Association between the lactate-albumin ratio and microcirculation changes in Pediatric Septic patients

Abstract

A lactate/albumin ratio (LAR) greater than 0.5 measured early in the course of pediatric critical illness is associated with greater mortality. Whether the elevated LAR can be explained by microcirculation disorders in children with sepsis is not known. In this longitudinal retrospective study (January 2021-January 2024), serum albumin and lactate were measured on admission to the pediatric intensive care unit (PICU), with sublingual video microscopy performed simultaneously to measure microcirculation. A total of 178 children were included, 37% of whom had septic shock measured with the Phoenix Sepsis Score. Patients with remote sepsis had greater odds of an elevated LAR (aOR 6.87: 95% CI 1.98-23.73; p < 0.01). Children with an elevated LAR had more microvascular blood flow abnormalities (aOR 1.31 95% CI 1.08-1.58; p < 0.01), lower 4-6-micron capillary density (aOR 1.03 95% CI 1.01-1.05; p < 0.01) and greater odds of dying (aOR 3.55 95% CI 1.21-10.38; p = 0.02) compared to those with a low LAR. We found no association between LAR and endothelial glycocalyx degradation. A normal LAR is associated with less risk of microcirculatory injury (aOR 0.77 95% CI 0.65-0.93; p < 0.01). In children with sepsis, an elevated LAR is associated with microcirculation abnormalities (microvascular density and flow). The lactate/albumin ratio is a potentially useful biomarker for microcirculatory injury in sepsis.

Keywords: Children; Fluid bolus; Mortality; Sepsis; Septic shock.

Fig. 1

Sublingual video microscopy images taken in patients with and without sepsis. Panel A shows a video microscopy image of a patient without sepsis in our database. It shows an appropriate distribution of venules, capillaries and arterioles. Panel B shows an image from a patient included in the study with septic arthritis of the knee caused by S. aureus. It shows few recruited capillaries, poor red blood cell distribution and tissue hypoperfusion. Images published with parental permission. Panel C shows sublingual microcirculation measurement using video microscopy, software analysis of the data obtained, and PBR measurement as an indicator of glycocalyx thickness. A greater distance between the red blood cells and the endothelial wall (and therefore a greater PBR) can be seen in the damaged glycocalyx. DAMPs: damage-associated molecular patterns. PBR: perfused boundary region.

Fig. 2

Microcirculatory and lactate-albumin ratio changes on admission in children with sepsis. LAR: lactate-albumin ratio. PBR: perfused boundary region. CBV: capillary blood volume. MVHS: Microvascular Health Score (relationship between the CBV/PBR). The Mann-Whitney U test was performed on the analyzed variables.