Cardiovascular Drugs and Medications Q 43
A 68-year-old client with a history of mild CHF and glaucoma is receiving IV mannitol (Osmitrol) to decrease intraocular pressure. The nurse would monitor the client for signs and symptoms of:
A. Fluid volume excess.
B. Fluid volume deficit.
C. Hyperkalemia.
D. Hypernatremia.
Correct Answer: A. Fluid volume excess.
Mannitol’s osmotic effect extends to the bloodstream, where increased osmotic pressure draws fluid into the vascular space, thus elevating intravascular volume. Mannitol may be used to reduce intraocular pressure when given intravenously. The mannitol is a new solute in the intravascular space, which increases the tonicity of the blood plasma. The increased tonicity of the blood plasma draws water out of the vitreous humor of the eye and into the intravascular space. Once in the intravascular space, the mannitol and associate water are excreted by the kidney. The decreased water of the vitreous humor lowers the intraocular pressure.
Option B: Mannitol can be used in acute renal failure to help prevent or treat the oliguric phase. During the oliguric phase, urine output decreases to less than 0.5 mg/kg/hour for children and less than 400 mL/day in adults. The fluid which does not get excreted remains in the body and causes fluid overload. Fluid overload causes issues such as decreased oxygenation and ventilation, electrolyte abnormalities, swelling, encephalopathy, and cardiac arrest.
Option C: Much like mannitol given for oliguria of acute renal failure, mannitol can be given to increase the excretion of toxic materials, substances, and drugs. The kidneys excrete mannitol. The mannitol is poorly reabsorbed once excreted and thus draws extra water with it into the renal collecting ducts. The extra water in the renal collecting ducts can help increase the excretion of water-soluble toxic materials, substances, and drugs.
Option D: Since mannitol is a sugar and it provides a sweet taste when ingested orally. Mannitol also mostly passes through the intestine and is excreted in the feces as the small intestine absorbs it poorly. Thus, mannitol is used as a sweetener in food for diabetic patients as mannitol can provide sweetness to the food without increasing the blood sugar as much as sucrose.