You are performing orotracheal intubation on an average-sized, apneic adult. At what depth marking should the airway be properly positioned 2 to 3 cm above the carina?

Correct Answer: C

Rationale: The correct answer is C (19 to 23 centimeters). The proper depth marking for an orotracheal intubation in an average-sized adult is typically around 21 centimeters at the teeth for females and 23 centimeters for males. This positioning ensures that the tip of the endotracheal tube is approximately 2 to 3 cm above the carina, allowing for adequate ventilation while minimizing the risk of complications such as mainstem bronchus intubation. Choices A, B, and D are incorrect as they do not fall within the appropriate depth range for proper positioning of the endotracheal tube. Option A is too shallow, option B is too deep, and option D is also too deep and carries a risk of complications.

Correct Answer: C

Rationale: The correct answer is C because inducing mild hypothermia in a post-arrest patient with a return of spontaneous circulation helps reduce intracranial pressure, cerebral metabolic rate, and the brain's demand for oxygen. This is crucial in preventing secondary brain injury and improving neurological outcomes. Explanation: 1. Reduced intracranial pressure: Hypothermia causes vasoconstriction, reducing cerebral blood flow and lowering intracranial pressure. 2. Decreased cerebral metabolic rate: Hypothermia slows down cellular metabolism, decreasing the brain's oxygen and energy requirements. 3. Lowered brain's demand for oxygen: With reduced metabolic rate and blood flow, the brain requires less oxygen. Summary of other choices: A: Hypothermia does not directly reduce the body's need for stored energy (sugar) but rather decreases metabolic rate. B: Hypothermia may alter blood flow distribution but does not specifically increase blood flow to the brain and heart. D: Hypothermia primarily affects the

Correct Answer: D

Rationale: The correct answer is D: Admit the patient to the intensive care unit. This is the most appropriate management because an 8-year-old boy with a spleen laceration after falling from a height needs close monitoring and potential interventions that can be provided in an intensive care setting. Admission to the ICU allows for continuous monitoring of vital signs, blood loss, and potential complications. Type and crossmatch for blood (A) may be necessary but is not the most urgent step in this scenario. Requesting consultation of a pediatrician (B) can be done after initial stabilization, and transferring the patient to a trauma center (C) may delay necessary interventions that can be provided in the current setting.

Correct Answer: D

Rationale: The correct answer is D, Elevated central venous pressure. Transfer to a burn center is based on the extent and severity of burns, not on central venous pressure. A: Partial-thickness and full-thickness burns on greater than 10% of the body surface area (BSA) are criteria for transfer due to the increased risk of complications. B: Any full-thickness burn is a critical criterion for transfer since full-thickness burns require specialized care. C: Burns involving the perineum and skin overlying major joints are also criteria for transfer to a burn center due to the risk of functional impairment and infection.

Correct Answer: D

Rationale: The correct answer is D because in this scenario, the patient presents with signs suspicious of aortic injury, indicated by the widened mediastinum on chest x-ray. However, the definitive test for aortic injury is a CT scan of the chest, which is more sensitive and specific than contrast angiography. If the CT scan is normal, it effectively rules out aortic injury, making further imaging with contrast angiography unnecessary. Performing angiography in this case would expose the patient to unnecessary risks without providing additional diagnostic value. Therefore, the correct approach is to first perform a CT scan of the chest, and if it is normal, no further imaging is required. Choice A is incorrect as contrast angiography is indicated in suspected aortic injury cases. Choice B is incorrect as performing contrast angiography after a CT scan would be redundant and expose the patient to unnecessary risks. Choice C is incorrect as the accuracy of contrast angiography in diagnosing aortic rupture is not as high as indicated in the