A nurse is caring for a client who reports a new onset of severe chest pain. Which of the following actions should the nurse take to determine if the client is experiencing a myocardial infarction?

Choice A reason: Hypermagnesemia, or high levels of magnesium in the blood, is not typically associated with refeeding syndrome. Instead, refeeding syndrome can lead to hypomagnesemia, which is a low level of magnesium in the blood, due to shifts of magnesium into the cells during insulin secretion in the refeeding process.

Choice B reason: Hyponatremia, or low levels of sodium in the blood, is not a hallmark of refeeding syndrome. While fluid shifts can affect sodium levels, the key electrolyte disturbances in refeeding syndrome involve phosphorus, potassium, and magnesium.

Choice C reason: Hyperkalemia, or high levels of potassium in the blood, is not a common finding in refeeding syndrome. Similar to magnesium, potassium can shift into cells during refeeding, which can actually lead to hypokalemia, or low levels of potassium in the blood.

Choice D reason: Hypophosphatemia, or low levels of phosphorus in the blood, is the hallmark of refeeding syndrome. When a malnourished individual is refed, insulin secretion is stimulated by the increased carbohydrate intake. Insulin promotes cellular uptake of glucose, which is accompanied by phosphate, potassium, and magnesium, leading to a decrease in the serum levels of these electrolytes. Phosphorus is critical for cellular processes, and its deficiency can lead to muscle weakness, respiratory failure, hemolysis, and impaired cardiac function. During refeeding, careful monitoring of electrolytes is essential to prevent and manage refeeding syndrome. Hypophosphatemia is the most significant laboratory finding to anticipate in a patient with refeeding syndrome, and it requires prompt recognition and treatment to prevent serious complications.

Choice A reason: Occasional bubbling in the water-seal chamber can indicate an air leak, which is not necessarily a sign of lung re-expansion. It could suggest that the lung has not fully re-expanded or that there is a persistent air leak.

Choice B reason: While the absence of pleuritic chest pain is a positive sign, it is not a definitive indicator of lung re-expansion. Pleuritic chest pain can subside even if the lung has not fully re-expanded.

Choice C reason: No tidaling in the water-seal chamber is a strong indicator that the lung has re-expanded. When the lung is fully expanded, it presses against the chest wall, eliminating the space where air could collect and thus stopping the water level from fluctuating with respiration.

Choice D reason: An oxygen saturation of 95% is within normal limits and suggests adequate oxygenation, but it does not specifically indicate lung re-expansion. Oxygen saturation can be maintained with supplemental oxygen or other supportive measures even if the lung has not fully re-expanded.