Urinary12 - IV Fluids

Question 1

5 reasons patients need IV fluid

Answer 1

1. ) Nil By Mouth
2. ) Malfunctioning GI Tract
3. ) Dehydration
4. ) Fluid Losses
5. ) Abnormal Electrolytes

Question 2

Maintenance Fluids

Substances Lost
Replacement Doses
Routine Maintenance

Answer 2

1. ) Substances Lost
   - fluids: urine (1-2.5L/day) and insensible losses (500ml)
   - water, electrolytes, glucose
2. ) Replacement Doses
   - water: 25-30ml/kg/day (<30 if frail, renally impaired)
   - electrolytes (Na+, Cl-, K+): 1mM/kg/day
   - glucose: 50-100g/day (avoid starvation and ketosis)
3. ) Routine Maintenance - given day 1
   - 25-30 ml/kg/day of NaCl 0.18% in 4% glucose
   - add 27 mM potassium

Question 3

5 features of giving 1L of 5% dextrose

Glucose Content
Osmolarity
Osmolarity Change
Fluid Displacement
1L of Blood Replacement

Answer 3

1. ) Glucose Content - contains 50g of glucose
   - glucose is rapid taken up by cells so hyperglycaemia can occur if infusion rate > uptake and metabolism

2.) Osmolarity is 278 mOsm/kg

3. ) Osmolarity Change - reduces for all compartments
   - glucose rapidly enters the ICF and the free water is distributed in all compartments, reducing osmolarity
4. ) Fluid Displacement - enters ICF and ECF
   - 2/3 ICF = 666ml, 1/3 ECF = 333ml
   - interstitium = 75% of ECF = 250ml
   - intravascular = 25% of ECF = 84ml

5.) 1L of Blood Replacement - need 12L of dextrose
(84ml x 12)

Question 4

5 features of giving 1L of 0.9% saline

Tonicity
Osmolarity
Osmolarity Change
Fluid Displacement
1L of Blood Replacement

Answer 4

1. ) Isotonic - contains 154 mM of Na+ and Cl- ions
2. ) Osmolarity - 308 mOsm/kg
3. ) Osmolarity Change - No change in all compartments
   - isotonic solution so doesnt affect osmolarity
4. ) Fluid Displacment - only enters the ECF
   - doesn’t enter ICF due to no change in osmolarity
   - interstitium = 75% of ECF = 750ml
   - intravascular = 25% of ECF = 250ml

5.) IL of Blood Replacement - need 4 litres of saline (250ml x 4)

Question 5

5 features of giving 1L of Hartmann’s solution

Contents
Osmolarity
Osmolarity Change
Fluid Displacement
1L of Blood Replacement

Answer 5

1. ) Contents - composition closer to normal blood fluid
   - 131 mM of sodium, 111mM of chloride
   - 5mM of potassium, 2mM of calcium
   - 29mM of bicarbonate as lactate

2.) Osmolarity - 280 mOsm/kg

3. ) Osmolarity Change - no change in all compartments
   - osmolarity is maintained with effective osmoles of sodium, potassium, and calcium
4. ) Fluid Displacement - only enters ECF
   - doesn’t enter ICF due to no change in osmolarity
   - interstitium = 75% of ECF = 750ml
   - intravascular = 25% of ECF = 250ml

5.) IL of Blood Replacement - need 4 litres of Hartman’s (250ml x 4)