Search

A letter to the editor is presented related to Nephrocheck, an apparatus for early detection of acute kidney injury (AKI).

Background: Elevated plasma concentrations of syndecan-1 and heparan sulfate in studies of trauma, sepsis, and major surgery are commonly assumed to indicate acute glycocalyx degradation. We explored a possible role of the kidneys for these elevations., Methods: Plasma and urine concentrations of syndecan-1, heparan sulfate, and biomarkers of inflammation were measured over 5 hours in 15 hospital patients treated for post-burn injury. The renal clearances of syndecan-1 and heparan sulfate (CL R ) were calculated and their influence on the plasma concentration predicted by simulation., Results: The urine/plasma concentration ratio was 0.9 (0.3-3.0) for syndecan-1 and 2.8 (2.0-4.3) for heparan sulfate. The CL R varied 250-fold for syndecan-1 and 10-fold for heparan sulfate. Multiple linear regression analysis showed that CL R for syndecan-1 was positively associated with the creatinine clearance (P < .0032) and the urine flow (P < .015). CL R for heparan sulfate increased with interleukin-6 (P < .003) and the urine flow (P < .01). Simulations suggested that a change in CL R from the mean of the highest 3 to the lowest three values would double plasma syndecan-1 within 4 hours and cause a 7-fold rise after 24 hours. A similar change in CL R for heparan sulfate would triple the plasma level within 24 hours, even if no increased shedding of the glycocalyx takes place., Conclusions: The renal elimination of syndecan-1 and heparan sulfate varied greatly. A change in kidney function, which is common after trauma and major surgery, might alone induce several-fold changes in their plasma concentrations., (© 2021 The Authors. Acta Anaesthesiologica Scandinavica published by John Wiley & Sons Ltd on behalf of Acta Anaesthesiologica Scandinavica Foundation.)

The Revised (or "Extended") Starling principle is based on highly controlled laboratory-based frog and rodent experiments and remains a hypothesis awaiting clinical validation. A key point is that the endothelial glycocalyx layer moves the oncotic gradient from being between the plasma and the interstitium to between the plasma and a virtually protein-free space between the glycocalyx and the endothelial cell membrane, which dramatically changes the prerequisites for fluid absorption from tissue to plasma. However, many experimental and clinical observations in humans agree poorly with the new microcirculatory proposals. The most troubling aspect of the explanation regarding the role of the glycocalyx in the Revised Starling principle is the effective reabsorption of fluid by skeletal muscle when the capillary filtration pressure is acutely reduced. Other issues include the plasma volume effects of hypertonic saline, iso-oncotic and hyper-oncotic albumin, fluid distribution during cardio-pulmonary bypass, and the virtually identical capillary leakage of plasma and albumin despite marked inflammation found in our fluid therapy studies. The Revised Starling principle deals mainly with steady-state conditions, but the circulatory system is highly dynamic. Second to second vasomotion is always operational and must be considered to understand what we observe in humans., (© 2020 The Authors. Acta Anaesthesiologica Scandinavica Foundation published by John Wiley & Sons Ltd on behalf of Acta Anaesthesiologica Scandinavica Foundation.)