4-Fluid and Electrolyte

The percentage of body weight that is composed of water.

The average TBW for young adult females is 50% of their body weight.

The average TBW for young adult males is 60% of their body weight.

Calculate the TBW by multiplying the body weight by the percentage of water for the individual's gender and age group.

The TBW of an average 1-year-old male is around 65% of their body weight.

High potassium levels in the blood.

A medication used to treat hyperkalemia by removing potassium from the body through the intestines.

Oral or intravenous potassium supplements can cause hyperkalemia if taken in excess.

Conditions like hemolysis, rhabdomyolysis, and crush injuries can lead to hyperkalemia by releasing potassium from damaged cells.

Calcium infusion can help counteract the harmful effects of hyperkalemia on the heart, but it should be administered cautiously in patients taking digoxin, as it might increase the risk of digoxin toxicity.

A condition characterized by increased fluid volume in the body.

The movement of fluid from the blood vessels into the surrounding tissues, leading to swelling.

A condition where the body loses too much fluid, resulting in a decreased volume of circulating blood.

A test that measures the ability of the kidneys to filter waste products from the blood.

A measure of the concentration of dissolved substances in urine.

A test that measures the concentration of sodium in urine.

A measure of the concentration of dissolved substances in blood.

Potassium is essential for cardiac and neuromuscular function.

Hyperkalemia can cause symptoms in the gastrointestinal, neuromuscular, and cardiovascular systems.

Signs of hyperkalemia on an ECG include high peaked T waves, widened QRS complex, flattened P wave, prolonged PR interval, sine wave formation, and ventricular fibrillation.

The goal of hyperkalemia treatment is to reduce total body potassium, shift potassium from the extracellular to the intracellular space, and protect cells from its effects.

Removing exogenous sources of potassium is an important step in treating hyperkalemia.

Rapid correction of hyponatremia can lead to serious complications like cerebral edema and herniation.

K sparing diuretics, ACE inhibitors, and NSAIDs can impair potassium excretion, potentially leading to hyperkalemia.

The average daily water loss through urine and stool for a 60kg male is between 800 mL and 1750 mL.

The normal osmolality of the extracellular fluid is between 280 and 310 mOsmol/kg.

Insensible water loss refers to the water lost through evaporation from the skin and lungs. A healthy male typically loses around 600 mL per day.

Conditions such as fever and hyperventilation can increase insensible water loss.

The body gains and loses most of its fluid directly through the extracellular compartment, which includes blood and lymph.

The average daily water consumption for a healthy person is 2000 mL.

Hypothyroidism is a condition characterized by decreased metabolic activity, which may lead to decreased insensible water loss.

Hyperventilation is a condition where breathing is abnormally fast and deep, resulting in increased insensible water loss through evaporation.

Total body water (TBW) is the amount of water contained within an organism. It is typically expressed as a percentage of total body weight, and it varies depending on age, gender, and body composition.

In newborns, approximately 80% of their total body weight is composed of water.

In one-year-old children, the percentage of body water decreases to approximately 65% of their total body weight.

Adults typically maintain a total body water percentage of around 60% for males and 55% for females. This percentage remains relatively constant throughout adulthood.

Intracellular fluid (ICF) refers to the fluid contained within cells. It represents approximately 40% of total body water in males.

Extracellular fluid (ECF) refers to the fluid found outside of cells. It includes interstitial fluid (the fluid surrounding cells) and plasma (the fluid component of blood).

The Gibbs-Donnan equilibrium describes the distribution of ions across a semipermeable membrane, such as the cell membrane, when there are non-diffusible charged molecules present. It explains the slightly higher protein content and cation composition in plasma compared to interstitial fluid.

Malnutrition significantly impacts body composition, including total body water. Malnourished individuals typically have a higher percentage of body water than well-nourished individuals.