Megan's patient is on strict intake and output measurements. Her patient's total output is 2200 mL. What should the total intake be for an average adult?

Choice A reason: This is incorrect because intracellular fluid is greater than extracellular fluid in a hypertonic state, not an isotonic state. A hypertonic state is when the solute concentration of the extracellular fluid is higher than the intracellular fluid, which causes water to move out of the cells and shrink them.

Choice B reason: This is incorrect because extracellular fluid is less than intracellular fluid in a hypotonic state, not an isotonic state. A hypotonic state is when the solute concentration of the extracellular fluid is lower than the intracellular fluid, which causes water to move into the cells and swell them.

Choice C reason: This is correct because intracellular and extracellular fluid is equal in an isotonic state. An isotonic state is when the solute concentration of the extracellular fluid is the same as the intracellular fluid, which causes no net movement of water across the cell membrane.

Choice D reason: This is incorrect because interstitial fluid is less than the transcellular fluid in a situation of fluid imbalance, not an isotonic state. Interstitial fluid is the fluid that surrounds the cells, while transcellular fluid is the fluid that is contained in specialized cavities, such as cerebrospinal fluid, synovial fluid, or pleural fluid. The amount of transcellular fluid is normally very small compared to the interstitial fluid, but it can increase in certain conditions, such as edema, ascites, or hydrocephalus.

Choice A reason: For an average adult, the total intake should be approximately equal to the total output every day¹². Therefore, if the patient's total output is 2200 mL, the total intake should also be around 2200 mL.

Choice B reason: 3000 mL is more than the recommended daily fluid intake for an average adult, which is about 2500 mL³. If the patient's intake is higher than their output, they may develop fluid overload or edema.

Choice C reason: 3800 mL is much more than the recommended daily fluid intake for an average adult, which is about 2500 mL³. If the patient's intake is higher than their output, they may develop fluid overload or edema.

Choice D reason: 2400 mL is slightly less than the recommended daily fluid intake for an average adult, which is about 2500 mL³. However, if the patient's intake is lower than their output, they may develop dehydration or electrolyte imbalance.