Which of the following is NOT a type of mechanical ventilation?

The correct answer is waste gas ventilation, which is not classified as a type of mechanical ventilation. In mechanical ventilation, different techniques are utilized to assist or replace spontaneous breathing. Negative pressure ventilation, for example, utilizes a mechanism that creates a negative pressure around the thorax, promoting inhalation. Positive pressure ventilation involves pushing air into the lungs through an endotracheal tube or mask, which is common in many clinical settings. High-frequency ventilation refers to a mode of mechanical ventilation that uses very rapid respiratory rates and small tidal volumes, often used for specific populations, such as neonates with conditions like respiratory distress syndrome.

Waste gas ventilation does not represent a recognized form of mechanical ventilation. It may refer to processes that deal with the evacuation of gases rather than actively delivering air into the lungs to facilitate breathing, thereby distinguishing it clearly from the established mechanical ventilation modalities.