CV 6 Flashcards
Potassium is a primary ______cation
intracellular
what do insulin and catecholamines do?
promote shift of k into cells
primary route of K+ elimination?
Kidneys
3 physiological functions of K+
protein and glycogen synthesis
cell metabolism and growth
determination of the resting membrane potential across cell membranes
Normal K+ range
3.5-5 mmol/L
Hypokalaemia
low potassium
hyperkalaemia
high potassium
Hypokalemia classification
mild = 3-3.5
moderate = 2.5-3
severe = <2.5
estimation of K+ deficit
0.3mmol/L on average for every 100mol
Hypokalemia decreased intake causes
starvation, clay ingestion
redistribution into cells hypokalemia cause
metabolic alkalosis
- vomiting etc
Hormonal
- insulin, b2agonsits
Anabolic state
- body building
Increased net loss hypokalemia non renal causes
GI losses - vomiting, diarrhea, draining fistures, plasma volime contraction
Integumentary loss - sweat
increased net loss hypokalemia renal causes
increased distal flow and increased secretion of K+
Transcellular K+ shift - hypokalemia - drugs
B2 adrenergic agnoists
Bronchodilators
epinephrine
decongestants
theophyline
insulin overdose
caffeine
Increased renal K+ loss - hypokalemia - drugs
diuretics
thiazides
chlorthalidone
furosemide
mineralcorticocoids
high dose gluccorticoids
high dose abx
drugs associated w/ mg depletion
excess potassium in the stool - hypokalemia - drugs
sodium polystyrene sulfonate
hypokalemia preventative therapy
20-40mmol/day
hypokalemia - 2.5-3.5 treatment in an asymptomatic pt
40-200mmol/day in divided doses
check serum K+ levels daily
K+ less than 2.5 OR K+ 2.5-3.5 WITH symptoms - name the symptoms
cardiac arrhythmias
conduction disturbances
respiratory muscle weakness
paralysis
K+ less than 2.5 OR K+ 2.5-3.5 WITH symptoms - treatment - IV intermittent
general nursing units:
20mmol/50mL centrally or 20mmol/250mL peripherally administered over 1 hour
Critical/special care areas: 40 mmol/100mL centrally over 1 hour. ECG monitored required for rates above 20 mmol/hr.
K+ less than 2.5 OR K+ 2.5-3.5 WITH symptoms - treatment - IV infusion
Peripheral line: usual 20-40mmol/L (max 80 mmol/L) infused at max rate of 10mmol/hour)
Central Line: usual 20-40mmol/L (max 120mol/L) infused at max rate of 20 mmol/hour)
most common Potassium preparation
KCl
Preferred route
oral, IV if life threatening
appropriate rate of administration
divide it up and give it 3-4 times daily
pseudohyperkalemia define
- artifact produced during the in vitro measurement of serum K+
- produced due to the release of K+ in the process of drawing blood or from lysis of cells in blood prior to assay
- diagnosed if serum k+>plasma k+ by >0.3 mmol/L
Pseudohyperkalemia common causes
related to collection and storage of specimen
- difficulty in collecting sample
- pt clenched fist when sample was taken
- sample was shaken
- contaminated, cooled, deterioration
Related to pre-existing conditions
- thrombocytosis
- severe leukocytosis
- hereditary and acquired red cell disorders
Hyperkalemia Treatment, antagonizers
CaCl, 1g (10ml) IV direct over 2-5mins
CaGlu, 1g (10ml) IV in D5W 50mL infused over 15 mins
Hyperkalemia Treatment Shifters
- Insulin 50% Glucose, dextrose 50%: 25g (50mL) IV direct over 5 mins followed by insulin regular 10U IV direct
- Salbutamol 0.5mg IV 20mg via neb
