Fluids Flashcards
How much is TBW in terms of percentage? How is the TB split up into intracellular and extracellular water?
60% of total body weight= total body water. 2/3 of TBW= intracellular; 1/3 of TBW= extracellular.
What does extravascular mean?
tissue fluid. It is 3/4 of ECF
What does intravascular mean?
plasma. It is 1/4 of ECF
How to calculate plasma osmolarity?
2 x [Na] + [glucose] + [urea]
how do we diagnose severe hyponatremia, and some symptoms?
< 120 meq/L of Na+
and headaches, nausea, vomiting, fatigue, seizures, obtundation, coma, resp.arrest
What can cause hyponatraemia? (think broad categories)
can be due to overall loss of fluid volume (diarrhoea/vomiting/waterloss) or due to increased fluid volume- diluting effect (water retention, chronic organ failure) or due to conditions like SIADH
How do we treat hyponatraemia due to hypovolemia? How about for hypervolemia?
IV N.S for hypovolemia
Fluid restriction and +/- loop diuretics
What can cause hypernatremia?
fluid loss (renal/GI), or sodium gain
How do we treat hypernatremia due to fluid loss?
Rehydrate with 5% dextrose
What urine out do we want for a fasting patient on maintenance fluids?
> 30 ml/h
What are some types of fluid replacement?
5% dextrose- equilibrates between intravascular and extravascular space within hrs
0.9 NaCl - mainly stays in intravascular space
What causes hypokalemia?
GI losses like diarrhoea, renal losses , insulin dextrose, beta agonists
How is severe hypokalemia diagnosed? what are some symptoms? What would you see on ECG?
Severe= <2.5meq/L
Symptoms include muscle cramps, weakness, fatigue, palpitations.
On ECG= peaked P wave, PR prolongation, ST depression, flat/inverted t wave, U hump
What can cause hyperkalemia?
K sparing diuretics, Ace inhibitors, Acidosis, cotrimoxazole, renal tubular acidosis type 4
What do you see on ECG for hyperkalemia? what are some short term treatments for hyperkalemia?
ECG: peaked T waves, flat/nonexistent p waves, longPR segment
In short term= treat with insulin/dextrose
+ beta agonist
what can cause hyperchoremic metabolic acidosis?
giving too many bags of normal saline
what are the daily sodium requirements in maintenance fluid therapy?
1-2 mmol/ kg/ day of sodium
what are the daily potassium requirements in maintenance fluid therapy?
1-2 mmol/ kg/ day of potassium
what are the basal requirements of water?
30 ml/kg/day of water
what is hartmann’s fluid?
sodium lactate, crystalloid fluid replacement (CSL)
how much fluid do we replace if there is significant blood loss?
If used to replace blood loss, 3 to 4 times the volume lost must be administeredas only 1/3 to 1/4 remains intravascularly.
what kind of fluid is dextrose 5%?
Maintenance fluid
what kind of fluid is normal saline?
replacement fluid
what kind of fluid is Hartmann’s solution?
replacement fluid
what is in Hartmann’s solution?
131 mEq of sodium ion = 131 mmol/L. 111 mEq of chloride ion = 111 mmol/L. 29 mEq of lactate = 29 mmol/L. 5 mEq of potassium ion = 5 mmol/L. 4 mEq of calcium ion = 2 mmol/L.
what is a consideration of Hartmann’s solution?
contains calcium ions which can cause clotting of blood. so not recommended for use during blood transfusion
How might we assess fluids?
Urine output, skin turgor mucus membranes, lactate
