Episode 27: The Endothelial Glycocalyx — The Vascular Barrier We Keep Accidentally Punching

The VetEmCrit Academy built for ER and ICU vets who want to grow, level up, and learn together: https://academy.vetemcrit.com/join

In this episode, Dr. Lance Wheeler, DVM, DACVECC tackles the vascular structure we damage constantly and almost never measure - the endothelial surface layer, and why a patient's blood pressure can look better while the microcirculation is still a disaster. Drawing from Chapter 9 of Small Animal Critical Care Medicine (3rd edition) by Lisa Smart and Deborah Silverstein, Lance builds the anatomy from the ground up using a forest analogy, with syndecans and glypican-1 as the trunks, heparan sulfate and chondroitin and dermatan sulfate as the branches, hyaluronan as the undergrowth, and the immobile plasma layer as fog trapped inside the canopy, then connects that structure to the revised Starling principle, the protein-poor subglycocalyx space, and why sustained capillary reabsorption does not happen the way most of us were taught. He then moves into how the layer gets shed and what that costs at the bedside, including trauma, inflammation, hyperglycemia, hemodilution and hypervolemia as the major hits, thrombin and plasmin cleaving syndecan ectodomains, lipopolysaccharide accelerating shedding, glycocalyx fragments acting as DAMPs that amplify the very inflammation that caused them, perfused boundary region as an inverse measure of glycocalyx thickness, and loss of hemodynamic coherence when the monitor improves but the tissue does not. Along the way, he integrates the latest veterinary evidence, including 2021-2026 studies on perioperative crystalloid rate and circulating hyaluronan, fluid challenges in healthy anesthetized cats, shelf-stable blood products in a canine hemorrhagic shock model, fresh-frozen plasma in critically ill dogs, trauma biomarker dynamics over 24 hours, feline hemotropic mycoplasmosis, and cardiopulmonary bypass, and closes with a high-yield rapid-fire board review covering every key number worth memorizing.

If you enjoy this episode and want the full experience, weekly deep-dives, interactive simulators, and clinical algorithms you can use on shift, come join us inside the VetEmCrit Academy.