Fluid and Electrolyte Balance Flashcards
Where is interstitial fluid?
It is in between the cells and tissues
What is transcellular fluid?
It is synovial fluid, cerebrospinal fluid, retinal fluid
What is another word for intravascular fluid?
Plasma
What are the functions of water?
The fluid prevents friction in body Transports nutrients and wastes Exrection of waste medium for cellular metabolism Temperature control maintain BV Part of most activities in body
What is the function of electrolytes?
1) Regulate water distribution
2) Transmission of impulses
3) Clotting of blood
4) Generation of energy
5) Regulation of acid-base balance
What electrons are involved in acid-base balance?
Hydrogen and Bicarb ions
What is tonicity?
Tonicity is a measure of the effective osmotic pressure gradient, as defined by the water potential of two solutions separated by a semipermeable membrane
What is specific gravity?
Specific gravity is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume
What is normal serum osmolality?
300 mosm/KG
What are the two membranes that separate fluid compartments?
- Capillary membrane
- Plasma (cell) membrane
What three things happen in fluid imbalance?
Dehydration
Overhydration
Oedema – third space
Describe the three spaces of fluid:
1st- normal amount, normal space
2nd- extra interstitial fluid
3rd- extra fluid in spaces where there usually isn’t any fluid, like perinatal
What are the four causes of oedema?
1) Increased hydrostatic pressure
2) decreased osmotic pull
3) impaired lymph drainage
4) increased capillary permeability
Describe hydrostatic pressure:
Pressure exerted by a fluid
What is osmotic pressure?
Pressure resulting from concentration of substances in a solution
How can you manage oedema?
1) Elevate limb
2) Increase movement
3) Compression
4) Decrease salt and fluid intake
5) Diuretics
What is a haematocrit?
The haematocrit is a measure of the viscosity or ‘thickness’ of the blood.
How do you calculate cardiac output?
CO = SV x HR
Saline is given instead of water in cases of fluid loss because of?
Normal saline is an isotonic solution, meaning that it has the same salt concentration as the body. If you used sterile water for the purpose of serum dilution, the cells would swell and burst because water would be drawn into them. If you used a hypertonic solution (greater content of salt than in the body), the cells would shrivel up because the water would be drawn out of them. Isotonic solutions are the same as the body, so the cells can maintain their normal appearance. Kind of like the story of Goldilocks and the three bears. Hypertonic solutions are too salty. Hypotonic solutions (such as water) are not salty enough. And isotonic solutions (normal saline) are just right!
What is a colloid?
a homogeneous non-crystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; the particles do not settle, and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.
What could be the cause of too much aldosterone in the body?
This system is activated when the body experiences a decrease in blood flow to the kidneys, such as after a drop in blood pressure, or a significant drop in blood volume after a hemorrhage or serious injury.
(Renin releases angiotensin which triggers release o aldosterone).
What is the normal urine output per hour?
30-50 mls per hour
What is the rationale for using colloids or crystalloids to replace fluid loss?
Plasma volume expanders - crystalloid, colloid or a mixture of both - are used to restore vascular volume, stabilise circulatory haemodynamics and maintain tissue perfusion
What is crystalloids?
a substance that, when dissolved, forms a true solution rather than a colloid and is able to pass through a semipermeable membrane.
What is a plasma volume expander? Give two examples:
Plasma volume expanders, in the form of colloid or crystalloid solutions, work to restore intravascular volume by increasing the oncotic pressure in the intravascular space.
Give the main reasons for intravenous fluid therapy:
Maintain normal blood pressure Replace previous losses of fluid or electrolyte losses Meet current losses Vehicle for IV medication Provide nutrition Correct acid-base imabalance
What are examples of crystalloid fluid?
The most commonly used crystalloid fluid is normal saline, Ringer’s Acetate, and a solution of 5% dextrose
What are examples of colloid fluid?
Include albumin and fresh frozen plasma.
