The Effects of Thoracic Epidural Anesthesia on Pulmonary Shunt during One Lung Anesthesia / 대한마취과학회지

ABSTRACT

BACKGROUND: Hypoxemia during one lung ventilation (OLV) for thoracotomy in patients in the lateral position remains a clinical problem. And thoracic epidural anesthesia (TEA) during one lung ventilation recently has been combined with general anesthesia in our clinical practice for thoracic surgery. Then the effects of TEA combined with general anesthesia on PaO2 remains controversial. The aim of this study to investigate whether thoracic epidural anesthesia (TEA) affect PaO2 and pulmonary shunt during one lung anesthesia. METHODS: Fifteen patients undergoing lobectomy with one lung ventilation were examined. Each group was injected normal saline (control group, n = 7) or 1% lidocaine (TEA group, n = 8) 8 ml through thoracic epidural catheter after induction. We compared pulmonary shunt fraction (Qs/Qt) after OLV 30, 60 minutes and after two lung ventilation (TLV). RESULTS: We found the significant increases of intrapulmonary shunt fraction (%) in the TEA group compared to control group at each event, OLV30, 60 and TLV. And significant increase of intrapulmonary shunt was found after one lung ventilation in the both groups. CONCLUSIONS: These results suggest that TEA may influence hypoxic pulmonary vasoconstriction (HPV) by blockade of sympathetic activity during OLV.