You are assessing an adult patient experiencing sudden-onset chest pain and dyspnea. He quickly exhibits jugular vein distension and cool, clammy skin. His trachea is midline, but there are palpable air pockets under the skin on his upper chest on the left side that feel as though they pop or vanish when you palpate them. What is this abnormal finding?

Correct Answer: A

Rationale: The correct answer is A: Subcutaneous emphysema. This finding is indicative of air trapped under the skin, leading to palpable air pockets that pop or vanish upon palpation. This occurs commonly in the context of chest trauma or underlying lung pathology. Jugular vein distension, cool, clammy skin, and chest pain with dyspnea are consistent with a possible pulmonary embolism or tension pneumothorax, both of which can lead to subcutaneous emphysema. Atelectasis (B) is the collapse of alveoli, not associated with palpable air pockets. Pitting edema (C) is fluid accumulation in the tissues, not related to air. Ascites (D) is fluid accumulation in the peritoneal cavity, not presenting as palpable air pockets.

Correct Answer: D

Rationale: The correct answer is D: "Fracture of the cribiform plate." Nasogastric intubation involves passing a tube through the nose into the stomach. A fracture of the cribiform plate, located in the skull near the nose, can lead to serious complications like cerebrospinal fluid leakage and infection if the nasogastric tube punctures it. Choices A, B, and C are incorrect because although they are serious conditions, they are not direct contraindications to nasogastric intubation.

Correct Answer: A

Rationale: Rationale for Correct Answer (A): - Cerebral contusion is a bruising of brain tissue due to head trauma. - It can lead to the pooling of blood and form an intracerebral hematoma. - This process involves the collection of blood within the brain tissue. Summary for Incorrect Choices: - B: Epidural hematomas are typically seen in the temporal region, not frontal. - C: Subdural hematomas are often caused by bridging veins rupture, not middle meningeal artery. - D: Subdural hematomas usually appear crescent-shaped, not lenticular on CT scan.

Correct Answer: D

Rationale: Step-by-step rationale for why answer choice D is correct: 1. Massive hemothorax involves significant blood accumulation in the pleural space. 2. Shock and unilateral absent breath sounds are classic signs of massive hemothorax. 3. Immediate recognition and treatment are crucial to prevent further deterioration. 4. Prompt diagnosis and intervention are essential in managing massive hemothorax. Summary of other choices: A: Blunt thoracic trauma can cause hemothorax, but not specifically massive hemothorax. B: Pneumothorax involves air in the pleural space, not blood. C: Confirming the diagnosis with an upright chest x-ray may delay urgent treatment.

Correct Answer: B

Rationale: The correct answer is B: Pulmonary contusion. Pulmonary contusion is a common injury following blunt chest trauma and can lead to impaired gas exchange. In this case, the patient's low PaO2 and respiratory alkalosis (low PaCO2 and elevated pH) are indicative of a ventilation-perfusion mismatch caused by pulmonary contusion. The flail chest may also contribute to impaired gas exchange, but the absence of hyperresonance or dullness on auscultation makes a significant pneumothorax less likely. Hypoventilation would typically present with hypercapnia and acidosis, which is not seen in this patient. Hypovolemia would not directly affect blood gas values in this way.