Fluids

Question 1

Body fluid composition

Answer 1

Total water: 60% of 70kg = 42L
- 2/3 intracellular = 28L
- 1/3 extracellular = 14L
• Plasma 1/4 = 3L 
• Interstitial 3/4 = 10L
• Transcellular = 1L

Question 2

3rd Space Losses

Answer 2

Decreases ECF

• Bowel obstruction → less fluid reabsorption

• Sudden diuresis on day 2-3 post op = recovery of
ileus

• Peritonitis → ascites

Question 3

Resuscitation fluids

Answer 3

0.9% saline 500ml/15 mins

Hartmanns - sodium lactate

Question 4

Maintenence

Answer 4

5% Dextrose

Question 5

Assessing fluid status

Answer 5

Hx: balance chart, surgery, other losses, thirsty

Impression: drowsy, alert

Inspection: drips, drains, stomas, catheters, CVP

Question 6

Examination

Answer 6

• IV volume

• Cap refill
• HR
• BP lying and standing
• JVP

• Tissue perfusion

• Skin turgor
• Oedema: ankle, pulmonary, ascites
• Mucus membranes

• End-organ

• urine output
• increased serum Cr
• Consciousness
• Lactate

Question 7

Daily requirements

Answer 7

Water: 25 mL/kg/day
Na+: 1.0 mmol/kg/day
K+: 1.0 mmol/kg/day
Glucose: 50g/day

Question 8

Fluid challenge

Answer 8

250ml or 500ml over 15-30mins

Question 9

Dehydration hypovolaemia presentation

Answer 9

Tachycardia
Hypotension
Orthostatic drop
Increased capillary refill time

Thirst - less specific

Question 10

Colloids disadvantages

Answer 10

Increased risk of coagulopathies
Hypersensitivity reactions,
High cost

Question 11

Complications of saline

Answer 11

Hyperchloraemic acidosis

Question 12

Hartmanns

Answer 12

Na+ 
Cl- 
K+ 
HCO3 - 
Ca2+

Question 13

Saline contents

Answer 13

Na+

Cl-

Question 14

Dextrose contents

Answer 14

50g

Question 15

K+

Answer 15

Can only give 10mmol per hour

Therefore 40mmol per 4 hours

Question 16

Emergency blood replacement

Answer 16

2 unit O packed red cells STAT
Major haemorrhage protocol

+ plasma
+ platelets

Question 17

Cryoprecipitate

Answer 17

Contains VWF

Question 18

Head injury

Answer 18

Avoid dextrose as can cause cerebral swelling