Diffusion
- Movement of solute from high concentration to low concentration
- Membrane has to be solute permeable
Osmosis
Movement of water from high concentration to low concentration
-Membrane has to be solute impermeable
Osmolarity
The measure of solute concentration per unit volume of solvent
Osmolality
The measure of solute concentration per unit mass of solvent
Tonicity
The measure of the osmotic pressure gradient between 2 solutions
Where is osmolality the same?
In the ICF and the ECF
What is the normal fluid make up of a 70kg man?
- 42L of water
- 2/3 (28L) intracellular
- 1/3 (14L) extracellular of which only 20% (3L) is intravascular
Give examples of cells present in the blood.
- Platelets
- RBC
- WBC
What are our basic requirements per day?
Water
25-30ml/kg/day
Sodium
1mmol/kg/day
Potassium
1mmol/kg/day
Glucose
50-100g/day
What are the 4 questions which will help you administer fluid correctly?
- What is my patients volume status?
- Does my patient need IV fluids?
- How much fluid do they need?
- What types of fluid do they need?
How do you determine your patient’s volume status?
- Airway
- Breathing
- Circulation
- Disability
- Extremities
What are the signs of euvolaemia?
- Feels well, not Thirsty
- Veins well filled
- Warm extremities
- Mild sweat
- Normal BP and HR
- Normal Urine
What does someone who is euvolaemic need?
No fluids (unless electrolyte deplete or low BP)
What are the signs of hypovolaemia?
- Feels nauseous, thirsty
- Flat veins
- Cool peripheries
- No sweat
- Low or postural BP and high HR
- Concentrate oliguria
- Responds to SLR
What does someone who is hypovolaemia need?
- Resuscitaion fluids (if low BP)
- Rehydration fluids
- ‘Plug the leak’
What are the signs of hypervolaemia?
- Feels breathless, not thirsty
- Veins distended
- Warm and oedematous extremities
- Sweaty
- High BP and High HR
- Dilute urine (could be oliguric or polyuric)
What does someone who is hypervolaemic need?
- No more fluids
- Possibly diuretics (if respiratory compromise)
- Haemofiltration (if anuric)
What can complicate things?
- Low oncotic pressure (low protein/albumin)
- Heart failure
How can low oncotic pressure complicate things?
- Low Albumin or protein can cause oedema in dehydrated patients due to loss of intracapilliary fluid.
- Tend to be oedematous, but behave hypovolaemic (Low BP, high HR, thirsty)
How can heart failure complicate things?
-Can cause oedema and low BP but still require diuresis due to high circulating volume caused by RVP
How can you tell how much fluid your patient needs?
Work out the water deficit
- Catheters, drains
- input charts
- Vomit bowls
- Sputum pots
- Stool charts ad stoma losses
What insensible losses are there?
- Sepsis (sweat)
- Ventilation
- Open wounds
- Burns
- Bleeding
What is the normal loss due to insensible factors per day?
- No solute loss
- 400-800mls water loss
What are the 5Rs of fluid types?
- Resuscitation
- Routine maintenance
- Replacement
- Redistribution
- Reassessment
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Anaesthetics: Principles and Pharmacology39
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Anaesthetics: Conduct of General Anaesthesia40
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Anaesthetics: Pre-Op Assessment20
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Anaesthetics: Critical Care36
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Anaesthetics: Essential Pain Management72
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Geriatrics: Pathophysiology of Ageing22
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Geriatrics: Comprehensive Geriatric Assessment25
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Geriatrics: Immobility and Falls32
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Geriatics: Confusion28
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Geriatrics: Drugs and Polypharmacy24
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Geriatrics: Continence39
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Genetics: Predisposition to Cancer34
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Genetics: Multi-System Disease25
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Genetics: Predisposition to Adult Onset Disease21
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Clinical Pharmacology: Medicine Management24
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Clinical Pharmacology: Drug Safety16
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Clinical Pharmacology: Complementary Medicine39
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Clinical Pharmacology: The Use of Medicines39
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IV Fluids37
