Critical Care Nursing Exam Questions

Correct Answer: B

Rationale: The correct answer is B: Oxygen that is chemically combined with hemoglobin. This is because oxygen primarily travels in the blood by binding to hemoglobin in red blood cells, forming oxyhemoglobin. This process allows for efficient transport of oxygen to tissues throughout the body. Choices A, C, and D are incorrect because: A: Alveolar oxygen tension refers to the partial pressure of oxygen in the alveoli of the lungs, not the specific form of oxygen in the blood. C: Oxygen physically dissolved in plasma refers to the small amount of oxygen that is not bound to hemoglobin and is less significant in oxygen transport compared to oxygen bound to hemoglobin. D: Total oxygen consumption is the overall amount of oxygen utilized by the body, not specifically the form of oxygen bound to hemoglobin for transport.

Correct Answer: C

Rationale: Correct Answer: C - Regular insulin Rationale: 1. Insulin promotes cellular uptake of potassium. 2. When insulin is administered, it moves potassium from extracellular to intracellular space. 3. This decreases plasma potassium levels safely. 4. Other options do not directly lower potassium levels in the same manner. Summary of Other Choices: A: Sodium polystyrene sulfonate - exchanges sodium for potassium in the intestines, not reducing total body potassium. B: Sodium polystyrene sulfonate with sorbitol - similar to A, does not reduce total body potassium. D: Calcium gluconate - does not directly lower potassium levels, used for treating hyperkalemia-induced cardiac toxicity.

Correct Answer: B

Rationale: The correct answer is B because a low Mean Arterial Pressure (MAP) indicates inadequate perfusion, which may require adjusting the norepinephrine infusion rate to increase blood pressure. A: A heart rate of 58 beats/minute is within a normal range and may not necessarily indicate a need for adjustment. C: Elevated Systemic Vascular Resistance (SVR) may be an expected response to norepinephrine and does not necessarily indicate a need for adjustment. D: A low Pulmonary Artery Wedge Pressure (PAWP) may indicate fluid volume deficit but does not directly relate to the need for adjusting norepinephrine infusion rate.

Correct Answer: A

Rationale: The correct answer is A: New ST segment elevation is noted on the cardiac monitor. This finding is concerning because it may indicate myocardial ischemia or infarction, which can be exacerbated by the physiological stress of weaning from mechanical ventilation. It is crucial to address any cardiac issues before initiating a spontaneous breathing trial to prevent potential cardiac complications during the weaning process. Explanation for why the other choices are incorrect: B: Enteral feedings being given through an orogastric tube are not contraindicated for starting a spontaneous breathing trial. C: Scattered rhonchi heard when auscultating breath sounds may indicate retained secretions but are not a contraindication for a spontaneous breathing trial. D: The use of HYDROmorphone to treat postoperative pain is not a contraindication for a spontaneous breathing trial unless it is causing respiratory depression, which would need to be addressed separately.

Correct Answer: D

Rationale: The presence of a bruit over the thyroid indicates increased blood flow, characteristic of hyperthyroidism. This excess blood flow is due to the hypermetabolic state in hyperthyroidism, leading to turbulent blood flow and the audible bruit. A bruit is not typically associated with hypothyroidism, thyroid cysts, or thyroid cancer, as these conditions do not cause increased blood flow. Therefore, the correct interpretation is hyperthyroidism.