Arterial oxygenation during one-lung ventilation: Combined versus general anesthesia

The optimal anesthetic management of patients undergoing thoracotomy for pu lmonary resection has not been definitely determined. We evaluated whether general IV anesthesia (propofol-fentanyl) provides superior PaO2 during one -lung ventilation (OLV) compared with thoracic epidural anesthesia (TEA) wi th supplemental local and general anesthetics. We studied 60 patients who h ad prolonged periods of OLV for elective thoracic surgery for lung cancer a nd who were prospectively randomized into two groups. In 30 patients (GA gr oup), fentanyl/propofol/rocuronium anesthesia was used. Another 30 patients (TEA group) were anesthetized with propofol/rocuronium/epidural thoracic b upivacaine 0.5%. A double-lumen endotracheal tube was inserted, and mechani cal 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. We measured PaO2, venous central oxygen tens ion, arterial and central venous oxygen saturation, venous admixture percen tage (Qs/Qt%), and arterial and central venous oxygen content. The mean val ues for Pao,during OLV in the GA group after 15 min (175 mm Hg) and 30 min (182 mm Hg) were significantly (P < 0.05) higher compared with the TEA grou p (120 and 118 mm Hg, respectively). Furthermore, Qs/Qt% was significantly (P < 0.05) increased in the TEA group during OLV. There were no other signi ficant differences; We conclude that using the TEA regimen is associated wi th a lower Pao, and a larger intrapulmonary shunt during OLV than with tota l TV anesthesia alone. Implications: Sixty patients undergoing elective lun g surgery during a prolonged period of intraoperative one-lung ventilation were studied and randomized to receive general IV anesthesia or general IV anesthesia combined with thoracic epidural anesthesia. The arterial oxygena tion in the first group was better than that in the second group during one -lung ventilation.