How does providing positive pressure ventilation affect cardiac output?

When positive pressure ventilation is provided, it increases intrathoracic pressure. This phenomenon occurs because the pressure in the thoracic cavity rises as air is mechanically pushed into the lungs, either through a bag-mask device or a ventilator. The elevation in intrathoracic pressure can have notable effects on the cardiovascular system.

One significant consequence is the potential reduction in venous return to the heart. As intrathoracic pressure rises, it can impede the filling of the right atrium due to decreased pressure gradient between the venous system and the right atrial chamber. This will ultimately lead to a decrease in stroke volume and cardiac output.

Understanding the increase in intrathoracic pressure during positive pressure ventilation is crucial, as it highlights the interplay between respiratory management and cardiac function. Correctly managing positive pressure ventilation can help mitigate its adverse effects on hemodynamics while ensuring adequate ventilation for the patient.