Under what condition should chest compressions be started during resuscitation?

Chest compressions during resuscitation should be initiated in specific scenarios to effectively support circulation when the heart is not adequately pumping blood. Starting chest compressions is particularly crucial when the heart rate is below 60 beats per minute (bpm) after 30 seconds of effective positive pressure ventilation (PPV) in infants.

The rationale behind this is based on the understanding that a heart rate below this threshold indicates that the heart is not functioning effectively enough to maintain adequate blood flow to vital organs, including the brain. The effectiveness of PPV in increasing heart rates is a key consideration; if, after providing breaths for at least 30 seconds, the heart rate remains low, it signals that stronger measures are necessary to support circulation. Hence, chest compressions become an immediate intervention to provide artificial circulation until more definitive treatment can be rendered.

Other choices may not activate the need for chest compressions as directly. A heart rate below 100 bpm or signs of respiratory distress may not sufficiently indicate that circulation is compromised to the extent necessitating compressions, while the absence of a detected pulse also signals the need for compressions but does so under different considerations that may follow broader guidelines for resuscitation. Therefore, focusing on the specific threshold in choice B highlights