Continuous cardiac output measurements with a newly developed pulmonary artery Doppler catheter.

十多年来，一直在开发一种连续测量心输出量的方法。虽然血管内超声技术已被用于连续测量心输出量，但超声波束和血流之间的入射角是一个问题，这将构成速度测量和心输出量测量的误差。我们新研制的肺动脉多普勒导管可以提供与超声和血流形成的入射角无关的真实血流速度。在肺动脉导管的远端安装一对固定角度的超声换能器，以定位于主肺动脉。用两个探头在主动脉间隔较近的两个点采样，检测多普勒频移(DELTAf1、DELTAF2)。用DELTAF1和DELTAF2的值计算两个流速测量值，得到的肺动脉真实流速为…用下列公式计算：V=((V1)^2+(V2)^2)1/2；其中V=真速度，V1和V2=传感器1和2检测到的速度。用新发展的相位差分技术计算速度。同时测定热稀释法的心输出量和肺动脉真实血流速度。然后根据肺动脉的真实血流速度连续计算心输出量。在IRB批准后，对肺动脉多普勒导管(日本东京ALOKA)进行了动物实验评估。麻醉犬(19~30 kg)将多普勒导管前移至肺动脉。开胸手术后，在肺动脉周围放置电磁血流探头。心输出量采用肺动脉多普勒导管、热稀释法和电磁流量计三种方法同时测量，并比较三种方法的相关性，其中CO-多普勒与CO-EMF高度相关(Y=1.16x-0.27，r^2=0.99，n=71，p&lt；0.001)。CO-多普勒与CO-Thermo也呈正相关(r^2=0.72)。使用新研制的肺动脉多普勒导管，我们能够连续估测心输出量。我们提出的技术在实时测量心输出量方面优于其他用于连续心输出量监测的改良热稀释技术。较少

Development of a method for continuous cardiac output measurements has been under way over a decade. Although intravascular ultrasound techniques have been used for measuring cardiac output continuously, a problem would be the angle of incidence between the ultrasound beam and the blood flow, which would constitute the errors in velocity measurements and in cardiac output measurements. We newly developed pulmonary artery Doppler catheter which could provide true flow velocity independent of the angle of incidence formed by the ultrasound beam and the flow.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 (DELTAf1, DELTAF2) were detected by two transducers sampling at closely spaced two points in the main pulmonary artery. The values of DELTAF1 and DELTAf2 were used to compute two velocity measurements, and true flow velocity of pulmonary artery was … More 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. Cardiac output by thermodilution technique and true flow velocity of pulmonary artery were measured simultaniously. Then, cardiac output was calculated from true flow velocity of pulmonary artery continuously. After IRB approval, the pulmonary artery Doppler catheter (Aloka, Tokyo, Japan) was evaluated in animal experiments. The Doppler catheter was advanced to the pulmonary artery of anesthetized dogs (19-30kg). After thoracotomy, an electromagnetic flow probe was placed around the pulmonary artery. Cardiac output was measured by the pulmonary artery Doppler catheter (CO-Doppler), by thermodilution method (CO-Thermo) and by electromagnetic flowmeter (CO-EMF) simultaneously, and CO-Doppler, Co-Thermo and CO-EMF were compared.Co-Doppler was highly correlated with CO-EMF (Y=1.16x-0.27, r^2=0.99, n=71, p<0.001). CO-Doppler was also correlated with CO-Thermo (r^2=0.72).Using a newly developed pulmonary artery Doppler catheter, we are able to estimates cardiac output continuously. Our technique presented would be superior in measuring cardiac output at real time basis than other modified thermodilution techniques for continuous cardiac output monitoring. Less