What physiological effect can CPAP have on blood pressure?

Continuous Positive Airway Pressure (CPAP) primarily functions by keeping the airways open through the delivery of a constant stream of air. This mechanism increases intrathoracic pressure, which can have significant physiological effects on the cardiovascular system.

When CPAP elevates intrathoracic pressure, it can decrease the return of blood to the heart, consequently reducing venous return. This effect can subsequently lead to a reduction in stroke volume and ultimately drop blood pressure in some patients. Moreover, the increased intrathoracic pressure can influence systemic vascular resistance and cardiac output, affecting overall hemodynamics.

Understanding the physiological impact on intrathoracic pressure is essential for interpreting the therapeutic effects of CPAP in various clinical scenarios, particularly in patients with respiratory failure or sleep apnea. By recognizing that CPAP increases intrathoracic pressure, one can appreciate its role in both alleviating respiratory distress and its influences on blood pressure regulation.