Fluid and Electrolytes Flashcards
Name five roles of body fluid.
- transports nutrients, electrolytes and oxygen to cells
- transports wastes from cells
- regulates body temperate
- lubricates joints and membranes
- assists in digestion
What is homeostasis?
State of equilibrium in the internal environment of the body.
Explain body intake and output of fluid.
INTAKE
- food, fluids, IV infusion
- intra-osseous, rectal, intraperitoneal infusion
OUTPUT
- urine, faeces, respiration, perspiration, lacrimal loss, haemorrhage, burns (serious fluid loss)
What are the two body fluid compartments.
Intracellular compartment (2/3 total body weight) Extra cellular compartment (1/3 total body weight)
Explain the difference between diffusion and osmosis.
DIFFUSION
- is the movement of charged or uncharged particles along a pressure gradient from higher concentration to a lower concentration.
OSMOSIS
- is the movement of water across a semi-permeable membrane down a concentration gradient.
Explain tonicity and the three main types.
Tonicity is fluids that have varying osmotic effects on body cells. The three kinds are:
- hypertonic
Higher solute concentration, fluid shifts into higher concentrated area - isotonic
Same concentration solutes, no shift - hypotonic
Lower solute concentration that another solution, fluid move from hypotonic solution
Explain the two common types of IV fluids.
CRYSTALLOIDS - mimic body’s fluid composition; moves quickly between fluid compartments.
COLLOIDS - contain undissolved solutes which are too large to pass through capillary walls; stay longer intravascular and draws fluid from interstitial therefore increasing blood pressure for longer.
Crystalloids come in isotonic, hypotonic or hypertonic form. Name and explain one common IV solution for each.
ISOTONIC
- 0.9% NaCl (normal saline) = expands intravascular volume = replaces extracellular fluid losses = may cause intravascular overload and hypokalaemia = no free water, energy or electrolytes
- Hartmann’s Solution (compound sodium lactate)
= electrolytes similar composition to plasma (no Mg++)
= no free water or kilojoules
= used in mild metabolic acidosis - 5% Dextrose in water
= provides free water
= some energy and no electrolytes
= should not be used in large volumes
HYPOTONIC
- 4% Dextrose and 0.18% NaCl (4% and 1/5)
= routine maintenance fluids
= need to replace other electrolytes
HYPERTONIC
- 5% Dextrose in 0.9% Normal Saline
= provides some energy and electrolytes - 10% Dextrose
= free water
= provides energy
Name three solutions that are colloids.
- Albumin/Albumex
- Dextran
- Gelofusion
- Haemaccel
- Voluven
Movement between cells is created through pressure. Name and explain these two types of pressures.
Hydrostatic pressure (this is the blood pressure) - movement of fluid and solute through capillary wall into the interstitial space.
Oncotic pressure (this is the plasma protein pressure) - created by proteins which draw fluid into intravascular space.
Diseases that affect fluid status in the body can either prevent fluid from entering, exiting or cause it to increase within the body. Name three issues associated with each.
Entering the body:
- GIT problems
- mouth damage
- paralysis
- psychological problems
Exiting the body:
- renal failure
- bowel obstruction
- electrolyte imbalances
- loss of plasma proteins
Increase fluid loss from the body:
- renal failure
- burns
- haemorrhage
- diarrhoea
- vomiting
- gastric sanctioning
- fistulas
- drain tubes
- electrolyte imbalances
What are three mechanisms of the body for water balance regulation.
Thirst
- thirst centre stimulated
- doesn’t work well in the aged or young
Kidneys
- fluids and electrolytes are excreted or retained
GIT regulation
- ingestion of water
- excretes fluid in faeces
Insensible losses
- water evaporates from the skin and lungs (500ml skin, 100ml stool)
Hormones - anti-diuretic hormone (ADH) = stimulates kidneys to reabsorb water - renin-angiotensin-aldosterone system = water and sodium retention - atrial natriuretic peptide = causes diuresis (tells kidneys to excrete more sodium and in turn, water)
What are electrolytes?
Electrolytes are substances whose molecules split into electrically charged particles called ions. Positively charged ions are cations, whilst negatively charged ions are anions.
Concentration of electrolytes are monitored between two compartments. What are they?
Intracellular and extracellular.
Name the five of the seven electrolytes found within our body, and explain each.
Sodium
- controls and regulates volume of body fluids; maintains water balance
Potassium
- chief regulator of cellular enzyme activity and water content
Calcium
- nerve impulse, blood clotting and muscle contraction
Magnesium
- metabolism of carbohydrates and proteins; involved in vital reactions involving enzymes
Chloride
- acts with sodium to maintain osmotic pressure in blood; plays a role in acid-base balance
Bicarbonate
- body’s primary buffer system
Phosphate
- helps maintain acid base balance and is involved in important chemical reactions in the body and in cell division.
