Evaluation of microcirculation by Sidestream Dark Field imaging: Impact of hemodynamic status on the occurrence of pressure artifacts -A pilot study

Abstract : Objective: The aims of the study were to evaluate the influence of hemodynamic status on pressure artifacts and the impact of pressure artifacts on microcirculatory flow. Methods: Sublingual microcirculation was assessed using a Sidestream Dark Field handheld imaging device in 7 anesthetized piglets, submitted to pharmacologically-induced blood pressure variations. For each video, a pressure score of 0, 1, or 10 was assigned for the category "pressure artifacts" of the "microcirculation image quality score". Videos with a pressure score of 0 and 1 were considered as "passing videos". The videos with a score of 10 were considered as "failing videos". Multivariate logistic regression models and multivariate linear mixed models with individual random effects were used. Results: As blood pressure decreased, the probability of obtaining a "failing video" increased (P = 0.0008). Pressure scores of 10 influenced significantly the perfused De Backer score (small and all vessels), the proportion of perfused vessels (small and all vessels), the microvascular flow index and the heterogeneity index. Pressure scores of 1 influenced significantly the parameters above-mentioned, except the perfused De Backer score for all vessels. Conclusion: The probability of obtaining pressure artifacts during recording of microcirculation videos was higher when the arterial pressure was low. The presence of acceptable pressure artifacts also influenced microcirculation analysis.