Which situation requires immediate resuscitation efforts?

Cardiac arrest is a medical emergency where the heart suddenly stops beating effectively, leading to a cessation of blood flow to the body's organs. This dire situation necessitates immediate resuscitation efforts because without prompt intervention, such as CPR (cardiopulmonary resuscitation) and defibrillation, a person can lose consciousness within seconds and face irreversible brain damage or death within minutes.

In comparison, while a severe allergic reaction and respiratory distress are also critical situations that require urgent care, they do not typically require the immediate resuscitation efforts that cardiac arrest does. Severe allergic reactions may require epinephrine administration, and respiratory distress may necessitate airway management or oxygen therapy, but both of these conditions can be stabilized or managed with time and appropriate interventions. High fever, while concerning, is usually less acute and does not immediately threaten life in the same way cardiac arrest does.