Severe impairment of microcirculatory perfused vessel density is associated to post-operative lactate and acute organ injury after cardiac surgery

ABSTRACT Objective Resuscitation after cardiac surgery needs to address multiple pathophysiologic processes that are associated with significant morbidity and mortality. Functional microcirculatory derangements despite normal systemic hemodynamics have been previously described but must be tied to clinical outcomes. We hypothesized that microcirculatory dysfunction after cardiac surgery would include impaired capillary blood flow, impaired diffusive capacity, and that subjects with the lowest quartile of perfused vessel density would have an increased post-operative lactate level and acute organ injury scores. Design Prospective, observational study. Setting A single, tertiary university cardiovascular surgical intensive care unit. Participants 25 adults undergoing elective cardiac surgery requiring cardiopulmonary bypass. Intervention Sublingual microcirculation was imaged using incident dark field microscopy before and 2-4 hours after surgery in the intensive care unit. Measurements and Main Results Compared to baseline measurements, post-operative vessel-by-vessel microvascular flow index [2.9 (2.8-2.9) vs. 2.5 (2.4-2.7), p Conclusion In patients undergoing cardiac surgery, we observed a significant decrease in post-operative microcirculatory convective blood flow and diffusive capacity during the early resuscitation phase after cardiac surgery. Severely impaired perfused vessel density, represented by the lowest quartile of distribution, is significantly related to hyperlactatemia and early organ injury.