Agreement Between Continuous Non-invasive Arterial Blood Pressure Monitoring and Pulmonary Artery Catheter-guided Thermodilution in Estimating Haemodynamic Parameters After Coronary Artery Bypass Graft Surgery

Background: Pulmonary artery catheter-guided thermodilution (PACT) has traditionally served as the gold standard for evaluating cardiac output. Nevertheless, its invasive nature has been linked with heightened procedural complexity and potential complications. The introduction of innovative non-invasive tools, such as continuous non-invasive arterial blood pressure monitoring (CNAP), has opened doors to alternative approaches for haemodynamic monitoring. Compared with invasive techniques, CNAP is more user-friendly, carries a lower risk of infection and is more cost-effective. The aim of this study was to determine the agreement between CNAP and PACT in monitoring haemodynamic parameters. Methods: This prospective study included 63 patients who underwent elective coronary artery bypass grafting. Cardiac output (CO), cardiac index, stroke volume and systemic vascular resistance were obtained simultaneously using both CNAP and PACT. Three consecutive sets of measurements were recorded for each patient at 3-hour intervals. Results: The mean differences in CO between PACT (PACT-CO) and CNAP (CNAP-CO) immediately after surgery and 3 and 6 hours after the procedure were −0.81, −0.81 and −0.77 l/min, respectively. These findings indicate a significant difference between PACT and CNAP measurements. Nevertheless, the correlation coefficient at the 0-, 3- and 6-hour time points was 0.5384, 0.5158 and 0.6265, respectively, indicating a positive correlation between PACT-CO and CNAP-CO. Conclusion: CNAP-derived haemodynamic parameters had a high mean difference compared with PACT, suggesting that there was no agreement between the two methods. However, there was a positive correlation between PACT-CO and CNAP-CO, making it possible for CNAP to track haemodynamic changes when other invasive methods are not available.