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At least 19 recordsLinked to original sources
PubMed1978

Some aspects of the clinical use of thermodilution in measuring cardiac output. With particular reference to the Swan-Ganz thermodilution catheters.

Accuracy of the thermodilution method in measuring cardiac output was tested in a model and against Fick in ten patients. Reproducibility was determined from 573 thermodilution curves. The influence of catheter position, catheter irrigation, post-injection aspiration, and the substitution of rectal temperature for central blood temperature was also studied. The thermodilution method showed very good correlation to direct measurements in the model (corr. coeff. 1.00) and the Fick method in patients (corr. coeff. 0.97). Mean standard deviation for cardiac outputs calculated from individual thermodilution curves was 5%. Post-injection aspiration and variation in catheter tip location did not influence the results. Catheter irrigation during recordings and the use of rectal temperature for TB resulted in underestimation of cardiac output.

Calibration↗
PubMed1977

Monitoring of cardiac output by thermodilution after open-heart surgery.

One hundred twenty-five separate cardiac output determinations were obtained after open-heart surgery in 10 patients by simultaneous use of thermodilution and dye-dilution techniques. Mean thermodilution cardiac output was 1.6 per cent greater than mean dye-dilution cardiac output (5.24 versus 5.16 L. per minute). Reproducibility of thermodilution cardiac output (coefficient of variation, 8.6 per cent) was superior to that of dye-dilution cardiac output (coefficient of variation, 12.3 per cent) for outputs ranging from 2.5 to 8.7 L. per minute (p less than 0.001). Linear regression analysis revealed a correlation showing that COtd = 0.86 COdye + 0.80 (r = 0.9, p less than 0.001) and indicating a similarity between thermodilution and dye-dilution output figures except in extremely low output states. In such cases, thermodilution cardiac output becomes progressively larger than dye-dilution cardiac output. The results indicate that thermodilution cardiac output is a valid method for determining cardiac output in the rapidly changing clinical setting following cardiopulmonary bypass. Clinical applications of this technique include evaluation of the efficacy of inotropic agents, effectiveness of intra-aortic balloon counterpulsation, and status of the low output syndrome postoperatively. Routine use in patients with Class III or IV cardiac disease appears justified.

Cardiac Output↗
PubMedDate not supplied

Thermodilution measures of right ventricular ejection fraction and volumes in heart transplant recipients: a comparison with radionuclide angiography.

A reliable, convenient measure of right ventricular ejection fraction may be a useful adjunct to evaluate cardiac allograft rejection. The purpose of this investigation was to compare two measures of right ventricular ejection fraction: (1) radionuclide angiography with the first-pass technique and (2) thermodilution with a balloon flotation catheter. The study was performed in 26 heart transplant recipients; hemodynamics, thermodilution cardiac output, and right ventricular ejection fraction were measured. First pass radionuclide angiography was performed either simultaneously (n = 11) or within 4 hours (n = 15) of the thermodilution study. Mean thermodilution right ventricular ejection fraction was 39% +/- 8%, and radionuclide angiography ejection fraction was 47% +/- 9%, which represents a highly significant difference (p < 0.001) in techniques. Linear regression showed no correlation between the two techniques (r = 0.3; p = NS). No differences in results were observed in those studied simultaneously versus less than 4 hours. We conclude that the thermodilution technique underestimates right ventricular ejection fraction in heart transplant recipients and that its usefulness as a tool to screen for systolic dysfunction related to rejection is limited.

Cardiac Catheterization↗
PubMed1979

Cardiac output measurement by thermodilution.

The accuracy of thermodilution for measuring cardiac output was studied by comparing this method with measurements obtained by an electromagnetic flowmeter in the dog. Thermal curves were computed by a cardiac output computer and absolute flows were obtained by pump calibration of the flowmeter. Regression analysis showed an excellent correlation (P less than 0.001) between thermodilution measurements with injectates at 0 degrees C and flowmeter measurements using either cannulating probes (n = 105, r = 0.98) or periaortic probes (n = 100, r = 0.96). With the use of normal room temperature injectates, a good correlation was also found with absolute flows (n = 75, r = 0.92, P less than 0.001). Thermodilution overestimated cardiac output by 3% to 9%. In 32 pairs of successive cardiac output determinations by thermodilution, there was no significant difference between the two measurements (P greater than 0.05). In eight patients cardiac output was measured postoperatively by thermodilution with injectates at 0 degrees C and 24 degrees C administered in rapid succession. Regression analysis of 50 pairs of measurements at the two temperatures showed a strong correlation between the two techniques (r = 0.96) and the two results were not significantly different (P = 0.00001).

Animals↗
PubMed1978

Cardiac output measured by thermodilution in infants and children.

To determine the accuracy and reproducibility of cardiac output determination by thermodilution (COT) in children, simultaneous outputs were measured by the Fick technique (COF) (using measured oxygen consumption) and thermodilution in 26 children, ranging in age from 8 to 86 months, who were undergoing cardiac catheterization. There was excellent correlation between mean output by thermodilution and by the Fick technique: COT = 1.10 COF -- 0.2 l/minute, R = 0.91. In three-quarters of the patients with COT differed by 15% or less and in none differed by more than 25%. Serial values of thermodilution outputs were reproducible in each patient with a SD of 5.5%. Our observations indicate that COT is accurate, reproducible, and valuable in the care of critically ill infants and children.

Cardiac Catheterization↗
PubMed1978

Determination of renal blood flow by thermodilution method.

The single bolus thermodilution method for measurement of renal vein blood flow was tested. In model experiments the thermodilution method was compared with graduated cylinder measurements over a flow range from 50 to 1050 ml/min. There was a good correlation between the two methods (r = 0.98) with a mean of differences of 5.2%. In eighteen patients measurements were performed in duplicate in thirty-one renal veins. Comparison was made between the first (x) and second (u) measurement--performed within 3 min. The correlation between the two was very good (r = 0.99; y = 1.03x - 11.48). In twelve patients bilateral renal vein blood flow measurements were performed simultaneous to blood flow measurement by PAH clearance. The correlation between total flow measured by thermodilution (y) and by the clearance method (x) was good (r = 0.98; y = 0.79x + 221). It is concluded that the thermodilution method requires catheterization of the renal veins, but is otherwise simple to perform, is inexpensive and gives reliable results. It is particularly advantageous when repeated measurements in the study of acute changes in renal haemodynamics is desirable.

Humans↗
PubMedDate not supplied

An assessment of cardiac output by thermodilution in infants and children following cardiac surgery.

A 4 F thermodilution catheter for measuring cardiac output was evaluated for accuracy and linearity in the laboratory and by comparison with the dye dilution method in infants and children following cardiac surgery. When 2 ml of 0 degrees C injectate were used, the correlation of computer determined flows to calibrated pump flows, over a range encountered clinically, was r = 0.998. The means of triplicate determinations by both the thermal and dye methods were compared in 8 of 25 patients and the comparison found to be favorable (r = 0.976). The complications of thermodilution catheter placement are described and related to the need for post-surgical chest x-ray and thermodilution recordings. The simplicity of the thermodilution technique and other advantages over the dye method in children, such as repeatability, and ease of calibration are discussed in relation to the increased flexibility in management which accrues.

Cardiac Catheterization↗
PubMed1979

Multiple cardiac output measurements in man. Evaluation of a new closed-system thermodilution method.

Cardiac output estimates by a new closed-system automatic injection thermodilution method (COI-TD) were compared serially with the direct Fick technique (COFICK) and the standard open-system manual injection thermodilution method (COTD). Comparison with cardiac outputs determined simultaneously by the direct Fick technique in 100 measurements involving ten patients showed close agreement with the new closed system method using both 25 degrees C and 3 degrees C injectates. The cardiac output range was between 1.9 to 11.6 L/min. The open-system manual injection thermodilution method under identical conditions produced a wide scatter of measurements when compared to the direct Fick technique. Reproducibility of simultaneous COI-TD and COTD measurements was examined in quadruplicate. The reproducibility of measurements was within 1.9 percent with COI-TD and 5.9 percent with the COTD method using both 25 degrees C and 3 degrees C injectates. The COI-TD method eliminates the technical problems of recirculation, unstable indicator baseline changes, thermal continuity, and reproducibility encountered with the current COTD method. Analysis of cardiac output by the closed-system automatic injection thermodilution method provides a simple, rapid, reproducible, and highly accurate method for multiple cardiac output measurements suitable for use at the bedside.

Cardiac Catheterization↗
PubMed1979

Simple method for measurement of cardiac output by thermodilution after cardiac operation.

Cardiac output by the thermodilution technique was measured by a new No. 2 Fr. transthoracic (2F-TT) thermistor catheter placed at cardiac operation into the pulmonary artery directly through the right ventricular outflow tract. Cold (0 degree C) 5% dextrose in water (D5W) was used as indicator and injected through a percutaneously placed central venous pressure (CVP) catheter in the jugular vein. Comparison to the No. 7 Fr. Swan-Ganz (7F-SG) catheter demonstrated a close correlation (r = 0.87) and almost identical mean thermodilution cardiac output values during 530 determinations in 10 patients. No difficulty was experienced in insertion or removal of the 2F-TT catheter and no bleeding complications were noted. Experiments in six dogs showed that variation in position of the tip of the CVP catheter within the superior vena caval venous system and right atrium was not a critical factor in measurement of thermodilution cardiac output. The thermodilution cardiac output technique in general and the ease of insertion, as well as the small size of the 2F-TT catheter, should make this method especially advantageous in infants and small children.

Cardiac Output↗
PubMed1976

Assessment of thermodilution cardiac output in small subjects.

Thermodilution cardiac output determinations were compared with dye-dilution measurements in normovolemic and hypovolemic puppies. Good correlation was achieved with small volumes of cold and warm saline. Injectate volumes and significant caval displacement of the injectate port did not significantly affect thermodilution output measurements. This study demonstrates that thermodilution is a reliable and practical method of cardiac output determination in small subjects and suggests that this technique may be useful in the clinical management of neonates and small infants.

Animals↗
PubMed1992

Thermodilution right ventricular ejection fraction measurement reproducibility--a study in patients undergoing coronary artery bypass graft surgery.

OBJECTIVE: To assess the effects of heart rate, right ventricular systolic performance (ejection fraction), chamber dimensions, and flow rate (cardiac index) on the reproducibility of algorithm-derived triplicate thermodilution right ventricular ejection fraction measurements. DESIGN: Prospective study; combined hemodynamic and echocardiographic clinical evaluation. SETTING: Operating room in a university hospital. PATIENTS: Twenty-one coronary artery bypass graft patients. MEASUREMENTS AND MAIN RESULTS: The right atrial delivery site was positioned by analysis of transduced pressure waveform and echocardiographic imaging of tracer agitated saline cavitations. Measurement reproducibility was quantified by determining the variation (standard deviation) within 101 triplicate thermodilution measurement sets. There was no significant relationship between measurement reproducibility and estimates of right atrial area (21.6 +/- 6.9 cm2), diameter (5.1 +/- 0.8 cm) and supero-inferior length (5.1 +/- 0.9 cm) and right ventricular maximal minor axis diastolic diameter (4.21 +/- 1.05 cm). Reproducibility was also unrelated to right ventricular end-diastolic volume index (97.9 +/- 32.7 mL/m2) and cardiac index (2.9 +/- 0.9 L/min/m2). Measurement reproducibility was directly related to mean right ventricular ejection fraction (0.39 +/- 0.14) and inversely related to heart rate (80.8 +/- 18.6 beats/min) (p < .01 and < .001, respectively). CONCLUSIONS: Thermodilution-derived right ventricular ejection fraction measurement reproducibility was unrelated to estimates of right atrial and ventricular dimensions and cardiac index. Measurement reproducibility was a direct function of right ventricular systolic performance and an indirect function of heart rate. Measurement should be interpreted with these constraints in mind.

Adult↗
PubMed1978

In vivo validation of a thermodilution method to determine regional left ventricular blood flow in patients with coronary disease.

Several methods have been used to measure left ventricular regional blood flow in humans. However, limitations and lack of validation in patients are major problems. A continuous thermodilution technique to measure regional left ventricular blood flow in patients with coronary disease was validated in vivo. This technique permits simultaneous assessment of venous blood flow draining predominantly from the anterior wall and of the total left ventricular effluent. Thermodilution measurements with simultaneous electromagnetic flowmeter recordings from anterior descending vein grafts were compared in patients with occluded or subtotally occluded anterior descending coronary arteries. The thermodilution method yielded values for both absolute anterior regional blood flow and changes in anterior regional flow that compared closely to anterior descending bypass graft flow measured independently. The multithermistor technique may be useful in monitoring flow effects of regional coronary disease over time, as well as in studies of agents purported to alter regional blood flow.

Blood Flow Velocity↗
PubMed1979

Measurement of postoperative cardiac output by thermodilution in pediatric and adult patients.

Serial cardiac output determinations were made by the thermodilution technique in 51 patients by means of a No. 2 Fr. thermistor catheter placed directly into the pulmonary artery at cardiac operation. Correlations were determined prospectively between thermodilution measurements of cardiac output and other commonly used indirect clinical parameters. Serial indicator dye-dilution curves were performed in 24 of these patients and compared with simultaneous thermodilution measurements. A high correlation (r = 0.97) was noted between dye curve measurements of cardiac output and thermal measurements. Statistically significant correlations were also seen between cardiac output and both the quality of the peripheral pulses and the duration of cardiopulmonary bypass, but no significant correlations were found between the measured cardiac outputs and other variables. This study confirms the necessity for direct measurement of cardiac output for its accurate assessment.

Adolescent↗
PubMed1976

On-line computation of cardiac output with the thermodilution method, using a digital minicomputer.

In the present study, several techniques for calculating cardiac output were evaluated in order to find an accurate technique suitable for on-line digital computation. The thermodilution method was evaluated by different calculation techniques and by comparing these techniques with electromagnetic flowmeter values. Comparison of thermal dilution curves, manually calculated by the log-normal and the exponential assumption, showed a correlation coefficient of 0.978 between the two methods, the former values being 11% higher. The exponential method correlated very well with the technique, using a correction factor for injection errors (r = 0.999). Since the exponential technique correlated well with the electromagnetic values (r = 0.84) and since it was less complicated than the technique, using correction factors, this technique was chosen for automation. Comparison of exponential calculated thermodilution values with a digital computer and manually, showed a correlation coefficient of 0.991. Therefore, it was concluded that on-line computation of thermodilution curves improves the applicability of the termodilution techniques as a means of measuring cardiac output.

Animals↗
PubMed1975

The peri-operative measurement of cardiac output in infancy by the thermodilution technique.

Cardiac output has been measured in infants by thermodilution during and after surgery. A method employing commerically available equipment has been developed. An animal model has been devised whereby right heart outputs of 210 ml to 2240 ml, measured by thermodilution, could be compared with left heart outputs measured by an aortic by-pass. The results of this study suggest that thermodilution is a simple, accurate method for measurement of cardiac output in infancy.

Age Factors↗
PubMed1976

Estimation of cardiac output in the horse by thermodilution techniques.

An evaluation and comparison of thermodilution technique with dye dilution technique was made in the computation of cardiac output in 39 conscious adult horses (av body wt, 450 kg). Estimation of cardiac output by thermodilution was found to compare favorably with values obtained from dye dilution when a volume of 30 to 40 ml at a temperature of 0 C was used. Difficulties in obtaining accurate thermodilution curves in the horse seem predominantly associated with errors in mixing and observation.

Animals↗
PubMed1979

Experimental evaluation of 2F transthoracic thermodilution cardiac outputs in small animals.

Cardiac output can be measured with a computer using a 2F transthoracic catheter placed during surgery. When injections are made into a central venous catheter, this technique allows for cardiac output measurements to be made in children with complex congenital heart disease not appropriate for placement of a transvenous pulmonary artery catheter. Using rabbits similar in size to the infants most likely to need this technique, 26 experimental comparisons of thermodilution and indocyanine green dye cardiac outputs were made with cardiac outputs as low as 0.2-0.4 liter/min. The relationship between green dye and thermodilution was statistically significant (p less than 0.001) and almost linear (r = 0.92). This documents the validity of both the 2F transthoracic catheter technique in the low range of cardiac outputs appropriate for infants and children.

Animals↗
PubMed1979

Comparative value of eight M-mode echocardiographic formulas for determining left ventricular stroke volume. A correlative study with thermodilution and left ventricular single-plane cineangiography.

Sixty-six consecutive patients without left ventricular volume overload, significant arrhythmia or significant pericardial effusion were examined by M-mode echocardiography immediately before diagnostic left- and right-heart catheterization. Using various echocardiographic measurements, left ventricular stroke volume (SV) was calculated according to eight different echocardiographic formulas (SVE) that have been proposed previously. At catheterization SV was also determined by thermodilution (SVT) and by single-plane left ventricular cineangiography in the right anterior oblique projection (SVA). When comparing SVE with SVT, the four formulas developed to calculate mitral or aortic flow failed (r = 0.10 to 0.54). As expected, poor correlations (r = 0.22 to 0.47) were also found when formulas used to calculate ventricular volumes from the ventricular diameter or SV from the change in diameter (left ventricular formulas) were used in coronary patients with grossly asymmetrical ventricular contraction patterns. When the use of the left ventricular formulas was confined to patients with symmetrical or almost symmetrical contraction, two formulas yielded favorable correlations of r = 0.84, SEE = 12.7 ml and r = 0.86, SEE = 12.2 ml, respectively. These correlations were comparable to the correlation between our two invasive reference techniques (r = 0.81; SEE = 12.2 ml). The comparison between SVE and SVA confirmed the results of the thermodilution study, though the correlations were generally weaker. We conclude that the formula of Teichholz et al., which was the best of all tested formulas, may be used to obtain a clinically useful estimate of SV in patients in whom symmetrical or almost symmetrical left ventricular contraction can be anticipated.

Aortic Valve↗