You have a simple lap chole case. Patient is 80 y/o M 78kg with Hx of HTN, Emphysema, O2 use at night. You get the patient in the room and start preoxygenating him. Induce and tube. Easy airway grade 1 view with the MAC 3. Tube is taped at 22cm at the lip + ETCO2, good chest rise with manual ventilation. You switch the patient over to the vent and start on your charting and giving the ABX.

A few minutes go by and you look at your vent settings and you have the patient on VC with a Vt of 600, RR 10, PIP at this time is 15, and PEEP of 5. ETCO2 is 36, but now you notice the Vt expired is reading 1200-1400s even though you have it set on 600. You have already confirmed proper tube placement, VSS, good ETCO2 waveform, but you have had consistently higher expired Vt than what is set.

Students go through your differential and plan of action step by step.