COMPARISON OF NON-INVASIVE CARDIAC OUTPUT MEASUREMENT USING INDIGENOUS IMPEDANCE CARDIOGRAPHY (ICG) WITH INVASIVE FICK METHOD

Introduction: Cardiac output (CO) is a functional tool to evaluate the cardiovascular performance. To estimate CO, several invasive methods like the Fick method and thermodilution method are available which require catheterization of the patient. Impedance cardiography (ICG) is well-established noninvasive technique for measurement of cardiac output. The cardiac output monitor based on ICG has been indigenously designed and developed by Bhabha Atomic Research Center, Mumbai. For validatation of this indigenous equipment, we compared measurement of cardiac output using ICG with conventional Fick method. Materials and methods: We simultaneously measured cardiac output in 10 patients (mean age 40 years, range 21-54 years, 6 males and 4 females) using impedance cardiography versus that derived after utilization of Fick’s principle in cardiac catheterization laboratory patients undergoing cardiac catheterization. We compared the cardiac indices obtained by two methods. Results: There is a very good correlation (r=0.9, for n=10) between the cardiac index obtained by impedance cardiography and that derived invasively after cardiac catheterization using the Fick method. The mean values of cardiac indices by ICG method and the Fick method were 3.8±0.6 l/min/m2 and 2.9±0.5 l/min/m2 respectively. The average bias from the ICG to Fick is 0.8 l/min/m2 whereas individual variability is 0.3 l/min/m2. Conclusion: These results support use of this indigenous ICG equipment in patient care for monitoring cardiac output measurement with the further validation.