A 4-month-old becomes unresponsive and apneic. A pulse is present. The team calls for help, supplies oxygen and begins bag-mask ventilation. The displayed checks occur while the nurse corrects the mask seal and reassesses. Click the first check that meets the indication to add chest compressions.

D. D combines a heart rate below 60/min with persistent poor perfusion despite effective ventilation and oxygen support.

The low rates at the first two checks accompany ineffective ventilation. Correcting chest expansion is essential. At C, the pulse is above 60/min. At D, effective ventilation is documented but bradycardia and poor perfusion persist, meeting the pediatric criterion to begin CPR without further delay.

The observations are fictional teaching data. Apply the stated context; the selected feature does not by itself replace a complete bedside assessment.

Combine heart rate, perfusion and response to oxygenation and ventilation.

Combine heart rate, perfusion and response to oxygenation and ventilation.

A and B precede effective chest expansion and call for correction of ventilation. C still requires care for poor perfusion but its rate is 68/min. D is the first displayed check meeting all specified compression criteria.

• Infant heart rate after ventilation support — Combine heart rate, perfusion and response to oxygenation and ventilation.
• Comparison with context — A has a lower pulse than D but precedes effective ventilation; rate alone is insufficient.