Severe Impairment of Microcirculatory Perfused Vessel Density Is Associated With Postoperative Lactate and Acute Organ Injury After Cardiac Surgery

Objective: Resuscitation after cardiac surgery needs to address multiple pathophysiological 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. The authors hypothesized that microcirculatory dysfunction after cardiac surgery would include impaired capillary blood flow and impaired diffusive capacity and that subjects with the lowest quartile of perfused vessel density would have an increased postoperative 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 to 4 hours after surgery in the intensive care unit. Measurements and Main Results: Compared with baseline measurements, postoperative vessel-by-vessel microvascular flow index (2.9 [2.8-2.9] v 2.5 [2.42.7], p < 0.0001) and perfused vessel density were significantly impaired (20.7 [19.3-22.9] v 16.3 [12.8-17.9], p < 0.0001). The lowest quartile of perfused vessel density (<12.8 mm/mm(2)) was associated with a significantly increased postoperative lactate level (6.0 +/- 2.9 v 1.8 +/- 1.2, p < 0.05), peak lactate level (7.6 +/- 2.8 v 2.8 +/- 1.5, p = 0.03), and sequential organ failure assessment (SOFA) score at 24 and 48 hours. Conclusion: In patients undergoing cardiac surgery, there was a significant decrease in postoperative microcirculatory convective blood flow and diffusive capacity during early postoperative resuscitation. Severely impaired perfused vessel density, represented by the lowest quartile of distribution, is significantly related to hyperlactatemia and early organ injury. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

Resuscitation after cardiac surgery must address multiple pathophysiological processes, including microcirculatory dysfunction which may lead to increased lactate levels and acute organ injury. A study on 25 adults undergoing elective cardiac surgery found that severely impaired perfused vessel density was significantly related to hyperlactatemia and early organ injury.