Surgery & anaesthesia: 16 papers
Peer-reviewed work on the endothelial glycocalyx, microvascular health and the ingredients in our formulas, newest first. Abstracts are indexed here and every paper links to the journal.
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Published paper
Sidestream dark field video microscopy demonstrates shelf-stable blood products preserve the endothelial glycocalyx in a canine hemorrhagic shock model
Six anesthetized dogs underwent induced hemorrhagic shock and were each resuscitated with five different fluid or blood-product strategies in a crossover design, with the endothelial glycocalyx assessed by sidestream dark field video microscopy (perfused boundary region, PBR). Crystalloid plus hydroxyethyl starch resuscitation was associated with increased PBR (indicating glycocalyx degradation), whereas chilled whole blood, plasma plus packed red cells, and shelf-stable products (freeze-dried plasma with a hemoglobin-based oxygen carrier, with or without lyophilized platelets) did not show significant PBR change from baseline.
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Published paper
Diminished Microvascular Health in Heart Transplant Recipients Relative to Healthy Controls
This conference abstract reports a prospective cross-sectional comparison of sublingual microvascular health in 90 heart transplant recipients versus 23 healthy adults, measured with a sidestream dark-field camera and GlycoCheck software. Transplant recipients showed lower capillary density and capillary blood flow, a lower global microvascular HealthScore, and higher perfused boundary region (PBR) values, the latter interpreted as glycocalyx damage.
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Published paper
Microvascular Responses to Donor Specific HLA Antibodies in Heart Transplantation. Sidestream Dark Field Imaging Results
This conference abstract reports a cross-sectional comparison of sublingual microvascular health in 90 heart transplant recipients, measured with sidestream dark field imaging and GlycoCheck software. Patients with donor-specific HLA antibodies (DSA) did not show worse microvascular parameters than those without; in fact, capillary density and blood flow were somewhat higher in the DSA group. The authors conclude that, in this preliminary dataset, DSA presence was not associated with impaired microvascular health.
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Published paper
Changes in the capillary plasma cell-free layer during a crystalloid or colloid fluid challenge in healthy volunteers
This work, presented as part of a doctoral thesis on perioperative hemodynamic optimization, examined how the capillary plasma cell-free layer (a marker closely tied to endothelial glycocalyx thickness) changes when healthy volunteers receive either a crystalloid or a colloid fluid bolus. The accompanying text provided is the thesis introduction, which frames questions about goal-directed therapy, fluid responsiveness, and the effect of fluid loading on glycocalyx integrity and microcirculatory perfusion. No numerical results for the volunteer fluid-challenge study are reported in the available text.
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Published paper
Cerebrovascular glycocalyx damage and microcirculation impairment in patients with temporal lobe epilepsy
Researchers used intraoperative sidestream dark-field video microscopy (GlycoCheck) to measure the endothelial glycocalyx and capillary blood flow directly on the exposed brain surface of 15 patients undergoing surgery for drug-resistant temporal lobe epilepsy and 15 non-epileptic surgical controls. Cortical perfused boundary region (PBR), an indirect marker of glycocalyx damage, was roughly twice as high in epilepsy patients, and their capillary recruitment capacity was markedly reduced. In vivo vessel surface area correlated strongly with ex vivo lectin-stained vessel area in the same resected tissue.
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Published paper
Non-invasive evaluation of macro- and microhemodynamic changes during induction of general anesthesia – A prospective observational single-blinded trial
In 150 women undergoing gynecologic surgery, non-invasive bioimpedance monitoring showed that induction of general anesthesia caused a larger fall in cardiac output (~40%) than in mean arterial pressure (~26%). Patients who later needed norepinephrine already had lower baseline cardiac output, stroke volume and contractility, and norepinephrine raised blood pressure without restoring cardiac performance. Sidestream dark-field imaging in a subset showed a 6.4% rise in perfused boundary region by the end of surgery, consistent with glycocalyx impairment.
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Published paper
Evaluation of jejunal microvasculature of healthy anesthetized dogs with sidestream dark field video microscopy
This veterinary study tested whether sidestream dark field (SDF) video microscopy could image and quantify the small blood vessels of the jejunum (small intestine) in 30 healthy anesthetized dogs during spay surgery. Imaging was feasible and produced reference values for microvascular density, red blood cell filling, vessel width, and the perfused boundary region (PBR), an indirect index of glycocalyx thickness. The authors conclude the technique warrants further study, including in dogs with intestinal disease.
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Published paper
Microvascular Alterations During Cardiac Surgery Using a Heparin or Phosphorylcholine-Coated Circuit
In this single-center randomized, blinded trial, 26 adults having on-pump CABG surgery received either a heparin-coated or a phosphorylcholine-coated cardiopulmonary bypass circuit. Sublingual sidestream dark-field imaging (GlycoCheck) and plasma shedding markers showed glycocalyx thinning and shedding in the phosphorylcholine group but not the heparin-coated group, while the fall in perfused vessel density during bypass was similar in both groups.
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Published paper
Neuraxial anesthesia is less harmful to the endothelial glycocalyx during elective joint surgery compared to general anesthesia1,2.
This prospective observational study used sidestream dark-field imaging of the sublingual microcirculation to measure the perfused boundary region (PBR), an inverse marker of endothelial glycocalyx thickness, before and 2 hours after elective hip or knee replacement. PBR increased significantly after surgery in both anesthesia groups, indicating glycocalyx perturbation. The increase was greater in patients receiving general anesthesia than in those receiving neuraxial anesthesia.
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Published paper
Alterations of conjunctival glycocalyx and microcirculation in non-septic critically ill patients
This single-center prospective observational study used sidestream dark-field imaging to assess glycocalyx thickness (perfused boundary region, PBR) and microcirculatory perfusion in the sublingual mucosa and, for the first time, the ocular conjunctiva of non-septic ICU patients. Both cardiac surgical and neurocritical patients showed increased PBR (indicating glycocalyx thinning/damage) at both sites and higher blood syndecan-1 than healthy controls. Correlations between systemic glycocalyx shedding markers and local conjunctival glycocalyx measures were weak or absent.
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Published paper
Impact of Intravenous Fluid Challenge Infusion Time on Macrocirculation and Endothelial Glycocalyx in Surgical and Critically Ill Patients.
This open randomized single-center trial compared fast (5-10 min) versus slow (20-30 min) infusion of a 5 ml/kg balanced crystalloid fluid challenge in 50 spinal surgery patients and 16 septic patients, measuring sublingual perfused boundary region (PBR, a marker inversely related to glycocalyx integrity) with GlycoCheck side-stream dark-field imaging plus standard hemodynamics. Fluid administration raised PBR regardless of infusion speed, with recovery by 60 minutes in surgical patients but persistent elevation in septic fluid responders. Infusion time did not change the rate of fluid responsiveness, though fast boluses produced a larger but transient blood pressure rise.
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Published paper
The Effect of Fluid Loading and Hypertonic Saline Solution on Cortical Cerebral Microcirculation and Glycocalyx Integrity.
In a rabbit craniotomy model, researchers compared one hour of liberal (30 mL/kg/h) versus restrictive (<2 mL/kg/h) balanced isotonic fluid administration, followed by a bolus of either 3.2% hypertonic saline or 0.9% saline. Cortical cerebral microcirculation was imaged with sidestream dark-field video microscopy, and glycocalyx integrity was assessed by the perfused boundary region (PBR) and serum syndecan-1. Liberal fluid loading was associated with poorer cortical vessel perfusion and signs of greater glycocalyx shedding, while hypertonic saline had no measurable effect on these parameters.
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Published paper
Protocol for intraoperative assessment of the human cerebrovascular glycocalyx.
This is a published study protocol (no results) for a multicenter prospective case-control study in the Netherlands that plans to image the endothelial glycocalyx intraoperatively in the human brain. Using sidestream dark-field video microscopy with GlycoCheck software, investigators will measure the perfused boundary region (PBR) and perfused diameter in sublingual, cortical, and (in epilepsy patients only) hippocampal microvessels. The hypothesis is that cerebrovascular glycocalyx thickness is reduced in temporal lobe epilepsy compared with controls, potentially linking glycocalyx damage to blood-brain barrier leakage and seizure susceptibility.
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Published paper
Perturbation of the microvascular glycocalyx and perfusion in infants after cardiopulmonary bypass
Researchers used sidestream dark-field imaging at the ear conch to measure the perfused boundary region (an inverse marker of glycocalyx thickness) and microcirculatory perfusion in 40 infants having congenital heart surgery, compared with children undergoing cardiac catheterization or cleft palate surgery. After surgery with cardiopulmonary bypass, the perfused boundary region increased significantly (indicating glycocalyx thinning) and microvascular perfusion transiently fell, both recovering to baseline by day 7. Control groups showed no significant glycocalyx changes.
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Published paper
Side-by-Side Alterations in Glycocalyx Thickness and Perfused Microvascular Density During Acute Microcirculatory Alterations in Cardiac Surgery
This observational study of 36 coronary bypass patients used sublingual sidestream dark-field imaging (GlycoCheck) to track perfused vessel density and perfused boundary region (PBR, an inverse index of glycocalyx thickness) before, during, and after surgery. Onset of cardiopulmonary bypass was accompanied by a fall in perfused vessel density and a rise in PBR, while off-pump surgery showed no such deterioration. Postoperative recovery of both measures occurred with pulsatile but not nonpulsatile bypass flow.
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Published paper
Acute ischemic injury to the renal microvasculature in human kidney transplantation
During transplant surgery, researchers used sidestream darkfield imaging to observe peritubular capillaries in kidneys from donors after cardiac death (DCD, substantial ischemia) and from living donors (minimal ischemia). DCD kidneys showed markedly poorer microvascular perfusion and biochemical and imaging signs of endothelial glycocalyx degradation, despite similar overall renovascular resistance. The authors conclude that ischemia-reperfusion in kidney grafts involves impaired capillary flow and loss of glycocalyx integrity.
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