Alterations of conjunctival glycocalyx and microcirculation in non-septic critically ill patients

Abstract As of now the relationship between glycocalyx degradation and microcirculatory perfusion abnormalities in non-septic critical ill patients is unclear. In addition, conjunctival sidestream dark field-imaging for the purpose of glycocalyx thickness estimation has never been performed. We aimed to investigate whether changes in glycocalyx thickness in non-septic patients are associated with microcirculatory alterations in conjunctival and sublingual mucosa. In this single-centre prospective observational study, using techniques for direct in-vivo observation of the microcirculation, we performed a single measurement of microcirculatory perfusion parameters and visualized glycocalyx thickness in both ocular conjunctiva and sublingual mucosa in mixed cardio surgical (n = 18) and neurocritical patients (n = 27) and compared these data with age-matched healthy controls (n = 20). In addition we measured systemic syndecan-1 levels. In the sublingual and conjunctival region we observed a significant increase of the perfused boundary region (PBR) in both neuro-critical and cardiac surgical ICU patients, compared to controls. There was a significant increase of syndecan-1 in ICU patients comparing with controls and in cardiac patients comparing with neurological (120.0[71.0–189.6] vs. 18.0[7.2–40.7], p