Reliability of transcardiopulmonary thermodilution cardiac output measurement in experimental aortic valve insufficiency.

Martin Petzoldt,Jan Ridder,Matthias S Goepfert,Constantin J Trepte,Hans Peter Richter,Jan F Kersten,Stefan Maisch,Philipp Klapsing,Jens C Kubitz,Daniel A Reuter,Yoshihiro Fukumoto

doi:10.1371/journal.pone.0186481

Abstract

BackgroundMonitoring cardiac output (CO) is important to optimize hemodynamic function in critically ill patients. The prevalence of aortic valve insufficiency (AI) is rising in the aging population. However, reliability of CO monitoring techniques in AI is unknown. The aim of this study was to investigate the impact of AI on accuracy, precision, and trending ability of transcardiopulmonary thermodilution-derived COTCPTD in comparison with pulmonary artery catheter thermodilution COPAC.MethodsSixteen anesthetized domestic pigs were subjected to serial simultaneous measurements of COPAC and COTCPTD. In a novel experimental model, AI was induced by retraction of an expanded Dormia basket in the aortic valve annulus. The Dormia basket was delivered via a Judkins catheter guided by substernal epicardial echocardiography. High (HPC), moderate (MPC) and low cardiac preload conditions (LPC) were induced by fluid unloading (20 ml kg-1 blood withdrawal) and loading (subsequent retransfusion of the shed blood and additional infusion of 20 ml kg-1 hydroxyethyl starch). Within each preload condition CO was measured before and after the onset of AI. For statistical analysis, we used a mixed model analysis of variance, Bland-Altman analysis, the percentage error and concordance analysis.ResultsExperimental AI had a mean regurgitant volume of 33.6 ± 12.0 ml and regurgitant fraction of 42.9 ± 12.6%. The percentage error between COTCPTD and COPAC during competent valve function and after induction of substantial AI was: HPC 17.7% vs. 20.0%, MPC 20.5% vs. 26.1%, LPC 26.5% vs. 28.1% (pooled data: 22.5% vs. 24.1%). The ability to trend CO-changes induced by fluid loading and unloading did not differ between baseline and AI (concordance rate 95.8% during both conditions).ConclusionDespite substantial AI, transcardiopulmonary thermodilution reliably measured CO under various cardiac preload conditions with a good ability to trend CO changes in a porcine model. COTCPTD and COPAC were interchangeable in substantial AI.

Highlights

In critically ill patients monitoring cardiac output (CO) can be the keystone in hemodynamic assessment and therapy in the operating theater or on the intensive care unit [1,2,3]
The percentage error between COTCPTD and COPAC during competent valve function and after induction of substantial aortic valve insufficiency (AI) was: High cardiac preload conditions (HPC) 17.7% vs. 20.0%, Moderate cardiac preload conditions (MPC) 20.5% vs. 26.1%, low cardiac preload conditions (LPC) 26.5% vs. 28.1%
COTCPTD and COPAC were interchangeable in substantial AI

Summary

Introduction

In critically ill patients monitoring cardiac output (CO) can be the keystone in hemodynamic assessment and therapy in the operating theater or on the intensive care unit [1,2,3]. Remarkably little is known about the reliability of CO monitoring devices in patients with valvular heart disease, in those with aortic valve insufficiency (AI) [6,7,8,9,10]. Thermal loss by conductive rewarming is considered to be promoted by the cyclic movement of the indicator in valvular regurgitation (prolonged travel of the indicator with increased escape to surrounding tissues) [12, 14]. Monitoring cardiac output (CO) is important to optimize hemodynamic function in critically ill patients. The aim of this study was to investigate the impact of AI on accuracy, precision, and trending ability of transcardiopulmonary thermodilution-derived COTCPTD in comparison with pulmonary artery catheter thermodilution COPAC

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