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1、血压和心音的测量第1页，本讲稿共64页What is blood pressure Blood is carried from the heart to all parts of your body in vessels called arteries.Blood pressure is the force of the blood pushing against the walls of the arteries.Each time the heart beats(about 60-70 times a minute at rest),it pumps out blood into the
2、arteries.Your blood pressure is at its highest when the heart beats,pumping the blood.This is called systolic pressure.When the heart is at rest,between beats,your blood pressure falls.This is the diastolic pressure.BLOOD PRESSURE第2页，本讲稿共64页Blood pressure is always given as these two numbers,the sys
3、tolic and diastolic pressures.Both are important.Usually they are written one above or before the other,such as 120/80 mmHg.The top number is the systolic and the bottom the diastolic.Blood pressure can vary based on many factors,including age,gender,weight and physical condition.In general,a person
4、s blood pressure is lower during sleep and higher when he or she is active.Blood pressure can change easily in response to physiological changes.The setting in which a persons blood pressure is measured may also affect the results.BLOODPRESSURe第3页，本讲稿共64页 Blood pressure changes during the day.It is
5、lowest as you sleep and rises when you get up.It also can rise when you are excited,nervous,or active.Still,for most of your waking hours,your blood pressure stays pretty much the same when you are sitting or standing still.That level should be lower than 120/80.When the level stays high,140/90 or h
6、igher,you have high blood pressure.With high blood pressure,the heart works harder,your arteries take a beating,and your chances of a stroke,heart attack,and kidney problems are greater.BLOODPRESSURE第4页，本讲稿共64页Categories for Blood Pressure Levelsin Adults(In mmHg,millimeters of mercury)BLOOD PRESSUR
7、ECategorySystolic(Top number)Diastolic(Bottom number)Normal Less than 120Less than 80Prehypertension120-13980-89High Blood PressureSystolicDiastolicStage 1140-15990-99Stage 2160 or higher100 or higher第5页，本讲稿共64页Blood Pressure as a Tool Blood pressure is an important diagnostic index,especially of ci
8、rculatory function.It is an important diagnostic index for many reasons.Firstly,any condition that dilates or contracts the blood vessels or affects their elasticity,affects the blood pressure.Secondly,any disease of the heart that interferes with its pumping power,affects the blood pressure.In a he
9、althy animal,the blood pressure normal for its species is maintained within a certain range with great constancy.Thus if blood pressure is abnormally low or high,it usually indicates that greater health problems are present.BLOODPRESSURE第6页，本讲稿共64页Blood pressure measurement What is a blood pressure
10、measurement?Blood pressure is measured by inflating a cuff placed around the arm.Most people have had their blood pressure taken at some time or other.It is a simple and painless examination that gives a lot of useful information about the heart and the condition of the blood vessels.BLOOD PRESSURE第
11、7页，本讲稿共64页What is measured?The doctor measures the maximum pressure(systolic)and the lowest pressure(diastolic)made by the beating of the heart.The systolic pressure is the maximum pressure in an artery(which carries blood from the heart)at the moment when the heart is beating and pumping blood thro
12、ugh the body.The diastolic pressure is the lowest pressure in an artery in the moments between beats when the heart is resting.Both the systolic and diastolic pressure measurements are important-elevation of either one(or both)constitutes high blood pressure BLOODPRESSURE第8页，本讲稿共64页临床上血压测量技术直接法：将一跟导
13、管经皮插入欲测部位的血管或心脏内，通过导管内的液柱同放在体外的应变式传感器、线性可变电感式差动变压器、电容式传感器等相连，从而测出导管端部的压力。另一种形式是把传感器放在导管的末端，直接测出端部所在点的血压值。这种方法的优点是测量值准确，并能进行连续测量。但它必须经皮将导管放入血管内，所以是一种创伤性的方法。间接法：利用脉管内压力与血液阻断开通时刻所出现的血流变化间的关系，从体表测出相应的压力值。由于这种方法不需要剖切的外科手术，同时测量简便，因此在临床上得到广泛的应用。其缺点是测量精度较低，不能进行连续测量以及不能用以测定心脏、静脉系统的压力。BLOODPRESSURE第9页，本讲稿共64页
14、血压直接测量法血压直接测量法导管术导管术 导管法不仅可用来测量动脉压，而且可以测量和监护中心静脉压、肺动脉和肺毛细血管楔入压和左心房、右心室的压力。中心静脉压（CVP,central venous pressure)一般是指右心房、上腔静脉或锁骨下静脉血液所给出的压力。静脉压正常范围：右心房0490Pa；上腔或锁骨下静脉5881176Pa。肺动脉压力(PAP,pulmonary artery pressure)为3.3/2kPa，平均压小于2.4kPa。肺毛细血管压力(PCWP pulmonary capillary wedge pressure)平均值小于22.4kPa.用不透射线的聚乙烯导
15、管通过皮肤插入或通过臂中的大静脉或锁骨下静脉，有时也可将颈静脉割开插到欲测部位。测量肺动脉楔入压采用漂浮导管，是一根在末端带有一个可膨胀气球的双腔导管。使用时先抽去气球内空气，当进入到锁骨下静脉时，用空气或二氧化碳将气球充气到一半容积（0.40.6mL），血液顺流将导管推送到右心房，然后使气球完全膨胀（0.8mL），在血流的推动下，通过三尖瓣而进入右心室，最后通过肺主动脉瓣漂流到肺动脉，挤进末端的动脉枝，从而测出PCWP值。BLOODPRESSURE第10页，本讲稿共64页血压直接测量法血压直接测量法导管术导管术 在循环休克期间，由于低血压值和低心输出量，这时不可能使用间接测压法。当需观察主动
16、脉瓣机能，常需采用动脉压力监护。它把一根细而短的导管插入外周动脉，如股动脉逆行进入至左心室。这种手术特别要注意避免出现由导管顶端血液凝块所引起的栓塞。心导管术要在装由X线机的专门实验室里进行，以便观察心脏的结构和压力导管所处的位置。此外，导管法测压也可通过导管管腔对血液取样，分析血液的血氧饱和度、代谢产物、心输出量、血气和呼吸气体等许多参数的测量，并能检出所在位置的异常血流通路。通过导管管腔注入放射性的染料，医生就可确定心室或主动脉的功能。给冠状动脉注射不透射线的X线染料，对冠状动脉造影，诊断心脏疾病。通过压力测量还可以提取心内心音。BLOOD PRESSURE第11页，本讲稿共64页 血压标
17、定方法 测量血压用的各种类型传感器，与血压值相对应的传感器输出必须经过放大和处理后才能显示和记录。由于传感器特性的离散性，不同传感器配用相同测量电路时，所得结果不可能一致。因此必须对传感器的灵敏度加以标定，并使不同灵敏度的传感器与同一测量电路相配时，仍可得到同样的显示结果。解决标定问题通常有三种方法：一是严格要求制造厂的出厂指标；二是采用传感器内部的灵敏度调节，三是每只传感器使用定标系数，以便和已知的压力放大器一起工作。目前大多采用第三种方法。BLOODPRESSURE血压标定电原理图第12页，本讲稿共64页 压力放大器 根据血压传感器激励电压的不同，有四种基本形式的压力放大器：直流（DC）、
18、直流隔离、脉冲激励和交流（AC）载波放大器。DC放大器只适用于电阻应变式传感器；AC载波放大器既可用于电阻应变式传感器，也可用于电感式传感器；脉冲激励放大器可以与电感式传感器相匹配，但一般用于电阻应变式传感器。BLOODPRESSURE直流压力放大器实际上是直流放大器，首先应考虑温漂和时漂问题。关键在挑选第一级运放，选择高稳定度、低漂移的运放。这种形式的放大器对第一级运放要求高，电路虽然简单，但不能解决零漂问题，所以只能用在测量精度不高的场合。第13页，本讲稿共64页BLOOD PRESSURE脉冲激励压力放大器 激励信号是一双相短间期脉冲，A1为直流放大器，A2为单位增益的相减级。S1S5为
19、CMOS电子开关，所有电路的动作由四相时钟控制，1、2激励传感器，并使放大器漂移抵消电路工作；3使显示表显示最新数据；4相随后使数据复原。所有DC放大器都有因热引起零点漂移的现象，这可以由开关S2和S3、电容C1和放大器A2组成的漂移抵消电路来克服。传感器只有在1为高电平和2为低电平时受激励，而其余时间都不受激，这样使传感器的自热最小。第14页，本讲稿共64页BLOOD PRESSURE隔离式直流压力放大器隔离式直流压力放大器 由于用直接式直流压力放大器测量血压时，导管传感器必须通过液柱同体内测试点接触，这样容易遭受微电击，因此为了保障病人的安全，必须将病人地和仪器地 隔离开（这样由于增加了泄
20、露电流通路的阻抗，从而减少了通过人体的泄露电流，而确保人身安全）。目前血压测量仪器中大多数采用这种形式的放大器。交流载波压力放大器交流载波压力放大器 需用交流电源激励，因此很适应电阻应变仪和电感式传感器。一般压力监护仪自身包含有一个震荡源，而很多集中监护系统或架装的导管实验室则倾向于使用一个功率足以能推动几个载波放大器的公用载波震荡器。载波放大器由于采用交流激励，当对大气压校零时应力求使交流载波放大器的残余电压尽可能小。但传感器特性的不对称性以及桥路分布电容的影响都会使残余电压增大，因此必须加以平衡。压力载波放大器的解调电路使血压调制信号解调，恢复为原始的血压波形。第15页，本讲稿共64页BL
21、OODPRESSURE血压波形的基波频率约为2Hz,为了能不失真地取得血压波形,放大器频带应不小于10倍基波频率,故一般血压放大器的频响为20Hz,这样既可获得满意的结果。但当估计心脏泵血功能时,常用dp/dt微分波形或(dp/dt)/p参数。为了使微分器具有一定的增益，就需加宽放大器频带，在这种情况下带宽采用100Hz。滤波电路可用二阶无源或二阶有源低通滤波器。第16页，本讲稿共64页BLOODPRESSURE压力信号经放大后，由收缩压和舒张压保持电路检出血压波中的峰值和谷值。平均压值也可通过对血压波求积而得到。这些压力值通过A/D转换器转换成数字的形式来显示，也可通过放大器供CRT或记录器
22、显示记录。第17页，本讲稿共64页BLOODPRESSURE收缩压检测电路收缩压检测电路定时图定时图合上合上S S4 4后的延时电路和波形后的延时电路和波形第18页，本讲稿共64页BLOODPRESSURE血压间接测量间接式血压测量的方法很多，其中最主要的一种的利用袖带充气加压阻断动脉后，随后缓慢放气，在袖带下或动脉的远端检出脉搏的变化或血流的变化作为收缩压和舒张压的判断，也可把袖带内压力波动的形式作为判据。柯氏音法1905年苏联医生KOPOMKOB提出：在正常的情况下，完全受压的动脉并不产生任何声响，只有当动脉不完全受阻时才出现声音，因此可用声音来确定人体的血压。第19页，本讲稿共64页BL
23、OODPRESSURE柯氏音法测量精度较差的原因：就心脏血压而言，血压的读数随传感器的部位和高度而变。不在心脏水平高度所取得的读数应补加上以心脏为基准的相应读数。如用听诊器，则读数将受使用听力的影响，故使用的听诊器应符合 一定的标准。出现的运动伪迹与引入系统的振动形式有关。若病人在休克状态，因其脉搏微弱，柯式音振动很低，所以血压测量对移动特别敏感。无论对正常人还是情绪紧张的人，触摸手臂都能改变读数。另一方面，换气过度可以有减小压力的效应。错误的测量方法如末端的位置不适当、袖带放气速度不适当、水银压力计不垂直、听诊器间隙及袖带放置不适当等。第20页，本讲稿共64页BLOODPRESSURE 超声
24、法超声法超声法的原理是利用超声波对血流和血管壁运动的多普勒效应来检测收缩压和舒张压。第21页，本讲稿共64页BLOODPRESSURE 当袖带压力增加到超过舒张压而低于收缩压，动脉内的血压在高于或低于袖带压力间摆动。在血管被阻断期间，血管壁静止不动，所以无频移产生，无声频输出。当刚巧低于或高于袖带内压力的时刻，由于血流及管壁运动大，所以产生较大的频移信号，因而就能检出声频输出。因此，随着每次心搏血管呈现开 放和闭合，借助于超声系统就可把这种开放和闭合状态检测出来。在一个心周期内，随着袖带压力的增加，血管的开放和闭合的时间间隔就随之减小，直到开放和闭合两点重合，该点即为收缩压。相反，当袖带压力减
25、低时，开放和闭合之间的时间间隔增加，直到脉搏的闭合信号与下一次的开放信号重合，这一点可确定为舒张压。此时血管在整个心周期内都是开放的。超声测压法的优点是适用范围比较广，同时可用于噪声很强的环境中，另外应用超声法可以完整地再现动脉波。这时以心电图R波作为基准点，当动脉开放时，用袖带压力与心电图R波之间的关系，描绘出动脉波的上升部分；相反，在动脉闭合期间能描绘出动脉波的下降部分。缺点是受试者身体的活动可以引起传感器和血管之间超声波途径的变化。第22页，本讲稿共64页BLOODPRESSURE逐拍跟踪法逐拍跟踪法逐拍跟踪法是先将袖带充气达到预定的收缩压水平，然后根据每一心周期中柯式音的出现与否来决定
26、袖带压力是增加还是减小。第23页，本讲稿共64页BLOODPRESSURE系统工作过程：系统工作过程：心电电极检出II导联检测到R波，触发单稳态触发器微音器检出臂动脉上柯氏音计算机判断在R波后时间噪音略去不计袖带压力增加2mmHg袖带减压2mmHg是否在200375ms之间200ms之前200375ms之间不出现柯氏音第24页，本讲稿共64页BLOODPRESSURE脉搏延时法脉搏延时法脉搏延时法是利用血管内压力超过袖带压力时所产生的脉搏波滞后于心电图R波的原理，测量出R波和脉搏波之间的时间间隔T,找出T的特征点，从而求出欲测的收缩压和舒张压的数值。它克服了用柯氏音法难于提供明确的舒张压辨识点
27、的缺点。上图所示血压波形中的斜线是袖带压力。当袖带压力刚低于血管内压力时，就出现脉搏波。随这袖带压力的降低，R波和脉搏波之间的间隔T将随袖带内压力而变，即随袖带压力的降低，间隔T逐渐减小。T间隔最大时所对应的袖带压力为收缩压；而最小T值对应的袖带压力为舒张压，根据测出的T值和相应的袖带压力即可求出血压值。第25页，本讲稿共64页BLOODPRESSURE 延迟时间最短的Tn点所对应的10.7kPa(80mmHg)即为舒张压；而延迟时间 最长的T1点所对应的16kPa(120mmHg)即为收缩压。这种方法其特征点极 易识别，测量精度也较柯氏音法为好。第26页，本讲稿共64页 血压的自动测量血压的
28、自动测量 （无创血压模块无创血压模块NIBPNIBP）NIBP血压模块采用测振法进行血压的无创测量。方法时通过监测因血液流经弹性动脉而引起袖带内压力的波动来实现的。在测量中，首先绕在病人手臂或其他肢端的袖带充气加压使动脉血管阻断；然后袖带以阶梯量逐渐放弃，当袖带内压力下降到一定压力时，血液开始在血管内流动。随着压力的下降，血流量加大，同时引起袖带内压力脉搏波动幅度（pressure pulse)的增大直至达到最大值；当压力进一步下降时，波动幅度开始减小。即袖带压力以阶梯量逐渐下降，压力波动幅度会以先上升后下降的规律下降。根据压力波动幅度的包络曲线就可以计算出平均动脉压、收缩压和舒张压。BLOO
29、DPRESSURE第27页，本讲稿共64页BLOODPRESSURE硬件电路硬件电路硬件电路由CPU、EPROM、RAM、实时时钟、A/D转换器、放大电路和两个压力传感器组成，其中一个压力传感器用于检测过压并激活看门狗电路，如果压力超过某一设定值，则微处理器复位，从而关闭电磁阀和气泵。第28页，本讲稿共64页BLOODPRESSURE气动部分气动部分气动部分由一个直流电动机带动的气泵、两个电磁阀和两个传感器等机电元件组成。当电磁阀关闭时，启动气泵给袖带充气。采用两个阀的目的是保证一个阀出现故障时，仍能安全的减压。微处理器根据袖带内的空气容量和压力选择适当的阀进行快速或者精确放气，单向阀的作用是
30、将系统的漏气减至最小，过滤器能够防止灰尘进入系统而引起元器件的故障。第29页，本讲稿共64页BLOODPRESSURE系统软件系统软件软件模块固化在64K的EPROM中，软件的变化主要是用户的串行通信协议和自检程序。通常软件模块可分为有一定背景的确定状态机构和中断任务处理。初始化之后，等待主命令以便进入测量或校准模式。有效中断诸如气泵的调节、通信以及各种定时器均有优先权。在检测周期中通过中断来保持模块与主机的通信、A/D转换和阻止看门狗电路复位。第30页，本讲稿共64页BLOODPRESSURE电路概述电路概述电源NIBP需要一个+7V的直流电源输入，再由电压调整电路转换为+5V电源。过压保护
31、电路由一个压力传感器、一个差动放大器和一个比较器构成。压力传感器根据压力值产生的电压经差动放大器放大后与一个精密电压相比较。当袖带压力超过定压力值时，比较器翻转、微处理器复位。第31页，本讲稿共64页BLOODPRESSURE袖带压力放大器与过压保护电路相似，只是没有比较器。脉动压力放大器第32页，本讲稿共64页BLOODPRESSURE看门狗电路作用是为了保证患者的安全，当模块出现某种情况时，使微处理器复位，气泵停止工作、电磁阀放气。监测内容有：1.+5V直流电源工作范围。2.主机发来控制信号。3.袖带压力过高。A/D转化器气动元件的控制第33页，本讲稿共64页BLOODPRESSURESt
32、ores up to 14 measurements.Prints stored measurements in both digital and bar graph form with time and date.Curved contour cuff fits arms 9”to 13”in circumference.Large digital display measures 1”x 3 1/2”.Includes zippered carrying case,2 rolls of thermal printing tape and instructions.Operates on 4
33、”C”batteries(not included).IntelliSense technology offers automated level setting and electronic deflation control 12 Memory storage Completely automatic,operates with a push of a button,and has a clear digital display Ultra compact design travels anywhere Quickly and accurately measures blood press
34、ure and pulse Fits writs 5 1/4 to 8 1/2 in circumference OMRON MEMORY,PRINT-OUT&GRAPH BLOOD PRESSURE MONITORHEM-705CPN HEM-609 第34页，本讲稿共64页BLOODPRESSURESamsung Blood Pressure Monitor 1000sLarge easy-to-read LCD panel Secure and comfortable arm cuff(fits arms 9-13)Standard cuff fits up to 13,larger c
35、uff available from manufacturer using a coupon enclosed in box Simple,one button automatic inflation Quiet,rolling motor inflation pump Automatic power conservation Pulse monitor The Heart Sense Automatic Blood Pressure MonitorThis exclusive system uses advanced technology to sense exactly how high
36、to inflate the arm cuff,automatically adjusting for each individual user.That means quick,easy blood pressure and pulse measurements every time.It also means comfortable home monitoring because the cuff will never be inflated higher than necessary.Heart Sense home blood pressure monitors are sensiti
37、ve to your needs-only from Samsung第35页，本讲稿共64页BLOODPRESSUREEW3111W Precise Logic Upper Arm Blood Pressure Monitor with 3 color light systemPrecise Logic TechnologyPanasonics own patented technology,Precise Logic,checks both the height and width of your pulse to provide you with measurements of clini
38、cally-proven accuracy and reliability.One Touch OperationTake your blood pressure and pulse rates easily with the touch of a button.Large LCD DisplayMakes your blood pressure and pulse rate results easy to read.Blood Pressure/Pulse Rate Display For immediate and reliable results,you can read blood p
39、ressure and pulse rate results at the same time.Measurement TrackingHelps you track your progress by storing the last 60 readings with the date and time indicated right in the monitor.第36页，本讲稿共64页BLOODPRESSURELight and PortableWherever you travel,this monitor is durable,portable and lightweight.At l
40、ess than 4 around and just over 4 ounces,you can check your blood pressure and pulse rate anywhere.Protective Hard CaseComes with a compact carrying case which protects the unit from damage and doubles as an arm rest for taking proper readings.Long-Lasting,Energy EfficientThe wrist units enable up t
41、o 400 readings on two AAA alkaline batteries(included).The arm units enable approximately 200 uses on four AA batteries(included).Range of Circumference Wrist units fit wrists from 5-1/4 to 7-3/4 around.(Available on all wrist models)Arm unit fit upper arms from 7-7/8 to 15-3/4.第37页，本讲稿共64页BLOODPRES
42、SUREHypertension(over 140)Normal/High(130-139)Normal(under129)SystolicHypertension(over90)Normal/High(over85-89)Normal(inder84)DiastolicPrecise Logic?Technology Yes Method of Measurement Oscillometric system with Precise Logic Technology Measuring Range Pressure:20-300 mmHg/Pulse:30-160 beats/minute
43、 Measuring Accuracy Pressure:+/-4mmHg;Pulse rate:+/-5%Range of Circumference Approx.7-3/4 to 15-3/4(20cm to 40cm)Power Source Four AA Batteries(included)Operating Environment 50-104 degrees F/30%-85%RH Accessories Cuff storage holder w/carrying handle Operation Time Up to 200 uses on four AA batteri
44、es(included)Memory 42 readings(21 readings x 2 persons)Measurement Tracking Yes Protective Hard Case No Dimensions(H x W x D)411/32 x 53/32 x 77/8 Weight 1.07 lbs 第38页，本讲稿共64页BLOOD PReSSUREHeine Sphygmomanometer This top model of the HEINE GAMMA Sphygmomanometer range features one tube system and a
45、new screw-type valve for precise selection of air release rate.The HEINE GAMMA 5.5 is an elegant precision instrument which is designed to last a lifetime.Screw-type valve system.All-metal case with matte chrome finish.Oversized inflator speeds up the inflation process.Big 60 mm scale is clear and e
46、asy to read.Detachable rubber ring protects instrument and glass.Patented“2 in 1”tube design.Microfilter protects valve and pressure proof manometer.Gamma 5.5 with adult cuff(14 cm)and pouch.第39页，本讲稿共64页BLOODPRESSURETycos ProCheck TR2-Sphygmomanometer Lightweight and compact,the Tycos TR-2 hand aner
47、oid provides portability in an affordably priced,hand-held design.The trigger-release air valve is positioned for optional left or right-handed use and allows for easy fingertip control of cuff deflation.Large easy-to-read dial face with bright graphics.Balanced palm design allows for comfortable us
48、e over repeated measurements.Meets AAMI accuracy standard of 3mmHg.Comes in a zippered case.Five year warranty.All latex free 第40页，本讲稿共64页BLOODPRESSUREABPM(Ambulatory Blood Pressure Monitoring)Ambulatory blood pressure measurement(ABPM)is becoming more and more popular as a standard method in clinic
49、al practice.Due to various inaccuracies and phenomenons associated with conventional Riva-Rocci/Korotkoff technique of blood pressure measurement(e.g.white-coat hypertension),the method of ambulatory blood pressure measurement is becoming increasingly popular as a standard in clinical practice.INTRO
50、DUCTIONAdvantages of ABPM Series of measurements More accurate documentation of blood pressure Blood pressure profile independent of medical environment,therefore:Documentation of blood pressure behaviour over 24-h period during daily life activities Identification of blood pressure characteristics