Use of IV Fluids Flashcards
Total body water is what percentage of body mass?
60%
What are the 2 compartments TBW is split into?
- ICF
- 2/3 of total water
- ECF
- 1/3 of total water
- Composed of interstitial fluid (ISF, 80%) and plasma (20%)
What is ECF composed of?
- Composed of interstitial fluid (ISF, 80%) and plasma (20%)
What is osmosis?
Osmosis = water diffuses from diluted solution to concentrated solution through a semi-permeable membrane
How is osmosis prevented?
Can prevent osmosis by applying pressure to concentrated solution – osmotic pressure:
- The more particles in solution the higher the rate of osmosis and therefore the osmotic pressure
Through a permeable barrier, high concentration solution on one side and diluted on the other, where does water move?
From diluted solution to concentrated solution
Describe the difference between osmolality and osmolarity?
- Osmolality = number of osmoles of solute/kg
- Osmolarity = number of osmoles solute/litre
- 1 osmole = 6.02 x 1023 particles
- Body fluids measured in mOsm/kg
Body fluid osmolarity is measured in what?
mOsm/kg
How many particles are in 1 osmole?
- 1 osmole = 6.02 x 1023 particles
What is normal plasma osmolarity?
298mOsml/L
What are the dailty requirements of:
- water
- sodium
- potassium
- magnesium
- calcium
- phosphorus
- glucose
- energy
- protein
What is tonicity?
Tonicity = effective osmolarity
- Only particles restricted to one of the compartments will determine water distribution
- Particles that move freely will not influence water distribution
- Hypertonic solution – causes water to leave cell and cell to shrink
- Hypotonic solution – causes water to enter cell and cell to swell
Who do hypertonic and hypotonic solutions cause RBC to do?
- Hypertonic solution – causes water to leave cell and cell to shrink
- Hypotonic solution – causes water to enter cell and cell to swell
Na and K are greater in ECF or ICF?
- Na is greater in ECF than ICF
- K is greater in ICF than ECF
What are some symptoms of tonicity change?
- Largely neurological
- Swelling
- Raised ICP, compromised CBF, herniation
- Shrinkage
- ICH venous sinuous thrombosis
What are different fluid types?
- 0.9% NaCl – 100/250/500/1000ml
- 0.9% NaCl/0.15% KCl
- 0.9% NaCl/0.3% KCl
- 0.9% NaCl/5% glucose
- Hartmann’s solution
- 5% glucose
- 5% glucose/0.15% KCl
- 5% glucose/0.3% KCl
- 0.18%NaCl/4% glucose
- 0.18%NaCl/4% glucose/0.15%KCl
- 0.45%NaCl/5% glucose/0.15%KCl
- Geloplasma
- Isoplex
What should never be given for resuscitation?
Different fluids distribute in the body in different ways due to composition:
-
DO NOT give 5% glucose to resuscitate
- Need fluid in intervascular space which this will not do
What are the different categories of IV fluid types?
- Crystalloids
- Aqueous solutions that are soluble in water
- Colloids
- Insoluble in water, larger molecules
What are crystalloids and colloids?
- Crystalloids
- Aqueous solutions that are soluble in water
- Colloids
- Insoluble in water, larger molecules
What are examples of crystalloids and colloids?
What are possible side effects of colloids?
- Anaphylaxis
- Coagulopathy
- Renal failure
- Rheology
What are possible side effects of crystalloids?
- ECF expansion
- Oedema/increased vascular pressure
What are sensible and insensible losses?
What are examples of sensible losses and the typical values per day?
What are examples of insensible losses and the typical values per day?
What are some methods of measuring body fluid?
- Clinical assessment (used most often)
- ABCD assessment, history (thirst, abnormal losses), examination (pulse, BP, capillary refill, JVP, oedema, postural hypotension), clinical monitoring (NEWS, fluid balance charts, weight) and lab assessments (FBC, urea, creatinine and electrolytes)
- Oesophageal Doppler
- Pulmonary artery catheter
- IVC collapsibility
- Minimally invasive CO monitors
Describe a fluid chart?
- 24 hour chart
- Patient weight
- Guidance
- Structured framework to support prescribing
- 4 questions
- Assess patient – hypovolaemic, auvolaemic or hypervolaemic
- Why give fluid – maintanence, replacement or resuscitation
- How much
- Which fluid
What aspects of the history are important for assessing body fluid?
- Thirst
- Abnormal losses
What aspects of examination are important for assessing body fluid?
- Pulse
- BP
- Capillary refill
- JVP
- Oedema
- Postural hypotension
What lab assessments are useful for assessing body fluid?
- FBC
- Urea
- Creatinine
- Electrolytes
What clinical monitoring is useful for assessing body fluid?
- NEWS chart
- Fluid balance charts
- Weight
How much fluid should be given for maintanence?
- 30ml/kg/24 hours (20-25 in frail and elderly)
For maintanence, should never give more than x ml/hour?
100ml/hour due to risk of hyponatraemia
How is all IV maintanence administered?
- All IV maintenance given in ml/hour via volumetric pump
What fluid is best to use for maintenance?
- 0.18% NaCl/4% glucose/0.3% KCl (40mmol/l KCl)
- Contraindications – K>=5 then use 0.18% NaCl/4% glucose
How much fluid should be given for replacement?
- Add up losses in last 24 hours and give volume back
- Such as bleeding, D and V, drain output, fistulae
What fluid should be given for replacement?
- Plamalyte 148
- Administration – gravity giving set or volumetric pump
- Contraindications – upper GI loses use 0.9% NaCl with KCl
For plamalyte 148:
- administration
- contraindications
- Administration – gravity giving set or volumetric pump
- Contraindications – upper GI loses use 0.9% NaCl with KCl
How much fluid should be given for resuscitation?
- For severe dehydration, sepsis or haemorrhage leading to hypovolaemia and hypotension
- Fluid challenge 250-500ml over 5-15 mins and reassess
- Use fluid challenge algorithm
What fluid should be used for resuscitation?
- PlasmaLyte 148/colloid/blood
