压力-容积曲线指导个体化保护性单肺通气在开胸术中的应用

The individual lung protective ventilatory parameters setting guided by pressure-volume curve in patients undergoing one-lung ventilation during thoracic surgery

目的:应用动态压力-容积曲线设定全身麻醉单肺通气时个体化的潮气量和呼气末正压(PEEP)。方法:42例ASAⅠ～Ⅱ级择期行肺叶切除术患者,常规双肺通气30min后(T0)行单肺通气,按照患者单肺通气即刻动态压力-容积曲线低位拐点对应的压力(PLIP)+0.196kPa设定PEEP值,依次按照100%、80%、60%高位拐点对应的容量(VUIP)设定潮气量,分别通气30min(T1、T2、T3)。记录各时点血流动力学和呼吸力学参数,并采集动脉和混合静脉血行血气分析,根据公式计算肺内分流率。结果:T1、T2、T3的PEEP值均为(0.64±0.13)kPa,潮气量分别为(10.1±1.2)mL/kg、(7.2±1.1)mL/kg、(5.6±0.7)mL/kg,与T1相比,T2的气道峰压、气道阻力、分流率降低;动脉氧分压、胸肺顺应性增加;T3的平均动脉压、动脉二氧化碳分压增高,差异有统计学意义(P<0.05)。结论:根据动态压力-容积曲线,80%VUIP联合PLIP+0.196kPa水平的PEEP有助于改善单肺通气氧合,降低分流,对血流动力学影响轻微。

Objective To investigate the optimal individual tidal volume and positive end-expiratory pressure （PEEP） based on the dynamic pressure-volume curve for patients with one-lung ventilation. Methods Forty-two ASA Ⅰ - Ⅱ patients scheduled for an elective lobeetomy were randomly enrolled in this study. The conventional two lung ventilation was kept for 30 min （To） and followed by one-lung ventilation（OLV） operation. PEEP was applied to the lung ventilation by PuP ＋ 0.196 kPa of P-V curve, three different tidal volume modes were conducted successively, Tl （100% VUIP）, T2 （80% VUIP） and T3 （60% VUIP）, each mode was kept for 30 min. Value of tidal volume, MAP, HR, CVP, peak airway pressure （Ppeak）, airway resistance （Raw） and lung-thorax compliance （CT） were recorded, and the blood gas and pulmonary shunt fraction （Qs/Qt） were calculated. Results PEEP was （0.64 ±0.13）kPa and tidal volume was （10.1±1.2） mL/kg, （7.2±1.1）mL/kg, （5.6±0.7） mL/kg at T1, T2 and T3. Compared with Tl, the Ppeak, Raw and Qs/Qt reduced, PaO2 and CT got corresponding improvement at T2, MAP, and PaCO2 increased at T3 significantly （P 〈 0.05）. Conclusion In terms of dynamic P-V curve, 80% VUIP adding PUIP ＋ 0.196 kPa PEEP can improve arterial oxygenation and pulmonary compliance, and decrease pulmonary shunt fraction during OLV, however, the effect of haemodynamics is not significant.