Preoperative Concentrated Urine Increases the Incidence of Plasma Creatinine Elevation After Major Surgery.

Postoperative elevation of plasma creatinine is a frequent complication to major surgery. A rise by 50% fulfills the criterion for Acute Kidney Injury. We studied the relationship between concentrated urine before surgery, which is usually a sign of chronically low intake of water, and the perioperative change in plasma creatinine.

Can perioperative hemodilution be monitored with non-invasive measurement of blood hemoglobin?

Background: Trends in non-invasive measurements of blood hemoglobin (Hb) may be useful for identifying the need for transfusion in the perioperative period.

Methods: Crystalloid fluid (5-20 mL/kg) was administered intravenously or by mouth to 30 volunteers and 33 surgical patients in five non-randomized clinical studies where Hb was measured on 915 occasions by non-invasive (Radical-7™) and invasive methodology. The hemodilution curves were compared by volume kinetic analysis and linear regression, with the slope and scattering of the data as key outcome measures.

The intracellular fluid compartment is smaller than commonly believed when measured by whole-body bioimpedance.

Objectives: To report our data on the total body water (TBW), intracellular volume (ICV), extracellular volume (ECV), and fat-free mass (FFM) from studies using whole-body bioimpedance (BIA) with the aim of contrasting them to commonly cited reference values.

Methods: Data were retrospectively retrieved from three single-center studies of adult healthy male volunteers and one study of women scheduled for abdominal hysterectomy where multifrequency BIA had been applied to obtain measurements of TBW, ICV, ECV, and FFM.

Results: Based on measurements performed in 44 males, the TBW, ICV, ECV, and FFM represented 49.

Plasma concentrations of syndecan-1 are dependent on kidney function.

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.

Elevated Plasma Concentrations of Syndecan-1 Do Not Correlate With Increased Capillary Leakage of 20% Albumin.

Background: Preclinical experiments show that an inflammatory reaction causes degradation of the endothelial glycocalyx layer and accelerated capillary leakage of albumin and fluid. The hypothesis in the present study was that elevated plasma concentrations of glycocalyx degradation products are associated with greater capillary leakage in humans.

Methods: This open clinical trial involved administration of an intravenous infusion of 20% albumin at 3 mL/kg over 30 minutes to 15 postburn patients who showed an activated inflammatory response.

Renal water conservation and the volume kinetics of fluid-induced diuresis: A retrospective analysis of two cohorts of elderly men.

Renal water conservation after an overnight fast mirrors the habitual intake of liquid. The hypothesis in the present study was that water conservation influences the diuretic response to infusion of two types of crystalloid fluid. Twenty-three elderly male patients (mean age 72 years) underwent a total of 46 intravenous infusions of 1.

Fluid escapes to the "third space" during anesthesia, a commentary.

Background: The "third fluid space" is a concept that has caused much confusion for more than half a century, dividing anesthesiologists into believers and non-believers.

Aim: To challenge the existence of the "third fluid space" based on analysis of crystalloid fluid kinetics.

Methods: Data on hemodilution patterns from 157 infusion experiments performed in volunteers and from 85 patients undergoing surgery under general anesthesia were studied by population volume kinetic analysis.

Electrolyte-based calculation of fluid shifts after infusing 0.9% saline in severe hyperglycemia.

Background: Early treatment of severe hyperglycemia involves large shifts of body fluids that entail a risk of hemodynamic instability. We studied the feasibility of applying a new electrolyte equation that estimates the degree of volume depletion and the distribution of infused 0.9% saline in this setting.

Intraoperative Intravascular Effect of Lactated Ringer's Solution and Hyperoncotic Albumin During Hemorrhage in Cystectomy Patients.

Background: The intraoperative effect of 20% albumin on plasma volume during surgery involving major blood loss has not been explored extensively due to methodological difficulties. Crystalloids poorly expand the plasma volume, and using a colloid might then be a way to avoid fluid overload. As doubts have been raised about synthetic colloids, albumin solutions are currently used more extensively.

Signs of Dehydration after Hip Fracture Surgery: An Observational Descriptive Study.

Dehydration might be an issue after hip fracture surgery, but the optimal tools to identify the dehydrated condition have not been determined. The aim of the present study was to compare the characteristics of elderly postoperative patients who were classified as dehydrated according to the methods used in the clinic. Thirty-eight patients aged between 65 and 97 (mean, 82) years were studied after being admitted to a geriatric department for rehabilitation after hip fracture surgery.

Water content of the endothelial glycocalyx layer estimated by volume kinetic analysis.

Background: The water volume of the endothelial glycocalyx layer has been estimated at 0.7 to 1.7 L using tracer methods of unclear value.

Intravenous fluid therapy in the perioperative and critical care setting: Executive summary of the International Fluid Academy (IFA).

Intravenous fluid administration should be considered as any other pharmacological prescription. There are three main indications: resuscitation, replacement, and maintenance. Moreover, the impact of fluid administration as drug diluent or to preserve catheter patency, i.

Effects of diet, habitual water intake and increased hydration on body fluid volumes and urinary analysis of renal fluid retention in healthy volunteers.

Purpose: To increase our knowledge about the causes and physiological consequences of concentrated urine, the relevance of which in the general population is uncertain.

Methods: Twenty healthy volunteers (mean age 42 years) recorded all intake of food and water for 2 weeks. During the 2nd week, they increased their daily consumption of water by 716 mL (32%).

Kinetics of crystalloid fluid in hyperglycemia; an open-label exploratory clinical trial.

Background: Infusion with 0.9% saline is a mainstay in the treatment of severe hyperglycemia, but the kinetics of the saline volume in this setting has not been studied.

Methods: An intravenous infusion of 1 L of 0.

Volume kinetic analysis of fluid retention after induction of general anesthesia.

Background: Induction of general anesthesia increases the hemodilution resulting from infusion of crystalloid fluid, which is believed to be due to slower distribution caused by arterial hypotension. When normal distribution returns is not known.

Methods: An intravenous infusion of 25 mL kg of Ringer's lactate was infused over 30 min to 25 volunteers just after induction of general anesthesia for open abdominal hysterectomy.

The Extended Starling principle needs clinical validation.

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.

Understanding volume kinetics.

The distribution and elimination kinetics of the water volume in infusion fluids can be studied by volume kinetics. The approach is a modification of drug pharmacokinetics and uses repeated measurements of blood hemoglobin and urinary excretion as input variables in (usually) a two-compartment model with expandable walls. Study results show that crystalloid fluid has a distribution phase that gives these fluids a plasma volume expansion amounting to 50%-60% of the infused volume as long as the infusion lasts, while the fraction is reduced to 15%-20% within 30 minutes after the infusion ends.

Hypervolemia does not cause degradation of the endothelial glycocalyx layer during open hysterectomy performed under sevoflurane or propofol anesthesia.

Background: Fluid-induced hypervolemia may stimulate the release of natriuretic peptides and cause degradation (shedding) of the endothelial glycocalyx layer. Sevoflurane is believed to protect the glycocalyx, but the importance of using sevoflurane to prevent shedding during routine surgery is unclear.

Methods: The plasma concentrations of brain natriuretic peptide and two biomarkers of glycocalyx shedding, syndecan-1, and heparan sulfate, were measured in 26 patients randomized to receive general anesthesia with sevoflurane or propofol during open abdominal hysterectomy.

Kinetics of Ringer's Solution in Extracellular Dehydration and Hemorrhage.

Background: Ringer's solution might be used to treat volume depletion (extracellular dehydration) and hemorrhage, but there is no integrated view of how these fluid balance disorders influence the kinetics of the infused volume.

Methods: Acute dehydration (mean 1.7 L) was induced by repeated doses of furosemide (5 mg) in 10 healthy male volunteers, and 0.

Long Intravascular Persistence of 20% Albumin in Postoperative Patients.

Background: Albumin may persist intravascularly for a shorter time in patients after major surgery than in healthy volunteers due to a surgery-induced breakdown (shedding) of the endothelial glycocalyx layer.

Methods: In this nonrandomized clinical trial, an IV infusion of 3 mL/kg of 20% albumin was given at a constant rate during 30 minutes to 15 patients on the first day after major open abdominal surgery (mean operating time 5.9 h) and to 15 conscious volunteers.