215 Fluid and Electrolyte Terms

isotonic solutions (0.9 nacl and LR)

are given to expand intravascular fluid volume and have the same osmolality as plasma. They do not move from the vascular system; these solutions replace fluid volume caused by vomiting and diarrhea, burns, and traumatic injury

hypotonic solutions (d5W, 0.45 Sodium Chloride)

when infused, water moves by osmosis from the vascular system into the cells

hypertonic solutions (D5 0.9 Sodium Chloride; D5 0.45 Sodium Chloride, D10W, 3% Sodium Chloride)

when infused, water moves by osmosis from the cell into the vascular system

Situations that promote thirst

excessive fluid loss, excessive sodium intake, decreased fluid intake

Situations that inhibit thirst

a high intake of fluids

fluid retention

excessive IV infusion of hypotonic solutions

and low sodium intake

Sensible and Insensible fluid loss

Sensible fluid loss is measurable (e.g. urine output)

Insensible fluid loss is not measurable (e.g. exhalation water loss, evaporation from skin); insensible water loss approx. 900mL per day

Sodium

135-145 meq/L; regulates fluid volume; conducts electrical impulses

Potassium

3.5-5 meq/L; regulates cardiac rhythm, conducts electrical impulses

Calcium

transmission of nerve impulses, cardiac automaticity

Magnesium

maintains potassium, involved in electrical activity in nerve and muscles including the heart

Phosphate

assists with acid base balance, promotes muscle and nerve action

dehydration

loss of water in the intracellular, extracellular or intravascular spaces. Can be caused by insufficient fluid intake, excessive fluid loss or fluid shifts.

hypervolemia

shift of fluid from cells into the extracellular fluid

Signs of fluid overload

-elevated BP, bounding pulse, distended neck veins, and increased shallow respirations

SEVERE= crackles in lungs, dyspnea, and ascites.

ascites

accumulation of fluid in the peritoneal cavity

Hyponatreima s/s

anorexia, nausea and vomiting , weakness, lethargy, confusion, muscle cramps or twitching, seizures

Hypernatremia S/S

thirst, elevated temperature, dry mouth Severe=hallucinations, irritability, lethargy, seizures

Hypokalemia S/S

Fatigue, Anorexia, N/V, Muscle weakness, Decreased GI motility, Dysrhythmias, Paresthesia

Hyperkalemia S/S

Muscle weakness

Dysrhythmias

Flaccid paralysis

Intestinal colic

Tall T waves on ECG