Temporal Dissociation Between Intravascular Albumin Mass and Transcapillary Escape Dynamics in Sepsis: A Longitudinal Characterization of Albumin Homeostasis Using Routine Laboratory Parameters

TL;DR

The study tracks albumin balance in sepsis patients over time, revealing that albumin leakage and recovery processes are not synchronized, which could help in understanding and managing sepsis.

Contribution

The study introduces a new framework using routine lab data to assess albumin homeostasis in sepsis, showing temporal dissociation between albumin leak and recovery.

Findings

The transcapillary escape rate (TER-like index) peaked early and declined by day 5, showing a decrease in positive escape dynamics.

Net albumin leakage (NAL) was often negative, indicating a persistent intravascular albumin deficit despite reduced escape rates.

A dissociation state (TER-like index ≤ 0 with NAL < 0) increased significantly from day 1 to day 5, highlighting uncoupling between leak and recovery.

Abstract

Background: In sepsis, albumin homeostasis is altered by capillary leak and recovery mechanisms (synthesis and interstitial–lymphatic return), which are difficult to capture clinically. A joint evaluation of ratio-based escape dynamics and mass-based balance may clarify their temporal interplay in sepsis. Methods: In a prospective longitudinal cohort of 389 sepsis patients admitted to an intermediate medical care unit, serial daily sampling (up to five reassessments; 1897 observations) was used to derive: a transcapillary escape rate (TER)-like index from the hourly percent change in the albumin/hemoglobin ratio and net albumin leakage (NAL) from changes in intravascular albumin mass normalized to plasma volume. Indices were analyzed as continuous measures and by sign-defined combined states. Generalized estimating equations (GEE), patient-level slope analyses, and state-transition analyses were performed. Baseline SOFA and 30-day mortality were explored as effect modifiers. Results: The TER-like index peaked early (median +0.34%/h at day 1) and declined to negative values by day 5 (median −0.07%/h), with the TER-like index > 0 decreasing from 65.3% to 45.8%. NAL was frequently negative and heterogeneous (NAL ≥ 0 in 37.5% of observations). TER-like index and NAL were inversely correlated (ρ = −0.54; p < 0.001). In GEE, the TER-like index was associated with NAL (β = −7.46 g/L per 1%/h; 95% CI −8.69 to −6.22; p < 0.001) with time-varying effects (interaction p < 0.01). The dissociation state (TER-like index ≤ 0 with NAL < 0) increased from 2.3% at day 1 to 22.6% at day 5 (p < 0.001). Conclusions: TER-like index escape dynamics attenuate early; however, net intravascular albumin balance often remains negative, supporting temporal uncoupling between “leak” and recovery. An integrated TER-like/NAL assessment offers a pragmatic framework for the clinical phenotyping of albumin homeostasis using routine laboratory data.

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