What happens during Stage 3, plane 4 of anesthesia?

During Stage 3, plane 4 of anesthesia, the patient experiences a significant loss of respiratory effort. This stage is characterized by a gradually deepening level of anesthesia where the patient is effectively unconscious, and the respiratory drive is diminished. In this plane, the respiratory muscles may become paralyzed, leading to apnea or a lack of spontaneous breathing.

At this level, the cardiovascular function is still generally stable, but the complete lack of respiratory effort indicates that the anesthesiologist or surgical team should closely monitor the patient's airway and provide ventilation support as needed. This state allows for more invasive surgical procedures to be performed safely, as the patient does not respond to stimuli, thereby not feeling or remembering the surgical experience. The awareness of this stage is crucial for ensuring patient safety during procedures requiring general anesthesia.