Two days after surgical fixation of a fractured femur, a client suddenly reports chest pain and difficulty in breathing. The nurse suspects the client had a pulmonary embolus. Which action should the nurse take first?

Choice A: Determining the need for urinary catheterization is not a task that the nurse should assign to the PN, as this requires clinical judgment and critical thinking, which are beyond the scope of practice of the PN. This is a distractor choice.

Choice B: Titrating oxygen to prescribed parameters is a task that the nurse can assign to the PN, as this involves following orders and protocols, which are within the scope of practice of the PN. Therefore, this is the correct choice.

Choice C: Receiving a postoperative client and conducting the assessment is not a task that the nurse should assign to the PN, as this requires initial assessment and data collection, which are the responsibility of the registered nurse. This is another distractor choice.

Choice D: Evaluating and updating plans of care for clients is not a task that the nurse should assign to the PN, as this requires nursing diagnosis and outcome identification, which are part of the nursing process that only the registered nurse can perform. This is another distractor choice.

Choice C is correct because serum potassium, calcium, and phosphorus are electrolytes that can be affected by ESRD. ESRD is a condition in which the kidneys lose their ability to filter waste products and excess fluids from the blood. This can cause electrolyte imbalances that can lead to serious complications, such as cardiac arrhythmias, bone disorders, or metabolic acidosis. The nurse should closely monitor these electrolytes and report any abnormal values.

Choice A is incorrect because blood pressure, heart rate, and temperature are vital signs that are not specific to ESRD. Vital signs can be influenced by many factors and may not reflect the severity of kidney damage. The nurse should monitor vital signs regularly, but not as closely as electrolytes.

Choice B is incorrect because leukocytes, neutrophils, and thyroxine are not laboratory results that are directly related to ESRD. Leukocytes and neutrophils are types of white blood cells that are involved in immune response and inflammation. Thyroxine is a hormone that regulates metabolism and growth. These laboratory results may be altered by other conditions or medications, but not by ESRD.

Choice D is incorrect because erythrocytes, hemoglobin, and hematocrit are laboratory results that measure the red blood cell count and oxygen-carrying capacity of the blood. These laboratory results may be decreased in ESRD due to anemia, which is a common complication of chronic kidney disease. However, anemia is not as life-threatening as electrolyte imbalances and can be treated with erythropoietin injections or iron supplements.