Concordancia de la evaluación de tres medidas del gasto cardiaco en pacientes adultos para cirugía cardiaca del hospital cardiovascular del niño de Cundinamarca
Mejía Ortiz, Claudia Patricia | 2016-01-08
Introduction: The standard way to measure cardiac output is through thermodilution, which gives parameters that are widely known and evaluated. However, the main disadvantage is its invasiveness, which has been associated with several complications. Transesophageal Echocardiography offers a dynamic and functional alternative to thermodilution, enabling measurement of cardiac output by using measurements from either the mitral annulus or the left ventricle outflow tract.
Objective: To determine the correlation when measuring the cardiac output by two dimensional Transesophageal Echocardiography on the mitral valve annulus using four cameras compared to the measurement on the left ventricle outflow tract by deep gastric penetration obtained by thermodilution.
Methods: An observational study to measure correlation of readings was undertaken in 25 patients who were to have cardiovascular procedures that required pulmonary artery catheterization and ETE. Their cardiac outputs were measured on both the mitral annulus and the left ventricle outflow tract with echocardiography, and the results were compared to the measurements taken by thermodilution. Correlation was evaluated by using Lin's concordance correlation coefficient. All statistical analysis was undertaken in STATA 13.0.
Results: The average age of patient tested was 59 ± 15.2, the average ejection fraction was 39.8%, with 52% of those tested being male. The cardiac output measurement by thermodilution was, on average, 3.5 liters/minute, while the output measured on the left ventricle outflow tract was 3.8 liters/minute and 9.3 liters/minute on the mitral annulus. When the correlation was measured between the three measurements using Lin's concordance correlation coefficient, the values for thermodilution were different to the values that came from the mitral annular velocities (Lin concordance= 0.071; Confidence Interval 95% = -0.010 to 0.152), and, as such the values obtained from the TSVI manifested important discrepancies with those obtained by thermodilution (Lin concordance= 0.232; Confidence Interval 95% = -0.11 to 0.576).
Conclusions: The results from the cardiac output measurement by doppler and two dimensional transesophageal echocardiography on both the mitral annulus and the left ventricle outflow tract do not correlate with those obtained by thermodilution. Undoubtedly, transesophageal echocardiography in early post-operation, when the doctor is faced with a low postoperative cardiac output, regularly provides additional information in real time.