Anaes Vivas · Measurement & monitoring physics
Data viva — the normal capnogram and the abnormal traces
A data viva on the capnogram — the phases (the baseline, the upstroke, the alveolar plateau, the end-tidal value, the inspiratory downstroke), and the diagnostic patterns (the disconnect, the malignant hyperthermia, the rebreathing, the airway obstruction).
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Prompt
A capnogram (the end-tidal CO2 against time) and three abnormal traces: a flat trace, a rising baseline, and a slurred upstroke. Interpret each.
Stimulus
The capnogram shows the end-tidal CO2 against time. Describe the normal phases. Three abnormal traces follow: (A) a flat line at zero; (B) a gradually rising baseline and end-tidal; (C) a slurred, prolonged upstroke with a shark-fin shape. Interpret each.
References2ShowHide
- [4]Ishihara T, et al. Time-based capnography to diagnose airway obstruction. Animals, 2025.PMID 41375427
- [41375428]Bersten AD, Soni N (eds) Oh's Intensive Care Manual. 8th edition, Elsevier, 2018.