IV Fluids Flashcards
Definition of crystalloid
Small molecules that dissociate into ions and form true solutions
Number of moles of calcium in calcium chloride and gluconate
Chloride - 0.68mmol/ml
Gluconate 0.22mmol/ml
Potential Effect of calcium gluconate on cardiac function
Can be negatively inotropic and cause coronary vasospasm
Why is bicarb expensive
Usually fluids steralised by heat
If this is done to bicarb produces co2 thus lost
Thus bicarb must be filtered. Expensive
Osmolality of 0.9%nacl
Osmolality of na bicarb 8.4%
Nacl 300
Na bicarb 2000 (!)
How many mmol of na in 1L Na bicarb
1000
Which of colloids or crystalioids has the most impact on the freezing and boiling points of their solute
Crystalloids as lower number of molecules in colloids
Why do colloids also have electrolytes in them
Little osmotic pressure (all oncotic from the large molecules) so needs electrolytes to achieve is osmolality
mmol/l of na in has 4.5 and 20%
100-160
50-120
Ph of HAS
6.4 to 7.4
Ph of 0.9% nacl
Dextrose
5
4
Instance of serious adverse reactions to human albumin, gelofusin and dextran 70
Has 1:30,000
Gelofusin 1:13,000
Dextran 70 1:4500
How are gelatins made
Example
Molecular weight of gelatin
Hydrolysing collagen
Gelofusin
30000 daltons
Mmol of calcium in gelofusin and hartmanns
Gels 0.4 mmol/l
Hartmanns 2mmol/l
Constituents of dextran 70
Molecular weight
Dextrans (glucose polymers) in sodium chloride
Ave 70000 daltons
Composition of hydroxyethyl starches
Molecular weights
90% amylopectin that is etherified
Polysaccharide with starches and glucose with hydroxyethyl groups
Huge range but up to 450,000!
Other than anaphylaxis issues with hydroxyethyl starches
Interfere with coagulation
Can persist outside of vascular compartment
Renal impairment
How is human albumin solution produced
Clinical implication
Fractionation of plasma
Heat sterilised so infection risk very low
20% has made by removal of water and dissolved salts
Weight of albumin in 1L of 4.5% and 20%
4.5% 40-50g
20% 150-250g
What % of protien in has is albumin
> 95%
Potential advantages of albumin (unproven)
Colloid properties
Molecular carriage
Coagulation
Membrane Integrity
Free radicle scavenger
Advantages of stroma free haemoglobin
Good o2 carrier
Enters smallest capillaries
No need to cross match
Minimal infection risk
Easy to store and transport
Long shelf life
Disadvantages of stroma free hb
Low p50 (oxygen tension at which hb is 50% saturated) - high affinity
Poor persistence
Nephrotoxicity
Immunological effect
Free radicle production
Increased nitric oxide scavenging
p50 of intracellular (in RBC) and free Hb
Why
Intracellular 3.6kpa
Free 1.6kpa
Lack of 23dpg so much higher affinity
Why doesn’t stroma free hb persits
Very quickly dissociates to monomers and diners which have molecular weights well below renal threshold of 69000 so excreted in urine
What is the source of risk of nephrotoxicity for stroma free hb
Formed by red cell lysis so needs to be well washed
How can the low p50 of stroma free hb be addressed
Microencapsulated hb
Put hb in mesh bag with DPG! Essentially an artificial cell
How can oxygen be artificially carried (ie no Hb)
Chelating agents based on porphyrin
Perflorocarbons - fluoridated carbon skeleton - can absorb and carry oxygen. Still needs hyperbaric oxygenation to be successful
