不同水平呼气末正压通气联合60%吸入氧浓度对单肺通气患者氧合及术后肺部并发症的影响

The combined physiologic effects of using different positive end-expiratory pressure and inspired oxygen fraction of 0.6 during one lung ventilation

目的:探讨单肺通气(one-lung ventilation,OLV)期间不同水平呼气末正压(positive end-expiratory pressure,PEEP)联合60%吸入氧浓度(inspired oxygen fraction,Fi O_(2))对OLV患者氧合及术后肺部并发症(postoperative pulmonary complication,PPC)的影响。方法:择期行经左胸食管癌根治术患者120例,随机分为A、B、C、D 4组,每组30例,OLV时各组均使用60%的Fi O_(2),通气侧分别采用0、5、8、10 cm H_(2)O PEEP。于OLV前即刻(T_(1))、OLV 10 min(T_(2))、OLV 15 min(T_(3))、OLV 30 min(T_(4))、OLV 60 min(T_(5))、OLV 120 min(T_(6))时分别经桡动脉与右颈内静脉中抽取动静脉血行血气分析,计算肺内分流率;记录各时间点的血流动力学与呼吸力学等指标;记录术后第2天的临床肺部感染评分(clinical pulmonary infection score,CPIS)和PPC的发生情况。结果:A组2例患者OLV中发生低氧血症而退出本研究,共118例患者完成试验。T_(2)~T_(6)时D组动脉血氧分压(PaO_(2))明显高于A组、肺内分流率明显低于A组(P<0.05);T_(3)~T_(4)时C组Pa O_(2)明显高于A组、肺内分流率明显低于A组(P<0.05)。T_(4)时B组Pa O_(2)明显高于A组、肺内分流率明显低于A组(P<0.05)。T_(2)~T_(5)时D组PaO_(2)明显高于B组(P<0.05);T_(2)~T_(4)时D组肺内分流率明显低于B组(P<0.05)。T_(5)时D组PaO_(2)明显高于C组(P<0.05)。T_(2)~T_(6)时B、C、D组驱动压明显低于A组(P<0.05),T_(2)~T_(5)时C、D组驱动压明显低于B组(P<0.05)。T_(4)~T_(6)时C、D组肺动态顺应性(dynamic compliance,Cdyn)明显高于A、B组(P<0.05)。术后第2天B、C、D组CPIS明显低于A组。结论:OLV时FiO_(2)为60%条件下,联合5、8和10 cm H_(2)O PEEP均可改善氧合、降低肺内分流、增加肺动态顺应性,降低驱动压及CPIS,从而具有一定的肺保护作用,其中10 cm H_(2)O PEEP改善氧合的效应出现得更早,效果更佳。

Objective:To investigate the combined physiologic effects of different positive end-expiratory pressure(PEEP)and decreased inspired oxygen fraction(FiO_(2))during one lung ventilation(OLV).Methods:This study is a prospective,single-blind,randomized controlled study.One-hundred and twenty patients were equally randomized into four groups of A(OLV with 0 cm H_(2)O),B(OLV with 5 cm H_(2)O),C(OLV with 8 cm H_(2)O),and D(OLV with 10 cm H_(2)O).All patients breathed an inspiratory oxygen fraction of 0.6.Arterial blood and venous blood were taken for gas analysism,and intrapulmonary shunt rate(Qs/Qt)were calculated before OLV(T_(1)),OLV 10 min(T_(2)),OLV 15 min(T_(3)),OLV 30 min(T_(4)),OLV 60 min(T_(5)),and OLV 120 min(T_(6)).Haemodynamics and respiratory mechanics parameters were monitored continuously.The clinical pulmonary infection score(CPIS)was recorded on the second day after the surgery and the incidence of postoperative pulmonary complication was recorded.Results:Among the 120 patients assessed for eligibility,118 completed the study.At T_(2)~T_(6),PaO_(2) in group D was significantly higher than that in group A,Qs/Qt in group D was significantly lower than that in group A(P<0.05).At T_(3)~T_(4),PaO_(2)in group C was significantly higher than that in group A,Qs/Qt in group C was significantly lower than that in group A(P<0.05).At T_(4),PaO_(2) in group B were significantly higher than that in group A,Qs/Qt in group B were significantly lower than that in group A(P<0.05).At T_(2)~T_(5),PaO_(2) in group D were significantly higher than that in group B,At T_(2)~T_(4),Qs/Qt in group D were significantly lower than that in group B(P<0.05).At T_(5),PaO_(2)in group D were significantly higher than that in group C(P<0.05).At T_(2)~T_(6),driving pressure(DP)in group B,C,and D were significantly lower than that in group A(P<0.05).At T_(2)~T_(5),DP in group C and D were significantly lower than that in group B(P<0.05).At T_(4)~T_(6),dynamic compliances in group C and D were significantly higher than those in group A and B(P<0.05).The CPIS score was significantly lower in group B,C and D than that in group A on the second day after the surgery(P<0.05).Conclusion:During one lung ventilation with 0.6 FiO_(2),10 cm H_(2)O PEEP improves pulmonary function without changing the hemodynamic parameters and reduces driving pressure,and plays an important role in lung protection.