Which mode delivers the exact amount of pressure needed to overcome the ETT?

• A. PSV
• B. ATC
• C. PCV
• D. BiPAP

Answer: (B)

Automatic Tube Compensation offsets the pressure loss caused by the endotracheal tube in real time, so the pressure reaching the lungs matches the set target. It measures inspiratory flow and uses a model of the tube’s resistance to add just enough pressure on top of the delivered breath to overcome the ETT drop. This keeps the alveolar pressure (and delivered tidal volume) accurate despite the extra resistance from the tube.

Other modes don’t specifically compensate for ETT resistance: one provides a fixed pressure that doesn’t adjust for tube drop, another augments breaths based on patient effort without offsetting the tube’s pressure loss, and the last is designed for noninvasive two-level pressure without targeting ETT-related resistance.