Continuous cardiac output measurements using a newly developed pulmonary artery Doppler catheter combined with intravascular ultrasound tehnique.

使用新开发的肺动脉多普勒导管结合血管内超声技术进行连续心输出量测量。

基本信息

批准号：
09557126
负责人：
AKAMATSU Shigeru
金额：
$ 5.12万
依托单位：
Gifu University School of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

项目摘要

Cardiac output is one of the most crucial parameters measured in critically ill patients. The current procedure used to measure cardiac output has been as bolus thermodilution, a technique based on the law of conservation of energy. Although the bolus thermodilution technique is widely accepted as the clinical standard, the technique provides only intermittent information, and the procedure is time-consuming. In critically ill patients, as hemodynamic status may change rapidly, continuous cardiac output monitoring would provide timely information to permit rapid institution and adjustment of therapy. Various technologies for continuous monitoring of cardiac output have been examined by many researchers and clinicians for overa decade.Measurement of cardiac output using continuous thermodilution technique is technology clinically available. Continuous-thermodilution using pulmonary artery catheter is an injectless system, which incorporates a thermal filament to provide intermittent per … More iods of heat, which is sensed by a distal thermistor. This system provides the average cardiac output over several minutes with a 30-second update. Continuous thermodilution provides acceptable accuracy for clinical situalion, however, it does not provide real-time values. The value indicates the average cardiac output over several minutes, it does not indicate real-time value. Doppler ultrasound techniques have been used for measurement of continuous velocity and, thus, of cardiac output. These techniques are superior in real time basis, however, they suffer from inaccuracy because of their inherent dependency on the angle between the ultrasound beam and the now direction(Doppler angle). Doppler angle would constitute the errors in velocity measurements and in cardiac output measurements. Cardiac output measured by these techniques would not be reliable clinically. So, We have devdoped a new pulmonary artery Doppler catheter, which overcomes this angle dependency, to accurately monitor cardiac output continuously.Our pulmonary artery Doppler catheter is a modified PA catheter. The catheter has a special lumen for measurement of cross sectional area of pulmonary artery using intravascular ultrasound technique. The catheter was also modified by mounting 2 ultrasound transducer crystals on its distal tip. We combined Doppler ultrasound technique with pulmonary artery catheter, and also combined intravascular ultrasound technique with Doppler ultrasound technique. Thus, cardiac output is able to measure using flow velocity and cross-sectional area of pulmonary artery. A pair of ultrasonic transducers positioned at a fixed angle was mounted on the distal section of pulmonary artery catheter to be positioned in the main pulmonary artery. The Doppler shifts(Δf1, Δf2)were detected by two transducers sampling at closely spaced two points in the main pulmonary artery. The values of Δf1 and Δf2 were used to compute two velocity measurements, and true flow velocity of pulmonary artery was calculated using following equation : V=(V1)^2+(V2)^2)^<1/2>, where V=true velocity, V1 and V2 =velocity detected by the transducer 1 and 2. The velocities were calculated using newly developed phase differential techniques. Cross-sectional area of pulmonary artery was revealed and measured using intravascular ultrasound technique through the special lumen of our pulmonary artery catheter. For the measurements of cross-sectional area of pulmonary artery, intravascular ultrasound technique is more accurate than transthoracic or transecophageal echocardiography. Regarding to continuous cardiac output measurements, after IRB approval, we evaluated the availability of our newly developed pulmonary artery Doppler catheter in animal experiments. We found that cardiac output measured by our newly developed pulmonary artery Doppler catheter gave us accurate value, which could applicable for critically ill patients.Using a newly developed pulmonary artery Doppler catheter, we are able to continuously measure cardiac output. This technique for continuously measuring cardiac output in real time is superior to other modified thermodilution techniques. Less

心输出量是重症患者中最关键的参数之一。用于测量心输出量的当前程序是推注热稀释性，这是一种基于能源保护定律的技术。尽管推注热技术被广泛接受为临床标准，但该技术仅提供间歇性信息，并且该过程耗时。在重症患者中，随着血液动力学状态可能会迅速变化，持续的心输出监测将提供及时的信息，以允许快速机构和调整治疗。十多年来，许多研究人员和临床医生都检查了各种用于对心输出量进行持续监测的技术。使用连续热稀释技术对心脏输出的测量在临床上是技术可用的。使用肺部伪像的连续热稀释是一个无注射的系统，它结合了热丝，可提供间歇性的每人……更多的热量热量，这是通过远端热溶性感所感受到的。该系统提供了几分钟的平均心脏输出，并进行了30秒的更新。连续热稀释为临床情况提供了可接受的准确性，但是它不提供实时值。该值表示在几分钟内的平均心输出量，这并不表示实时值。多普勒超声技术已用于测量连续速度，从而测量心脏输出。这些技术在实时的基础上是优越的，但是由于它们固有地依赖超声梁和现在的方向（多普勒角），它们遭受了不准确性。多普勒角将构成速度测量和心输出测量中的误差。这些技术测量的心输出在临床上不会可靠。因此，我们已经开发了一个新的肺动脉多普勒导管，该导管克服了这种角度的依赖性，以连续准确监测心脏输出。该导管具有特殊的管腔，用于使用血管内超声技术测量肺动脉横截面区域。还通过将2个超声传感器晶体安装在其独特的尖端上，可以修饰导管。我们将多普勒超声技术与肺动脉导管相结合，还将血管内超声技术与多普勒超声技术相结合。这是，心输出量能够使用肺动脉的流速度和横截面面积来测量。将位于固定角度的一对超声传感器安装在肺动脉导管的远端部分，该肺动脉导管位于主肺动脉中。通过在主肺动脉的两个近距离两点取样的两个换能器中检测到多普勒偏移（ΔF1，ΔF2）。 values of Δf1 and Δf2 were used to compute two velocity measurements, and true flow velocity of pulmonary artery was calculated using following equation: V=(V1)^2+(V2)^2)^<1/2>, where V=true velocity, V1 and V2 =velocity detected by the transducer 1 and 2. The velocities were calculated using newly developed phase differential技术。通过血管内超声技术通过我们的肺部伪像的特殊腔体揭示并测量了肺动脉的横截面区域。对于肺部伪像的横截面区域的测量，血管内超声技术比经胸膜或经植物学超声心动图更准确。关于连续的心输出量测量，IRB批准后，我们评估了在动物实验中新开发的肺部伪像多普勒导管的可用性。我们发现，通过新发展的肺动脉多普勒导管测量的心脏输出使我们获得了准确的价值，这可能适用于重症患者。使用新发育的肺动脉多普勒导管，我们能够连续测量心脏输出。这种用于实时连续测量心脏输出的技术优于其他改良的热氧化技术。较少的