New York State Basic Emergency Medical Technician (EMT-B) Practice Exam

An elevated blood pressure with a decreasing pulse rate may indicate what condition?

1. Myocardial infarction

2. Shock

3. Dehydration

4. Brain injury in a patient with head trauma

The correct answer is: Brain injury in a patient with head trauma

An elevated blood pressure combined with a decreasing pulse rate can be indicative of brain injury, particularly in cases of head trauma. This phenomenon occurs because the body responds to increased intracranial pressure, which may arise from swelling or bleeding in the brain. In such scenarios, the body attempts to maintain cerebral perfusion despite rising pressure within the skull. To do so, it often elevates blood pressure as a compensatory mechanism to ensure adequate blood flow to the brain tissues. Simultaneously, the vagus nerve may get stimulated due to increased pressure, leading to bradycardia, or a slowing down of the heart rate. This combination of hypertension and bradycardia is a classic sign often referred to as the Cushing's reflex, which is seen in patients with significant head injuries or elevated intracranial pressures. In contrast, other options represent different physiological responses or conditions. For instance, myocardial infarction usually presents with chest pain and may not consistently show the specific combination of elevated blood pressure and decreasing pulse rate. Shock typically involves both low blood pressure and elevated or normal heart rate as the body tries to compensate for low perfusion. Dehydration tends to lead to lowered blood pressure and increased heart rate, again differing from the symptoms