University:
University of Virginia
Course:
NUIP 2430 | Pharmacology and Clinical Management I
Academic year:

2024
Views:

239

Pages:

2
Author:

Zoe C.

‭Body Fluid Volume and Concentration‬ ‭●‬ ‭Volume status/amount and osmolality‬ ‭○‬ ‭Extracellular and intracellular fluids‬ ‭●‬ ‭Kidneys responsible for maintaining balance‬ ‭●‬ ‭Abnormal states of hydration‬ ‭○‬ ‭Volume contraction: Total water in body decreases‬ ‭○‬ ‭Volume expansion: Total water in body increases‬ ‭■‬ ‭Ex. with diuretic use‬ ‭Subclassifications of Abnormal Volume States‬ ‭●‬ ‭Isotonic: Normal osmolality‬ ‭●‬ ‭Hypertonic: Increased osmolality/solutes‬ ‭●‬ ‭Hypotonic: Decreased osmolality/solutes‬ ‭●‬ ‭Osmolality is based on Na‬ ‭○‬ ‭Normal total plasma = 280-300 mOsm/kg water‬ ‭○‬ ‭135-145 mEq/L‬ ‭Isotonic Contraction‬ ‭●‬ ‭Decrease in total volume of extracellular fluid‬ ‭●‬ ‭Na and H‬‭2‬‭O loss is proportional‬ ‭●‬ ‭Osmolality remains normal; Na concentration is normal‬ ‭●‬ ‭Causes: Vomiting, diarrhea, kidney disease, diuretic use (loss of water and Na)‬ ‭●‬ ‭Treatment: Isotonic fluid replacement (0.9% NaCl)‬ ‭Hypertonic Contraction‬ ‭●‬ ‭Decrease in total volume‬ ‭●‬ ‭H‬‭2‭O ‬ loss exceeds Na loss; Na > H‬‭2‬‭O remaining‬ ‭●‬ ‭Osmolality increases; serum Na is high (hypernatremia)‬ ‭●‬ ‭Causes: Excess sweating, osmotic diuresis (mannitol), excessive tube feeding with‬ ‭concentrated formula, extensive burns‬ ‭●‬ ‭Treatment: Hypotonic fluid replacement (0.45% NaCl, D5W)‬ ‭○‬ ‭Half of deficit is replaced in a few hours‬ ‭Hypotonic Contraction‬ ‭●‬ ‭Decrease in total volume‬ ‭●‬ ‭Na loss exceeds H‬‭2‬‭O loss; Na < H‬‭2‬‭O remaining‬ ‭●‬ ‭Osmolality decreases, serum Na low‬ ‭●‬ ‭Causes: Excessive loss of sodium (ex. Aldosterone causes renal Na retention)‬ ‭●‬ ‭Treatment:‬ ‭○‬ ‭Isotonic fluid replacement: Slight hyponatremia, normal saline‬ ‭○‬ ‭Hypertonic fluid replacement: Severe hyponatremia (< 130 mEq/L), 3% NaCl‬ ‭■‬ ‭Risk for fluid overload‬ ‭Volume Expansion‬ ‭●‬ ‭Increase in total volume‬ ‭●‬ ‭Can be isotonic, hypotonic, or hypertonic‬ ‭●‬ ‭Causes: Excessive IV fluid admin, heart failure, nephrotic syndrome, ascites‬ ‭●‬ ‭Treatment: Diuretics‬ ‭Acid-Base Disturbances‬ ‭●‬ ‭Impacted by:‬ ‭○‬ ‭Bicarb-acid balance/intake‬ ‭○‬ ‭Respiratory system: Expiring CO‬‭2‬ ‭(acid)‬ ‭○‬ ‭Renal system: Retention H‬‭2‬‭CO‬‭3‬ ‭●‬ ‭4 types of imbalance:‬ ‭○‬ ‭Respiratory alkalosis: Not enough CO‬‭2‬ ‭(acid)‬ ‭■‬ ‭Hyperventilation‬ ‭○‬ ‭Respiratory acidosis: CO‬‭2‬ ‭retention‬ ‭■‬ ‭Hypoventilation‬ ‭○‬ ‭Metabolic alkalosis: Loss of gastric acid‬ ‭■‬ ‭N/V, gastric suction NG tube, excessive tx with sodium bicarbonate‬ ‭○‬ ‭Metabolic acidosis: Acid retention‬ ‭■‬ ‭Renal failure (not getting rid of protons), severe diarrhea, ketoacidosis‬ ‭Magnesium Imbalances‬ ‭●‬ ‭Magnesium regulates neurochemical transmission and muscle excitability‬ ‭●‬ ‭Hypomagnesemia:‬ ‭○‬ ‭Causes: Diarrhea, dialysis, kidney disease, low Mg intake (enteral feeding)‬ ‭○‬ ‭S/S: Tetany (muscle spasm), disorientation, psychosis, seizures‬ ‭○‬ ‭Tx: Magnesium sulfate (slow IV infusion), magnesium oxide (PO)‬ ‭●‬ ‭Hypermagnesemia:‬ ‭○‬ ‭Causes: Renal insufficiency‬ ‭○‬ ‭S/S: Muscle weakness, hypotension, sedation, ECG changes‬ ‭○‬ ‭Tx: IV calcium‬