Performance of a minimally invasive uncalibrated cardiac output monitoring system (Flotrac™/Vigileo™) in haemodynamically unstable patients †

Abstract

Background. Early haemodynamic assessment is of particular importance in the evaluation of haemodynamically compromised patients, but is often precluded by the invasiveness and complexity of the established cardiac output (CO) monitoring techniques. The FloTrac TM /Vigileo TM system allows minimally invasive CO determination based on the arterial pressure waveform derived from any standard arterial catheter, and the algorithm underlying CO calculation was recently modified to allow a more precise estimate of aortic compliance.Methods. Using the new software, we studied 25 haemodynamically unstable patients who had a radial artery catheter and underwent invasive haemodynamic monitoring with the PiCCO TM system. PiCCO TM -derived transpulmonary thermodilution and pulse contour CO (reference-CO) were compared with the CO values obtained with the FloTrac TM /Vigileo TM system (AP-CO). Reported CO values are indexed to body surface area. Agreement between reference-CO and AP-CO recorded during routine clinical care was assessed using Bland -Altman statistics.Results. Overall bias between the reference-CO and the AP-CO (n¼324) was 0.68 litre min 21 m 22 with a high percentage error of +58.8% (95% limits of agreement +1.94 l min 21 m 22 ). There was a significant difference (P,0.001) between the radial and the femoral mean arterial pressures, and bias was significantly larger for a mean pressure difference of .5 mm Hg (0.93 vs 0.57 litre min 21 m 22 , P¼0.032). No connection was found between the norepinephrine dose and the CO agreement.Conclusions. Despite the updated algorithm, AP-CO still showed a limited agreement with the reference-CO and systematically underestimated the CO so that the method is not suitable to replace invasive CO monitoring at present.

Failure of the Flotrac?/Vigileo? (3.01) to Track Rapid Hemodynamic Changes in an Unstable Cardiac Surgical Patient

“…While similar observations were reported with earlier generations of the device [3], recent reports on newer software generations Flotrac™/ Vigileo™ (3.01) have reported more accurate measurements of cardiac output and stroke volume in patients with sepsis [4]. Our patient differs from this cohort in several ways.…”

Minimally Invasive Measurement of Cardiac Output during Surgery and Critical Care

“…However, our data can be compared with a recent review and meta-analysis of studies on the accuracy and precision of the FloTrac by Mayer et al 91 These authors found a percentage error of 44% for earlier versions of the device and 30% for later versions (v1.07ϩ), but this review excluded studies involving patients with hemodynamic instability or vasodilatory states, thus restricting their analysis to cardiac surgery alone. Subanalysis of our data for studies on the FloTrac found a percentage error of 47.3% for earlier versions and 44.7% for v1.07ϩ, but the latter contained two studies in septic or critically ill patients, 99,100 where high cardiac outputs and hemodynamic instability present greater challenges to the accuracy and precision of a measurement device. Therefore these results for the FloTrac still compared well with the other methods we have surveyed in the current review.…”

An Observational Comparative Study of Cardiac Index Estimated By FloTrac and Intermittent Thermo Dilution in Off-Pump Coronary Artery Bypass Grafting

“…Critchley and Critchley proposed that the acceptance of any method of determination of CO should be judged against the accuracy of the reference method which is till date considered being the ITD method obtained by PAC [22]. Since the measurement of this physiological variable generally lacks precision, error of +10-20% are common even for the reference method.…”

“…Similar alterations were also observed when the arterial pressure waveform is changed as in patients with aortic insufficiency and in patients on IABP. Many other studies involving other different subsets of patients have produced inconsistent results when the CO was measured with thermodilution and pulse contour analysis techniques [4][5][6][14][15][16]22,[28][29][30][31][32]. Thus, although FloTrac method has many potential advantages including non-invasiveness, simplicity, no need for external calibration and minimal operator intervention, it still has many limitations in a variety of situations.…”