S5 L2 Fluids

Question 1

Recap on term:

• Osmolality
• Osmolarity
• Tonicity

Answer 1

Question 2

Recap:

• Distribution of body fluids in the body
• TBW of newborn baby
• TBW in the elderly

Answer 2

Newborn baby: 75%
Elderly: 45% (as low muscle mass)

Question 3

Electrolyte distribution between compartments
- Composition in each compartment and why

Answer 3

Question 4

Movement of water, Na+, K+ across intravascular, interstitial and intracellular compartments

Answer 4

Question 5

Fluid comparments and shifts:
- What happens to water movement when blood and cells are isotonic
- What happens to water movement with hypernatreamia, what is the effect of hypernatremia on cells?
- What happens to water movement with hyponatreamia, what is the effect of hyponatremia on cells?
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Answer 5

Question 6

5% Dextrose:

• How does this move/not move through the compartments
• Why?
• What does this include?

ALL FLUIDS GIVEN IN 1L

Answer 6

Question 7

0. 9% Saline:
   - How does this move/not move through the compartments
   - What does this include?
   - Why?

Answer 7

Question 8

Hartman’s:

• How does this move/not move through the compartments
• What does this include?
• Why?

Answer 8

Question 9

Combination bags: e.g. Mixture of dextrose and 0.9% saline:

• How does this move/not move through the compartments
• What does this include?
• Why?

Answer 9

Question 10

Why do patients need fluids?

Which fluids should you give?

Answer 10

Question 11

Hospitalised Patients
- What do you also need to consider? What other things will affect their fluid requirements?

Answer 11

Question 12

NICE Guidelines for Intravenous fluid:
State these and all the ranges of values…

Answer 12

Question 13

Body secretion and the Na+, K+, Cl-, HCO3-, volume in this?

• Vommit
• Diarrhoea

Answer 13

Question 14

For the following, state roughly the values of Na, Cl, K+, volume, glucose

• Sodium chloride 0.9% (Saline)
• Sodum chloride 0.18%/4% glucose
• 0.45% NaCl/4% glucose
• 5% glucose (Dextrose)
• Hartmann’s
• How is K+ added?

GO TO PP FOR QUESTIONS - REALLY HELPFUL FOR UNDERSTANDING (more than what’s in these flashcards)

Answer 14

Potassium added in the form of KCl

Question 15

Q: A 55 year old man has been admitted for colorectal surgery. He needs to remain
NBM until his surgery tomorrow. He weighs 96kg. All electrolytes are within
normal ranges.

Write a fluid regime for him (using NICE guidelines)

Answer 15

Question 16

Q: A 24 year old woman is admitted with appendicitis. She weighs 65kg and is due
for theater in 24 hours time. She needs to remain nil by mouth, has normal U&Es
and is euvolemic. You have been asked to prescribe fluids. What would you
prescribe and why? All bags of fluid are 1L.

Answer 16

Question 17

Q: A 38 year old female (65kg) presents to hospital with a 5 day history of diarrhea
and vomiting secondary to gastroenteritis. She has vomited 10 times today
(approximately 1L). Suggest a fluid regime for her

Answer 17

Question 18

Points to remember about fluid prescribing:

• Low BP and tachycardia
• Diahorrea and vommiting
• Potassium given…
• Nil by mouth
• Elderly

Answer 18

• Low BP and tachycardia - means low blood volume - need to increase ECF. Do this with saline or Hartmann’s
• Diahorrea or vommitting - loose potassium
• Potassium + has to be given slowly e.g. over 8 hours
• Nil by mouth - need glucose (e.g. dextrose or Hartmann’s)
• Elderly - don’t want to overload too quickly with fluid, add fluid slowly, e.g. over 12 hours

Question 19

GW:

• *Case of hyperkalaemia:**
• What does ECG look like?
• Why is it a medical emergency?

Following steps are made (potassium is 9.0):

• Given Calcium gluconate, why?
• Given insulin-dextrose infusion, why?
• How can excessive potassium be removed from the body?

What can cause hyperkalaemia?

Answer 19

ECG:
Wide QRS
Looks like string is being pulled
Hyperkalaemia

Why is it a medical emergency?
Cardiac arrthymias -> can lead to cardiac arrest

Calcium gluconate:
Stabilises the myocardium. Doesn’t help to remove K from body
Helps prevent arrhythmia. K+ above pH6 with ECG changes, or K+ above pH6.5, give this. Cardiac membrane stabilising effects takes approx. 15-30 mins

Insulin-dextrose infusion:
Insulin stimulates uptake of K+ from blood into cells via cell surface sodium-potassium pumps. Dextrose is also added to prevent hypoglycaemia - Doesn’t remove K+ from the body. Just causes redistribution

Excess potassium excreted: 3 ways-
• Calcium resonium - A large insoluble molecule that binds to
potassium in the large intestines, where it is excreted in
faeces
• Furosemide - Potassium wasting dieuretic. Helps to excrete
potassium in conjunction with hydration of fluids
• Dialysis - Gold standard for removing potassium from the
body, provides immediate removal

What can cause hyperkalaemia?

• Spirnolactone - spirinolactone acts on aldosterone (Potassium-sparing dieuretic)
• Ketoacidotic - low pH - also causes hyperkalaemia
• Lack of insulin? - Type 2 diabetes
• Lying on the floor potentially for 3 days - rhabdomyolysis, also releases potassium
• Acidosis: H+ transported into cells at the expense of K+ efflux
• Renal failure
• Aldosterone deficiency
• ACEi, ARB

Question 20

GW:

• What is a bolus
• Difference between fluid bag and bolus
• What is fluid resuscitation?
• How to monitor fluid resuscitation?
• How is potassium added in a fluid regime? What other ion does this ‘add to’?
• When doing a fluid regime, think about…
• ECF compartment loss examples
• ICF compartment loss examples

Answer 20

Bolus:
• Quick way to get fluid in, e.g. 500ml over 15 mins, then assess… if still
haemodynamically unstable, may need another bolus… etc
Difference between fluid bag and bolus:
• bag enters body ‘slower’
Fluid resuscitation:
• Replacing fluid lost
How to monitor fluid resuscitation:
• Blood pressure monitor
KCl:
• Adds to both K+ and Cl-
Can add in a 20 or 40mmol
Fluid regime, think about:
• Volume of fluid
• Electrolytes
• Glucose
• Potassium (in the form of KCl)
ECF:
Loss e.g. vomiting, diahorrea, bleeding
ICF:
Loss e.g. burns

Question 21

GW:
- Fluid ressucitation of ECF…

Answer 21

ALWAYS RESTORE ECF FIRST, before trying to restore ICF. There is no proint trying to sort ICF, when don’t have the blood pressure for blood movement