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

心输出量是危重患者测量的最重要的参数之一，目前用于测量心输出量的方法是推注热稀释技术，尽管推注热稀释技术被广泛认为是一种基于能量守恒定律的技术。根据临床标准，该技术仅提供间歇性信息，并且该过程非常耗时，因为血流动力学状态可能会迅速变化，连续心输出量监测将提供及时的信息，以便快速制定和调整治疗方法。持续监测心输出量使用连续热稀释技术测量心输出量是临床上可用的技术，使用肺动脉导管进行连续热稀释是一种无注射系统，它采用热丝来提供间歇性的每次碘量。该系统通过 30 秒的连续热稀释提供几分钟内的平均心输出量，为临床提供了可接受的准确性。然而，它不提供实时值，该值表示几分钟内的平均心输出量，它并不表示已使用多普勒超声技术来测量连续速度，从而测量心脏的实时值。这些技术在实时性方面是优越的，但是，由于它们对超声波束和当前方向之间的角度（多普勒角）的固有依赖性，它们会造成速度测量和心脏测量的误差。输出量测量。这些技术在临床上并不可靠，因此，我们开发了一种新型肺动脉多普勒导管，它克服了这种角度依赖性，可以连续准确地监测心输出量。我们的肺动脉多普勒导管是一种改良的 PA 导管。使用血管内超声技术测量肺动脉横截面积的管腔还通过在其远端尖端安装2个超声换能器晶体进行了改进，我们将多普勒超声技术与肺动脉导管导管相结合，并且还结合了血管内超声技术。因此，利用多普勒超声技术可以利用肺动脉的流速和横截面积来测量心输出量，一对超声换能器以固定角度安装在要定位的肺动脉导管的远端部分。多普勒频移（Δf1，Δf2）由在主肺动脉中间隔很近的两个点采样的两个传感器检测到，Δf1和Δf2的值用于计算两个速度测量值。使用以下公式计算肺动脉的真实流速：V=(V1)^2+(V2)^2)^<1/2>，其中V=真实速度，V1和V2=传感器1检测到的速度， 2. 使用新开发的相位微分技术计算速度，并使用血管内超声技术通过我们的肺动脉导管的特殊管腔来测量肺动脉的横截面积。肺动脉，血管内超声技术比经胸或经食管超声心动图更准确。关于连续心输出量测量，在IRB批准后，我们在动物实验中评估了我们新开发的肺动脉多普勒导管的可用性，我们发现通过我们新开发的肺动脉测量心输出量。多普勒导管给我们提供了准确的值，这可以适用于危重病人。使用新开发的肺动脉多普勒导管，我们能够连续测量心输出量，这种实时连续测量心输出量的技术优于其他改良技术。较少的热稀释技术。