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Critical Care Research and Practice
Volume 2012, Article ID 102483, 6 pages
Research Article

Comparison of Different Methods for the Calculation of the Microvascular Flow Index

1Servicio de Terapia Intensiva, Clínica Bazterrica, Juncal 3002, C1425AYN Buenos Aires, Argentina
2Cátedra de Farmacología Aplicada, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina
3Servicio de Terapia Intensiva, Sanatorio Otamendi y Miroli, Azcuénaga 870, C1115AAB Buenos Aires, Argentina
4Department of Intensive Care Adults Erasmus MC, University Medical Centre Rotterdam, 3000 CA Rotterdam, The Netherlands

Received 24 December 2011; Revised 16 February 2012; Accepted 2 March 2012

Academic Editor: Michael Piagnerelli

Copyright © 2012 Mario O. Pozo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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 ( ), (2) the direct assessment during the bedside video acquisition ( ), and (3) the mean value of the MFIs determined in each individual vessel ( ). We hypothesized that the agreement between the MFIs is poor and that the 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 and (1.46), between and (2.85), and between and (2.56). The MFIs significantly correlated with the RBC velocity and with the fraction of perfused small vessels, but showed the best . Although the different methods for the calculation of MFI reflect microvascular perfusion, they are not interchangeable and might be better.