Fluids Flashcards
What are the daily fluid requirements for 70kg man?
2 - 2.5L over 24 hours
What are the normal daily fluid losses?
Urine - 1500ml
Stool - 200ml
Insensible losses -800ml
How is the daly fluid requirement met?
Food - 1000ml
Drink - 1500ml
When are IV fluids given?
If sufficient fluids cannot be maintained orally
What is the risk of cannula to give fluids?
How is this reduced?
MRSA infection
Remove cannula and resume oral fluid intake as soon as possible
What other fluid losses do you need to consider in a sick patient?
Drains
Fever
Diarrhoea
How can fluid balance be monitored?
Daily weighing
Fluid balance charts
What is the total body fluid in a 70kg man?
What fluid compartments does fluid go into?
Total body fluid = 42L (60% of body weight)
28L = intracellular 14L = extracellular
Of the extracellular compartment, 1/3rd is intravascular (blood) 5L
What does a 5% dextrose solution contain?
What is it useful for?
What is it useless for?
Isotonic, but only contains a small amount of glucose so provides little energy
Useless for fluid resus
Suitable for maintaining hydration
Why is a 5% glucose solution useless for fluid resuscitation?
Only contains a small amount of glucose so provides little energy
The liver rapidly metabolises all the glucose leaving only water, which rapidly equilibrates throughout all the fluid compartments
Which solution is most appropriate for fluid resuscitation?
Why?
0.9% saline
Same Na+ concentration as plasma and is isotonic with plasma
Rapidly equilibrates throughout the extracellular compartment only, and takes longer to reach intracellular compartment than 5% glucose
Why is 0.9% saline useful for fluid resuscitation and for maintaining hydration?
Same Na+ concentration as plasma and is isotonic with plasma
Rapidly equilibrates throughout the extracellular compartment only, and takes longer to reach intracellular compartment than 5% glucose
What is the osmotic content of colloids?
High osmotic content similar to that of plasma
Where do colloid IV fluids tend to stay?
Why?
Remain in intravascular space for longer than other fluids, making them appropriate for fluid resuscitation but NOT for general hydration
Due to high osmotic content similar to that of plasma
What is the disadvantage of colloids?
Expensive
May cause anaphylactic reactions
What will effective fluid resus contain?
Combination of colloid and 0.9% saline
What IV fluid is used for hypoglycaemia?
Hypertonic glucose (10% or 50%)
What is the disadvantage of hypertonic glucose solution?
How is this risk minimised?
Irritant to veins, so care is needed
Infusion sites should be inspected regularly and flushed with 0.9% saline after use
Where is glucose with sodium chloride solution mainly used?
Paediatric setting
1/5th normal saline
What is an alternative solution to 0.9% saline?
Hartmann’s solution
Contains Na+, Cl-, lactat, K+, HO3- and Ca2+
Some consider it more physiological than saline
What are the signs of hypovolaemia?
Tachycardia
Postural drop in BP
Decreased capillary refill time
Decreased urine output
Cool peripheries
Dry mucus membranes
Decreased skin turgor
Sunken eyes
What the signs of a fluid overloaded patient?
Raised JVP
Pitting oedema of sacrum, ankles or legs/abdomen
Tachypnoea
Bibasal crepitations
Pulmonary oedema on CXR
What needs to be considered when there is increased fluid loss from the gut?
GI fluids are rich in K+ so increased fluid loss from the gut (diarrhoea, vomiting, high output stoma, intestinal fistula)
Will require increased K+ replacement
What fluids should be given in liver failure?
Patients often have raised total body sodium, so use salt-poor albumin or blood for resuscitation and avoid 0.9% saline for maintenance
What fluids should a patient in shock be given?
Colloid or 0.9% saline via large bore cannula
What consideration do you need to give to the elderly/heart failure patient when giving fluids?
Prone to fluid overload so give IV fluids with care
What fluids are given in acute blood loss?
Resuscitate with colloid or 0.9% saline with large bore cannula until blood is available
What is the concern about K+ replacement in a renal patient?
K+ may be retained in renal failure, beware giving too much IV
What solutions can K+ ions be given with?
5% glucose or 0.9% saline
Why is Hartman’s solution rarely used?
Due to low K+ content
Would have to give a lot to meet daily requirements
What are the daily ion requirements?
25-30ml/kg per day of water
1mmol/kg/day of Na+, K+ and Cl-
50-100g/day of glucose
How can you assess fluids in a patient?
Ask the patient
Fluid balance chart - not very reliable unless patient has catheter
Look at JVP
How can you administer K+?
As KCL 20 or 40mmol
Can be mixed with 0.9% saline of 5% dextrose
How much sugar does 5% dextrose have?
50g
Isomolar solution
How much Na+ does 0.9% saline contain?
154mmol Na+
And
154mmol Cl-
How many hours would you give bags of fluid over if you wanted to give 3L over 24 hours?
8 hours
What is suitable fluids for a healthy 54year old NBM for 24 hours?
2 x 1L 5% dextrose
And
1L 0.9% saline and 40mmol KCL
How much fluid would an elderly patient need?
2L
Why are patients in severe asthma attacks given fluid?
Unable to drink which can result in thick mucus
Thick mucus can block the airways and lead to worsening symptoms
What fluids would a patient with a perforated peptic ulcer require?
Acute blood loss, may have peritonitis and leak fluid. They will be taken to surgery shortly so need adequate fluid for surgery.
General anaesthetic can cause vasodilation
Will require 4L of fluid over 24 hours
1L 0.9% saline + 1L 5% dextrose and 40mmol KCL + 1L 0.9% saline + 1L5% dextrose and 40mmol KCL
What effect does general anaesthetic have on the vasculature?
Dilation
Can result in low BP
When are fluid bolus’s given?
To raise BP rapidly
500ml over 15mins
E.g. sepsis patient
What can cause a large mass in the pelvis?
How is this managed?
Blocked bladder - could be due to prostate
Will require catheter - monitor urine output
Replace lost fluids
What should you do with diuretic medication when giving fluids?
Stop medications e.g. furosemide
Monitor for clinical signs of fluid overload
What may rampiril cause?
K+ retention
