Electrolyte Imbalances Flashcards
Major electrolyte found in ECF. Essential for acid-base, fluid balance, active and passive transport mechanism, irritability and conduction of nerve-muscle tissue
Sodium (Na+)
Explain thirst compensatory mechanism
Experience dehydration
Decrease in blood volume
Increase in Na+ osmolality (concentration)
Osmoreceptors in hypothalamus stimulates thirst centre
Pituitary releases ADH to increase water absorption in kidney to decrease osmolality and increase ECF volume
Explain ADH mechanism in response to low blood volume and increased blood osmolarity
Hypothalamus as a receptor responds to stimuli
Hypothalamus stimulates posterior pituitary to release ADH into the blood
ADH binds to effectors:
Hypothalamus - activating thirst centre to stimulate fluid intake increasing blood volume and pressure
Kidneys- increase water reabsorption, decrease water loss in kidneys to maintain blood volume and decrease blood osmolarity
Blood vessels - cause vasoconstriction to increase peripheral resistance and bp
Explain RAAS compensatory mechanism in response to low blood pressure and sympathetic division stimulation
Receptor juxtaglomerular apparatus responds to stimuli
JG apparatus release renin enzyme into the blood
Renin activates angiotensinogen to AT I
Angiotensin converting enzyme (ACE) in the lungs converts AT I to AT II
AT II binds to effectors:
Systemic blood vessels - causing vasoconstriction increasing peripheral resistance and increasing BP
Kidneys - decrease glomerular filtration rate (GFR), decreasing UO to maintain blood volume and BP
Hypothalamus - activate thirst centre to increase fluid intake, release ADH to maintain blood volume and decrease UO
Adrenal cortex - release aldosterone to maintain blood volume and decrease UO
Explain Aldosterone mechanism in response to decreased Na+ and increased K+ blood plasma levels
Receptor adrenal cortex responds to stimuli
Adrenal cortex releases aldosterone into the blood
Aldosterone binds to effectors:
Kidney - to increase Na+/ H20 reabsorption into blood, decrease Na+/H20 and increases K+ UO, increases K+ secretion into tubular fluid
Na+ is maintained and K+ decreases in the blood plasma, therefore, blood volume and BP is maintained
S&S of fluid volume deficit
Low BP and high HR Dry mouth, thirsty Rapid weight loss Low UO Confusion and lethargic
Nursing intervention for fluid volume deficit
Oral fluids
IV (normal saline - no K until UO is increased)
daily weight and strict vital signs
causes of fluid volume excess
Hypervolemia - too much IV fluid, kidney failure, corticosteroids
Water intoxication - CHF, ADH problems
Excess sodium intake - salt intake excess
S&S of fluid volume excess
rapid weight gain Oedema High BP, bounding pulses Increased UO JVD, crackles and dyspnea
Nursing intervention for fluid volume excess
Diuretics
fluid restriction (no IV fluids)
sodium intake restriction
daily weights and strict I&O
Causes of Hypernatraemia
Excess Na+ intake
Inadequate H2O intake
excess water loss
Hypernatraemia results in
fluid shift from ICF to ECF where water follows sodium
S&S of Hypernatraemia
Thirsty Fever (flushed skin) Restless, anxious, confused and irritable Increased BP and fluid retention Pitting oedema Decreased UO
Nursing intervention for Hypernatraemia
Restrict Na intake
Diuretics
Seizure precautions
Dialysis if severe
Causes of Hyponatraemia
excess water and loss of Na Increased Na excretion due to diaphoresis, diarrhoea, NGT suction and diuretics Low Na diet Kidney failure Heart failure
S&S of Hyponatraemia
Stupor/ coma anorexia lethargy tachycardia Limp muscle weakness orthostatic hypotension seizures/ headache stomach cramping
Nursing intervention for Hyponatraemia
Add Na to diet
administer IV sodium chloride infusions (hypovolemia)
administer diuretics (hypervolemia)
restrict fluid if caused by hypervolemia
Daily weights for fluid excess (as where Na goes H2O follows)
Safety precautions for orthostatic hypotension
Limit water intake
Causes of Hyperkalemia
Kidney failure Medications - potassium sparring diuretics, ACE inhibitors, NSAIDs Tissue damage Acidosis Hypoxia Hypercatabolism Hyperuricemia
S&S of Hyperkalemia
Muscle cramps & weakness
Urine abnormalities - oliguria (low UO) and anuria (inability to produce urine in the kidney)
Respiratory distress
Decreased cardiac contractility (Low HR & BP)
ECG changes (tall T waves, flat P waves, widened QRS complexes and prolonged PR intervals)
Reflexes increases DTR (deep tendon reflexes)
Causes of Hypokalemia
Loss of total body K
inadequate K intake
Vomiting and diarrhoea
NG suction
Alkalosis and Hyperinsulinism causing the movement of K from ECF to ICF
Dilution of serum K caused by water intoxication and IV therapy with K deficient solution
S&S of Hypokalemia
Dysrhythmias (thready, weak and irregular pulse)
Orthostatic hypotension
shallow RR
anxiety, lethargy, confusion and coma
paresthesias (prickling sensation to extremities)
Hyporeflexia (decreased reflex response)
Constipation
N&V
ECG changes (ST depression, inverted T wave and prominent U wave)
Nursing intervention for Hyperkalemia
Monitor ECG Discontinue potassium IV and PO Restrict K diet Administer K excreting diuretics Administer IV Ca gluconate & IV Na bicarb Dialysis
Nursing intervention for Hypokalemia
Monitor ECG
Administer PO K supplements, liquid potassium chloride and potassium retaining diuretic
K is NEVER administered via IV push, IM and subQ (IV potassium is always diluted & administered using an infusion device)
Potassium imbalance if not treated can cause
Cardiac Dysrhythmias which is life threatening