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
When do we use Fresh Frozen plasma, cryoprecipitate?
FFP, cryoprecipitate = clotting factors
- bleeding
- DIC
- OD of direct oral anticoagulants
What’s the aim of fluid resuscitation?
To keep fluid intravenously (in intravascular space)
What is usually given for fluid resuscitation in sepsis?
Hartmann’s or normal Saline (0.9%)
In fluid resuscitation, can we use colloids on their own?
No, we use colloids in conjunction with crystalloids
Do fluids require a prescription?
Yes! Just like any other drugs
Include on prescription:
- type of fluid
- volume to be administrated
- time and date to start
- rate of fluid administration
What IV fluid management plan should include details of?
*that is according NICE guidelines, but rarely happens in reality
- fluid and electrolyte prescription over the next 24 hours
- assessment and monitoring plan
- assessment of risks, benefits and harms of IV fluids
Potential complications of fluid mismanagement
- hypovolaemia (before fluid administration)
- pulmonary oedema
- hyponatraemia
- hypernatraemia
- peripheral oedema
- hyperkalaemia
- hypokalaemia
What daily assessments (monitoring) are required if the patient is continuing to receive IV fluids?
- clinical fluid status
- laboratory values (haem, urea, creatinine, electrolytes)
- fluid balance charts
- twice weekly weight measurement
*long term IV fluid therapy - may require less monitoring but must be specified in IV fluid management plan
What monitoring is required in patients receiving IV fluids containing Cl >120 mmol/l?
Daily chloride bloods
NICE guidelines for Resuscitation
- ABCDE
- identify cause of the deficit
- give bolus of 500 ml of crystalloid
- reassess patient: further bolus of 250-500 mls crystalloid, expert help, continuous reassessment and ABCDE
Can tetrastarch be used for fluid resuscitation?
NO !!!
When to consider resuscitation with human albumin?
Only in patients with severe sepsis (resuscitation with human albumin 4-5%)
