Validation of a Capillary Leak Index During Septic Shock, Based on Haemoglobin Level Variations Induced by Fluid Resuscitation. A Pilot Study.

Overview

This study aims to validate a simple and reproducible index of capillary leak (CLI) in septic shock, based on haemoglobin (Hb) variation induced by standardised fluid resuscitation. To achieve this, the correlation between CLI and biomarkers of endothelial dysfunction-angiopoietin-2 and syndecan-1-will be assessed in both septic and non-septic shock patients. CLI may contribute to the individualisation of fluid management in patients with septic shock.

Septic shock is characterised by systemic inflammation leading to endothelial dysfunction and increased capillary permeability. This results in intravascular hypovolaemia and interstitial oedema, contributing to tissue hypoperfusion and organ failure. Despite the prognostic implications, bedside assessment of capillary leak remains difficult, with no simple or standardised method available. Fluid resuscitation is the first-line therapy for circulatory failure in septic shock, but excessive fluid administration has been associated with increased mortality. Recent trials investigating restrictive fluid strategies have failed to show a survival benefit, likely due to the lack of patient stratification based on the severity of capillary leak. A bedside marker could guide personalised fluid and vasopressor therapy. A standardised fluid bolus (8 ml/kg of ideal body weight, Ringer's lactate) will be administered in both septic and non-septic shock patients. Haemoglobin levels will be measured before and after infusion, and the CLI will be calculated as (Hb pre - Hb post) / Hb pre \* 100. Bioimpedance analysis will be used to estimate extracellular water in selected patients.