Replacement of assumed preoperative deficits, in addition to generous substitution of an unsubstantiated increased insensible perspiration and third space loss, plays an important role in current perioperative fluid regimens. The consequence is a positive fluid balance and weight gain of up to 10 kg, which may be related to severe complications. Because the intravascular blood volume remains unchanged and insensible perspiration is negligible, the fluid must accumulate inside the body. This concept brings into question common liberal infusion regimens. Blood volume after fasting is normal, and a fluid-consuming third space has never been reliably shown. Crystalloids physiologically load the interstitial space, whereas colloidal volume loading deteriorates a vital part of the vascular barrier. The endothelial glycocalyx plays a key role and is destroyed not only by ischemia and surgery, but also by acute hypervolemia. Therefore, undifferentiated fluid handling may increase the shift toward the interstitial space. Using the right kind of fluid in appropriate amounts at the right time might improve patient outcome.

Background-The astonishing thickness of the endothelial glycocalyx, which rivals that of endothelial cells in the microvasculature, was disclosed in the last 15 years. As already demonstrated, this structure plays a key role in the regulation of inflammation and vascular permeability. Methods and Results-Two components of the glycocalyx, syndecan-1 and heparan sulfate, were measured in arterial blood of 18 patients undergoing surgery of the ascending aorta with cardiopulmonary bypass (nϭ12 with and nϭ6 without deep hypothermic circulatory arrest) and of 14 patients undergoing surgery for infrarenal aortic aneurysm. Basal values of syndecan-1 (1.2 g/dL) and heparan sulfate (590 g/dL) of patients were similar to those of control subjects. Anesthesia and initiation of surgery caused no changes. Global ischemia with circulatory arrest (nϭ12) was followed by transient 42-and 10-fold increases in syndecan-1 and heparan sulfate, respectively, during early reperfusion (0 to 15 minutes). After regional ischemia of heart and lungs (cardiopulmonary bypass; nϭ6), syndecan-1 increased 65-fold, and heparan sulfate increased 19-fold. Infrarenal ischemia was followed by 15-and 3-fold increases, respectively (nϭ14). The early postischemic rises were positively correlated (rϭ0.76, PϽ0.001). Plasma concentrations of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 did not change. Circulating polymorphonuclear granulocytes and the level of postischemic heparan sulfate corresponded negatively. Immunohistochemical imaging and immunoassay of isolated hearts (guinea pig) substantiated syndecan-1 and heparan sulfate as components of the endothelial glycocalyx released into the coronary venous effluent. Electron microscopy revealed shedding of the glycocalyx after ischemia/reperfusion. Conclusions-This study provides the first evidence in humans for shedding of the endothelial glycocalyx during ischemia/reperfusion procedures.

Damage of the endothelial glycocalyx, which ranges from 200 to 2000 nm in thickness, decreases vascular barrier function and leads to protein extravasation and tissue oedema, loss of nutritional blood flow, and an increase in platelet and leucocyte adhesion. Thus, its protection or the restoration of an already damaged glycocalyx seems to be a promising therapeutic target both in an acute critical care setting and in the treatment of chronic vascular disease. Drugs that can specifically increase the synthesis of glycocalyx components, refurbish it, or selectively prevent its enzymatic degradation do not seem to be available. Pharmacological blockers of radical production may be useful to diminish the oxygen radical stress on the glycocalyx. Tenable options are the application of hydrocortisone (inhibiting mast-cell degranulation), use of antithrombin III (lowering susceptibility to enzymatic attack), direct inhibition of the cytokine tumour necrosis factor-alpha, and avoidance of the liberation of natriuretic peptides (as in volume loading and heart surgery). Infusion of human plasma albumin (to maintain mechanical and chemical stability of the endothelial surface layer) seems the easiest treatment to implement.

: The management of perioperative bleeding involves multiple assessments and strategies to ensure appropriate patient care. Initially, it is important to identify those patients with an increased risk of perioperative bleeding. Next, strategies should be employed to correct preoperative anaemia and to stabilise macrocirculation and microcirculation to optimise the patient's tolerance to bleeding. Finally, targeted interventions should be used to reduce intraoperative and postoperative bleeding, and so prevent subsequent morbidity and mortality. The objective of these updated guidelines is to provide healthcare professionals with an overview of the most recent evidence to help ensure improved clinical management of patients. For this update, electronic databases were searched without language restrictions from 2011 or 2012 (depending on the search) until 2015. These searches produced 18 334 articles. All articles were assessed and the existing 2013 guidelines were revised to take account of new evidence. This update includes revisions to existing recommendations with respect to the wording, or changes in the grade of recommendation, and also the addition of new recommendations. The final draft guideline was posted on the European Society of Anaesthesiology website for four weeks for review. All comments were collated and the guidelines were amended as appropriate. This publication reflects the output of this work.