What might happen to your airway pressure with positive pressure ventilation?

Positive pressure ventilation can significantly impact physiological parameters, including venous return and intracranial pressure (ICP). When positive pressure ventilation is applied, it artificially increases the pressure within the thoracic cavity during inspiration. This elevated intrathoracic pressure can impede venous return from the body to the heart, leading to a decreased preload – the amount of blood returning to the heart to fill the ventricles before contraction.

As the return of blood to the heart decreases, the cardiac output may consequently be reduced, which can contribute to increased intracranial pressure. This occurs because the brain is housed within a rigid skull, and any increase in volume (whether from blood, cerebrospinal fluid, or other factors) can elevate ICP.

Thus, the correct understanding is that the application of positive pressure ventilation can lead to a decreased return of blood to the heart, which subsequently can increase ICP due to the constraints of the cranial cavity. This relationship emphasizes the importance of considering hemodynamic effects when administering positive pressure ventilation in trauma and critical care scenarios.