全静脉麻醉腹腔镜胆囊切除手术患者在不同呼气末CO2分压时的脑血流变化

Changes of Cerebrovascular Variables at Different End Tidal CO2 during Laparoscopic Cholecystectomy under Total Intravenous Anesthesia

目的：观察在舒芬太尼和异丙酚全静脉靶控输注麻醉（TCI）下行腹腔镜胆囊切除术患者在不同呼气末CO2分压时的脑血流变化情况。 方法：30位行腹腔镜胆囊切除手术患者为研究对象，采用舒芬太尼和异丙酚TCI麻醉，麻醉前经颅多普勒超声仪（TCD）测定其脑血流速度变化数据作为基数，麻醉诱导气管插管后约20分钟后开始行CO2气腹。根据监测的呼气末CO2分压的不同，将患者随机分为两组，第一组为允许性高碳酸血症组（N=15），在气腹后通气条件不作进一步调节，维持患者呼气末CO2分压为45mmHg左右；第二组为适度低碳酸血症组（N=15），在气腹后增加每分通气量，维持CO2分压在33mmHg左右。在气腹过程中取8个不同的时间点记录脑血流变化特征。 结果：第一组的脑血流速度随CO2分压的升高而升高，而第二组没有这种显著变化。脉动指数在观察过程中维持稳定。 结论：本临床观察提示，在异丙酚TCI加舒芬太尼麻醉的腹腔镜胆囊切除手术中．患者呼吸末CO2分压升高可引起脑血流增加，预防性的过度通气能减少因气腹中加。

Objective： To evaluate the influence of two different management strategies, regarding end tidal CO2, on cerebral blood flow velocities and pulsatility index, examined by means of transcranial Doppler ultrasonography. Methods： 30 patients, aged from 18-60 years and ASA physical status Ⅰ or Ⅱ, undergoing laparoscopic cholecystectomy under anaesthesia with sufentanil and TCI of propofol were enrolled. The patients were randomly assigned to two groups： permissive hypercapnia （up to 45mmHg,Group Ⅰ, n=15） versus intervention to ensure mild hypocapnia, （around 33 mmHg, Group Ⅱ, n=15）. Baseline measurements of investigated parameters were recorded before anaesthesia and CO2 insufflation started 20 min after intubation. In Group Ⅰ, no further adjustment was performed and end-tidal CO2 partial pressure rose, while in Group Ⅱ end-tidal CO2 partial pressure was kept stable, by ventilatory patterns adjustment. Cerebrovascular variables were recorded during pneumoperitoneum and in post-desufflation period, at eight checking time points. Results： In Group Ⅰ, cerebral blood flow velocities increased according to CO2 elevation, whereas in Group Ⅱ no significant alterations were noticed. Pulsatility index was almost constant over time without clinical difference between groups. Conclusion： Our study suggests that under anaesthesia with sufentanil and TCI of propofol, prophylactic hyperventilation limits the cerebral blood flow velocities enhancing effect of CO2 insufflation, during laparoscepies.