You are preparing to perform synchronized electrical cardioversion with a biphasic defibrillator on your unstable adult patient who is experiencing supraventricular tachycardia at 160 beats per minute on the monitor. Which of the following initial energy settings would be recommended if he was exhibiting a narrow complex, regular supraventricular tachycardia, in which his palpable carotid pulse matches the rhythm on the monitor?

Correct Answer: A

Rationale: The correct initial energy setting for synchronized electrical cardioversion in a patient with stable supraventricular tachycardia is A: Synchronized cardioversion at 50-100 joules. This is because the patient is hemodynamically stable, with a narrow complex, regular rhythm, and a palpable carotid pulse matching the monitor. The recommended energy range for synchronized cardioversion in such cases is typically between 50-100 joules. This energy level is sufficient to terminate the tachyarrhythmia without causing unnecessary harm to the patient. Choices B, C, and D are incorrect because defibrillation energy settings (100-360 joules) are too high for a stable supraventricular tachycardia patient. Using such high energy levels could lead to unnecessary myocardial damage and potentially worsen the patient's condition. Therefore, the correct choice is A, as it aligns with the principles of providing effective treatment while minimizing the risk of

Correct Answer: C

Rationale: The correct answer is C: Upper airway protection. The highest priority should be given to ensuring the patient's airway is clear and protected, as facial edema and crepitus indicate potential airway compromise. This is crucial to prevent respiratory distress or failure. Assessing the carotid pulse or determining associated injuries can wait until the airway is secured. A lateral c-spine x-ray may be necessary later but is not the immediate priority.

Correct Answer: D

Rationale: Rationale for Correct Answer (D): Widened symphysis pubis is normal in pregnancy due to hormonal changes softening the ligaments, allowing for increased flexibility during childbirth. This physiological adaptation helps in the delivery process. Summary of Incorrect Choices: A: "Increased residual lung volume" is not normal in pregnancy. Respiratory changes include increased tidal volume and minute ventilation, but residual lung volume does not significantly change. B: Decreased plasma volume is not normal in pregnancy. Plasma volume increases to support the growing fetus and maternal circulation. C: Decreased total RBC mass is not normal in pregnancy. Total RBC mass increases to support increased oxygen demands for the mother and fetus.

Correct Answer: A

Rationale: The correct answer is A: "10 min". The brain can be anoxic, or deprived of oxygen, for about 10 minutes before irreversible damage occurs. During oxygen deprivation, brain cells begin to die within minutes, leading to permanent brain damage. Oxygen is essential for brain function and prolonged anoxia can result in cognitive impairment, disability, or even death. Choice B (5 min), C (2 min), and D (20 min) are incorrect because they do not align with the typical timeframe for irreversible brain damage due to oxygen deprivation.

Correct Answer: C

Rationale: The correct answer is C: Traumatic brain injury. In this scenario, the patient's hemodynamic changes are primarily related to fluid resuscitation, as evidenced by the initial response to crystalloid infusion. Traumatic brain injury typically does not cause such acute and direct hemodynamic changes. Ongoing blood loss (choice A) is a common cause of hemodynamic instability and should be considered. Blunt cardiac injury (choice B) can lead to hemodynamic compromise, especially with changes in blood pressure. Inadequate resuscitation (choice D) can also contribute to hemodynamic instability. However, in this case, traumatic brain injury is the least likely cause given the patient's response to fluid infusion and the nature of the presentation.