摘要：The microvascular flow index (MFI) is commonly used to semiquantitatively characterize the velocity of microcirculatory perfusion as absent (0), intermittent (1), sluggish (2), or normal (3). There are three approaches to compute MFI: (1) the average of the predominant flow in each of the four quadrants (MFIbyquadrants), (2) the direct assessment during the bedside video acquisition (MFIpointofcare), and (3) the mean value of the MFIs determined in each individual vessel (MFIvesselbyvessel). We hypothesized that the agreement between the MFIs is poor and that the MFIvesselbyvessel better reflects the microvascular perfusion. For this purpose, we analyzed 100 videos from septic patients. In 25 of them, red blood cell (RBC) velocity was also measured. There were wide 95% limits of agreement between MFIbyquadrants and MFIpointofcare (1.46), between MFIbyquadrants and MFIvesselbyvessel (2.85), and between MFIbypointofcare and MFIvesselbyvessel (2.56). The MFIs significantly correlated with the RBC velocity and with the fraction of perfused small vessels, but MFIvesselbyvessel showed the best 𝑅2. Although the different methods for the calculation of MFI reflect microvascular perfusion, they are not interchangeable and MFIvesselbyvessel might be better.
