Which diagnostic test should be ordered to search for reversible causes during a cardiac arrest?

Ordering arterial blood gases (ABGs) during a cardiac arrest is essential for several reasons. ABGs provide critical information about a patient's respiratory status, acid-base balance, and oxygenation levels. These parameters can help identify reversible causes of cardiac arrest such as hypoxia (low oxygen levels), acidosis (an imbalance in acidity), or alkalosis. By assessing the levels of carbon dioxide, oxygen, and the pH of the blood, healthcare providers can make informed decisions about immediate interventions.

In the context of cardiac arrest, it’s crucial to determine whether the patient has adequate oxygenation and if there are metabolic derangements that need to be addressed. For example, severe metabolic acidosis can occur during cardiac arrest due to tissue hypoperfusion, and recognizing this allows for timely administration of appropriate treatment.

The other diagnostic tests listed have narrower applications in this emergency context. While urine analysis can help reveal underlying renal issues, and a CT scan might be beneficial for diagnosing structural problems, they are not immediate priorities during an arrest. A complete blood count may provide some necessary information, but it typically does not directly address the immediate metabolic and respiratory needs of a patient in cardiac arrest. Therefore, arterial blood gases are the most pertinent diagnostic test within the acute management setting