Which of the following is considered a critical sign of inadequate airway in a patient?

The absence of breath sounds is a critical sign of inadequate airway. This situation indicates that air is not moving into the lungs, which can happen due to various factors such as airway obstruction from foreign objects, swelling, or severe bronchospasm. The inability to hear breath sounds suggests that the airway is either occluded or severely compromised, which requires immediate intervention by medical personnel to secure the airway and restore adequate ventilation.

In contrast, an oxygen saturation of 95% generally indicates that the patient is receiving enough oxygen, at least in the initial stages, while patient alertness reflects whether the individual is responsive and oriented, which is not a direct indicator of airway patency. A heart rate of 80 beats per minute, although within a normal range, does not provide information about airflow or airway management. Therefore, recognizing the absence of breath sounds is crucial as it directly signals a potential life-threatening situation that needs to be addressed promptly.