Diuretic responses to Ringer's solution and 20% albumin at different arterial pressures.

Intravenous volume loading is a common treatment when hypovolemia is a potential cause of oliguria. We studied whether the effectiveness of Ringer's solution and 20% albumin in inducing diuresis differs depending on the mean arterial pressure (MAP). For this purpose, volume kinetic analysis was performed based on urine output and hemoglobin-derived plasma dilution obtained during and after 136 infusions of Ringer and 85 infusions of 20% albumin.

Sequential recruitment of body fluid spaces for increasing volumes of crystalloid fluid.

Introduction: The interstitial space harbours two fluid compartments linked serially to the plasma. This study explores conditions that lead to fluid accumulation in the most secluded compartment, termed the "third space".

Methods: Retrospective data was collected from 326 experiments in which intravenous crystalloid fluid was administered to conscious volunteers as well as a small group of anaesthetized patients.

Is the NICE Guideline for maintenance fluid therapy in adults in hospital appropriate?

Background And Aims: The National Institute for Health and Care Excellence's (NICE) Guideline for Maintenance Fluid Therapy in Adults in Hospital is widely used, but the recommendations have not been evaluated properly. In this study, we investigated whether the recommendation of providing 25-30 mL/kg/day of fluid and 1 mmol/kg each of sodium and potassium is sufficient for human needs.

Methods: First, we calculated the distribution of fluid between the extracellular fluid volume (ECV) and intracellular fluid volume (ICV) during a cross-over infusion experiment where 12 volunteers received 25 mL/kg/day of either a high-sodium (154 mmol/L) or low-sodium (54 mmol/L) solution over 48 h.

Fluid distribution during surgery in the flat recumbent, Trendelenburg, and the reverse Trendelenburg body positions.

Background: The distribution and elimination of infused crystalloid fluid is known to be affected by general anesthesia, but it is unclear whether changes differ depending on whether the patient is operated in the flat recumbent position, the Trendelenburg ("legs up") position, or the reverse Trendelenburg ("head up") position.

Methods: Retrospective data on hemodilution and urine output obtained during and after infusion of 1-2 L of Ringer's solution over 30-60 min were collected from 61 patients undergoing surgery under general anesthesia and 106 volunteers matched with respect to the infusion volume and infusion time. Parameters describing fluid distribution in the anesthetized and awake subjects were compared by population volume kinetic analysis.

Anesthesia-induced Lymphatic Dysfunction.

General anesthetics adversely alters the distribution of infused fluid between the plasma compartment and the extravascular space. This maldistribution occurs largely from the effects of anesthetic agents on lymphatic pumping, which can be demonstrated by macroscopic fluid kinetics studies in awake versus anesthetized patients. The magnitude of this effect can be appreciated as follows: a 30% reduction in lymph flow may result in a fivefold increase of fluid-induced volume expansion of the interstitial space relative to plasma volume.

Accelerated lymph flow from infusion of crystalloid fluid during general anesthesia.

Background: Kinetic analysis of crystalloid fluid yields a central distribution volume (V) of the same size as the expected plasma volume (approximately 3 L) except during general anesthesia during which V might be only half as large. The present study examined whether this difference is due to influence of the intravascular albumin balance.

Methods: A population volume kinetic analysis according to a three-compartment model was performed based on retrospective data from 160 infusion experiments during which 1-2.

Blood volume and hemodynamics during treatment of major hemorrhage with Ringer solution, 5% albumin, and 20% albumin: a single-center randomized controlled trial.

Background: Volume replacement with crystalloid fluid is the conventional treatment of hemorrhage. We challenged whether a standardized amount of 5% or 20% albumin could be a viable option to maintain the blood volume during surgery associated with major hemorrhage. Therefore, the aim of this study was to quantify and compare the plasma volume expansion properties of 5% albumin, 20% albumin, and Ringer-lactate, when infused during major surgery.

Detection of low urine output by measuring urinary biomarkers.

Background: Urine output < 1 L per 24 h is a clinical warning sign that requires attention from hospital staff, who should determine whether the low flow is due to low habitual intake of water or disease-induced dehydration. The incidence of this condition is unclear.

Methods: A cohort of 20 healthy volunteers (mean age 42 years, range 23-62 years) recorded their food and water intakes daily for 8 days.

A Slow-Exchange Interstitial Fluid Compartment in Volunteers and Anesthetized Patients: Kinetic Analysis and Physiology.

Background: Physiological studies suggest that the interstitial space contains 2 fluid compartments, but no analysis has been performed to quantify their sizes and turnover rates.

Methods: Retrospective data were retrieved from 270 experiments where Ringer's solution of between 238 and 2750 mL (mean, 1487 mL) had been administered by intravenous infusion to awake and anesthetized humans (mean age 39 years, 47% females). Urinary excretion and hemoglobin-derived plasma dilution served as input variables in a volume kinetic analysis using mixed-models software.

Study of the f-cell ratio using plasma dilution and albumin mass kinetics.

Background: The f-cell ratio of 0.91 is a conversion factor between the hematocrit measured in peripheral blood and the hematocrit obtained by separate measurements of the red blood cell mass and plasma volume. The physiological background of the f-cell ratio is unclear.

Plasma Volume Oscillations during Fluid Therapy in Humans.

Introduction: Oscillations are frequently observed on plasma dilution curves during intravenous fluid therapy. This study aimed to examine how common these oscillations are and what they represent.

Methods: Fourier transforms were used to analyze the residuals obtained during fitting of a volume kinetic model to 269 plasma dilution curves.

Modulation of the capillary leakage by exogenous albumin in a rat model of endothelial glycocalyx damage.

Background: Endothelial glycocalyx (EG) plays a crucial role in maintaining the plasma proteins within the intravascular space.

Objective: We studied whether exogenous albumin protects the EG in an experimental model of EG enzymatic damage in rats.

Methods: Rats were divided into three groups of 10 animals that received (1) Evans blue (2) Evans blue + hyaluronidase, or (3) Evans blue + hyaluronidase + 20% human albumin via the tail vein.

Role of Crystalloids in the Perioperative Setting: From Basics to Clinical Applications and Enhanced Recovery Protocols.

Perioperative fluid management, a critical aspect of major surgeries, is characterized by pronounced stress responses, altered capillary permeability, and significant fluid shifts. Recognized as a cornerstone of enhanced recovery protocols, effective perioperative fluid management is crucial for optimizing patient recovery and preventing postoperative complications, especially in high-risk patients. The scientific literature has extensively investigated various fluid infusion regimens, but recent publications indicate that not only the volume but also the type of fluid infused significantly influences surgical outcomes.

Multidisciplinary expert panel report on fluid stewardship: perspectives and practice.

Although effective and appropriate fluid management is a critical aspect of quality care during hospitalization, the widespread adoption of consistent policies that ensure adequate fluid stewardship has been slow and heterogenous. Despite evidence-based guidelines on fluid management being available, clinical opinions continue to diverge on important aspects of care in this setting, and the consistency of guideline implementation is far from ideal. A multidisciplinary panel of leading practitioners and experts convened to discuss best practices for ongoing staff education, intravenous fluid therapy, new training technologies, and strategies to track the success of institutional fluid stewardship efforts.

Protection of the endothelium and endothelial glycocalyx by hydrogen against ischaemia-reperfusion injury in a porcine model of cardiac arrest.

Background: Hydrogen is a potent antioxidant agent that can easily be administered by inhalation. The aim of the study was to evaluate whether hydrogen protects the endothelial glycocalyx layer after successful cardiopulmonary resuscitation (CPR).

Methods: Fourteen anesthetized pigs underwent CPR after induced ventricular fibrillation.

Evidence of serial connection between the plasma volume and two interstitial fluid compartments.

Background: Kinetic analysis of fluid volume shifts can identify two interstitial fluid compartments with different turnover rates, but how they are connected to the bloodstream is unknown.

Methods: Retrospective data were retrieved from 217 experiments where 1.5 L of Ringer's solution (mean) had been administered by intravenous infusion over 30 min to awake and anesthetized humans (mean age 40 years).

Concentrated urine, low urine flow, and postoperative elevation of plasma creatinine: A retrospective analysis of pooled data.

Elevations of plasma creatinine are common after major surgery, but their pathophysiology is poorly understood. To identify possible contributing mechanisms, we pooled data from eight prospective studies performed in four different countries to study circumstances during which elevation of plasma creatinine occurs. We included 642 patients undergoing mixed major surgeries, mostly open gastrointestinal.

The kinetics of isotonic and hypertonic resuscitation fluids is dependent on the sizes of the body fluid volumes.

Background And Aims: The extracellular and intracellular fluid volumes (ECV and ICV) vary not only with age, gender, and body weight but also with the habitual intake of water. The present study examines whether the baseline variations in the ECV and ICV change the distribution and elimination of subsequently given infusion fluids.

Material And Methods: Twenty healthy male volunteers underwent 50 infusion experiments with crystalloid fluid for which the fluid volume kinetics was calculated based on frequent measurements of the hemodilution using mixed-effects modeling software.

Reforming regulation with an eye toward equity.

The Biden administration seeks to change how agencies weigh the effects of regulation.

Hypovolemia with peripheral edema: What is wrong?

Fluid normally exchanges freely between the plasma and interstitial space and is returned primarily via the lymphatic system. This balance can be disturbed by diseases and medications. In inflammatory disease states, such as sepsis, the return flow of fluid from the interstitial space to the plasma seems to be very slow, which promotes the well-known triad of hypovolemia, hypoalbuminemia, and peripheral edema.

Recruitment of efferent lymph during infusion of 20 % albumin.

Background: Intravenous infusion of hyper-oncotic 20 % albumin expands the plasma volume by approximately twice the infused volume. We investigated whether the recruited fluid stems from accelerated flow of efferent lymph, which would add protein to the plasma, or from reversed transcapillary solvent filtration, where the solvent is expected to be low in protein.

Methods: We analyzed data from 27 intravenous infusions of 20 % albumin (3 mL/kg; approximately 200 mL) over 30 min given to 27 volunteers and patients.

Predicting fluid responsiveness using esophagus Doppler monitoring and pulse oximetry derived pleth variability index; retrospective analysis of a hemodynamic study.

Background: Fluid therapy during major surgery can be managed by providing repeated bolus infusions until stroke volume no longer increases by ≥ 10%. However, the final bolus in an optimization round increases stroke volume by < 10% and is not necessary. We studied how different cut-off values for the hemodynamic indications given by esophagus Doppler monitoring, as well as augmentation by pulse oximetry, are associated with a higher or smaller chance that stroke volume increases by ≥ 10% (fluid responsiveness) before fluid is infused.