During anesthesia, which finding suggests airway obstruction?

• A. Rise in peak airway pressure with decreased tidal volume
• B. Decrease in heart rate with unchanged capnography
• C. Elevated blood pressure with stable capnography
• D. Stable oxygen saturation

Answer: (B)

Airway obstruction shows itself most clearly when the ventilator has to work harder to push air through a narrowed or blocked airway. That translates to a rise in peak airway pressure while the tidal volume delivered decreases. The tube or circuit is resisting flow, so the machine must generate more pressure to deliver less air, which is the hallmark sign of obstruction (secretions, kinked tube, bronchospasm, etc.).

If you look at the other patterns, a decrease in heart rate with unchanged capnography doesn’t reflect a mechanical blockage of the airway; bradycardia can be related to anesthetic depth or vagal effects, but ventilation metrics would typically change if there’s a significant obstruction. Elevated blood pressure with stable capnography isn’t specific for obstruction, and stable oxygen saturation doesn’t rule it out but isn’t the pattern you’d rely on to identify an airway problem. So the combination of increased peak airway pressure and decreased delivered tidal volume is the clearest indicator of airway obstruction.