Fluid and Electrolyte Balance

Question 1

Where is interstitial fluid?

Answer 1

It is in between the cells and tissues

Question 2

What is transcellular fluid?

Answer 2

It is synovial fluid, cerebrospinal fluid, retinal fluid

Question 3

What is another word for intravascular fluid?

Answer 3

Plasma

Question 4

What are the functions of water?

Answer 4

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

Question 5

What is the function of electrolytes?

Answer 5

1) Regulate water distribution
2) Transmission of impulses
3) Clotting of blood
4) Generation of energy
5) Regulation of acid-base balance

Question 6

What electrons are involved in acid-base balance?

Answer 6

Hydrogen and Bicarb ions

Question 7

What is tonicity?

Answer 7

Tonicity is a measure of the effective osmotic pressure gradient, as defined by the water potential of two solutions separated by a semipermeable membrane

Question 8

What is specific gravity?

Answer 8

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

Question 9

What is normal serum osmolality?

Answer 9

300 mosm/KG

Question 10

What are the two membranes that separate fluid compartments?

Answer 10

• Capillary membrane

- Plasma (cell) membrane

Question 11

What three things happen in fluid imbalance?

Answer 11

Dehydration
Overhydration
Oedema – third space

Question 12

Describe the three spaces of fluid:

Answer 12

1st- normal amount, normal space
2nd- extra interstitial fluid
3rd- extra fluid in spaces where there usually isn’t any fluid, like perinatal

Question 13

What are the four causes of oedema?

Answer 13

1) Increased hydrostatic pressure
2) decreased osmotic pull
3) impaired lymph drainage
4) increased capillary permeability

Question 14

Describe hydrostatic pressure:

Answer 14

Pressure exerted by a fluid

Question 15

What is osmotic pressure?

Answer 15

Pressure resulting from concentration of substances in a solution

Question 16

How can you manage oedema?

Answer 16

1) Elevate limb
2) Increase movement
3) Compression
4) Decrease salt and fluid intake
5) Diuretics

Question 17

What is a haematocrit?

Answer 17

The haematocrit is a measure of the viscosity or ‘thickness’ of the blood.

Question 18

How do you calculate cardiac output?

Answer 18

CO = SV x HR

Question 19

Saline is given instead of water in cases of fluid loss because of?

Answer 19

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!

Question 20

What is a colloid?

Answer 20

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.

Question 21

What could be the cause of too much aldosterone in the body?

Answer 21

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).

Question 22

What is the normal urine output per hour?

Answer 22

30-50 mls per hour

Question 23

What is the rationale for using colloids or crystalloids to replace fluid loss?

Answer 23

Plasma volume expanders - crystalloid, colloid or a mixture of both - are used to restore vascular volume, stabilise circulatory haemodynamics and maintain tissue perfusion

Question 24

What is crystalloids?

Answer 24

a substance that, when dissolved, forms a true solution rather than a colloid and is able to pass through a semipermeable membrane.

Question 25

What is a plasma volume expander? Give two examples:

Answer 25

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.

Question 26

Give the main reasons for intravenous fluid therapy:

Answer 26

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

Question 27

What are examples of crystalloid fluid?

Answer 27

The most commonly used crystalloid fluid is normal saline, Ringer’s Acetate, and a solution of 5% dextrose

Question 28

What are examples of colloid fluid?

Answer 28

Include albumin and fresh frozen plasma.