The nurse is caring for a postoperative client who has a chest tube connected to suction and a water seal drainage system. Which of the following indicates to the nurse that the chest tube is functioning properly?

Choice A Reason: This choice is correct because respiratory acidosis is a condition in which the lungs cannot eliminate enough carbon dioxide (CO2) from the blood, resulting in a high level of CO2 (PaCO2) and a low level of pH. A normal PaCO2 range is 35 to 45 mm Hg, so a value of 50 mm Hg indicates respiratory acidosis.

Choice B Reason: This choice is incorrect because HCO3 (bicarbonate) is a base that helps to buffer the excess acid in the blood. In respiratory acidosis, the kidneys try to compensate by retaining more HCO3 and excreting more hydrogen ions. Therefore, a high level of HCO3 (above 26 mEq/L) would indicate a chronic or compensated respiratory acidosis, not an acute or uncompensated one.

Choice C Reason: This choice is incorrect because pH is a measure of the acidity or alkalinity of the blood. A normal pH range is 7.35 to 7.45, so a value of 7.45 indicates a neutral or slightly alkaline blood, not an acidic one. A low pH (below 7.35) would indicate respiratory acidosis.

Choice D Reason: This choice is incorrect because potassium is an electrolyte that helps to regulate the nerve and muscle function, as well as the fluid balance in the body. In respiratory acidosis, the increased hydrogen ions in the blood may shift into the cells in exchange for potassium, resulting in a high level of potassium (hyperkalemia).

Therefore, a low level of potassium (below 3.5 mEq/L) would indicate hypokalemia, not respiratory acidosis.

Choice A Reason: Dextran 70 is not a medication that the nurse should plan to administer for a client who has a traumatic head injury and is exhibiting signs of increasing intracranial pressure. Dextran 70 is a plasma expander that increases the blood volume and viscosity, which can worsen the intracranial pressure by increasing the cerebral blood flow and edema.

Choice B Reason: Hydroxyethyl starch is not a medication that the nurse should plan to administer for a client who has a traumatic head injury and is exhibiting signs of increasing intracranial pressure. Hydroxyethyl starch is another plasma expander that has similar effects as dextran 70, and can also increase the risk of coagulopathy and renal failure.

Choice C Reason: Albumin 25% is not a medication that the nurse should plan to administer for a client who has a traumatic head injury and is exhibiting signs of increasing intracranial pressure. Albumin 25% is a colloid solution that increases the oncotic pressure and draws fluid from the interstitial space into the intravascular space, which can also worsen the intracranial pressure by increasing the cerebral blood flow and edema.

Choice D Reason: Mannitol 25% is a medication that the nurse should plan to administer for a client who has a traumatic head injury and is exhibiting signs of increasing intracranial pressure. Mannitol 25% is an osmotic diuretic that reduces the intracranial pressure by creating an osmotic gradient and drawing fluid from the brain tissue into the blood vessels, which can then be excreted by the kidneys. The nurse should monitor the urine output, serum osmolality, and electrolytes when administering mannitol 25%.