Lec 7- IV fluids

Question 1

Fluid balance

Answer 1

• Surgical loss
  
  • Drains
  • Fistula
  • Stoma
• Medical loss
  
  • Diarrhoea
  • Vomit
  • Skin lesions
• Insensible loss (800mL/day)
  
  • Gut
  • lungs
  • skin

Question 2

Body water composition

Answer 2

Question 3

Fluid and electrolyte compartments

Answer 3

Question 4

Assessing fluid needs

Answer 4

• General requirements for health
  
  • Weight based
• Volume status of the patient (Hypo, Normo or Hypervolaemic)
  
  • Fluid balance charts
  • Physical observation
• Type and volume of pathological losses
  
  • Electrolyte contents vary
• Oral intake

Question 5

Requirements in health

Answer 5

Question 6

Volume status

Answer 6

Question 7

Pathological losses

Answer 7

• Pottasium loss from Diarrhoea greater than other areas of loss
• Vomiting- can give a picture of alkalosis
• Stoma losses difficult to calculate
• Table losses in mMol/L

Question 8

Monitoring IV fluid therapy- reassessment

Answer 8

Question 9

Fluid choice- Crystalloid or Colloid

Answer 9

Question 10

Fluid distribution

Answer 10

Question 11

Crystalloids

Answer 11

• Made from simple crystal forming molecules such as salts or sugar
• Mainly act as a carrier for fluid (Makes water isotonic)
• Able to pass freely through semi-permeable membranes
• Have minimal oncotic pressure
• Allow fluid to be lost from the intravascular space easily
• Salt content allows some fluids to be retained in the intravascular space- so plasma expansion is poor
• Chloride component causes vasoconstriction in kidneys- preventing excretion of sodium in water

Question 12

Colloids

Answer 12

• Larger molecules (non-crystal forming)
• May be blood, starch, gelatin or dextran in origin
• Many have a crystalloid base (such as sodium chloride 0.9%)
• Are unable to pass through semi-permeable membranes
• This causes a higher oncotic effect, therefore they tend to retain fluid in intravascular space
• The downsides
  
  • Allergic reactions
  • Starches can impair clotting and cause itching
• Safety data in question

Question 13

Crystalloid v Colloid

Answer 13

• In the critically ill, capillaries become permeable
  
  • Colloids can escape leading to problems later on
• Colloids tend to be more expensive
• Crystalloid use is associated with oedema
• No solution is ideal
• Balanced salt solutions like Hartman’s being more widely used
• Albumin still has a role in sepsis but we have to be careful how much to give
• Moving to be more fluid conscious

Question 14

Is normal saline always the answer

Answer 14

• Nope
  
  • Hypernatremia
  • Problems with cholride imbalance
  • Where sodium content of mediciations is high
  • Hypercalcaemia
  • Tumour lysis syndrome
  • Acidosis

Question 15

Cannula or Central line

Answer 15

• Peripheral cannula
  
  • += simple fluids
  • • = No irritant drug administration
  • • = irritant drugs
  • • = Long term use (72 hours only)
• Central lines
  
  • • = Irritant and non-irritant drugs
  • • = Rapid fluid replacement
  • • = Long term use
  • • = RIsk (infection etc)

Question 16

Gravity infusion

Answer 16

• • = Simple fluids and drug administration
• • = Straightforward patients
• • = Where accuracy less important
• • = Time or rate critical drugs
• • = Vulnerable patients e.g. neonate, critical care

Question 17

Volumetric pumps and syringe drivers

Answer 17

• Volumetric pumps
  
  • Rates of 0.1mL/hour upwards
  • Line occulsion warning
  • Cost- approx £2000
• Syringe drivers
  
  • 0.01mL/hour upwards
  • Suitable for concentrated solution or where accuracy very important
  • Not suitable for large volumes

Question 18

Replacing sodium

Try to find the cause

Answer 18

• Replacing SodiumGeneral rules:
  
  • Mild dilutional hyponatraemia does not require replacement
  • Low sodium secondary to malnourishment should be corrected via increased oral nutrition intake
  • Low sodium secondary to chronic renal disease – increase oral sodium intake
  • Asymptomatic and chronic – fluid restriction
  • If sodium is to be replaced – isotonic solutions should be used
• Emergency situations <110mmol/L or severe symptoms:
  
  • Risk of convulsions; Replace slowly; Hypertonic solutions and furosemide

Question 19

Replacing sodium

Try to find the cause answers

Answer 19

• Check for drug causes
• Volume status
• Check urinary sodium
• Plasma and urine olmolality

Question 20

Replacing potassium

Try to find the cause answers

Answer 20

• Check for drug cause (table back of BNF)
• Volume status
• ECG (check for changes)
• Renal function
• Magnesium levels

Question 21

Replacing potassium

Answer 21

• 3-3.5
  
  • Identify cause and correct
  • Give Sando K tabs TDS until >3.5
• <3.0 With NO symptoms
  
  • Identify and correct cause
  • Give Sando K tabs QDS until >3.5
  • Consider IV if vomiting or other GI losses
  • Measure levels daily
• <3 With symptoms
  
  • Identify and correct cause
  • Give 20mmol KCl in 500mL 0.9% NaCl over 2 hours, check levels every 2 hours and repeat infusion every 4 until >3.5
• <2- Cardiac disease or symptoms
  
  • As above but in ITU for intensive monitoring

Question 22

Hypomagnesaemia

Answer 22

Question 23

Replacing Magnesium

Try to find the cause answers

Answer 23

• Check for drug causes
• Levels of other electrolytes
• Renal function
• Check for symptoms

Question 24

Replacing magnesium

Answer 24