6 - Use of IV Fluids

Question 1

what % of body weight is TBW (total body water)?

Answer 1

60%

Question 2

where is TBW contained?

Answer 2

2 compartments -

ICF (intracellular fluid)

ECF (extracellular fluid)

Question 3

how much TBW does an individual of 70kg have?

Answer 3

42 L

70kg x 60%

Question 4

how to calculate TBW?

Answer 4

patient’s weight x 60%

Question 5

how to calculate ICF?

Answer 5

patient’s weight x 40%

Question 6

how to calculate ECF?

Answer 6

patient’s weight x 20%

Question 7

ECF can be subdivided into 2 further categories?

Answer 7

interstitial fluid

plasma

Question 8

Describe equation related to osmotic pressure and the movement of water?

Answer 8

n x c (c/M) RT

n = no of dissociated particles 
c = conc (g/l)
M = molecular weight 
R = universal gas constant 
T = absolute Temp (K)

Question 9

Define osmolality?

Answer 9

No of osmoles of solute /KG

Question 10

Define osmolarity?

Answer 10

No of osmoles of solute/Litre

Question 11

How many particles are contained within an osmole?

Answer 11

6.02 x10 power of 23 particles

Question 12

What are bodily fluids measured in?

Answer 12

Millimolar concentrations - mosm/KG

Question 13

Describe the equation related to Na and K etc.

Answer 13

2([Na] + [K]) + urea + GLC

Question 14

What is the normal plasma osmolarity?

Answer 14

2([Na] + [K]) + urea + GLC
2 ([140]+[4]) + 5 + 5
298 mosm/L

Question 15

What are the values for Water, Na and K in terms of the daily requirement for routine maintenance of IV Fluids?

Answer 15

Water = 30ml/KG
Na = 1-2 mmol/KG
K = 0.7-1 mmol/KG

Question 16

What is tonicity?

Answer 16

Effective osmolality

Question 17

What does tonicity mean in terms of particles which move freely?

Answer 17

Only particles which are restricted to one of the compartments will determine water distribution - particles which move freely will not influence water distribution

Question 18

What does tonicity mean for ECF?

Answer 18

ECF - Na and accompanying anions

Question 19

What does tonicity mean for ICF?

Answer 19

ICF = K and macromolecules

Question 20

Describe hypotonicity?

Answer 20

Cell swelling

Question 21

Describe hypertonicity?

Answer 21

Cellular dehydration

Question 22

Describe neurological changes due to swelling/ shrinkage? (ie tonicity changes)

Answer 22

Swelling - raised ICP, compromised CBF, herniation

Shrinkage - ICH venous sinuous thrombosis

Question 23

Name 3 Crystalloids?

Answer 23

5% dextrose
0.9% saline
Hartmann’s solution

Question 24

Name 3 Colloids?

Answer 24

Gelatins
Starches
Dextrans

Question 25

2 benefits to crystalloids instead of colloids?

Answer 25

Cheap | Non-allergenic

Question 26

How do we assess and manage patients fluids?

Answer 26

24 hour chart - Daily adult IV/SC Fluid prescription Chart

Question 27

Name 3 things which are on the 24hour chart for patients?

Answer 27

Guidance 4 questions Patients weight

Question 28

Provide 3 pieces of guidance given in the 24 hr chart?

Answer 28

Structured framework for prescribers Traffic light for fluids Rationalise fluid available

Question 29

What 4 questions are asked in the 24 hr chart?

Answer 29

Is patient hypovolaemic/ euvolaemic/ hypervolaemic? Why give fluid? How much? Which fluid?

Question 30

Give 4 examples of when you should consult senior member of staff when using the 24hr chart?

Answer 30

Cardiac dysfunction Renal failure Liver failure Head injury

Question 31

Why should you never give over 100ml/hr regardless of weight?

Answer 31

Risk of hyponatraemia

Question 32

How should all IV maintenance be Accessed?

Answer 32

Via a volumetric pump

Question 33

How much should be given for maintenance fluid in frail & elderly?

Answer 33

20-25ml/kg/24hours

Question 34

How much should be given for maintenance fluid in most people?

Answer 34

30 ml/ kg/ 24hrs

Question 35

Taking 30 ml/ kg/ 24hrs into account, how much fluid is required for - a) 35-44 kg b) 45-54 kg c) 55-64 kg d) 65-74 kg e) >75 kg

Answer 35

a) 35-44 kg = 1200 ml b) 45-54 kg = 1500 ml c) 55-64 kg = 1800 ml d) 65-74 kg = 2100 ml e) >75 kg = 2400 ml

Question 36

Which fluid should be used for maintenance fluid?

Answer 36

0.18% NaCl / 4% GLC / 0.3% KCl | 40mmol/ l KCl

Question 37

What is the golden rule of replacement fluids?

Answer 37

If it hasn’t been lost then don’t give it

Question 38

Which fluid is used for replacement?

Answer 38

Plasmalyte 148

Question 39

Name 3 things contributing to daily intake source?

Answer 39

Drinks Food Cellular metabolism

Question 40

Name 5 things contributing to daily output source?

Answer 40

``` Urine Sweat Skin Lungs Faeces ```

Question 41

What are the average values for daily intake and output at temperate climates?

Answer 41

Intake - 2600 | Output - 2600

Question 42

Although difficult, name 4 ways to clinically measure body fluid?

Answer 42

Oesophageal Doppler Pulmonary artery catheter IVC collapsibility Minimally invasive co monitors