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Flashcards in Fluid and Electrolyte balance Deck (34):
1

Describe the different body fluid compartments and the approximate proportion of fluid inside each one.

Two fluid compartments:

- Intracellular fluid = 2/3 total body fluid
- Extracellular fluid= 1/3 total body fluid which consists of 80% interstitial fluid and 20% plasma

2

Discuss the pressures involved in the movement of water between the plasma, interstitial fluid, lymphatic vessels and intracellular fluid.

The pressures involved in the movement of fluid across the fluid compartments include:
• the capillary hydrostatic pressure (the blood pressure that tends to push against the vessel wall and drive fluid out of the capillary)
• the capillary oncotic pressure (the osmotic pressure of proteins in the blood that pull fluid into the intravascular space)
• the interstitial hydrostatic pressure (that pushes fluid towards the intravascular space)
• the interstitial oncotic pressure (the pressure of proteins in the intravascular space that pulls fluid out of the capillaries).
The latter force is fairly minimal. Normally, the balance of forces still means a small net loss of fluid into the interstitial space, which is drained back into the bloodstream by the lymphatic system.

3

Explain how an increase in capillary hydrostatic pressure causes oedema, and how a decrease in capillary oncotic pressure causes oedema.

If the capillary hydrostatic pressure rises above normal or the capillary oncotic pressure falls below normal, this encourages more fluid to move out of the capillaries and into the interstitium, causing oedema.

4

Describe what is meant by fluid being in the third space.

Third spacing refers to fluid that pools outside of a normal fluid compartment.

5

Briefly describe how sodium, chloride and potassium are normally kept in balance.


If serum sodium levels are decreased or potassium levels are too high, the renin-angiotensin-aldosterone system is activated and the body secretes aldosterone, which causes the kidneys to reabsorb sodium and secrete potassium into the filtrate, adjusting the balance back to normal. Aldosterone also causes more potassium to be excreted in sweat. Chloride has a negative charge that allows it to interact with sodium so the passive transport of chloride follows the active transport of sodium, with levels rising and falling in concert.

6

Briefly list some common causes of water deficit.

Blood loss  
Trauma 
surgery
Fluid loss – 
Severe vomiting/diarrhoea
Burns
Third spacing

7

List some causes of water excess. why is the healthy body unable to remain in a state of water excess.

• Acute kidney injury
• Severe congestive heart failure
• Liver cirrhosis

because of the lymphatic system

8

Discuss why metabolic dysfunctions occur in potassium deficiency and in potassium excess.

Potassium deficiency: hypokalemia
• Because insulin secretion is depressed and muscle excitability and liver glycogen synthesis is reduced


Potassium excess: hyperkalemia
• Because renal function is affected, resulting in fluid retention and oliguria. Muscle excitability

9

What is the most prominent ECG change associated with hyperkalaemia?

ST-segment depression, flat P wave, wide QRS complex and peaked T wave.

10

What is the most prominent ECG change associated with hypokalaemia?

Flattening of the T wave and the appearance of a U wave

11

Identify four clinical manifestations associated with respiratory alkalosis.

Lightheaded
Hypertension
Dry mouth
Palpitation
Bloating
Tachycardia
Decrease BP or normal

12

Explain how hyperglycaemia contributes to dehydration and metabolic acidosis.

High blood sugar causes further dehydration as your kidneys attempt to get rid of glucose and ketones by producing large amounts of urine. Increased dehydration causes higher blood sugars, which in turn cause further dehydration.

13

Identify five risk factors associated with the development of fluid, electrolyte and acid-base imbalances.


• Age
• Gender
• Body size
• Environmental temperature
• Lifestyle

14

Explain the clinical implications of hypovolaemia and hypervolaemia.

Hypovolemia:

Acute weight loss
Decrease skin turgor
Oliguria
Concentrated urine
Cool clammy skin due to peripheral vasoconstriction
Thirst
Anorexia
tachy

Hypervolemia:

Odema
Crackles, abnormal lung sounds
Increased BP
Bradycardia
Increased CVP
Increased weight
Increase urine output
SOB and wheezing

15

Discuss the role of Antidiuretic hormone in maintaining homeostasis of body fluids.

The antidiuretic hormone helps to control blood pressure by acting on the kidneys and the blood vessels. Its most important role is to conserve the fluid volume of your body by reducing the amount of water passed out in the urine.

16

What is PAO2?

It is partial pressure of carbon dioxide. (normal 35-45 mm Hg) reflects the respiratory status of patients as it measures the carbon dioxide content in the blood.

17

What is Base Excess?

is defined as the amount of H+ ions that would be required to return the pH of the blood to 7.35 if the pCO2 were adjusted to normal. It is used as an indicator of the degree of metabolic disturbance.

18

What is Haematocrit?

is a measurement of the proportion of blood that is made up of cells, it is the ratio of the volume of red blood cells to the total volume of blood.

19

What is Diffusion?

Movement of fluids from high to low concentration

20

What is Osmosis?

Movement of fluids to an area of high solute concentration and to low concentration

21

What is Active Transport?

The movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.

22

Discuss the difference between osmolarity and osmolality.

Osmolality and osmolarity are units of measurement.

Osmolarity is the concentration of an osmotic solution. VOLUME CONCENTRATION per litre

Osmolality deals with the concentration of the particles that are dissolved in a fluid. MASS CONCENTRATION per unit

23

Discuss the difference between osmotic pressure and tonicity.

Osmotic pressure:
Is the amount of hydrostatic pressure needed to stop the flow of water by osmosis, primarily determined by the concentration of solutes.

Tonicity:
The ability of all the solutes to cause an osmotic driving force that promotes water movement from one compartment to another.

24

Compare the mechanism of action of Potassium-sparing, Thiazide and Loop diuretics and provide one example of each.

Thiazide promotes excretion of sodium, potassium, chloride and water by decreasing the absorption in the distal tubules, examples include:
Hydrochlorothiazide

Pottasium-sparring promotes excretion of sodium and water by inhibiting Sodium-Potassium exchange in the distal tubule, examples include:
Amiloride

Loop diuretics inhibit sodium and chloride reabsorption in the ascending loop of Henle, it also excretes sodium, chloride, water and potassium

25

Metabolic Acidosis cause and effect, on ABG'S.

Excess of nonvolatile acids and bicarbonate deficiency.

PH decreases
Decrease of HCO3
Decrease of PaCO2

26

Metabolic Alkalosis cause and effect, on ABG'S.

Bicarbonate excess

Increase PH
Increase HCO3
Increase PaCO2

27

Respiratory Acidosis cause and effect, on ABG'S.

Retained CO2 and excess carbonic acid

Decrease PH
Increase PaCO2
Increase HCO3

28

Respiratory Alkalosis cause and effect, on ABG'S.

Loss of CO2 and deficient and carbonic acid

Increase PH
Decrease PaCO2
Decrease HCO3

29

Identify the regulatory mechanisms triggered by hypovolaemia.

.

30

What is Diuretics?

Increase urinary excretion of water and sodium
Three major groups
Thiazide
Potassium-sparing
Loop diuretics
Treat vascular fluid overload and oedema

31

Hypovolaemic shock – signs and symptoms

HR increase
RR increase
BP decrease
COOL
CLAMMY
PALE
Urine output decrease

32

Diagnostic tests for Hypovolemic shock

ABG
- Oxygen
- Serum lactate
HB
Hematocrit

33

Hypovolaemic shock - treatment

IV fluids
Blood transfusion
Platelets
Coagulation factors
Albumin
Vasopressors
Treat cause
Modified trendelenburg

34

Hypovolaemic shock – Nursing Care

A to E assessment
Increased frequency of observations (BP, TPR)
2 x large bore IV Cannulas
Cardiac monitoring
Administer medications/fluids as charted
Reassure patient
Escalate care to ICU
Position patient