Related Experiment Video

Updated: Jul 7, 2026

An Immature Murine Model of Reversible Unilateral Ureteral Obstruction
06:37

An Immature Murine Model of Reversible Unilateral Ureteral Obstruction

Published on: April 4, 2025

Urine sodium composition in ambulatory healthy children: hypotonic or isotonic?

Michael L Moritz1

  • 1Division of Nephrology, Children's Hospital of Pittsburgh, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213-2538, USA. Michael.Moritz@CHP.edu

Pediatric Nephrology (Berlin, Germany)
|February 22, 2008
PubMed

Insights

Healthy children excrete hypertonic urine, producing free water. This suggests that 0.9% sodium chloride (NaCl) is likely safe for maintenance parenteral fluids, avoiding hypernatremia in pediatric patients.

Area of Science:

  • Pediatric Nephrology
  • Clinical Chemistry

Background:

  • A debate exists regarding optimal sodium concentrations for maintenance parenteral fluids.
  • Determining appropriate fluid composition is crucial for pediatric patient care.

Purpose of the Study:

  • To evaluate urinary sodium composition in healthy children.
  • To assess the suitability of 0.9% sodium chloride (NaCl) for pediatric parenteral fluid maintenance.

Main Methods:

  • Analysis of 24-hour urine samples from 100 healthy children (aged 3-18 years).
  • Children were referred for hematuria or proteinuria to a pediatric nephrology clinic.
  • Measurement of urine sodium concentration, excretion, and urine flow rate.

Main Results:

  • Average urine sodium concentration was 158±59 mEq/L, closely matching 0.9% NaCl (154 mEq/L).
  • Average urine sodium excretion was 2.9±1.3 mEq/kg per 24 hours.
  • Average urine flow rate was 0.9±0.4 mL/kg per hour.

Conclusions:

  • Healthy children effectively generate free water through hypertonic urine excretion.
  • 0.9% NaCl is unlikely to cause hypernatremia when used as a maintenance parenteral fluid in children.

More Related Videos

Estimation of Urinary Nanocrystals in Humans using Calcium Fluorophore Labeling and Nanoparticle Tracking Analysis07:45

Estimation of Urinary Nanocrystals in Humans using Calcium Fluorophore Labeling and Nanoparticle Tracking Analysis

Published on: February 9, 2021

Related Concept Videos

Formation of Concentrated Urine01:23

Formation of Concentrated Urine

There is a gradient of solutes in the interstitial fluid from the renal cortex through the medulla, known as the medullary osmotic gradient. The juxtamedullary nephrons establish and maintain this gradient using countercurrent mechanisms with loops extending deep into the medulla. These nephrons also use countercurrent mechanisms to regulate urine volume and concentration. The interaction between the descending and ascending limbs of the nephron loop creates an osmotic gradient through...
Physiology of the Genitourinary System III: Urine Concentration and Dilution01:20

Physiology of the Genitourinary System III: Urine Concentration and Dilution

The kidneys concentrate or dilute urine to maintain water and electrolyte balance. Nephrons, particularly the loop of Henle, play a crucial role in this process through the countercurrent multiplication system. This system establishes a high osmolarity in the renal medulla, which is essential for water reabsorption. In the loop of Henle’s descending limb, water is reabsorbed into the surrounding medulla due to its permeability to water. In contrast, the ascending limb actively transports...
Formation of Dilute Urine01:20

Formation of Dilute Urine

The formation of dilute urine is a critical renal adaptation that maintains fluid balance, particularly during periods of high fluid intake. This process primarily involves the juxtamedullary nephrons. By adjusting the permeability of water and ions in response to physiological conditions, the kidneys can either conserve or excrete water, resulting in concentrated or dilute urine.
Filtrate Osmolarity in the PCT
Initially, as the filtrate passes through the proximal convoluted tubule (PCT), its...
Urine: Physical and Chemical Properties01:18

Urine: Physical and Chemical Properties

Urine comprises approximately 95% water and 5% solutes. The primary ingredient, apart from water, is urea - a byproduct of the breakdown of amino acids. Other notable components include uric acid, a residue from nucleic acid metabolism, and creatinine, a metabolite from creatine phosphate breakdown in skeletal muscle tissue.
The concentration of these solutes varies, with urea being the most abundant nitrogenous waste product. Other solutes include sodium, chloride, potassium, phosphate,...
Regulation of Water Intake01:25

Regulation of Water Intake

Osmolality refers to the number of solute particles per kilogram of solvent in a solution. Plasma osmolality specifically indicates the total number of solute particles per kilogram of water in blood plasma. This value reflects the body's hydration status and is tightly regulated through mechanisms controlling water intake and output. While water consumption is a conscious decision, the body has intrinsic regulatory systems to maintain fluid balance. Dehydration, a state of water deficit...
Composition of Body Fluids01:29

Composition of Body Fluids

Water functions as a solvent accommodating various solutes, which can be categorized under electrolytes and non-electrolytes. Non-electrolytes are usually held together by covalent bonds, restricting them from dissociating in solution, thereby leading to a lack of electrically charged components upon dissolving in water. They are predominantly organic molecules, such as glucose, creatinine, and urea. Electrolytes, on the other hand, are compounds that can break down into ions in water.