不同压力呼吸末正压通气对开胸手术单肺通气期间肺内分流及氧合的影响

Influence of different positive end-expiratory pressure on oxygenation and pulmonary shunt fraction during one-lung ventilation

目的:研究不同压力呼吸末正压通气(PEEP)对单肺通气(OLV)期间肺内分流及氧合的影响,探讨OLV期间应用的最佳PEEP值。方法:选择ASAⅠ-Ⅱ级择期行开胸手术OLV患者30例,患者侧卧位后分别于双肺通气30min(T1)、单肺通气30min(T2)、通气侧肺5cmH2O 30min(T3)及通气侧肺10cmH2O 30min(T4)时行血气分析,记录各时间点动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、动脉血氧饱和度(SaO2)、pH、心率(HR)、平均动脉压(MAP)及气道峰压(Ppeak),并计算肺内分流(Qs/Qt)。结果:与双肺通气比较,OLV时PaO2明显下降,Qs/Qt明显升高(P<0.05)。T2到T3期间PaO2从(200.20±145.25)mmHg上升到(299.55±138.83)mmHg,Qs/Qt下降(P<0.05)。T3到T4期间PaO2从(299.55±138.83)mmHg下降到(237.30±135.57)mmHg,Qs/Qt有所升高(P<0.05)。OLV时Ppeak值从T2(21.15±3.60)cmH2O上升到T4(27.20±3.78)cmH2O(P<0.05)。结论:OLV期间,通气侧肺应用PEEP 5cmH2O能有效提高PaO2,减少Qs/Qt,防止低氧血症的发生,血流动力学稳定,不影响手术操作,是较合适的PEEP值。

Objective To study the different positive end-expiratory pressure（PEEP） on pulmonary shunt fraction and oxygenation during one-lung ventilation（OLV）,and to explore the best PEEP value in OLV.Methods Thirty patients with ASA Ⅰ-Ⅱ level elective thoracotomy with OLV were selected.The blood gas analysis were performed in the lateral position at ventilation 30 min（T1）,OLV 30 min（T2）,5 cmH2O OLV PEEP 30 min（T3）,and 10 cmH2O OLV PEEP 30 min（T4）.At each time point,the PaO2,PaCO2,SaO2,pH,HR,mean arterial pressure（MAP）,and peak airway pressure（Ppeak） were recorded,and the intrapulmonary shunt（Qs / Qt） was calculated.Results Compared with two-lung ventilation,the PaO2 was decreased and the Qs / Qt was increased significantly（P0.05）,the PaO2 was increased from（200.20 ± 145.25） mmHg to（299.55±138.83） mmHg（P0.05） and the Qs / Qt was decreased（P0.05） at the duration of T2 to T3;the PaO2 was decreased from（299.55 ± 138.83） mmHg to（237.30 ± 135.57） mmHg（P0.05） and the Qs / Qt was increased（P0.05） at the duration of T3 to T4;the Ppeak value was increased from T2（21.15±3.60） cmH2O to T4（27.20±3.78） cmH2O（P0.05） in OLV.Conclusion During OLV,5 cmH2O PEEP applied in ventilated lung can increase the PaO2,decrease the Qs / Qt and prevent the occurrence of hypoxemia.It is more appropriate PEEP value.