血流动力学监测进展.ppt

血流动力学监测进展血流动力学监测进展 浙江省立同德医院ICU 陈扬波 History of Monitoring 1960s:golden age of vasopressors Pressure arterial line&CVP 1970s:golden age of inotropes Cardiac output,PA catheter 1980s:SvO2,relative balance between oxygen supply and demand 1990s till now:Better understanding of tissue oxygenation,right ventricular function Functional monitoring,PiCCO,continuous CO Less invasive,TEE 血流动力学监测是临床危重病急救的重要内容之一，是大手术和抢救危重病员不可缺少的手段。无创伤性血流动力学监测（noninvasive hemodynamic monitoring）创伤性血流动力学监测（invasive hemodynamic monitoring）一、无创血流动力学监测（一）心阻抗血流图（Impedance cardiogram,ICG）（二）超声心动图（ultrasonic cardiogram,echocardiogram,UCG）（三）多普勒心排血量监测（四）二氧化碳无创心排血量测定（一）心阻抗血流图 其基本原理是欧姆定律(电阻=电压/电流)。1966年Kubicek采用直接式阻抗仪测定心阻抗变化,推导出著名的Kubicek 公式。1981年Sramek提出胸腔是锥台型，因此改良了Kubicek 公式，应用8只电极分别安置在颈根部和剑突水平，测量心动周期胸部电阻抗的变化来测定左心室收缩时间（systolic time interval,STI)和计算每搏量,通过微处理机，自动计算CO,并演算出一系列心功能参数。SV=(Vept T Z/sec)/Zo Figure:Application of electrodes in impedance cardiography Impedance cardiography(ICG)is a safe,non-invasive method to measure a patients hemodynamic status.The ICG waveform is generated by thoracic electrical bioimpedance(TEB)technology,which measures the level of change in impedance in the thoracic fluid.Four small sensors send and receive a low amplitude electrical current through the thorax to detect the level of change in resistance in the thoracic fluid.With each cardiac cycle,fluid levels change,which affects the impedance to the electrical signal transmitted by the sensors.The technology behind ICG Figure 7:Variation of ventricular,aortic and atrial pressure,aortic flow,thoracic impedance change and fist derivative of impedance(dz/dt)as a function of time(t).ECG and phonocardiogram taken simultaneously is also shown.The curve depicts the cardiac events/performance.B Opening of the Aortic Valve,X Closure of the Aortic Valve,Y closure of pulmonary valve,O mitral valve opening/rapid ventricular filling,B-X Ventricular Ejection Time(VET),C Maximal deflection of dz/dt(Peak Flow),B-C slope Acceleration Contractility Index,A Atrial Systole,Q Start of ventricular depolarization Philips Impedance Cardiography(ICG)continuously measures hemodynamic parameters without the associated risks of traditional invasive methods.The Philips ICG measurement is ideal for hemodynamic evaluation of adult patients in:Emergency departments Step-down units Special procedure Using ICG for the appropriate patient population The ICG measurement is designed for assessment of most adult patients height 122-229 cm(4-7 6)and weight 30-159 kg(67-350 lb)but may demonstrate reduced accuracy when patients present with the following conditions or anomalies:Aortic valve regurgitation Minute ventilation sensor function pacemakers Connection to a cardiopulmonary bypass machine Sustained arrhythmias Connection to an intra-aortic balloon pump or chest tubes Connection to a respiratory ventilator Congenital heart defects Pericardial effusion Severe hypertension(MAP 130 mm Hg)Septic shock Severe anemia ICG是一项无创伤性的方法，操作简单、费用低、安全。可动态连续监测CO及与其有关的血流动力学参数，最新研制的阻抗血流图仪能显示和打印16个测定和计算参数及心功能诊断和治疗图。ICG 由于其抗干扰能力差,易受病人呼吸、心律失常及手术操作等的干扰,尤其是不能鉴别异常结果是由于病人的病情变化引起,还是由于机器本身的因素所致,其绝对值有时变化较大,故在一定程度上限制了其在临床上的广泛使用。（二）超声心动图 超声心动图是指利用超声波回声反射的形式记录心脏信息的检查方法，通过观察心脏和大血管的结构和动态变化，了解心房、心室收缩及舒张情况与瓣膜关闭、开放的规律为临床诊断提供信息和有关资料，对某些心脏疾病诊断的准确性较高，还能测量主动脉及各瓣膜口的直径，而且对病人无痛苦，因此是当前心血管疾病和血流动力学重要的诊断检查方法。Echocardiography:Seeing with Sound Echocardiogram 临床上有M型超声心动图、二维超声心动图及多普勒超声心动图及经食管超声心动图。可监测每搏输出量，左室射血分数（EF）、左室周径向心缩短速率（VCF）、舒张末期面积（EDA）、心室壁运动异常（RWMA）等。transthoracic echocardiogram,TTE transesophageal echocardiogram,TEE Echocardiogram An echocardiogram is a test in which ultrasound is used to examine the heart.Echocardiograms can evaluate:the presence of any abnormal fluid collection in the sac around the heart(pericardium).the chamber size,thickness of the heart muscle wall and how well it is functioning.the function of the heart valves-whether they are obstructing blood flow or leaking.any abnormal connections between chambers and vessels that may exist in congenital heart disease.wall motion abnormalities that occur when the heart muscle is not receiving enough blood.the presence of aneurysms,clots,tumors,vegetations(bacterial growths)on the valves.（三）多普勒心排血量监测 所谓多普勒原理是指声源与接收器之间的相对运动而引起接收频率与发射频率之间的差别。多普勒心排血量监测正是利用这一原理，根据已知频率超声波的反射频率，测定红细胞移动的速度来推算主动脉血流以及CO。CO=Vavg Area ao Tei HR area ao升主动脉横截面的面积值 HR心率 Vavg每搏的平均流速 Tei射血时间 由于降主动脉的血流量是CO 的70%(降主动脉血流与CO 的相关系数是0.92),故其计算公式也为:CO=降主动脉血流量降主动脉的横截面积70%多数研究结果显示它与热稀释法高度相关。多普勒超声技术测量左心室充盈期舒张末面积直接与每搏容量指数相关,可作为前负荷的定量指标。Both SV and CO can be reliably determined from the spectral flow profile as a product of the velocity time integral(vti)and the flow cross sectional area(CSA),and,for CO,times heart rate(HR).This method has been in use for over 20 years in clinical practice and is probably considered the clinical haemodynamic gold standard.多普勒超声技术操作水平要求高,多种因素影响可造成误差,操作者及结果分析者要有超声检查技术、图形分析基本理论知识、心血管疾病知识,而且要经过严格培训才能避免错误。此外设备、检查费用昂贵,所以此技术尚未推广。（四）二氧化碳无创心排血量测定 二氧化碳无创心排血量测定是利用二氧化碳弥散能力强的特点，以CO2作为指示剂，根据Fick原理来测定心