Fluid and Electrolyte Replacement Therapy

Dehydration

• What

• Loss of water also involves

• Decrease of ECF volume causes

• Causes

What: Condition in which water balance is disturbed where more water leaves the body than entering it

Loss of water also involves: Loss of electrolytes

Decrease of ECF volume causes: Decrease in blood volume

Causes: Excessive vomiting and diarrhea

Diuretics

• What

• How

What: Substances used to reduce excessive water through increased water excretion

How: Increase urine output by

• Increasing glomerular filtration rate

• Decreasing tubular water reabsorption

How does diuretics increase GFR?

• Increased atrial pressure

• Increased diameter of afferent arteriole

• Decreased diameter of efferent arteriole

• Reduce oncotic pressure

Why does diuretic need to promote both diuresis and natriuresis (excretion of Na+)

• During edema, water accumulates in ECF

• BUT NaCl also accumulates to maintain osmolality

• So if only water removed = ECF will be hypertonic

• This causes osmoreceptors to crenate and stimulate ADH secretion

• Resulting in increased water reabsorption, cancelling the diuretic effect

Kidney Dysfunction

• What is protenuria

• Damage to nephrons causes

• Polynuria

• Nocturia

• Oligouria

• Anuria

What is protenuria: Increase in glomerular capillary permeability so albumin, protein, RBC is found in urine

Damage to nephrons causes: Loss in the ability of kidney to concentrate or dilute urine

Polynuria: Increased volume of dilute urine

Nocturia: Increased passing of urine at night

Oligouria: Decreased formation of urine

Anuria: No formation of urine

Hemodialysis (kidney dialysis)

• What

• Function

What: Purifying the blood of a person whose kidneys are not working normally

Function: Removes waste products (creatinine and urea) from blood