While on-scene with a 70-year-old complaining of chest pain, what is one of the first indicators that should alert the paramedic to the probability that an acute myocardial infarction is occurring?

Correct Answer: B

Rationale: Step 1: Chest pain that is not relieved by oxygen therapy alone suggests that the cause of the pain is not related to a lack of oxygen to the heart muscle. Step 2: Acute myocardial infarction (heart attack) is caused by a blockage in the coronary arteries, leading to reduced blood flow and oxygen to the heart muscle. Step 3: If the chest pain is not affected by oxygen therapy, it indicates that the pain is likely due to a problem other than lack of oxygen, such as a heart attack. Step 4: Therefore, choice B is the correct answer as it points to a symptom consistent with an acute myocardial infarction. Summary: Choices A and C mention relief or lack of relief of chest pain with nitroglycerin, which is typically used for angina and may not necessarily indicate a heart attack. Choice D, cyanosis, is a late sign of inadequate oxygenation and not specific to an acute myocardial infarction

Correct Answer: A

Rationale: Rationale for Correct Answer (A): Children suffer spinal cord injury without x-ray abnormality more commonly than adults. This statement is true because children's spinal cords are more flexible and elastic, making them less likely to show bony abnormalities on x-rays even if there is an injury. This phenomenon is known as SCIWORA (spinal cord injury without radiographic abnormality) and is more common in children due to their unique anatomical characteristics. Summary of Incorrect Choices: B: An infant with a traumatic brain injury may become hypotensive from cerebral edema - This statement is incorrect because hypotension is not a common consequence of cerebral edema in traumatic brain injury. C: Initial therapy for the child with traumatic brain injury includes the administration of methylprednisolone intravenously - This statement is incorrect as the use of methylprednisolone in traumatic brain injury is controversial and not considered standard therapy. D: Children have more focal mass lesions as a result of traumatic brain injury

Correct Answer: C

Rationale: The correct answer is C: Class 2. In Class 2 hemorrhage, systolic blood pressure starts to decrease. This is because in Class 2 hemorrhage, there is approximately 15-30% blood volume loss, which leads to a decrease in blood pressure. Class 0, 1, and 3 hemorrhages do not involve significant blood loss to cause a decrease in systolic blood pressure. Class 0 represents minimal blood loss, Class 1 involves up to 15% blood volume loss, and Class 3 involves more than 30% blood volume loss, all of which are not significant enough to lead to a decrease in systolic blood pressure.

Correct Answer: C

Rationale: Rationale: C is incorrect because pulse oximetry provides a spot-check measurement, not continuous. A is true as room light can interfere. B is true as dysfunctional hemoglobin can affect accuracy. D is true as pulse oximetry relies on differential light absorption. Therefore, the correct answer is C.

Correct Answer: A

Rationale: The correct answer is A: "Requires surgical intervention" because cardiac tamponade is a life-threatening condition where fluid accumulates in the pericardial sac, compressing the heart. Surgical intervention, such as pericardial drainage or pericardiectomy, is necessary to relieve the pressure on the heart. Needle pericardiocentesis (choice B) is a temporary measure and may not definitively manage the condition. Discovering Beck's triad (choice C) in the Emergency Department (ED) may raise suspicion but is not always present in all cases. Kussmaul breathing (choice D) is associated with conditions like diabetic ketoacidosis, not specifically with cardiac tamponade.