MCAT Math Question 27: Answer and Explanation

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Question: 27

12. Which of the following methods would be most appropriate for an initial assessment of hemoglobin saturation during an experiment about breath holding?

  • A. A pulse oximeter, which uses a small light on an adhesive bandage.
  • B. An arterial cannula, which permits repeated blood draws with a single puncture.
  • C. Repeated venipuncture, because a single puncture would cause data overlap.
  • D. A Swan–Ganz catheter inserted through the femoral artery, which can measure saturation nearest the heart.

Correct Answer: A

Explanation:

While it may appear that this question is asking to determine which method is the most accurate or reliable, this is an ethics question. All of these methods (with the exception of venipuncture, choice (C)) measure oxygen saturation. According to the principle of beneficence, we must minimize potential harms associated with our investigations, thus the noninvasive pulse oximeter should be greatly favored over other measurements for an initial assessment.

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