Correct Answer: D

Rationale: The correct answer is 'Electrolyte.' Electrolytes are substances that dissociate into ions when dissolved in water. Intracellular fluid, interstitial fluid, and plasma are not substances that dissociate into ions in a water solution. Intracellular fluid is the fluid inside cells, interstitial fluid is the fluid between cells, and plasma is the liquid component of blood. These choices do not dissociate into ions in a water solution, unlike electrolytes.

Correct Answer: D

Rationale: Assessing the specific gravity in a patient with SIADH helps the nurse evaluate the patient's fluid volume status. Specific gravity indicates the concentration of solutes in the urine and can detect if the patient has a fluid volume deficit or excess. Nutritional status, potassium balance, and calcium balance are not directly assessed through specific gravity testing. Nutritional status is typically evaluated through dietary intake and anthropometric measurements. Potassium balance is assessed through blood tests and ECG monitoring. Calcium balance is evaluated through blood tests and bone density scans. Therefore, the correct answer is assessing fluid volume status through specific gravity testing.

Correct Answer: C

Rationale: The correct answer is C: Sodium. Sodium (Na+) is the most abundant cation in the extracellular fluid, including blood plasma. It plays a crucial role in maintaining fluid balance, nerve function, and is essential for various physiological processes. Choice A, Potassium, is also an important ion in the body but is predominantly found intracellularly. Choice B, Calcium, is an essential mineral in the body but is not the most abundant positive ion in blood plasma. Choice D is incorrect as sodium is the primary positive ion in blood plasma, with a much higher concentration compared to potassium.

Correct Answer: A

Rationale: The correct answer is A: Skin. After the kidneys, the skin is the second largest route of water loss through perspiration. Choice B, Lungs, is incorrect as the lungs primarily exchange gases and do not play a significant role in water loss. Choice C, Intestines, is also incorrect as water loss through the intestines is minimal since most water is reabsorbed during digestion. Choice D, Muscles, is incorrect as muscles are not a major source of water loss in the body.

Correct Answer: C

Rationale: Infiltration is the administration of a nonvesicant solution or medication into the surrounding tissue, typically due to the dislodgement or perforation of the vein wall by the IV cannula. It is characterized by edema around the insertion site, leakage of IV fluid, discomfort, coolness, and a decrease in flow rate. In this scenario, the presence of edema indicates infiltration, not air emboli, phlebitis, or fluid overload. Air emboli refer to air bubbles in the bloodstream, phlebitis is inflammation of the vein, and fluid overload is an excessive volume of fluid in the circulatory system.