What is the key difference between CPAP and BiPAP?

In noninvasive mechanical ventilation, the distinction between Continuous Positive Airway Pressure (CPAP) and Bilevel Positive Airway Pressure (BiPAP) is crucial for understanding their respective functionalities.

CPAP delivers a constant level of positive airway pressure throughout the entire respiratory cycle to keep the airways open. This support is particularly beneficial for patients with obstructive sleep apnea as it prevents airway collapse during both inhalation and exhalation. However, it does not actively adjust the pressure during exhalation, which means that the same pressure is maintained regardless of the patient's breathing phase.

On the other hand, BiPAP provides two different pressure settings—one for inhalation (IPAP) and a lower one for exhalation (EPAP). This dual-pressure mechanism allows for more comfort and easier exhalation, especially for patients who require ventilatory assistance and struggle with the constant pressure of CPAP.

Given this understanding, the statement that CPAP offers no support for exhalation accurately reflects the nature of CPAP. It emphasizes that while CPAP maintains airway patency, it does not reduce the pressure during exhalation as BiPAP does. This is a significant point of differentiation when evaluating treatment options for patients with respiratory