John C Greenwood1, David H Jang2, Audrey E Spelde3, Jacob T Gutsche3, Jiri Horak3, Michael A Acker4, Todd J Kilbaugh5, Frances S Shofer6, John G T Augoustides3, Jan Bakker7,8,9, Benjamin S Abella10. 1. Division of Critical Care Medicine, Department of Emergency Medicine, Department of Anesthesiology and Critical Care, Center for Resuscitation Science, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. 2. Division of Medical Toxicology and Critical Care Medicine, Department of Emergency Medicine, Center for Resuscitation Science, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. 3. Department of Anesthesiology and Critical Care, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. 4. Division of Cardiovascular Surgery, Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. 5. Department of Anesthesiology and Critical Care Medicine, Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania. 6. Department of Epidemiology and Biostatistics, Department of Emergency Medicine Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. 7. Division of Pulmonary, Allergy, and Critical Care Medicine, Columbia University Medical Center, New York, New York. 8. Department of Intensive Care Adults, Erasmus MC University Medical Center, Rotterdam, the Netherlands. 9. Department of Intensive Medicine, The Pontifical Catholic University of Chile, Santiago, Región Metropolitana, Chile. 10. Department of Emergency Medicine, Center for Resuscitation Science, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.
Abstract
INTRODUCTION: Lactic acidosis after cardiac surgery with cardiopulmonary bypass is common and associated with an increase in postoperative morbidity and mortality. A number of potential causes for an elevated lactate after cardiopulmonary bypass include cellular hypoxia, impaired tissue perfusion, ischemic-reperfusion injury, aerobic glycolysis, catecholamine infusions, and systemic inflammatory response after exposure to the artificial cardiopulmonary bypass circuit. Our goal was to examine the relationship between early abnormalities in microcirculatory convective blood flow and diffusive capacity and lactate kinetics during early resuscitation in the intensive care unit. We hypothesized that patients with impaired microcirculation after cardiac surgery would have a more severe postoperative hyperlactatemia, represented by the lactate time-integral of an arterial blood lactate concentration greater than 2.0 mmol/L. METHODS: We measured sublingual microcirculation using incident darkfield video microscopy in 50 subjects on intensive care unit admission after cardiac surgery. Serial measurements of systemic hemodynamics, blood gas, lactate, and catecholamine infusions were recorded each hour for the first 6 h after surgery. Lactate area under the curve (AUC) was calculated over the first 6 h. The lactate AUC was compared between subjects with normal and low perfused vessel density (PVD < 18 mm/mm2), high microcirculatory heterogeneity index (MHI > 0.4), and low vessel-by-vessel microvascular flow index (MFIv < 2.6). RESULTS: Thirteen (26%) patients had a low postoperative PVD, 20 patients (40%) had a high MHI, and 26 (52%) patients had a low MFIv. Patients with low perfused vessel density had higher lactate AUC compared with subjects with a normal PVD (22.3 [9.4-31.0] vs. 2.6 [0-8.8]; P < 0.0001). Patients with high microcirculatory heterogeneity had a higher lactate AUC compared with those with a normal MHI (2.5 [0.1-8.2] vs. 13.1 [3.7-31.1]; P < 0.001). We did not find a difference in lactate AUC when comparing high and low MFIv. CONCLUSION: Low perfused vessel density and high microcirculatory heterogeneity are associated with an increased intensity and duration of lactic acidosis after cardiac surgery with cardiopulmonary bypass.
INTRODUCTION: Lactic acidosis after cardiac surgery with cardiopulmonary bypass is common and associated with an increase in postoperative morbidity and mortality. A number of potential causes for an elevated lactate after cardiopulmonary bypass include cellular hypoxia, impaired tissue perfusion, ischemic-reperfusion injury, aerobic glycolysis, catecholamine infusions, and systemic inflammatory response after exposure to the artificial cardiopulmonary bypass circuit. Our goal was to examine the relationship between early abnormalities in microcirculatory convective blood flow and diffusive capacity and lactate kinetics during early resuscitation in the intensive care unit. We hypothesized that patients with impaired microcirculation after cardiac surgery would have a more severe postoperative hyperlactatemia, represented by the lactate time-integral of an arterial blood lactate concentration greater than 2.0 mmol/L. METHODS: We measured sublingual microcirculation using incident darkfield video microscopy in 50 subjects on intensive care unit admission after cardiac surgery. Serial measurements of systemic hemodynamics, blood gas, lactate, and catecholamine infusions were recorded each hour for the first 6 h after surgery. Lactate area under the curve (AUC) was calculated over the first 6 h. The lactate AUC was compared between subjects with normal and low perfused vessel density (PVD < 18 mm/mm2), high microcirculatory heterogeneity index (MHI > 0.4), and low vessel-by-vessel microvascular flow index (MFIv < 2.6). RESULTS: Thirteen (26%) patients had a low postoperative PVD, 20 patients (40%) had a high MHI, and 26 (52%) patients had a low MFIv. Patients with low perfused vessel density had higher lactate AUC compared with subjects with a normal PVD (22.3 [9.4-31.0] vs. 2.6 [0-8.8]; P < 0.0001). Patients with high microcirculatory heterogeneity had a higher lactate AUC compared with those with a normal MHI (2.5 [0.1-8.2] vs. 13.1 [3.7-31.1]; P < 0.001). We did not find a difference in lactate AUC when comparing high and low MFIv. CONCLUSION: Low perfused vessel density and high microcirculatory heterogeneity are associated with an increased intensity and duration of lactic acidosis after cardiac surgery with cardiopulmonary bypass.
Authors: John C Greenwood; Fatima M Talebi; David H Jang; Audrey E Spelde; Todd J Kilbaugh; Frances S Shofer; Michael A Acker; John G T Augoustides; Jan Bakker; Nuala J Meyer; Jacob S Brenner; Vladimir R Muzykantov; Benjamin S Abella Journal: PLoS One Date: 2022-08-26 Impact factor: 3.752