While completing a health assessment for a young adult female with acute appendicitis, the client informs the nurse that there is a chance that she may be pregnant. The operating team is preparing to take the client to surgery. Which intervention should the nurse implement immediately?

Choice A reason: Potassium 4.7 mEq/L (4.70 mmol/L) is within the normal reference range of 3.5 to 5 mEq/L (3.5 to 5 mmol/L). Potassium is an electrolyte that helps regulate the balance of fluids and acids in the body, as well as the function of nerves and muscles. A high potassium level (hyperkalemia) can cause muscle weakness, irregular heartbeat, and cardiac arrest. A low potassium level (hypokalemia) can cause muscle cramps, fatigue, and arrhythmias.

Choice B reason: Magnesium 2.1 mEq/L (0.86 mmol/L) is within the normal reference range of 1.3 to 2.1 mEq/L (0.65 to 1.05 mmol/L). Magnesium is an electrolyte that helps regulate the activity of enzymes, muscles, and nerves, as well as the balance of calcium and potassium in the body. A high magnesium level (hypermagnesemia) can cause nausea, vomiting, flushing, muscle weakness, and respiratory depression. A low magnesium level (hypomagnesemia) can cause muscle twitching, tremors, seizures, and cardiac arrhythmias.

Choice C reason: Calcium 6.5 mg/dL (1.63 mmol/L) is below the normal reference range of 9 to 10.5 mg/dL (2.3 to 2.6 mmol/L). Calcium is an electrolyte that helps regulate the function of muscles, nerves, bones, and blood clotting. A high calcium level (hypercalcemia) can cause nausea, vomiting, constipation, confusion, kidney stones, and bone pain. A low calcium level (hypocalcemia) can cause muscle spasms, cramps, tingling, numbness, and stridor (a high-pitched sound when breathing). **This is a critical value that should be immediately reported to the healthcare provider**, as it can indicate a serious condition such as acute pancreatitis, sepsis, or massive blood transfusion.

Choice D reason: Sodium 135 mEq/L (135 mmol/L) is slightly below the normal reference range of 136 to 145 mEq/L (136 to 145 mmol/L). Sodium is an electrolyte that helps regulate the balance of fluids and acids in the body, as well as the function of nerves and muscles. A high sodium level (hypernatremia) can cause thirst, dry mouth, confusion, seizures, and coma. A low sodium level (hyponatremia) can cause headache, nausea, vomiting, fatigue, muscle weakness, and confusion.

Choice A: A headache rated at 0 on 0 to 10 scale is not a specific indicator of the effectiveness of an antihistamine. A headache may be caused by other factors, such as dehydration, stress, or sinus congestion.

Choice B: Oxygen saturation level of 99% is a normal finding and does not reflect the effect of an antihistamine. Oxygen saturation measures the amount of oxygen in the blood and can be affected by respiratory conditions, altitude, or smoking.

Choice C: Ambulating easily without vertigo is a sign that the antihistamine is effective. Vertigo is a common symptom of Ménière's disease, which is a disorder of the inner ear that causes episodes of spinning sensation, hearing loss, and tinnitus. Antihistamines can help reduce the fluid buildup in the inner ear and relieve vertigo.

Choice D: Blood pressure of 120/80 mm Hg is a normal finding and does not indicate the effect of an antihistamine. Blood pressure measures the force of blood against the walls of the arteries and can be influenced by factors such as heart rate, cardiac output, blood volume, and vascular resistance.