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Are Technologies Interchangable?

New study shows that Pulse Pressure Waveform Analysis (‘PPWA’) technologies only measure changes in cardiac output in the correct direction half the time.

  • Agreement between the EDM, LiDCOrapid, and FloTrac was compared before and after fluid, metaraminol, and ephedrine boluses.
  • The LiDCOrapid and FloTrac only measured change in cardiac output in the same direction as the EDM 48% and 50% of the time respectively.
  • Agreement was poorest following metaraminol (31% and 29%) compared to that following fluid or ephedrine; further confirming that uncalibrated arterial pressure-based technologies are unreliable following changes in arterial compliance.
  • LiDCOrapid, and FloTrac are not interchangeable with EDM and should not be substituted for EDM in evidence-based intra-operative fluid management strategies.

This findings from this study by Phan et al. [1] are in agreement with others comparing the EDM with the LiDCOrapid (Nordstrom), the EDM with the FloTrac (Meng), and comparing all technologies (Davies and Hadian).

Nordstrom et al. [2] compared the EDM and LiDCOrapid and found that the LiDCOrapid only ‘saw’ the same change in SV as measured by the EDM 48% of the time. The authors concluded…

“LiDCOrapid and EDM devices are not interchangeable. We cannot recommend that the LiDCOrapid replace the standard Doppler method until further device-specific outcome studies on volume optimization are available.”

Meng et al. [3] compared the EDM and the FloTrac and found poor agreement between changes in CO measured by the two technologies. Agreement was only 23% following phenylephrine infusion. The authors concluded…

“Third-generation Vigileo-FloTrac’s ability in tracking changes in CO is profoundly affected by phenylephrine induced change in vasomotor tone…When using the third-generation Vigileo-FloTrac for perioperative fluid optimization, one must be aware that vasopressors impact the ability of this device to accurately track changes in CO. This suggests that the method adopted by the third-generation Vigileo-FloTrac still does not effectively compensate for acute changes in arterial vasomotor tone.”.

Davies et al. [4] compared the EDM, LiDCOrapid, and FloTrac and found similarly poor agreement between changes in SV measured by the EDM and LiDCOrapid (57%) and the EDM and FloTrac (45%). The authors concluded…

“Stroke volume as measured by the FloTrac and LiDCOrapid systems does not correlate with the esophageal Doppler and has limited concordance; the percentage error means the technologies are not interchangeable.”.

Hadian et al. [5] compared arterial-pressure devices and the PAC and concluded…

“if clinical trials of resuscitation based on CO values show efficacy when using one of these devices, it is not clear whether performing the identical trial with another CO monitoring device will also show similar benefit. Thus, until the agreement among minimally invasive CO measuring devices improves, each device needs to have its own clinical efficacy validated.”.

  1. Phan, T.D., R. Kluger, and C. Wan, Minimally invasive cardiac output monitoring: agreement of oesophageal Doppler, LiDCOrapid and Vigileo FloTrac monitors in non-cardiac surgery. Anaesth Intensive Care, 2016. 44(3): p. 382-90.
  2. Nordstrom, J., et al., Stroke volume optimization in elective bowel surgery: a comparison between pulse power wave analysis (LiDCOrapid) and oesophageal Doppler (CardioQ). Br J Anaesth, 2013. 110(3): p. 374-80.
  3. Meng, L., et al., The impact of phenylephrine, ephedrine, and increased preload on third-generation Vigileo-FloTrac and esophageal doppler cardiac output measurements. Anesth Analg, 2011. 113(4): p. 751-7.
  4. Davies, S.J., et al., Comparison of stroke volume and fluid responsiveness measurements in commonly used technologies for goal-directed therapy. J Clin Anesth, 2013.
  5. Hadian, M., et al., Cross-comparison of cardiac output trending accuracy of LiDCO, PiCCO, FloTrac and pulmonary artery catheters. Crit Care, 2010. 14(6): p. R212.