Fluid + Electrolytes

Body water over the lifespan trend?

Increased age → decreased body water → dehydration risk

Physiological changes in older adults contributing to TBW decrease? (4)

• Kidney changes → decreased water conservation

• Decrease in renin + aldosterone

• Increase in ADH + ANP

• Decreased SUBQ tissue → increased moisture loss

Nursing considerations for older adults r/t body water?

Increased age + decreased fluid intake + acute illness → watch for fluid volume deficit & electrolyte abnormalities

Fluid compartments?

ICF = inside cells

ECF = outside cells

• Intravascular = fluid b/w blood vessels

• Interstitial = fluid b/w cells

Third Spacing?

Fluid can switch between compartments → possible normal FV BUT not enough circulating volume

Correlation b/w kg & L

2.2lb body weight change = 1 kg body weight change = 1L fluid change

Most accurate measure of fluid change?

Daily weight w/ same scale/same time of day/similar clothing

Define first spacing

Normal distribution w/n ICF & ECF

Define second spacing

Edema r/t abnormal accumulation of ISF

Define third spacing

Trapped fluid that cannot move back into cells or BVs → edema + hypotension + decreased UOP (too little circulatory volume!)

Homeostatic regulator?

Hypothalamus

Anterior pituitary pathway electrolyte effects?

Increased ACTH (Adenocorticotropic hormone) → increased aldosterone + cortisol → increased Na+ and water reabsorption and increased K+ excretion

Posterior pituitary pathway electrolyte effects?

Increased ADH secretion → increased water retention

Stress effects on electrolytes and fluid balance

Physiologic stress (illness/trauma) → fluid retention & K+ loss (increased aldosterone → decreased K+)

Define hypervolemia (FVE)

Too much fluid w/n extracellular space, can → excess fluid impacting lungs → SOB/crackles/decreased SpO2

Define hypovolemia (FVD)

Not enough circulating ECF can → wt loss/hypotension/tachycardia

Main concern with sodium imbalances?

Think brain! → neuro changes (seizures/coma)

Main symptom of hyponatremia?

Fluid retention

Main concern with hyponatremia?

Swollen brain cells → seizure precautions

Tx for hyponatremia?

3& NaCl (hypertonic), decrease fluid intake, diuretics

Main symptom of hypernatremia?

Dehydration (low BP, high HR, high RR)

Main concern with hypernatremia?

Na+ > H2O → dehydrated cells → neuro changes

Tx for hypernatremia?

Oral fluids, hypo/isotonic fluids

Main concern with potassium imbalances?

Think cardiac → lethal dysrhythmias

Key s/s of hyperkalemia? (Mnemonic)

Muscle cramps/tetany
Urine abnormalities
Respiratory distress
Decreased cardiac contractility
EKG changes
Reflex abnormalities

Hyperkalemia Tx? (3 parts)

Force

• IV reg insulin w/ dextrose (insulin move K+ to ICF, dextrose prevent hypoglycemia)

• B - Adrenergic agonist

Stabilize

• IV calcium chloride (calcium to stabilize cardiac excitability)

• Calcium gluconate

Use

• Continuous monitoring

Hypokalemia s/s? (Mnemonic)

Lethargy

Low + shallow respirations

Lethal cardiac dysrhythmias

Lots of urine

Leg cramps

Limp muscles

Low BP + HR

IV Potassium safety? (4)

• ALWAYS DILUTE IV KCl

• NEVER PUSH IV/BOLUS KCl

• NEVER excede 10mEq/hr

• Use infusion pump

Main concern with calcium imbalances?