You are on-scene with an apneic adult who collapsed one to two minutes prior to your arrival, according to bystanders. Which of the following endotracheal tube size ranges would be most appropriate for an average adult respiratory arrest patient who shows no signs of airway trauma or obstruction?

Correct Answer: C

Rationale: The correct answer is C: 7.5-8.5 ET tube. This size range is most appropriate for an average adult respiratory arrest patient with no signs of airway trauma or obstruction. Rationale: 1. Size range 7.5-8.5 is standard for adult males and females with average airway anatomy. 2. Choosing too small a tube (option D) can lead to inadequate ventilation. 3. Choosing too large a tube (options A and B) can cause trauma to the airway and increase the risk of complications. 4. Considering the patient has no signs of airway trauma or obstruction, a mid-range size tube (option C) provides a balance between effective ventilation and minimizing potential harm. In summary, option C is the most appropriate choice as it balances the need for effective ventilation while minimizing the risk of complications in an average adult respiratory arrest patient.

Correct Answer: A

Rationale: The correct answer is A: Obtain a chest x-ray. In a closed head injury with decreased oxygen saturation, it is crucial to rule out potential concomitant injuries like a pulmonary contusion or pneumothorax. Obtaining a chest x-ray will help identify these conditions. Decreasing tidal volume (B) or PEEP (C) may worsen oxygenation. Increasing the rate of assisted ventilations (D) without addressing the underlying cause may not improve oxygen saturation.

Correct Answer: C

Rationale: The correct answer is C: Upper airway protection. This is the highest priority because the patient has marked facial edema and crepitus, indicating potential airway compromise from facial fractures or soft tissue injuries. Protecting the airway is crucial to prevent further complications like respiratory distress or failure. A: Lateral c-spine x-ray - While c-spine injury should be assessed, it is not the highest priority when there is a risk of airway compromise. B: Carotid pulse assessment - While important, it is not the highest priority compared to ensuring adequate airway protection. D: Determination of associated injuries - This can be done after ensuring airway protection, as other injuries may not be immediately life-threatening.

Correct Answer: D

Rationale: Step-by-step rationale for why option D is correct: 1. During pregnancy, the hormone relaxin causes the symphysis pubis to widen to accommodate childbirth. 2. This widening of the symphysis pubis is a normal physiological change in pregnancy to facilitate the passage of the baby. 3. It is essential for the baby to pass through the birth canal during labor. 4. Therefore, a widened symphysis pubis is a normal finding in pregnancy. Summary of why other choices are incorrect: A. "Increased residual lung volume" is not normal in pregnancy as lung volume decreases due to the elevation of the diaphragm. B. "Decreased plasma volume" is not normal in pregnancy as plasma volume increases to support the growing fetus. C. "Decreased total RBC mass" is not normal in pregnancy as RBC mass increases to meet the increased oxygen demands.

Correct Answer: A

Rationale: The correct answer is A (10 min). Brain cells start to die within 4-6 minutes without oxygen. After 10 minutes, irreversible damage is likely due to lack of oxygen causing cell death. Choice B (5 min) is too short for significant irreversible damage. Choice C (2 min) is even shorter and wouldn't allow for any meaningful recovery. Choice D (20 min) is too long and underestimates the critical window for preserving brain function.