Bedside measurement of individual oxygen uptake for direct Fick cardiac output determination was feasible and showed >20% deviation from assumed values in 9 of 28 patients.
Observational (n=33)
Does bedside measurement of individual VO2 using a breath-by-breath gas analyzer yield significantly different cardiac output values compared to indirect Fick calculations with assumed VO2 in patients undergoing right heart catheterization?
Bedside measurement of individual VO2 for direct Fick cardiac output determination is feasible and reveals that assumed VO2 values lead to >20% error in cardiac output in nearly a third of patients.
Abstract Objectives Cardiac output (CO) measurements employing the direct Fick principle represent the gold standard in right-sided heart catheterization (RHC). The current widespread approach in hemodynamic workup however uses the indirect Fick principle with assumed values for oxygen uptake (VO 2 ) leading to incorrect CO values in up to 25% of patients. We have tested a contemporary breath-by-breath gas analyzer that allows precise real-time measurements of VO 2 with appropriate time and effort to serve the direct Fick principle. Methods By means of a small and mobile metabolic cart assembled with widely used components of a standard spiroergometer, we performed bedside measurements of individual VO 2. In 33 unselected, consecutive patients with various indications for RHC we compared CO values derived from indirect vs. direct Fick calculations. Results In 28 of the 33 patients, VO 2 measurements were completed with a plausible dataset within a median of 3.2 (interquartile range 2.8–6.2) min. In nine of the 28 patients, CO values based on measured VO 2 values differed by more than 20% from CO calculations based on assumed VO 2 values with value deviations scattering over a broad range in both directions (maximally +52% to minimally −46%). Conclusions The bedside measurement of VO 2 for gold standard CO determination is technically feasible within a few min and can thus be easily included in any RHC protocol. As modern therapy for numerus indications demand a precise upfront measurement of hemodynamics, our method might help to correctly identify patients for costly therapies.
Schmücker et al. (Fri,) conducted a observational in Various indications for right-sided heart catheterization (n=33). Bedside measurement of individual VO2 (direct Fick principle) vs. Assumed VO2 values (indirect Fick principle) was evaluated on Difference in cardiac output values derived from indirect vs. direct Fick calculations. Bedside measurement of individual oxygen uptake for direct Fick cardiac output determination was feasible and showed >20% deviation from assumed values in 9 of 28 patients.
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