06/13/2026
📊📉VETERINARY CAPNOGRAPHY ANALYSIS: NORMAL VS. ABNORMAL 📊
As a clinician, mastering your patient's capnograph waveforms during anesthesia is one of the fastest ways to catch critical changes before they become emergencies! 🩺💨
This high-yield infographic breaks down the essential differences between a normal waveform and a classic obstruction pattern:
🟩 THE NORMAL WAVEFORM
Phase I (Baseline): Inspiration—should always be zero!
Phase II (Expiratory Upstroke): Rapid emptying of anatomical dead space and early alveoli.
Phase III (Alveolar Plateau): Uniform emptying of the alveoli. The highest point gives you your \text{EtCO}_2 value (Normal: 35-45 mmHg).
Phase IV (Inspiratory Downstroke): Fresh oxygen clears the sensor instantly.
⚠️ THE ABNORMAL WAVEFORM: "SHARK-FIN"
What it looks like: A blunted, slanting expiratory upstroke (Phase II) and a lost plateau.
What it means:
There is a partial airway obstruction or significant expiratory resistance causing air trapping and prolonged exhalation.
💡 Top Differentials: Bronchoconstriction (feline asthma/allergic airway disease), a kinked or partially occluded endotracheal tube, or a malfunctioning expiratory valve.
🗳️ SHARE YOUR EXPERIENCE:
What is the most common reason you encounter a "shark-fin" waveform in your clinical practice? Let’s discuss in the comments below! 👇
📌 Save this post to keep this quick diagnostic reference handy on your clinic phone!
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