Which condition must be present for CPAP to be indicated?

Continuous Positive Airway Pressure (CPAP) is indicated primarily in situations where a patient is experiencing significant difficulty breathing, particularly conditions such as acute pulmonary edema or chronic obstructive pulmonary disease (COPD) exacerbations. Tachypnea, which refers to an abnormally rapid breathing rate, is a key sign that indicates respiratory distress and the need for interventions to support the patient's breathing.

When a patient is tachypneic, it suggests that they are struggling to maintain adequate ventilation and oxygenation, making the application of CPAP crucial. The positive pressure provided by the CPAP device helps to keep the airways open, preventing collapse and allowing for better gas exchange, thereby relieving the work of breathing.

For CPAP to be appropriately indicated, the presence of a protected airway is also essential; however, this is implied in the context of the situations for which CPAP is typically deployed. Normotension (normal blood pressure) is not a requirement for CPAP use and hypotension can complicate the patient's condition but does not inherently prevent CPAP's application. Thus, tachypnea is the principal factor indicating that CPAP should be utilized to assist in the management of the patient's respiratory distress and ensure proper oxygenation.