Regulation Of Potassium And Fluid Replacement Therapy Flashcards
What is the normal range for serum potassium?
3.5-5.5 mmol/L
What are the findings on an ECG indicating hypokalaemia?
ST depression,
Shallow T wave,
Prominent U wave.
What findings on an ECG indicate hyperkalaemia?
Prolonged PR interval,
Widened QRS,
Tall, Peaked T wave,
Depressed ST segment.
Where is potassium reabsorbed in the nephron?
Proximal convoluted tubule,
Ascending limb,
Distal convoluted tubule.
Where is potassium secreted in the nephron?
Thick ascending limb,
Distal convoluted tubule,
Collecting duct.
What are the clinical features of hyperkalaemia?
Muscle weakness and cardiac arrhythmia.
How is hyperkalaemia treated?
Calcium gluconate to stabilise myocardium,
Insulin to drive K+ into cells
Furosemide or calcium resonium to increase K+ excretion.
What are the clinical effects of hypokalaemia?
Muscle weakness, cramps and tetany.
cardiac arrhythmia,
Metabolic acidosis.
What treatments are there for hypokalaemia?
Treat underlying cause eg stop diuretics,
Give potassium replacement
Oral - Sando-K
IV - KCL.
By which organs is potassium excreted?
Kidneys (80%) and bowels (20%)
What is Osmolality?
The number of particles of solute per kg of solvent (mOsm/kg)
What is Osmolarity?
Number of particles of solute per litre of solution (mOsm/L)
What is tonicity?
The measure of effective osmotic pressure gradient of two solutions separated by a semipermeable membrane
What proportion of fluid is found in the ECF?
1/3
What are the drawbacks of 1000ml 5% dextrose?
Fluid distributed across all compartments - poor for resuscitation
Can cause hyperglycaemia if infusion rate too quick
