117-128. Fluid and electrolyte balance

Question 1

What are the two main types of intravenous fluids and what are their principle use?

Answer 1

Colloids - to replace large molecular weights e.g. albumin, hydroxyethyl starch, haemaccel

Crystalloids - to replace water and electrolytes e.g. dextrose, saline, Ringer-Lactate, Hartmann’s

Question 2

What % of IV fluid is absorbed in the following solutions?

a) Colloid
b) Saline
c) Dextrose

Answer 2

a) Nearly 100%
b) 25%
c) 10%

Question 3

Why may a solution containing lactate be used in a patient with metabolic acidosis?

Answer 3

Lactate metabolism produces large amounts of bicarbonate

Question 4

List the factors which determine the rate of fluid replacement

Answer 4

Age
Cardiovascular status
Renal function

Severity of existing dehydration
Time it took to develop

Question 5

What are the main considerations when giving potassium IV supplementation?

Answer 5

There is a maximum concentration (40mmol/L for peripheral administration) you can give, and a maximum rate of administration (10 mmol/hour)

MUST BE DILUTED OTHERWISE LETHAL