Why is CPAP inappropriate for a patient in respiratory arrest?

In a situation where a patient is in respiratory arrest, the use of CPAP (Continuous Positive Airway Pressure) is not appropriate primarily because it does not effectively ventilate the patient. CPAP works by providing constant pressure to keep the airways open during both inhalation and exhalation, primarily benefiting patients with obstructive respiratory conditions like COPD or pulmonary edema. However, in respiratory arrest, the patient is unable to breathe on their own, meaning that they are not making any effort to inhale or exhale.

Because CPAP relies on the patient's ability to initiate breaths, its role is limited in cases of complete respiratory failure. When a patient is not breathing, effective ventilation is crucial to ensure that oxygen is delivered to the lungs and carbon dioxide is expelled. In such scenarios, other interventions, such as positive pressure ventilation through bag-mask ventilation or intubation, are necessary to provide adequate ventilation. Thus, the lack of ventilatory support from CPAP is the key reason it is not suitable for a patient experiencing respiratory arrest.