Agreement between cardiac output estimation by multi-beat analysis of arterial blood pressure waveforms and continuous thermodilution in post cardiac surgery intensive care unit patients

Abstract

We sought to assess agreement of cardiac output estimation between continuous pulmonary artery catheter (PAC) guided thermodilution (CO-CTD) and a novel pulse wave analysis (PWA) method that performs an analysis of multiple beats of the arterial blood pressure waveform (CO-MBA) in post-operative cardiac surgery patients. PAC obtained CO-CTD measurements were compared with CO-MBA measurements from the Argos monitor (Retia Medical; Valhalla, NY, USA), in prospectively enrolled adult cardiac surgical intensive care unit patients. Agreement was assessed via Bland-Altman analysis. Subgroup analysis was performed on data segments identified as arrhythmia, or with low CO (less than 5 L/min). 927 hours of monitoring data from 79 patients was analyzed, of which 26 had arrhythmia. Mean CO-CTD was 5.29 ± 1.14 L/min (bias ± precision), whereas mean CO-MBA was 5.36 ± 1.33 L/min, (4.95 ± 0.80 L/min and 5.04 ± 1.07 L/min in the arrhythmia subgroup). Mean of differences was 0.04 ± 1.04 L/min with an error of 38.2%. In the arrhythmia subgroup, mean of differences was 0.14 ± 0.90 L/min with an error of 35.4%. In the low CO subgroup, mean of differences was 0.26 ± 0.89 L/min with an error of 40.4%. In adult patients after cardiac surgery, including those with low cardiac output and arrhythmia CO-MBA is not interchangeable with the continuous thermodilution method via a PAC, when using a 30% error threshold.

Bias, trending ability and diagnostic performance of a non-calibrated multi-beat analysis continuous cardiac output monitor to identify fluid responsiveness in critically ill patients

“…CCO MBA displayed varying bias ranging between −0.15 L.min −1 to 0.90 L.min −1 with percentage errors between 38.2% and 70% in mixed ICU post-operative populations, using transesophageal doppler or pulmonary artery thermodilution as the reference method. [4] , [5] , [6] , [7] On the other hand, concordance rates depicting the accuracy of the device to detect changes in CCO were frequently adequate, above 88%. Most studies excluded patients with arrhythmia and with inadequate arterial line damping characteristics, and focused on post-cardiac surgery patients, in which median CCO values were below those measured in the present study.…”

“… 3 The device had the advantage of connecting directly to the AP module of the ICU monitor, without requiring changing the arterial catheter. The device analyses the AP waveform over multiple heartbeats to account for confounding wave reflections and was identified as having a percentage error >30% in a post-cardiac surgery population, [4] , [5] , [6] , [7] , [8] but its diagnostic performance to predict fluid responsiveness remains to date unknown. On the other hand, devices calibrated using transpulmonary thermodilution assess CCO with potentially higher precision (below the 30% percentage error) using pulse-contour analysis of AP waveform, at the price of requiring the placement of specific catheters and frequent recalibration.…”