A patient has been admitted to the intensive care unit with cardiogenic shock and their blood pressure is 78/38. Which vasopressor medication is recognized as the first-line treatment for cardiogenic shock?

Choice A rationale:

Severe acidemia: A pH of 6.9 indicates severe acidemia, a condition where the blood is too acidic. Sodium bicarbonate is an alkalizing agent that can help raise the blood pH back to a normal range.

Rapid correction: Intravenous (IVP) administration of sodium bicarbonate allows for rapid correction of acidemia, which is crucial in severe cases to prevent life-threatening complications.

Buffering action: Sodium bicarbonate acts as a buffer, accepting excess hydrogen ions (H+) in the blood and converting them into water and carbon dioxide (CO2), which can be exhaled.

Specific indications: Sodium bicarbonate is typically used in cases of severe acidemia caused by metabolic acidosis, such as diabetic ketoacidosis or lactic acidosis. It may also be considered in cases of respiratory acidosis, but other interventions like ventilatory support are often prioritized.

Choice B rationale:

Calcium carbonate is not a direct treatment for acidemia: It is primarily used as an antacid to neutralize stomach acid and as a calcium supplement for bone health. While it can have a mild alkalizing effect, it is not as effective as sodium bicarbonate in rapidly correcting severe acidemia.

Choice C rationale:

Alkalemia: A pH of 7.6 indicates alkalemia, a condition where the blood is too alkaline. Administration of sodium bicarbonate in this situation would worsen the alkalemia and potentially lead to serious complications.

Choice D rationale:

Hyponatremia: Low serum sodium levels do not directly require treatment with sodium bicarbonate. Sodium bicarbonate is primarily used to address acid-base imbalances, not electrolyte imbalances.

Choice A rationale:

Mixing insulins in a vial is generally not recommended unless specifically instructed by the healthcare provider. It can alter the effectiveness of the insulins and increase the risk of dosage errors.

Premixed insulins, which are already combined in a specific ratio, are available if a combination of insulins is needed.

However, in this case, the patient is instructed to administer regular and NPH insulin separately, indicating that they should not be mixed in a vial.

Choice B rationale:

Insulin can be injected into various subcutaneous sites, including the abdomen, thighs, upper arms, and buttocks.

There is no specific requirement to inject mixed insulin into the buttocks only.

The choice of injection site can be based on individual preferences, absorption rates, and the presence of lipohypertrophy (thickening of the subcutaneous tissue due to repeated injections).

Choice C rationale:

Drawing up NPH insulin first could lead to contamination of the regular insulin vial with NPH insulin.

NPH insulin is a suspension, and drawing it up first could introduce some of its particles into the regular insulin vial, potentially altering its absorption and action profile.

Choice D rationale:

It's crucial to draw up the regular insulin first to prevent contamination of the regular insulin vial with NPH insulin. The following steps outline the correct procedure:

Wash hands thoroughly with soap and water.

Inspect the insulin vials for clarity, expiration date, and any damage.

Roll the NPH insulin vial gently between the palms to resuspend the insulin particles (if applicable). Wipe the rubber stoppers of both vials with an alcohol swab.

Using a sterile syringe, withdraw air into the syringe equal to the amount of regular insulin to be drawn.

Inject the air into the regular insulin vial, keeping the needle tip above the fluid level to avoid creating bubbles. Invert the regular insulin vial and withdraw the prescribed dose of regular insulin.

Without injecting air into the NPH insulin vial, withdraw the prescribed dose of NPH insulin. Administer the insulin as directed, using proper injection technique.