食管癌术中硬膜外阻滞对单肺通气期间动脉氧合的影响

目的 探讨食管癌手术采取全麻复合硬膜外阻滞麻醉时对单肺通气（OLV）期间动脉氧合的影响。方法 选择60例行经左胸食管癌根治术患者（ASAI-II级），随机分为静脉全麻复合硬膜外阻滞麻醉组（A组，30例）和仅静脉全麻组（B组，30例）。两组患者分别于OLV前（T1）、OLV 15min（T2）、OLV 30min（T3）抽取桡动脉血和混合静脉血行血气分析，计算通气/血流比（Qs／Qt）值。结果 在T2和T3时，A组氧分压（PaO2）分别为（219.3±48.2）mmHg和（174.7±37.6）mmHg，显著低于B组的（268.1±81.2）mmHg和（221.6±87.0）mmHg。在OLV期间，A组的Qs／Qt显著高于B组（P＜0.05），各时间点A组血压均显著低于B组（P＜0.05）。结论 全麻复合硬膜外阻滞麻醉时会引起食管癌患者术中血压下降，而且会引起OLV期间肺内分流的增加和氧分压的降低。

Effect of thoracic epidural anesthesia with bupivacaine on arterial oxygenation during one-lung ventilation

Objective To study the effects of thoracic epidural anesthesia （TEA） with bupivacaine on oxygenation, shunt fraction during one-lung ventilation （OLV）. Methods Sixty patients who had prolonged periods of OLV for elective thoracic surgery for esophageal cancer were randomized into two groups. Thirty patients （group A） were anesthetized with propofol/atracurium/epidural thoracic bupivacaine 0.5%. In another 30 patients （group B）, fentanyl/propofol/atracurium anesthesia was used. A double-lumen endotracheal tube was inserted, and mechanical ventilation with 100% oxygen was used during the entire study. Arterial and venous blood gases were recorded before surgery in a lateral position with two-lung ventilation, 15 and 30 min after OLV （OLV＋15 and OLV＋30, respectively） in all patients. PaO2 , venous central oxygen tension, arterial and central venous oxygen saturation, venous admixture percentage （Qs/Qt） were measured. Results The mean values for PaO2 during OLV in the group A after 15min with （219.3±48.2） mmHg and 30min with （ 174.7±37.6） mmHg were significantly lower compared with the group B （ 268.1±81.2mmHg and 221.6±87.0mmHg, respectively）. Furthermore, Qs/Qt was significantly increased in group A during OLV. And, blood pressure was significantly lower in group A during surgery. There were no significant differences. Conclusion We conclude that using the TEA regimen is associated with a lower PaO2 and a larger intrapulmonary shunt during OLV than with total anesthesia alone.