危重病人的血流动力学监测课件.ppt

* * * * * The relevance of the filling pressures for assessing cardiac preload has long been disputed and has been refuted in numerous publications. Neither the absolute level of the CVP (shown on left) nor the changes in CVP (shown on right) correlate with stroke volume. CVP therefore not suitable for assessing volume status. * The pulmonary capillary wedge pressure (PCWP) and alterations of this do not show any correlation with cardiac ejection either. Thus measurement of cardiac preload is not possible by means of the traditionally employed PCWP either. * * FACCT study by the ARDS Networks, published in the New England Journal of Medicine: no difference in the outcome of ARDS patients with CVP-guided fluid management and those with volume therapy guided by the PCWP. Better: measure volumes directly instead of estimating them from the pressure measurement. The level of the filling pressures is subject to many influencing factors so a valid statement about volume status is not possible. Only exception: low filling pressures indicate hypovolaemia（血容量减少） * The principle of thermodilution with the PiCCO technology is identical to the pulmonary artery catheter (PAC), However, while the temperature bolus is detected in the pulmonary artery with the PAC, this takes place in a large peripheral artery (femoral, axillary or brachial) with the PiCCO system after passage through the heart and lungs. With both methods, not the entire injected indicator flows past the thermistor since this is in a branch of the pulmonary artery. This has no influence on the validity of the result with either measurement method as the detected amount of the indicator is not relevant but rather the difference in temperature over time. Pictorial comparison: a stone falls into smooth water and generates a wave that spreads in all directions. The height of the wave can be measured at any location but the same result will always be obtained. * PiCCO技术－结合经肺热稀释方法和动脉脉搏轮廓分析法 对血液动力学和容量进行监护管理。 需要提醒的是pic