机械通气患者不同呼气末正压及体位对中心静脉压的影响

目的探讨机械通气患者不同呼气末正压(PEEP)及体位对中心静脉压(CVP)的影响。方法选取因呼吸衰竭行机械通气患者48例,检测PEEP为0、3、6、9、12、15及18 cm H_2O时的CVP值以及患者取平卧位、平卧位下床头抬高15°、30°、45°及60°卧位时的CVP值。结果 CVP值随PEEP水平的升高而升高,且PEEP≥15 cm H_2O时的水平明显高于在0~12 cm H_2O时的测量值(P0.05或P0.01);不同PEEP对心率(HR)和平均动脉压(MAP)的影响不明显(P0.05),血氧饱和度(SpO_2)随着PEEP升高而升高,当PEEP≥12 cm H_2O时,SpO_2升高更明显,与PEEP≤6 cm H_2O时比较差异显著(P0.01)。平卧位时CVP值高于平卧位下床头抬高15°、30°、45°、60°卧位的CVP值(P0.05或0.01),且卧位角度越大,CVP值越小;不同体位对HR、MAP及SpO_2水平几乎无影响(P0.05)。结论不同PEEP和体位均影响CVP值,危重患者测量CVP时尽量保持原体位。

Influence of different positive end-expiratory pressure and postures on central venous pressure of patients with mechanical ventilation

Objective To explore the influence of different positive end-expiratory pressure (PEEP) and postures on central venous pressure (CVP) of patients with mechanical ventilation.Methods A total of 48 patients with mechanical ventilation due to respiratory failure were selected.CVP values when PEEP was at 0,3,6,9,12,15 and 18 cm H2O and the values when patients were placed in supine position or when bedside was lifted by 15°,30°,45°and 60°in supine position were detected.Results CVP value increased with the increase of PEEP level,and it was markedly higher when PEEP≥15 cmH2O than that when PEEP was 0 ～ 12 cmH2O (P ＜0.05 or P ＜0.01).Different PEEP had insignificant influence on heart rate (HR) and mean arterial pressure (MAP) (P ＞ 0.05).However,saturation of blood oxygen (SpO2) increased with the increase of PEEP level,which increased more significantly when PEEP ≥ 12 cmH2O than that when PEEP ≤6 cmH2O (P ＜ 0.01).CVP value was markedly higher in supine position than that when bedside was lifted by 15°,30°,45°and 60°(P ＜0.05 or P ＜0.01).The larger the angle of supine position was,and lower the CVP value became.And different postures had no influence on levels of HR,MAP and SpO2 (P ＞ 0.05).Conclusion Different PEEP and postures have great influence on CVP values,and severe patients should be placed in original position when detecting CVP.