Which of the following signifies inadequate respiratory effort?

Apnea is defined as the absence of breathing, which clearly indicates inadequate respiratory effort. When a patient is experiencing apnea, there is no airflow in or out of the lungs, meaning that gas exchange is not occurring. This can lead to serious consequences, such as hypoxia, as the body's oxygen levels will begin to diminish without respiratory activity. In a pediatric emergency, recognizing apnea is critical as it necessitates immediate intervention to restore breathing.

In contrast, hyperventilation refers to rapid or deep breathing that may not necessarily indicate inadequate effort but rather excessive effort. Normal breathing signifies a regular and adequate respiratory rate and depth, ensuring that the physiological demands for oxygen and carbon dioxide removal are met. Yawning, while it may indicate some physiological or neurological conditions, does not necessarily indicate inadequate respiratory effort either. It can occasionally occur in response to fatigue, boredom, or even as a reflex to increase oxygenation briefly but does not suggest a failure to breathe. Thus, apnea is the clear indicator of inadequate respiratory effort in this context.