体位及呼气末正压对危重病患者中心静脉压的影响

目的观察不同体位及呼气末正压(PEEP)水平对机械通气(MV)危重患者中心静脉压(CVP)的影响。方法选择2005年12月—2006年3月重症加强治疗病房(ICU)进行MV并监测CVP的患者23例,观察患者在30°卧位及平卧位时PEEP0、3、6、9、12和15cmH2O(1cmH2O=0.098kPa)条件下CVP、心率(HR)、平均动脉压(MAP)、脉搏血氧饱和度(SpO2)及Riker镇静-躁动评分(SAS)的变化。结果相同PEEP条件下,患者两种体位的CVP、HR及MAP均无明显变化(P均>0.05);30°卧位SpO2显著高于平卧位(P<0.01)。患者体位由30°卧位调至平卧位及固定体位脱机时,CVP随PEEP水平升高而递增,至PEEP15cmH2O时明显高于其他PEEP水平(P均<0.05);脱机时SpO2明显低于不同PEEP水平时(P均<0.05);SAS随PEEP水平升高而递减,至PEEP15cmH2O时,SAS有所升高(P均<0.05);HR和MAP无明显变化。结论体位改变对MV患者的CVP无明显影响,随PEEP水平增加,CVP逐渐增加;改变体位与脱机均会使患者缺氧加重、躁动增加;维持患者原体位及PEEP水平而测量CVP,可增加患者的安全性与舒适性,减少医护人员工作量。

Effect of posture and positive end expiratory pressure on central venous pressure in patients with mechanical ventilation

OBJECTIVE: To investigate the effect of posture and different positive end expiratory pressure (PEEP) on central venous pressure (CVP) in critically ill patients with mechanical ventilation (MV). METHODS: Twenty-three critically ill patients were enrolled in this study with MV and CVP measurement in intensive care unit (ICU) from December 2005 to March 2006. CVP, heart rate (HR), mean arterial pressure (MAP), oxygen saturation of pulse (SpO(2)), and Riker's sedation-agitation score (SAS) were obtained simultaneously with a backrest elevation of 30 degree angle or with a supine flat position under different PEEP conditions of 0, 3, 6, 9, 12 and 15 cm H(2)O (1 cm H(2)O=0.098 kPa). RESULTS: There were no differences in CVP, HR and MAP between the two positions at the same PEEP condition (all P>0.05). CVP increased gradually by the increment of PEEP with patients in both positions (all P<0.05), and significantly higher than other PEEP conditions when PEEP was 15 cm H(2)O. SpO(2) decreased and SAS increased when the position was adjusted from 30 degree angle to supination (both P<0.01), and when the mechanical ventilation was weaned, SpO(2) was the lowest than those at different PEEP conditions with patients in either position (all P<0.05). SAS decreased gradually by the increment of PEEP except at 15 cm H(2)O (all P<0.05). There were no differences in HR and MAP between different positions and in different PEEP conditions. CONCLUSION: CVP was not influenced by the posture. CVP increased gradually with the increase in PEEP. Changing posture and weaning of mechanical ventilation led to deterioration of oxygenation and increased agitation. Maintaining of posture and PEEP when measuring CVP could improve safety and comfort of patients, and reduce the work of nursing.