Clinical Problems: Electrolytes Flashcards Preview

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Flashcards in Clinical Problems: Electrolytes Deck (23):
1

Question to ask before giving IVF

  • is my patient, euvolaemic, hypovolaemic (dehydrated) or hypervolaemic (fluid overload)
  • Does my patient need IVF
  • How much?
  • What type do they need?

2

Types of Fluid

Hypotonic Fluid: (fluid→ cells, cells swell)

Hypertonic Fluid: (Fluid → out of cells, cells shrink) 

Isotonic Fluid: Keep everything the same

3

How do you assess volume status (fluid overload or dehydrated)

Fluid Overload:

  • Weight gain
  • Swollen ankles
  • High BP

Dehydration:

  • Weight loss
  • Dry mouth
  • Low BP
  • Dizziness

4

When DOESN'T the patient need IV fluids

Drinking enough, on enteral feed, already fluid overloaded

5

What are the IV fluids for?

  1. Maintenence: to maintain normal fluid balance (in patients not drinking/eating etc)
  2. Replacement of losses: replace lost body fluids + electrolytes (vomiting, poops etc)
  3. Rescuscitation: hypotensive, very very sick and need heaps of fluid to get system up.

6

How much is maintenence fluid?

~2-3L 

To counteract loss from pee, poo, sweat and breathing

7

What is the 4:2:1 rule for paediatric IVF

Babies don't need the same amount of fluid as adults (1L bag over 8hrs = 3L/day)

 

A image thumb
8

Replacement Fluid: What might you be replacing? How do you know what to replace

Vomiting, post-surgery drainage, poops!

 

Replacing loss + continue maintenence fluid!

  • Careful assessment of fluid status (weight and JVP helpful)
  • Patient record of losses (fluid balance charts)

9

What do we need to do if a patient is SHOCKED

Rescuscitation: give them a lot of fluid really quickly to bring the BP up

10

When do you give Isotonic fluid?

Generally give this (safest). Unless your giving maintanence fluid and your overloaded (give hypotonic), or have a high serum Sodium (give hypotonic)

 

Plasmalide or saline

11

When do you give hypotonic fluid?

Rarely, when the patient needs maintenence fluid but already overloaded or with a high serum Na+

 

Use 5% dextrose: start as isotonic but metabolised bu cells to → free water

12

When do you give Hypertonic Fluid?

For very low serum Na+

13

What is Hyponatraemia (low serum sodium)?

due to water excess (not low Na+). 

14

Where is the IV fluids going?

Extracellularly

15

Na+ loss is from?

  • GI loss  (vomiting, diarrhoea)
  • Hypo-aldosterone (less Na+ reabsorbed)
  • Sweat
  • Diuretics

16

What is Pseudohyponatremia??

When lab tests say you have low Na+ but you don't!!

Very high triglycerides or protein

17

When do you get water excess?

Syndromes with water overload:

  • Cirrhosis
  • Heart Failure
  • Nephrotic Syndrom

SIADH

Polydipsia

18

Whats the serum osmolality like in hyponatremia?

Low! (most of osmo from Na+)

19

Water Excess with euvolaemia

No signs of dehydration, oedema, JVP not elevated.

 

No evidence of fluid overload, so it's probably
-SIADH
-Polydipsia
-Overhydration with low Na IVF
Diuretics
 

 

20

How do you know the hyponatraemia is due to Polydipsia?

The patient will have a unusually low urine osmolarity

 

(usually hyponatraemic patients have high serum osmolarity)

21

SIADH

Usually in response to low BP or dehydration (sensed via baroreceptors and osmoreceptors)

ADH release despite neither of these occuring

Causes: tumors, CNS, drugs, lung disease

22

Diuretics

Commonest tohave low Na+ with Thiazides 

  • Increase ADH
  • cause decreased Na+

Like SIADH but due to a drug

23

Correction of Hyponatraemia

Saline for a dehydrated patient with sodium loss

 

Fluid restriction for patients with water excess