Endothelial glycocalyx in perioperative medicine current understanding and future direction

The endothelial glycocalyx (EG) is a dynamic, gel-like layer that lines the luminal surface of blood vessels, playing a crucial role in vascular biology. Previously considered a passive barrier, it is now recognized as a key regulator of vascular tone, permeability, inflammation, and coagulation. Composed mainly of proteoglycans, glycoproteins, and glycosaminoglycans, the EG serves as a semipermeable interface between blood and the endothelium, maintaining microvascular flow and modulating nitric oxide (NO) production while protecting against oxidative and inflammatory damage. This review highlights the physiological functions of the EG and its significance in perioperative medicine. It regulates shear-dependent NO release, ensuring adequate vasodilation and tissue perfusion, while its negative charge reduces friction and clot formation. Damage to this layer can lead to vascular dysfunction, particularly in surgical and critical care patients. The review examines the mechanisms of glycocalyx injury in various conditions. Hyperglycemia and diabetes accelerate degradation through reactive oxygen species and enzymes like heparanase. In sepsis, inflammatory mediators disrupt glycocalyx, leading to capillary leak syndrome. Ischemia-reperfusion injury causes rapid shedding of glycocalyx components, impairing vasodilation. Potential therapeutic strategies for preserving glycocalyx integrity include albumin, fresh frozen plasma, and sphingosine-1-phosphate, which stabilize endothelial junctions. Maintaining normovolemia during surgery is crucial, as both excessive fluid and hypovolemia can accelerate glycocalyx breakdown. Overall, the endothelial glycocalyx should be considered in perioperative care as it may influence patient outcome. We outline future avenues for research and clinical intervention.