【摘要】 目的 观察四种常用麻醉方法用于长时间（180min）单肺通气时,肺内分流率、动脉氧合及血液动力学的变化。方法 40例ASAⅠ～Ⅱ择期需单肺通气开胸手术病人,随机分为4组:异氟醚吸入组（GI组,n=10）,异氟醚吸入复合硬膜外组（GIE组,n=10）,静脉异丙酚组（GP组,n=10）和静脉异丙酚复合硬膜外组（GPE组,n=10）。GIE组和GPE组均以0.5％罗哌卡因持续胸段硬膜外阻滞。连续监测平均动脉压（MAP）、平均肺动脉压（MPAP）、心输出量（CO）、心电图（ECG）、脉搏氧饱和度（SpO₂）等。通过脑电双频指数（BIS）调整异氟醚吸入浓度或异丙酚输注速率。分别于清醒仰卧位（T₁）、侧卧位双肺通气30（T₂）、侧卧位单肺通气5（T₃）、15（T₄）、30（T₅）、60（T₆）、120（T₇）、180（T₈）min及再次双肺通气30min（T₉）测定动脉及混合静脉血血气,计算肺内分流率（Qs/Qt）。结果 各组肺内分流率及动脉血氧分压（PaO₂）T₂明显高于T₁（P<0.05）,单肺通气后肺内分流率进一步增加,分别在T₄、T₅时达到高峰（GI组46％±14％,GIE组34％±4％,GP组34％±5％,GPE组27％±7％）,之后逐渐降低。而PaO₂在单肺通气后明显下降,T₄～T₆时达到最低点之后开始回升。T₈的分流率及PaO₂已恢复到与T₉差异无显著性的水平。GI组单肺通气后肺内分流率高于其它各组（P<0.05）。各组间PaO₂更多还原

【Abstract】 Objective To investigate the changes in oxygenation and intrapulmonary shunt duringprolonged one-lung ventilation （OLV） and compare the effects of four different anesthetic techniques. MethodsForty ASAⅠ -Ⅱ patients （27 male, 13 female） aged 36-74 yr undergoing prolonged OLV during elective thoracicsurgery were randomly allocated to one of four groups: （1） isoflurane （GI, n = 10）; （2） isoflurane + epidural（GIE, n =10）; （3） propofol （GP, n = 10）; （4） propofol + epidural （GPE, n = 10）. Radial artery wascannulated and Swan-Ganz catheter was placed via right internal jugular vein before induction of general anesthesia.In group 2 and 4 an epidural catheter was inserted at T_7-8 or T_8-9 and advanced 3 .5-4.0 cm in the epidural spacecephalad. Epidural block was produced by a bolus of 0.5 % ropivacaine 7-9 ml followed by continuous infusion of0. 5 % ropivacaine at 3-5 ml·h^-1. Anesthesia was induced with propofol 1 .0-1. 5 mg·kg^-1, fentanyl 3μg·kg^-1 andvecuronium 0. 1 mg·kg^-1. A left-sided double-lumen tube was inserted and correct position was confirmed. Thepatients were mechenically ventilated. The ventilation collditions were FiO₂ = 100 %, V_T = 8-10 ml·kg^-1, I: E =1: 5 and respiratory rate was adjusted to maintained P_ET CO₂ at 35-45 mm Hg during both two-lung ventilation（TLV） and OLV. Anesthesia was maintained with isoflurane inhalation in group 1 and 2 or continuous infusion ofpropofol in group 3 and 4 supplemented with intermittent i. v. boluses of fentanyl. MAP, HR, ECG, MPAP,CVP, continuous cardiac output （CCO）, BIS and TOF were continuously monitored during anesthesia. BIS was maintained at 45-55. Arterial and pulmonary blood gases were analyzed before induction of anesthesia （T₁）, 30min after TLV was started （T₂ ）, and 5, 15, 30, 60, 120 and 180 min after OLV was started (T_3-8) and 30 minafter TLV was resumed （T₉ ）. The Qs/Qt （shunt fraction） was calculated at T_1-9 Results Qs/Qt was significantlyincreased after induction of general anesthesia and mechanical ventilation and increased further during OLVcompared with the baseline value （T₁） in all four groups. The calculated Qs/Qt values were highest at 15 min （T₄）or 30 min （T₅） of OLV and remained high for 30-60 min and then gradually decreasing. During OLV QS/Qt washigher in group 1 than in the other three groups （P<0.05）. PaO₂ was significantly lower after OLV was startedand reached the lowest level at T_4-6then was gradually increasing. There was no significant difference in PaO₂ at alltime points among the four groups （P>0.05）. Cardiac output was significantly higher in group 1 and 2 than thatin group 3 and 4 during OLV. Conclusion During prolonged OLV intrapulmonary shunt tends to decrease withincreasing oxygenation with time, regardless of anesthetic techniques employed. Isoflurane inhalation is associatedwith a signifficant increase in shunt fraction. Combined general and epidural anesthesia may induce greaterhemodynamic changes.更多还原