To verify the reliability of different markers of fluid-responsiveness during off-pump cardiac surgery (OPCAB).
A clinical prospective, nonblinded, nonrandomized study.
A community hospital.
Pulmonary artery catheter (PAC), LiDCO (LiDCO, London, UK), and transesophageal echocardiography (TEE) parameters were measured before (t0) and after (t1) a fluid challenge was performed 20 minutes after induction of anesthesia, but before sternotomy and without inotropic infusion. A Student t test and Spearman test were performed for statistical analysis.
According to the variation of cardiac index after the fluid challenge (DeltaCI%), 2 groups of patients were identified: the responders (Re, DeltaCI% > 15%) and the nonresponders (nRe). Mean pulse pressure variation (PPV) and mean stroke volume variation (SVV) before the fluid challenge (t0) were significantly different between the 2 groups. No significant differences were shown in systolic pressure variation (SPV), left ventricular end-diastolic area, left ventricular end-diastolic volume, and peak changes of aortic flow (DeltaVAo). A statistically significant correlation was observed between DeltaCI% and PPV (R = 0.793), DeltaCI% and SVV (R = 0.809), and DeltaCI% and SPV (R = 0.766). No correlation with central venous pressure and pulmonary capillary wedge pressure was found.
Dynamic parameters of fluid responsiveness by LiDCO are highly sensitive for assessment of intravascular volume status during OPCAB surgery. In contrast, even if static parameters by TEE reflect changes in ventricular diastolic volume, they are poor indicators of fluid responsiveness. Surprisingly, no significant correlation between DeltaVAo (TEE) and DeltaCI% was found.
"In practice, LiDCO is commonly applied with a pulse contour analysis that allows continuous monitoring of cardiac output. This system has been shown to be clinically effective at predicting volume responsiveness even when compared to TEE. "
[Show abstract][Hide abstract] ABSTRACT: Intraoperative fluid management is pivotal to the outcome and success of surgery, especially in high-risk procedures. Empirical formula and invasive static monitoring have been traditionally used to guide intraoperative fluid management and assess volume status. With the awareness of the potential complications of invasive procedures and the poor reliability of these methods as indicators of volume status, we present a case scenario of a patient who underwent major abdominal surgery as an example to discuss how the use of minimally invasive dynamic monitoring may guide intraoperative fluid therapy.
"Biais et al.  found acceptable limits of agreement between stroke volume variation derived by arterial pulse contour analysis using the FlowTrac/Vigileo device and transesophageal aortic flow Doppler. In contrast, Belloni et al.  showed that there was not a good correlation between pulse contour derived stroke volume variation using the LiDCO device and transesophageal parameters, including aortic flow-derived stroke volume variation and end-diastolic and end-systolic left ventricular areas. This discrepancy could also be impressively demonstrated in a small series of cardiac surgery patients, in which both, Doppler derived measurements of beat to beat stroke volume, and those derived from a peripheral (radial artery) arterial pulse contour signal were compared against measurements with a flow probe placed around the aorta (i.e. "
[Show abstract][Hide abstract] ABSTRACT: The goal of hemodynamic monitoring and management during major surgery is to guarantee adequate organ perfusion, a major prerequisite for adequate tissue oxygenation and thus, end-organ function. Further, hemodynamic monitoring should serve to prevent, detect, and to effectively guide treatment of potentially life-threatening hemodynamic events, such as severe hypovolemia due to hemorrhage, or cardiac failure. The ideal monitoring device does not exist, but some conditions must be met: it should be easy and operator-independently to use; it should provide adequate, reproducible information in real time. In this review we discuss in particular the role of intraoperative use of transesophageal echocardiography (TOE). Although TOE has gained special relevance in cardiac surgery, its role in major non cardiac surgery is still to be determined. We particularly focus on its ability to provide measurements of cardiac output (CO), and its role to guide fluid therapy. Within the last decade, concepts oriented on optimizing stroke volume and cardiac output mainly by fluid administration and guided by continuous monitoring of cardiac output or so called functional parameters of cardiac preload gained particular attention. Although they are potentially linked to an increased amount of fluid infusion, recent data give evidence that such pre-emptive concepts of hemodynamic optimization result in a decrease in morbidity and mortality. As TOE allows a real time direct visualization of cardiac structures, other potentially important advantages of its use also outside the cardiac surgery operation room can be postulated, namely the ability to evaluate the anatomical and functional integrity of the left and the right heart chambers. Finally, a practical approach to TOE monitoring is presented, based on a local experience.
Current Cardiology Reviews 08/2011; 7(3):184-96. DOI:10.2174/157340311798220511
"The recently introduced LiDCO monitoring system (LiDCORapid; LiDCO Group Ltd, London, UK) consists of an arterial pressure waveform analysis that provides beat-to-beat measurement of CI by analysis of the arterial blood pressure tracing. The underlying pulse power algorithm (PulseCO) originally was introduced as an algorithm requiring calibration by lithium indicator dilution to determine the individual vascular compliance and has been evaluated in different clinical scenarios [16,17]. Using a nomogram to assess the patient specific aortic compliance, the new software version estimates stroke volume without the need for calibration. "
[Show abstract][Hide abstract] ABSTRACT: Uncalibrated arterial pulse power analysis has been recently introduced for continuous monitoring of cardiac index (CI). The aim of the present study was to compare the accuracy of arterial pulse power analysis with intermittent transpulmonary thermodilution (TPTD) before and after cardiopulmonary bypass (CPB).
Forty-two patients scheduled for elective coronary surgery were studied after induction of anaesthesia, before and after CPB respectively. Each patient was monitored with the pulse contour cardiac output (PiCCO) system, a central venous line and the recently introduced LiDCO monitoring system. Haemodynamic variables included measurement of CI derived by transpulmonary thermodilution (CITPTD) or CI derived by pulse power analysis (CIPP), before and after calibration (CIPPnon-cal., CIPPcal.). Percentage changes of CI (ΔCITPTD, ΔCIPPnon-cal./PPcal.) were calculated to analyse directional changes.
Before CPB there was no significant correlation between CIPPnon-cal. and CITPTD (r2 = 0.04, P = 0.08) with a percentage error (PE) of 86%. Higher mean arterial pressure (MAP) values were significantly correlated with higher CIPPnon-cal. (r2 = 0.26, P < 0.0001). After CPB, CIPPcal. revealed a significant correlation compared with CITPTD (r2 = 0.77, P < 0.0001) with PE of 28%. Changes in CIPPcal. (ΔCIPPcal.) showed a correlation with changes in CITPTD (ΔCITPTD) only after CPB (r2 = 0.52, P = 0.005).
Uncalibrated pulse power analysis was significantly influenced by MAP and was not able to reliably measure CI compared with TPTD. Calibration improved accuracy, but pulse power analysis was still not consistently interchangeable with TPTD. Only calibrated pulse power analysis was able to reliably track haemodynamic changes and trends.
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