If the capnogram shows a rapid rise in CO₂ levels, what phase is this most likely associated with?

The rapid rise in CO₂ levels observed on a capnogram corresponds to Phase 2 of the respiratory cycle. During this phase, when the patient begins to exhale, the CO₂ from the alveoli is rapidly mixed with the dead space air which has low or no CO₂ concentration. This results in a sharp increase in the concentration of CO₂ in the measured expelled gas, leading to the steep incline seen during Phase 2 of the capnogram.

Phase 2 specifically represents the transition from dead space ventilation, where little to no CO₂ is present, to the presence of CO₂ from the alveolar gases. This sharp rise indicates effective gas exchange and corresponds with the physiological process of expiration, where the transition from exhaled air containing less CO₂ to that containing more CO₂ happens quickly as lung volumes are emptied.

Recognizing this rapid rise is critical for respiratory therapists and healthcare providers, as it provides insight into the patient's ventilation status and can help in assessing proper function of the respiratory system.