PaO2 的差别与脑损伤以及与颅脑外伤预后之间的关系 ,旨在为重症颅脑损伤患者提供一种方便、安全、实用的脑氧监测的方法。方法 :随机选择各型颅脑损伤 4 0例 ,按GCS评分分 4组 ,入院后 6h内同时抽取颈动脉和股动脉血做血气分析。并在随后 5天做连续动态颈、股动脉PaO2 和PaCO2 监测。全组中 2 6例于入院后同时行双侧脑底部大脑前、中动脉TCD检查。结果 :(1)Ⅰ组及Ⅱ组的颈动脉PaO2 显著低于股动脉PaO2 (P <0 .0 5 ) ;Ⅲ、Ⅳ组颈、股动脉PaO2 之间没有明显差别。 (2 )死亡及植物生存组颈动脉PaO2 在连续 5天监测中始终明显低于股动脉PaO2 (P <0 .0 5 ) ;而治愈和致残组没有这种差别。 (3)Ⅰ、Ⅱ组病人有颅内压增高的TCD表现 ,并且颈、股动脉PaO2 差随大脑中动脉的舒张期流速(Vd)的降低而增加。结论 :随着颅内压增高 ,脑部血流循环淤滞 ,使颈动脉PaO2 显著低于股动脉。因此 ,颈、股动脉PaO2 之差反映了脑颅脑损伤后存在氧的供给不足 ,提示尽管外周血PaO2 正常 ,并不意味着脑部氧供应充分。

Objective:To study difference in arterial oxygen(PO 2) pressure between the carotid artery and the femoral artery and its relation with hypoxia of brain after head injury.Methods:Forty patients with acute head injury were divided into four groups according to the GCS(Ⅰ:6 patients for GCS 3-5score;Ⅱ:16 patients for GCS 6-8 score;Ⅲ:8 patients for GCS 9-12 score;Ⅳ:10 patients for GCS 13-15score).The PO 2 of the carotid artery and the femoral artery was monitored for every patient.At the same time,26 patients from all groups were monitored using transcranial dopplergraphy.Additional,22 patients with severe head injury were continuously monitored on PO 2 of the carotid artery and the femoral artery for 5 days.Results:(1)The difference in PO 2 between the carotid artery and the femoral artery was identified in Ⅰ and Ⅱ groups.The PO 2 of carotid artery is much less than that of femoral artery(P<0.05).(2)When the PO 2 of carotid artery with severe head injury was reduced persistently during the first 5 days after admission,the prognosis of patients must be poor.(3)The changes of the difference in PO 2 between the carotid artery and the femoral artery correlated with the diastolic velocity of middle cerebral artery and the GCS.Conclusion:With the increase of ICP after head injury,the difference in PO 2 between the carotid and the femoral increases gradually.Therefore we suggest that the oxygen in short supply is one of the most important reasons for hypoxia of brain tissue.