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Flashcards in IV Fluids Deck (17)
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1
Q

Define osmolarity

A

Measure of solute concentration per unit VOLUME of solvent

2
Q

Define osmolality

A

Measure of solute concentration per MASS of solvent

Is the same in the ICF and ECF

3
Q

Define tonicity

A

The measure of osmotic pressure gradient between two solutions

Is only influenced by solutes that cannot cross semipermeable membrane as these are the only ones influencing osmotic pressure gradient

4
Q

Describe basic body fluid distribution

A

Average 70kg male; 42L water

2/3 IC
1/3 EC

5
Q

What do we need fluidwise?

A

No-one exactly the same

Water 25-30ml/kg/day

Sodium 1mmol/kg/day

Potassium 1mmol/kg/day

Glucose 50-100g/day

6
Q

Questions to ask when prescribing fluids

A
  1. What is my patient’s volume status? - ABCDE
  2. Does my patient need IV fluids?
  3. How much fluid do they need?
  4. What types of fluid do they need?
7
Q

Describe euvolaemia

A

Patient feels well, not thirsty

Veins well filled

Warm extremities

Mild sweat

Normal BP and HR

Normal urine

NEEDS no fluids (unless electrolyte deplete or low BP)

8
Q

Describe hypovolaemia

A

Feels nauseous, thirsty

Flat veins

Cool peripheries

No sweat

Low or postural BP and high HR

Concentrate oliguria

Responds to SLR

NEEDS fluid resus if low bp, rehydration fluids, “plug the leak”

9
Q

Describe hypervolaemia

A

Feels breathless not thirsty

Veins distended

Warm and oedematous extremities

Sweaty

High BP and HR

Dilute urine; may be oliguric or polyuric

NEEDS; no more fluids, possibly diuretics, haemofiltration if anuric

10
Q

How to work out how much fluid a patient needs

A

Work out water deficit

  • catheters, drains
  • input charts
  • vomit bowl
  • sputum pots
  • stool charts and stoma losses
Sepsis (sweat)
Ventilation
Open wounds
Burns
Bleeding
11
Q

Describe resuscitation fluids

A

IV fluisd urgently restore circulation with hypovolaemia

12
Q

Describe routine maintenance fluids

A

IV fluids if cannot take orally or enterally to meet patient maintenance requirements

13
Q

Describe replacement fluids

A

Some don’t need urgent IV resus but do need IV additional maintenance to correct existing deficits or ongoing abnormal EXTERNAL losses e.g. diarrhoea or fever

14
Q

Describe redistribution fluids

A

Some patients have abnormal INTERNAL fluid redistribution or fluid handling e.g. sepsis or major illness; cardiac, liver or renal disease

15
Q

Describe dextrose as an IV fluid

A

Moves through all compartments; not useful for blood volume expansion

Zero sodium load, isotonic

Useful in; chronic dehydration, hypernatraemia

Not useful in; resuscitation, low albumin

16
Q

Describe crystalloids as an IV fluid

A

Utilitarian, come in various combinations

Remain in ECF

Usually high Na load; can cause problems over time

Useful in; acute dehydration, AKI, resuscitation

Not useful in; long term maintenance, hypernatraemic patient

17
Q

Describe plasma expanders as an IV fluid

A

Colloid, stays exclusively in IVS

Trials show no better than crystalloid in resus

IV albumin sometimes used in cirrhosis

Remember blood and TPN are also colloids

Useful in; liver patients, selected intra-operative

Not useful in much else