Define positive pressure ventilation.

Positive pressure ventilation is characterized by a mode where air is actively pushed into the lungs. This is achieved through the use of mechanical ventilators, which deliver breaths by creating a positive pressure within the ventilatory circuit, effectively forcing air into the airways and lungs. This method contrasts with negative pressure ventilation, where the lungs expand due to a decrease in pressure around the thoracic cavity.

In clinical settings, positive pressure ventilation is often used for patients who cannot breathe adequately on their own, whether due to respiratory failure, sedation, or neuromuscular disorders. The goal is to ensure that the patient receives sufficient oxygen and clearance of carbon dioxide, which is vital for maintaining proper physiological function.

Regarding the other options, positive pressure ventilation does not involve the natural expansion of the lungs (as would be characterized by negative pressure ventilation), nor is it related to suctioning techniques, which are focused on clearing airway obstructions. Additionally, while flow rates can be important, positive pressure ventilation itself is not defined solely by high flow rates. Its essence lies in the mechanism of pushing air into the lungs rather than the specifics of flow or other techniques utilized.