S5 L2 Fluids Flashcards
Recap on term:
- Osmolality
- Osmolarity
- Tonicity
Recap:
- Distribution of body fluids in the body
- TBW of newborn baby
- TBW in the elderly
Newborn baby: 75%
Elderly: 45% (as low muscle mass)
Electrolyte distribution between compartments
- Composition in each compartment and why
Movement of water, Na+, K+ across intravascular, interstitial and intracellular compartments
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?
5% Dextrose:
- How does this move/not move through the compartments
- Why?
- What does this include?
ALL FLUIDS GIVEN IN 1L
- 9% Saline:
- How does this move/not move through the compartments
- What does this include?
- Why?
Hartman’s:
- How does this move/not move through the compartments
- What does this include?
- Why?
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?
Why do patients need fluids?
Which fluids should you give?
Hospitalised Patients
- What do you also need to consider? What other things will affect their fluid requirements?
NICE Guidelines for Intravenous fluid:
State these and all the ranges of values…
Body secretion and the Na+, K+, Cl-, HCO3-, volume in this?
- Vommit
- Diarrhoea
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)
Potassium added in the form of KCl
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)
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.
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
Points to remember about fluid prescribing:
- Low BP and tachycardia
- Diahorrea and vommiting
- Potassium given…
- Nil by mouth
- Elderly
- 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
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?
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
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
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
GW:
- Fluid ressucitation of ECF…
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
