Abstract:

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.