05/23/2026
If I could marry one piece of hospital equipment, it would be the capnograph. It would be a small wedding - close friends and family only. Allow me to read you my vows:
1. You know her, you love her, sheโs your normal capnograph. Confirms ventilation, perfusion, and circuit integrity in one glance. If the shape changes, something in your patient or equipment changed.
2. Rebreathing. Baseline is NOT dropping to 0. Multiple causes under GA. Change the absorbent, check valves, increase fresh gas flow, reassess circuit choice depending on cause
3. Shark fin, aka an obstruction or bronchospasm. Common in asthmatic patients; other causes include ETT related issues. Check the tube first (Measure distance, consider sterile suction, reposition), or consider bronchospasm/lower airway disease and consider bronchodilators like terbutaline.
4. ETT cuff leak. We know we need to immediately check for a cuff seal once we intubate, but what we sometimes forget is to check again once the patient is at a deeper plane and the cervical muscles relax! Check cuff inflation using a digital pressure reader: White, et. al showed this was the most effective method of 4 different ways to check cuff pressure.
5. Sudden drop to zero - This requires understanding the concept of ventilation/perfusion mismatch and is very thoroughly discussed in my CPR for general practice training in a simplified way. EtC02 is not just a representation of respiratory status but also perfusion status. We need perfusion to generate EtC02, so when a patient is in cardiac arrest and perfusion stops, EtC02 wonโt be produced. This is why the capnograph is SO important to have on patients, especially during CPR. Itโs the only non-invasive machine to tell you when your patient has arrested AND when they have ROSC!
Need help introducing (or reintroducing) a capnograph into your practice? Iโd love to help you with that - including formal, interactive lecture, helping to choose proper equipment, training your trainers based on adult learning principles, and nervous system regulation for those who get a little stressed from anesthesia. Book your discovery session today on mindfulvet.co