Anesthesia
The Anesthesia domain tests preanesthetic assessment, drug selection, induction, maintenance, monitoring, and recovery. The exam often asks which monitor or intervention is most appropriate when a value drifts.
Core rules
- Assign ASA status after history, physical examination, and minimum database; adjust protocol for age, breed, and disease.
- Premedicate for analgesia and anxiolysis; common combinations include an opioid with a sedative.
- Use a non-rebreathing circuit for small patients, generally under 7 kg, and a rebreathing circuit for larger patients.
- Monitor depth, heart rate, rhythm, respiratory rate, SpO2, ETCO2, blood pressure, temperature, and mucous membrane color.
- Calculate tidal volume at 10–15 mL/kg and check cuff seal and circuit connections before induction.
Worked example
A 20 kg dog is ventilated. Tidal volume = 10–15 × 20 = 200–300 mL. If the capnograph shows ETCO2 60 mmHg, ventilation is inadequate; increase respiratory rate or tidal volume and reassess. Normal ETCO2 is about 35–45 mmHg.
Traps
Monitoring only heart rate, ignoring hypothermia, using a rebreathing circuit in a 3 kg cat, and failing to check the endotracheal tube cuff. Also, extubating before the swallow reflex returns.