IV fluids Flashcards
Fluid distribution among bod compartments
67% intracellular
33% extraellular
*Intravascular is only 6% of the whole body compartment
Routine maintenance fluids- how much?
25-30 ml/kg/ day
*2-3 L for most people
What’s Na+ requirement a day?
1-2 mmol/day
What’s K+ requirement/day ?
1 mmol/day
What’s Cl- requirement per day?
1-1.5 mmol/day
What conditions require more fluids?
- vomiting
- diarrhoea
- diuresis
- bleeding
- burns
- hyperthermia
- sepsis
Signs of volume depletion (dehydration)
- thirst
- dry mucous membranes
- skin turgor
- sunken eyes
- capillary refill time
- weight loss
- tachycardia
- hypotension (particularly postural)
- organ hypoperfusion
What happens in postural hypotension?
When a person stands up BP falls too much
*normally BP should increase upon standing
Signs of volume overload
- probable hypertension (possible hypotension)
- raised JVP
- weight gain
- tachycardia
- oedema (peripheral, pulmonary, ascites)
- end organ damage
What is the best method to give fluids to the patient?
always aim for oral - the ideal way
What are crystalloids composed of?
Solutions of water + electrolytes
Can crystalloids move across semi-permeable membrane?
They can cross semi-permeable membrane -> can move between fluid compartments quickly/freely
Examples (3) of crystalloid fluids
- dextrose
- saline
- Ringer’s Lactate (Hartmann’s)
What are properties of normal saline?
Normal saline = 0.9%
Components: Cl-, Na+ and water
- cheapest and most commonly used
- used in fluid resuscitation
- replaces Na+ and Cl-
- only small proportion remains intravascularly (it moves the compartments)
- no calorie content
Dextrose
- components
- use of 5%
- use of 70%
- use
- caution
Dextrose = sugar + water
- 5% and 10% used commonly
- 50% and 70% - used only in ITU (given through central line due to irritation to small peripheral veins)
- used for maintenance fluids (not for resuscitation) *unless in hypoglycaemic episode
- caution: Diabetes Mellitus
Ringer’s Lactate (aka Hartmann’s)
- components
- what are the advantages
- Na + 130 mmol/l
- Cl - 109 mmol/l
- K+ 4 mmol/l
- Ca 1.5 mmol/l
- lactate
These are physiological and isotonic
Colloids
- components
- do they cross semi-permeable membrane
- effect on plasma
Colloids
- Components: high molecular weight molecules
- These are less able to cross semi- permeable membrane
- They exert oncotic pressure -> fluid is pulled into the veins -> plasma expansion
What are colloids useful in?
Colloids are useful in resuscitation when we try to raise BP
They exert oncotic pressure -> fluid is pulled into the veins -> plasma expansion
Gelatins
- most commonly used
- composition
- risk
- use
Gelatins
Most common: Gelofusine
Composition: bovine collagen, sodium and chloride (densly packed molecules)
Risk: anaphylaxis, bleeding risk, prothrombotic
Use: peri-arrest situation, very unwell + hypotension -> to increase BP
Examples of colloids
- gelatin
- hydroxyethyl starches
*these are plasma expanders
Hydroxyethyl starches
- what they are
Hydroxyethyl starches -> colloids
- very large, semi-synthetic molecules - similar to glycogen
- they have large molecules = oncotic pressure -> can pull fluids intra vascularly
Use: fluid resuscitation, to replace intravascular volume
*usually used in critically ill patient/ ITU
Adverse effects of use of Hydroxyethyl starches
- accumulation in interstitial spaces -> deposits in peripheral tissues (large molecules) -> pruritis / irritation of the skin
- coagulation problems
- anaphylaxis
- possible cause of renal impairment
What’s the best fluid to administer if someone is bleeding?
blood
When to use human albumin solution?
In a person with very low albumin
This may be due to: liver failure, nephrotic syndrome if we want to increase the albumin and therefore BP
*but we treat the cause usually
