본 연구는 심초음파를 이용한 심박출량 측정의 정확성을 평가하고, 수의학에서 심박출량 측정을 위해 처음 적용되는 Automated Contour Tracking method (ACT method)와 다른 심초음파 측정 방법간의 비교를 위한 목적으로 실시되었다. 따라서 본 연구에서는 흡입마취된 비글견에서 심초음파를 이용한 세가지 심박출량 측정 방법 (modified Simpson's method, left ventricular outflow method 그리고 ACT method)과 절대적 표준법으로 사용되어 오고 있는 열희석법의 성적을 비교 분석하였다. 결과의 검정은 피어슨 상관계수와 선형 회귀 분석법을 사용하였다. 실험에 사용된 실험견은 심혈관계 및 전신상태에 이상이 없는 10마리 비글견이며 호흡마취 유도하에 평가가 실시되었다. 실험은 심초음파법으로 측정한 다음 연이어 열희석법으로 측정하는 순서로 진행되었다. 세 가지 심초음파 측정법들은 모두 열 희석법과 유의적인 상관관계(p < 0.05)에 있음을 알 수 있었고 특히, 세 가지 방법 중에서는 ACT method에서 상관관계가 가장 높음을 확인할 수 있었다. 본 실험에서 심초음파를 이용한 심박출량 측정법은 절대적인 심박출량을 제시하지 못하였다. 하지만 심박출량 측정의 절대적 표준법으로 사용되는 열희석법과 유의적인 상관관계가 있음이 확인 되었으므로 심박출량의 간접적인 정보로 활용함으로써 환자의 마취시에 발생할 수 있는 혈역학적 장애의 발견이나 교정을 위해서 유용하게 사용될 수 있음을 확인하였다.
본 연구는 심초음파를 이용한 심박출량 측정의 정확성을 평가하고, 수의학에서 심박출량 측정을 위해 처음 적용되는 Automated Contour Tracking method (ACT method)와 다른 심초음파 측정 방법간의 비교를 위한 목적으로 실시되었다. 따라서 본 연구에서는 흡입마취된 비글견에서 심초음파를 이용한 세가지 심박출량 측정 방법 (modified Simpson's method, left ventricular outflow method 그리고 ACT method)과 절대적 표준법으로 사용되어 오고 있는 열희석법의 성적을 비교 분석하였다. 결과의 검정은 피어슨 상관계수와 선형 회귀 분석법을 사용하였다. 실험에 사용된 실험견은 심혈관계 및 전신상태에 이상이 없는 10마리 비글견이며 호흡마취 유도하에 평가가 실시되었다. 실험은 심초음파법으로 측정한 다음 연이어 열희석법으로 측정하는 순서로 진행되었다. 세 가지 심초음파 측정법들은 모두 열 희석법과 유의적인 상관관계(p < 0.05)에 있음을 알 수 있었고 특히, 세 가지 방법 중에서는 ACT method에서 상관관계가 가장 높음을 확인할 수 있었다. 본 실험에서 심초음파를 이용한 심박출량 측정법은 절대적인 심박출량을 제시하지 못하였다. 하지만 심박출량 측정의 절대적 표준법으로 사용되는 열희석법과 유의적인 상관관계가 있음이 확인 되었으므로 심박출량의 간접적인 정보로 활용함으로써 환자의 마취시에 발생할 수 있는 혈역학적 장애의 발견이나 교정을 위해서 유용하게 사용될 수 있음을 확인하였다.
Echocardiographic measurements of cardiac output, including the modified Simpson's method, Automated Contour Tracking(ACT) method, and left ventricular outflow method are well described methods of evaluating cardiac function due to its reliability and the benefits of its non-invasive technique in hu...
Echocardiographic measurements of cardiac output, including the modified Simpson's method, Automated Contour Tracking(ACT) method, and left ventricular outflow method are well described methods of evaluating cardiac function due to its reliability and the benefits of its non-invasive technique in human medicine. The purpose of this study was to evaluate the accuracy of an echocardiography estimate of cardiac output in isoflurane-anesthetized beagle dogs and was to compare the ACT method to the other methods used in measurement of cardiac output. In healthy beagle dogs, cardiac output results by echocardiography estimate methods showed an excellent correlations with those by the thermodilution method (The modified Simpson's method : r = 0.815, $r^2=0.665$, y = 0.434x + 0.311 ; ACT method : r = 0.86, $r^2=0.748$, y = 0.391x + 0.242 ; ventricular outflow method : r = 0.691, $r^2=0.478$, y = 0.593x + 0.242). Among the results obtained, the ACT method showed the highest correlation coefficient. In conclusion, our study demonstrated that echocardiography estimate methods did not prove to be suitable in accurately measuring absolute cardiac output values but showed an excellent correlation with thermodilution method. Therefore, by using the measurement of cardiac output as supplemental data, echocardiography estimate methods can be used for detection and correction of hemodynamic disturbances during emergency and anesthesia in veterinary practice.
Echocardiographic measurements of cardiac output, including the modified Simpson's method, Automated Contour Tracking(ACT) method, and left ventricular outflow method are well described methods of evaluating cardiac function due to its reliability and the benefits of its non-invasive technique in human medicine. The purpose of this study was to evaluate the accuracy of an echocardiography estimate of cardiac output in isoflurane-anesthetized beagle dogs and was to compare the ACT method to the other methods used in measurement of cardiac output. In healthy beagle dogs, cardiac output results by echocardiography estimate methods showed an excellent correlations with those by the thermodilution method (The modified Simpson's method : r = 0.815, $r^2=0.665$, y = 0.434x + 0.311 ; ACT method : r = 0.86, $r^2=0.748$, y = 0.391x + 0.242 ; ventricular outflow method : r = 0.691, $r^2=0.478$, y = 0.593x + 0.242). Among the results obtained, the ACT method showed the highest correlation coefficient. In conclusion, our study demonstrated that echocardiography estimate methods did not prove to be suitable in accurately measuring absolute cardiac output values but showed an excellent correlation with thermodilution method. Therefore, by using the measurement of cardiac output as supplemental data, echocardiography estimate methods can be used for detection and correction of hemodynamic disturbances during emergency and anesthesia in veterinary practice.
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제안 방법
The mean value was used for comparison with the echocardiographic methods. All of the thermodilution studies were performed within one hour after the determination of cardiac output by echocardiographic measurements.
also suggested that use of the apical window has the advantage of providing a shallow ( 20 degrees) angle between the sound beam and left ventricular outflow (20). For accurate assessments of the aortic anulus diameter, the transducer was placed in the parasternal position to obtain a long-axis view of the left ventricle and the aortic valve in this study. According to Jannet et al.
The modified Simpson's method was used for volume measurement calculation. For this measurement, it was necessary to display a long-axis cross sectional image from the cardiac apex (apical four chamber view). If the frame rate is low, an end-diastole image and end-systole image may not be acquired within the start and end of measurement.
It is to author’s knowledge that this study was performed, for the first time in veterinary practice, to measure cardiac output via such method.
Left ventricular outflow method was determined by the results of the time-velocity integral (TVI), the cross-sectional area (CSA) of the aortic annulus, and heart rate. The aortic TVI was determined from a left apical five chamber view and aortic flow was recorded using continuous wave Doppler (Fig 2).
SSA-660A, TOSHIBA, Japan). The ACT measurement was performed as off-line analysis from two-dimensional echocardiographic single display and cine frameadvance playback mode. The modified Simpson's method was used for volume measurement calculation.
0 MHz sector transducer. The echocardiographic studies were performed with the animals in lateral recumbency over a cut-out in the examination table and images and measurements were obtained by scanning from beneath the animals. The echocardiographic studies were performed just before the determination of cardiac output by thermodilution method.
The purpose of this study was to evaluate the accuracy of echocardiography estimates of cardiac output in isofluraneanesthetized beagle dogs and compare ACT method to other methods used in the measurement of cardiac output.
Therefore, in the present study, three time injections were made at each time point and only results that fall under an appointed degree (< 10%) of agreement with each other were used to determine a mean cardiac output value and performed visual inspection of the thermodilution washout curve for the accuracy of the technique.
대상 데이터
Cardiac output measurements were performed in 10 beagle dogs. The results ranged from 0.
All dogs were evaluated for heart worm kit, thoracic radiographs, and electrocardiograms. The dogs were housed in indoor cages. Food and water were withheld for 12 hours before experiment.
The ultrasound machine (Xario® SSA-660A, TOSHIBA, Japan) was used with a 5.0 MHz sector transducer.
데이터처리
In the present study, statistical analyses were performed with Pearson's correlation coefficient and linear regression analysis.
Statistical analyses were performed with SPSS version 14.0 (SPSS Inc., Chicago, U.S.A.) Results of echocardiographic (the modified Simpson's method, left ventricular outflow method and the Automated Contour Tracking method) and thermodilution measurements of cardiac output were compared by use of Pearson's correlation coefficient with p-value< 0.05 and p-value < 0.01 considered statistically significant and linear regression analysis.
이론/모형
In this study, the thermodilution method was used to compare the cardiac output measurement to echocadigraphic techniques since the thermodilution method is considered as the golden standard. Thermodilution method is respectable, consistent, well reproducible and widely used method (9,21).
The modified Simpson's method was used for volume measurement calculation.
Fig 2. Two dimensional echocardiographic image of aortic annulus and continuous wave Doppler image of aortic flow by the left ventricular outflow method. Still-frame images of the heart during systoles in the right parasternal long-axis view (left), showing where the aortic anulus diameter is measured (dotted line), and in the left apical five-chamber view (right), illustrating the position of the sample volume immediately proximal to the aortic valve.
Fig 3. Two dimensional echocardiographic images of left ventricle by the ACT method. In the first image, the end-diastolic image by left apical four chamber view is displayed (A).
Two dimensional echocardiographic images of left ventricle by the modified Simpson’s method.
성능/효과
The excellent correlations were demonstrated between thermodilution method and three echocardiographic measurements of cardiac output (Table 2). Among the results obtained, the ACT method showed the highest correlation coefficient (r = 0.865, r2 =0.748, y = 0.391x + 0.242) (Table 2).
As shown in Table 1 and 2, over all analysis of the data pairs obtained in the study revealed a high correlation (the modified Simpson's method, left ventricular outflow method, the ACT method : r = 0.815, r = 0.691, r = 0.865, respectively) between thermodilution method and echocardiographic methods but mean cardiac output by echocardiographic methods was underestimated compared with thermodilution method.
Therefore, the ACT method in measurement of cardiac output has two advantages in comparison with other echocardiographic methods in this study. First, the ACT method is simple. If an operator appoints three points in cardiac apex and at the both junction of the cardiac muscle and the valve ring, the measurements of cardiac out would automatically estimated.
Second, the ACT method is accurate and quick. In this study, the ACT method showed the highest correlation coefficient with thermodilution method among the echocardiographic methods and short time (2 to 3 seconds) for trace of the endocardial boundary. However, the underestimation of cardiac output was similarly identified by foreshortened apical image in the present study.
If an operator appoints three points in cardiac apex and at the both junction of the cardiac muscle and the valve ring, the measurements of cardiac out would automatically estimated. Second, the ACT method is accurate and quick. In this study, the ACT method showed the highest correlation coefficient with thermodilution method among the echocardiographic methods and short time (2 to 3 seconds) for trace of the endocardial boundary.
The results ranged from 0.632 to 1.420 L/min (mean, 1.090 ± 0.249 L/min), 0.723 to 1.825 L/min (mean, 1.307 ±0.402 L/min), 0.639 to 1.363 L/min (mean, 0.943 ± 0.212 L/ min), and 1.213 to 2.786 L/min (mean, 1.795 ± 0.469 L/min) for the modified Simpson's method, left ventricular outflow method, the ACT method and thermodilution method, respectively (Table 1).
There were significant differences between the modified Simpson's method and thermodilution method (p <0.01), between left ventricular outflow method and thermodilution method (p < 0.05), and between the ACT method and thermodilution method (p < 0.01) (Table 1).
후속연구
Moreover, the results of anesthetized dogs with normal car- diovascular function are not a representative of those that could be considered practical in veterinary clinics. Therefore, additional studies in echocardiographic measurement of cardiac output in conscious dogs are needed to evaluate the practical aspects of clinical usefulness of the echocardiographic methods.
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