Fluids

Question 1

How much is TBW in terms of percentage? How is the TB split up into intracellular and extracellular water?

Answer 1

60% of total body weight= total body water. 2/3 of TBW= intracellular; 1/3 of TBW= extracellular.

Question 2

What does extravascular mean?

Answer 2

tissue fluid. It is 3/4 of ECF

Question 3

What does intravascular mean?

Answer 3

plasma. It is 1/4 of ECF

Question 4

How to calculate plasma osmolarity?

Answer 4

2 x [Na] + [glucose] + [urea]

Question 5

how do we diagnose severe hyponatremia, and some symptoms?

Answer 5

< 120 meq/L of Na+

and headaches, nausea, vomiting, fatigue, seizures, obtundation, coma, resp.arrest

Question 6

What can cause hyponatraemia? (think broad categories)

Answer 6

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

Question 7

How do we treat hyponatraemia due to hypovolemia? How about for hypervolemia?

Answer 7

IV N.S for hypovolemia

Fluid restriction and +/- loop diuretics

Question 8

What can cause hypernatremia?

Answer 8

fluid loss (renal/GI), or sodium gain

Question 9

How do we treat hypernatremia due to fluid loss?

Answer 9

Rehydrate with 5% dextrose

Question 10

What urine out do we want for a fasting patient on maintenance fluids?

Answer 10

> 30 ml/h

Question 11

What are some types of fluid replacement?

Answer 11

5% dextrose- equilibrates between intravascular and extravascular space within hrs
0.9 NaCl - mainly stays in intravascular space

Question 12

What causes hypokalemia?

Answer 12

GI losses like diarrhoea, renal losses , insulin dextrose, beta agonists

Question 13

How is severe hypokalemia diagnosed? what are some symptoms? What would you see on ECG?

Answer 13

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

Question 14

What can cause hyperkalemia?

Answer 14

K sparing diuretics, Ace inhibitors, Acidosis, cotrimoxazole, renal tubular acidosis type 4

Question 15

What do you see on ECG for hyperkalemia? what are some short term treatments for hyperkalemia?

Answer 15

ECG: peaked T waves, flat/nonexistent p waves, longPR segment

In short term= treat with insulin/dextrose
+ beta agonist

Question 16

what can cause hyperchoremic metabolic acidosis?

Answer 16

giving too many bags of normal saline

Question 17

what are the daily sodium requirements in maintenance fluid therapy?

Answer 17

1-2 mmol/ kg/ day of sodium

Question 18

what are the daily potassium requirements in maintenance fluid therapy?

Answer 18

1-2 mmol/ kg/ day of potassium

Question 19

what are the basal requirements of water?

Answer 19

30 ml/kg/day of water

Question 20

what is hartmann’s fluid?

Answer 20

sodium lactate, crystalloid fluid replacement (CSL)

Question 21

how much fluid do we replace if there is significant blood loss?

Answer 21

If used to replace blood loss, 3 to 4 times the volume lost must be administeredas only 1/3 to 1/4 remains intravascularly.

Question 22

what kind of fluid is dextrose 5%?

Answer 22

Maintenance fluid

Question 23

what kind of fluid is normal saline?

Answer 23

replacement fluid

Question 24

what kind of fluid is Hartmann’s solution?

Answer 24

replacement fluid

Question 25

what is in Hartmann’s solution?

Answer 25

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.

Question 26

what is a consideration of Hartmann’s solution?

Answer 26

contains calcium ions which can cause clotting of blood. so not recommended for use during blood transfusion

Question 27

How might we assess fluids?

Answer 27

Urine output, skin turgor mucus membranes, lactate