Potassium and Hydrogen Homeostasis Flashcards
what is the potassium reference range
3.6-5mmol/L
what happens when K is outside its normal range
cardiac conduction defects
abnormal neuromuscular excitability
what does iatrogenic mean
caused by medical intervention
what is the problem with measuring serum potassium
don’t not actively reflect body potassium (ie small portion of total K in plasma)
what can affect K levels
acidosis
insulin / glucose
adrenaline
rapid cellular incorporation (leukaemia, TPN)
how does alkalosis vs acidosis affect K levels
acid - potassium moves out of cells = hyperkalaemia
alk - K moves into cells = hypo
what are the causes of hyperkalaemia
haemolysis, drug therapy AKI, CKD acidosis mineralocorticoid dysfunction (arden-cortical failure) cell death - cyctotoxic theory
what is the treatment for hyperkalaemia
correct acidosis stop supplement intake give insulin and glucose ion exchange resins dialysis
what are some causes of potassium depletion
low intake increased urine loss - diuretics, tubular dysfunction GT losses - vomiting diarrhoea alkalosis excess insulin or glucose
what are the physiological effects of potassium depletion
acute changes in ICF/ECF ratios - neuromuscular, lethargy, weakness, arrhythmias
chronic loss from ICF have same effect
Kinda - alkalosis (increased HCO3) polyuria
vascular
gut
how do you treat potassium depletion
supplementation
oral - 48 mmol/day and diet
IV - less than 20mmol/L
when do you need to monitor K levels
diuretic therapy
digoxin use
compromised renal function
in support of IV resuscitation
