呼气末正压对不同胸壁弹性阻力患者中心静脉压的影响

The effects of positive end-expiratory pressure on central venous pressure in patients with different chest wall elastic resistance

目的探讨呼气末正压(PEEP)对不同胸壁弹性阻力(Ecw)患者中心静脉压(CVP)的影响。方法选2017年11月至2018年12月东南大学附属中大医院重症医学科需要监测CVP的70例机械通气患者,依据Ecw与呼吸系统弹性阻力(Ers)比值将患者分为Ecw/Ers≥0.24组和Ecw/Ers<0.24组,观察2组患者PEEP为5、10、15 cmH_(2)O(1 cmH_(2)O =0.098 kPa)时的CVP等的变化。结果 Ecw/Ers≥0.24组患者体重指数高于Ecw/Ers<0.24组[(25.4±3.2)kg/m^(2) 比(23.4±3.2)kg/m^(2),P=0.011]。Ecw/Ers≥0.24组患者CVP随着PEEP增加而升高,PEEP从5 cmH_(2)O升高至10 cmH_(2)O时,Ecw/Ers≥0.24组患者CVP 升高值大于Ecw/Ers<0.24组[1.75(1.00,2.13)mmHg(1 mmHg=0.133 kPa)比 1.50(0.50,2.00)mmHg,P=0.038];PEEP从10 cmH_(2)O升至15 cmH_(2)O时,Ecw/Ers≥0.24组患者CVP 升高值大于Ecw/Ers<0.24组[2.00(1.50,3.00)mmHg比1.50(1.00,2.00)mmHg,P=0.041];PEEP从5 cmH_(2)O升至15 cmH_(2)O时,Ecw/Ers≥0.24组患者CVP 升高值高于Ecw/Ers<0.24组[3.75(3.00,4.63)mmHg比3.00(1.63,4.00)mmHg,P=0.012]。PEEP从5 cmH_(2)O升至10 cmH_(2)O时,CVP升高值与Ecw/Ers比值呈正相关(r=0.29,P=0.016);PEEP从10 cmH_(2)O升至15 cmH_(2)O时,CVP升高值与Ecw/Ers比值呈正相关(r=0.31,P=0.011);PEEP从5 cmH_(2)O升至15 cmH_(2)O时,CVP升高值与Ecw/Ers比值呈正相关(r=0.31,P=0.01)。结论机械通气患者PEEP的增加会引起CVP升高,高Ecw患者CVP升高更显著,Ecw与CVP升高程度密切相关。

Objective To investigate the role of chest wall elastic resistance in determining the effects of positive end-expiratory pressure(PEEP)on central venous pressure(CVP)in patients with mechanical ventilation(MV).Methods In this prospective study,according to the median of ratio of chest wall elastic resistance to respiratory system elastic resistance(Ers),patients were divided into high chest wall elastic resistance group(Ecw/Ers≥0.24)and low chest wall elastic resistance group[elastance of chest wall(Ecw)/Ers<0.24].PEEP was set at 5,10,15 cmH_(2)O(1 cmH_(2)O=0.098 kPa)respectively.Clinical data including CVP,heart rate(HR),blood pressure(BP)and respiratory mechanics were recorded.Results Seventy patients receiving MV were included from November 2017 to December 2018.Clinical characteristics including age,BP,HR,baseline PEEP,the ratio of arterial oxygen partial pressure to fractional inspired oxygen(P/F)and comorbidities were comparable in two groups.However,patients with high Ecw/Ers ratio presented higher body mass index(BMI)than those with low Ecw/Ers ratio[(25.4±3.2)kg/m^(2)vs.(23.4±3.2)kg/m^(2),P=0.011].As PEEP increased from 5 cmH_(2)O to 10 cmH_(2)O,CVP in high Ecw/Ers group increased significantly compared with that in low Ecw/Ers group[1.75(1.00,2.13)mmHg(1 mmHg=0.133kPa)vs.1.50(0.50,2.00)mmHg,P=0.038],which was the same as PEEP increased from 10 cmH_(2)O to 15 cmH_(2)O[2.00(1.50,3.00)mmHg vs.1.50(1.00,2.00)mmHg,P=0.041]or PEEP increased from 5 cmH_(2)O to 15 cmH_(2)O[3.75(3.00,4.63)mmHg vs.3.00(1.63,4.00)mmHg,P=0.012].When PEEP increased from 5 cmH_(2)O to 10 cmH_(2)O,10 cmH_(2)O to 15 cmH_(2)O and 10 cmH_(2)O to 15 cmH_(2)O,there were significant correlations between Ecw/Ers and CVP elevation(r=0.29,P=0.016;r=0.31,P=0.011;r=0.31,P=0.01 respectively).Conclusions In patients receiving mechanical ventilation,elevation of PEEP leads to a synchronous change of CVP,which is corelated with patients′chest wall elastic resistances.