Fluids Gastro tutorial (1) + Dominic teaching

Question 1

Normal daily requirements for adult (for 70kg)

Answer 1

• 25-30ml/kg/day of water - about 2L
• 1mmol/kg/day of Na+ and K+ - 70mmol
• 50-100g/day glucose

Question 2

How much glucose does dextrose 5% contain?

Answer 2

5g/100ml - 1L = 50g

Question 3

How to tell if someone hypernatraemic is this way due to dehydration?

Answer 3

Look at haematocrit - should be 3x Hb, if more than this blood is ‘thick’ and dehydrated

Question 4

Contents of 0.9% NaCl

Answer 4

154 mmol/L of sodium
154 mmol/L chloride

Question 5

Contents of Hartmanns

Answer 5

130 mmol/L sodium
4mmol/L potassium
3mmol/L calcium
109 mmol/L chloride

Question 6

How can we add K+ to bags?

Answer 6

20 or 40 mmol can come pre-added to litre bags of 0.9% saline or 5% dextrose

Question 7

Max amount of sodium you want to give daily

Answer 7

150mmol in one day - NO more than this really

Question 8

Fastest rate we can give potassium IV

Answer 8

10mmol/hr

Question 9

Do you give fluids in severe asthma attack?

Answer 9

• Increased losses from RR
• Thick mucus if dehydrated = worse
• Alkalosis, steroids and salbutamol can lower K+
• Low K+ = weak muscles

Question 10

How to work out what rate to give bags?

Answer 10

24hrs / number of bags given
eg 24 / 3 (litre bags)
= 1L over 9 hours

Question 11

What fluids to give in peptic ulcer?

Answer 11

• Nil by mouth due to surgery
• Peritonitis causes leakage of fluid into cavity
• Anaesthesia will dilate = lower BP
• May need more than maintenance slightly

Question 12

When to give fluids in diarrhoea?

Answer 12

• If origin is large bowel - only 1-1.5L of water removed here daily, can stay hydrated
• If from small bowel, this usually absorbs 12L per day = very dehydrated FAST
• May need 4L ish - alternate between saline and dextrose? with K+ in each bag (20mmol) as this will be lost

Question 13

Management for dilute hyponatraemia

Answer 13

Fluid restrict - 1.5L per day

Question 14

Cause of dilutional hyponatraemia

Answer 14

SIADH - caused by any stressor to older people eg head injury, stress, infection
= more water reabsorbed at CD
= dilute blood

Question 15

How to check ADH is cause for dilutional hyponatraemia?

Answer 15

Serum vs urine osmolarity
If urine osmolarity is high and serum = low
Dilutional ADH problems

Question 16

How many litres in general for maintenance fluids?

Answer 16

2-3L
Younger pts can have higher end, caution with elderly as HF/fluid overload

Question 17

What fluids to give in hypernatraemia if no need for resus fluids?

Answer 17

• Dextrose - hypotonic, will dilute blood

Question 18

What fluids to give in hypernatraemia if resus fluids needed?

Answer 18

Dexrose 5% - to dilute sodium
Sodium 0.9% to resusitate

Question 19

hypotonic fluids

Answer 19

0.45% saline
5% dextrose

Question 20

When NOT to give Hartmanns?

Answer 20

Kidney problems - has lactate, acidosis?

Question 21

Consequence of giving someone hypernatraemia through fluids or giving Na+ too fast

Answer 21

Central pontine myelinolysis - demyelination of neurones in pons

Question 22

Consequence of treating hypernatraemia too fast and causing hyponatraemia

Answer 22

Cerebral oedema

Question 23

Maximum rate to alter Na+ in blood

Answer 23

8-10mmol per 24hrs - DO NOT try to go faster than thus

Question 25

Causes of pulmonary fibrosis

Answer 25

• Sarcoidosis - upper crackles
• Silicosis
• Aspergillosis - fungal screening done for this
• Amiodarone, pulmonary fibrosis drug, nitrofurantoin, chemotherapy
• Asbestos/occupational exposure

Question 26

Management of effusion if ph <7.2

Answer 26

Empyema until proven otherwise - chest drain and commence abx

Question 27

Criteria for LTOT

Answer 27

• So <7.3 kPa O2
• CO2 should not rise on giving O2
• or <8kPa O2 if LVHF or pulmonary HTN