Fluids Flashcards
What is osmolarity?
Conc of osmotically active particles in solution
Daily requirements of water
30-40 ml/kg
Daily requirements of energy
30-40 kcal/kg
Daily requirements of sodium
1-2mmol/kg
Daily requirements of potassium
1mmol/kg
Is Na+ + K+ intra or extracellular?
Na+ major extracellular
K+ major intracellular
Stress response in homeostasis
ADH release Water retention Dilutional hyponatraemia Renin release Sodium retention Fluid overload
What is the total obligatory loss for water in adults?
1500ml
What is the definition of oliguria?
Urine output less than 0.5ml/kg/hr
What are crystalloids + give examples?
Water soluble crystalline substance that diffuses across a semi-permeable membrane
NaCl
Dextrose
Dex/Sal
Hartmanns/ Ringers/ compound sodium lactate
What are colloids?
Dispersion of finely divided particles in a medium Fluid stays in circulation Gelofusine Voluven Volulyte
Describe composition of 0.9% NaCl
% means g/100ml
9g NaCl per L
154 mmol Na 154 mmol Cl
How many litres of NaCl will give a 1L increase in plasma volume?
4.7L
What are the consequences of NaCl infusion?
Hyperchloraemic acidosis
Metabolic acidosis
High Cl + low HCO3
What does Hartmans contain?
Na Cl K Ca++ Lactate
What is the difference between Hartmans and Ringers?
Hartmans = has lactate
Describe the composition of dextrose + how much is needed for a 1L increase in plasma volume?
50g dextrose per L of water
14L to increase PV by 1L
How many calories in 5% dextrose?
170
What is HAS?
Human albumin solution
- pooled human plasma
What type of fluid is blood?
Colloid
What is HES?
Starch
How to assess fluid status?
Check mucous membranes Skin turgor Urine output BP HR JVP
What is the criteria for mild fluid deficit?
Loss of 4% body weight
Loss of skin turgor
Dry mucous membranes
What is the criteria for mod fluid deficit?
Loss of 5-8% body weight
Oliguria
Tachycardia
Hypotension
What is the criteria for severe fluid deficit?
Loss of >8% body weight
Profound oliguria
CVS collapse
What do you use for a fluid challenge + how do you do it?
Large bore IV cannula
Colloid 500ml bolus
Observe BP + HR
What patients have abnormal fluid losses?
GI - suction/ vomiting, bowel prep Hyperventilation Fever (12% loss per 1 degree rise) Burns Hyperglycaemia Diuretics
What are patients with DKA deficient in + what metabolic state are they in?
3-5L fluid deficiency 300-500mmol Na deficiency 150-250mmol K deficiency Hyperglycaemia Hyperketonaemia Metabolic acidosis
What fluids to give in DKA?
Initially 2-3L NaCl
Add K+
