U&E's Flashcards
Is water mainly intracellular or extracellular?
Intracellular
Is sodium mainly intracellular or extracellular?
Extracellular
Is potassium mainly intracellular or extracellular?
Intracellular
Give 2 examples of how you could loose an isotonic fluid?
- Haemorrhage
2. Fistula fluid
Describe the loss of isotonic fluids?
- Loss from ECF
- No change in sodium
- No fluid redistribution
Give an example of how you could loose a hypotonic fluid?
Insensible loss (dehydration)
Describe the loss of hypotonic fluids?
- Greater loss from ICF than ECF
- Small increase in sodium
- Fluid redistribution between ECF & ICF
Give an example of how you could gain isotonic fluids?
Saline drip
Describe the gain of isotonic fluids?
- Gain is to ECF
- No change in sodium
- No fluid redistribution
Give 2 examples of how you could gain hypotonic fluids?
- Water
2. Dextrose
Describe the gain of hypotonic fluid?
- Greater gain to ICF than ECF
- Small decrease in sodium
- Fluid redistribution between ECF & ICF
List 3 physiological compensatory mechanisms?
- Thirst
- ADH
- Renin / Angiotensin system
List 3 therapeutic compensatory mechanisms?
- IV therapy
- Diuretics
- Dialysis
What is the simple test to ascertain ADH status?
- Measure plasma & urine osmolality. If Urine > Plasma = ADH active
- Measure plasma & urine urea. If Urine»_space; Plasma = water retention
What is the Renin-angiotensin system activated by?
Reduced intra-vascular volume (IVV) ie. sodium depletion or haemorrhage
What is the simple test to ascertain renin-angiotensin system?
- Measure plasma & urine sodium
- If Urine <10mmol/L = R/A/A active
What happens if you replace 2L of lost isotonic fluid with hypotonic fluid?
- Fall in sodium
- Fluid redistribution
What happens if you replace 2L of lost isotonic fluid with isotonic fluid?
- No change in sodium
- No fluid redistribution
What happens if you replace 3L of hypotonic fluid with hypotonic fluid?
- Sodium is restored
- Fluid redistribution
What happens if you replace 3L of hypotonic fluid with isotonic fluid?
- Sodium slightly increased
- No fluid redistribution
What is urea?
Normal breakdown product of protein metabolism
Describe how Urea is important to monitor?
- In dehydration often first to show change
- Sodium and urea concentrations will often parallel each other during fluid correction
When is urea usually elevated?
- CCF
- Shock
- MI
- Severe burns
What is creatinine?
Breakdown product of protein and muscle