Comparison of cardiac output using invasive (Pulmonary Artery catheter Continuous cardiac Output), less invasive (FloTrac) and non invasive (Pulse Wave Transit Time) methods in patients undergoing off pump coronary artery bypass grafting

Abstract

Aim and Objective: This study was undertaken in patients undergoing off-pump coronary artery bypass grafting (OPCABG) with aim of comparing cardiac output using invasive pulmonary artery catheter continuous cardiac output (PAC CCO), less invasive (FloTrac pulse contour based) and non invasive pulse wave transit time (PWTT) methods. Materials and Methods: Longitudinal observational study carried out in the department of Anesthesiology (CVTS OT) of super speciality hospital tertiary care hospital run by state Government with total 995 data sets taken from 25 subjects undergoing off pump coronary artery bypass grafting. Swan Ganz pulmonary artery catheter was inserted through the right internal jugular vein through introducer sheath and attached to the Edward vigilance II continuous cardiac output monitor for continuous monitoring of cardiac output invasively. Similarly cardiac output was measured with less invasive (FloTrac) monitor attached to a dedicated left femoral artery line. Non invasive (Estimated Continuous cardiac output (esCCO) based on pulse wave transit time) monitor attached to ECG and Spo2 probe sensor & calibration done with non –invasive blood pressure (NIBP) and the required demographic characteristics entered. Results: Mean cardiac output assessed by invasive, less invasive and non invasive method was 3.91+/-0.87, 5.71+/-0.87 and 6.03 +/- 0.99 L/min respectively. There was poor correlation between less invasive and the invasive with r=0.25 and also poor correlation between non-invasive and invasive with correlation coefficient of r=0.27. Both less invasive (FloTrac) and non invasive methods (PWTT) showed higher estimation when compared to the invasive (PAC CCO). The Bland Altman analysis showed poor agreement between less invasive (FloTtrac) and the invasive (PAC CCO) method, whereas the non invasive (PWTT based esCCO) showed good agreement. Percentage error were 68% and 126% for non-invasive (PWTT based es CCO) and less invasive (FloTrac) respe