Effect of hypercapnia on cerebral oxygen metabolism under propofol anesthesia during one-lung ventilation / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of hypercapnia on cerebral oxygen metabolism under propofol anesthesia during one-lung ventilation (OLV) in patients.Methods Forty ASA physical status [or Ⅱ patients,aged 53-63 yr,scheduled for elective lobectomy performed via video-assisted thoracoscope,were enrolled in the study.Anesthesia was induced with iv injection of midazolam,fentanyl and vecuronium and target-controlled infusion of propofol and maintained with target-controlled infusion of propofol and intermittent iv boluses of fentanyl and vecuronium.BIS value was maintained at 40-60 during surgery.At 15 min of OLV,hypercapnia was performed and PaCO2 was maintained at 50-55 mm Hg lasting for 15 min,and then respiratory rate was adjusted to maintain PaCO2 at 40-45 mm Hg.Immediately before OLV (T0),at 15 min of OLV and hypercapnia (T1,2),and at 15 min after the end of hypercapnia (T3),arterial and jugular bulb venous blood samples were obtained for determination of arterial partial pressure of oxygen (PaO2),arterial oxygen saturation (SaO2),jugular bulb venous oxygen partial pressure (PjO2) and hemoglobin saturation (SjO2).The arterial to venous oxygen content difference (Da-jO2) and cerebral extraction rate of oxygen (CERO2) were calculated.Results SaO2 and PaO2 at T1-3,SjO2 and PjO2 at T1 and T3 and Da-jO2 at T2 were significantly lower and CERO2 at T1 and T3 was higher than those at T0 (P ＜ 0.05).SjO2 and PjO2 were significantly increased and Da-jO2 and CERO2 were significantly decreased at T2(P ＜0.05) and no significant changes were found in the parameters of cerebral oxygen metabolism at T3 as compared with those at T1 (P ＞ 0.05).Conclusion Hypercapnia can improve cerebral oxygen metabolism under propofol anesthesia during OLV in patients.