Sepsis and the microcirculation: the impact on outcomes.

PURPOSE OF REVIEW: Advances in the treatment of septic shock have historically focused on resuscitation endpoints, mainly mean arterial pressure and cardiac output. As the definitions of sepsis and septic shock have shifted to focus on the diversity of causes of dysregulated host-response we have seen an emerging phenotype where tissue hypoxia persists despite adequate macrocirculatory parameters. Interest in the topic of microcirculation is re-emerging as validated bedside techniques for hemodynamic monitoring, such as video microscopes, are becoming available. We review the current understanding of how sepsis induced hypoperfusion with a focus on recent advances in monitoring the microcirculation, and how a proliferation of biomarkers and emerging therapeutic targets may impact future research.

RECENT FINDINGS: Conventional hemodynamic monitoring systems fail to assess the microcirculation, and it's response to treatment. Lactate and venous oxygen saturations often drive biomarker-guided sepsis management. Visual assessments such as mottling and capillary refill time are often associated with predicting outcomes, but sometimes can have issues with inter-provider reliability. Microcirculatory damage can be observed sublingually and appears to have prognostic value.

SUMMARY: Sepsis is associated with changes in the microcirculation that can lead to tissue hypoxia and organ dysfunction. Further studies are needed to validate the usefulness of microcirculatory bedside tools in guiding resuscitative efforts.