MEASUREMENT OF CARDIAC OUTPUT, INTRACARDIAC SHUNTS AND VALVULAR REGURGITATION USING NEW THERMODILUTION APPARATUS

Introduction. Commercially available thermo-dilution apparatus for measurement of cardiac output (CO) are not able to assess intracardiac shunts (IS). Aim of our study was to develop a method and computer based instrumentation assessing all three basic flow parameters: CO, IS and regurgitation. We were not able to find any reference about such apparatus in the literature.
Apparatus: We have developed a thermo-probe which is 0.035 inch in diameter which can be inserted through the diagnostic 5F catheter. Thermic signal is fed through the interface into computer which measures continuously temperature of the blood, extrapolates the curve, calculates flow, displays the curve and all data on screen and produces hard copies, all on line during the procedure.
Results: Altogether 771 dilution curves were recorded in 116 patients. Using our apparatus we measured CO simultaneously with commercially available Braun instrument (BI) in 49 patients. Mean value was 5.02 l/min (SD 0.227), while by BI 4.98 l/min (SD 0.315), r=0.954. L-R was assessed in 37 patients and good correlation was found with oximetry: r =0.936. We measured R-L in 23 patients at rest and during Valsalva maneuver. Aortic regurgitation was estimated in 4 patients and tricuspid in 3 patients.
Conclusions. The method is fast, precise and safe using cheep indicator. It gives flow parameters in absolute values (l/min), provides unequivocal data and it is applicable even in infants. Sensitivity of the method is about 10 times higher than oximetry .