In which situation is the use of a bag-valve-mask (BVM) indicated?

The use of a bag-valve-mask (BVM) is specifically indicated in situations where a patient is unable to breathe adequately on their own, such as when they are apneic. In this case, providing positive pressure ventilation is crucial for ensuring that oxygen is delivered to the lungs when the patient's own respiratory drive has failed.

When a patient is apneic, their respiratory system is not functioning effectively, which can lead to hypoxia and inadequate gas exchange. The BVM allows for manual ventilation, thereby helping to maintain adequate oxygenation and ventilation until further medical care can be provided. This intervention is particularly important in emergency situations where quick action can prevent serious complications or worsen the patient's condition.

In contrast, using a BVM on a conscious patient or one who shows normal respiratory effort is unnecessary and could potentially cause harm. Similarly, while a patient who has a pulse but is unresponsive may require support, using a BVM is specifically indicated for those who are not ventilating effectively, making the second situation the correct context for its use.