Effect of continuous low- to medium-flow oxygen administration in non-ventilated lung on oxidative stress response of lung tissues during one-lung ventilation

Abstract

Objective To evaluate the effect of continuous low- to medium-flow oxygen administration in non-ventilated lung on the oxidative stress response of lung tissues during one-lung ventilation (OLV). Methods Fifty-seven American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients, aged 50-64 yr, weighing 40-74 kg, scheduled for elective pulmonary tumorectomy, were divided into 2 groups using a random number table: control group (group C, n=29) and continuous oxygen administration group (group O, n=28). The patients were intubated with the double-lumen tube after induction of anesthesia.Correct position of the tube was verified with the fiberoptic bronchoscope.In group O, the F14 tube was placed at 2-3 cm beyond the carina of trachea in the non-ventilated lung at the beginning of OLV, and low- to medium-flow oxygen was continuously administered at 1-4 L/min with the fractional concentration of inspired oxygen set at 25%-37%.Blood samples were taken from the radial artery and internal jugular bulb at the beginning of anesthesia induction (T1) and 30 min, 1 h and 2 h of OLV (T2-4) for blood gas analysis.Lung tissues at the site 5 cm lateral to the tumor were taken immediately after resection of diseased tissues for determination of superoxide dismutase and malondialdehyde levels (by chemical colorimetry) and heme oxygenase-1 expression (by Western blot). Results Compared with group C, the partial pressure of arterial oxygen was significantly increased at T2-4, the partial pressure of arterial carbon dioxide was decreased at T2, 3, the partial pressure of venous oxygen was increased at T2, 3, the partial pressure of venous carbon dioxide was decreased at T2-4, the malondialdehyde level was decreased, and the expression of heme oxygenase-1 was up-regulated (P 0.05). Conclusion The mechanism by which continuous low- to medium-flow oxygen administration in non-ventilated lung exerts pulmonary protection is related to inhibiting oxidative stress responses of lung tissues during OLV. Key words: Respiration, artificial; Respiratory distress syndrome, adult; Oxidative stress