Anesthesia and Analgesia
Anesthesia questions ask you to plan a safe protocol, monitor depth, and recognize problems before they become arrests. The exam expects drug-class knowledge plus machine and airway competence.
Protocol and monitoring
- Premedication usually combines an opioid with a sedative (alpha-2 agonist, benzodiazepine, or acepromazine); anticholinergics treat bradycardia but are not routine in every patient.
- Induction agents include propofol, alfaxalone, and ketamine-midazolam; maintenance is typically isoflurane or sevoflurane.
- Monitor heart rate, respiratory rate, mucous membrane color, capillary refill time, palpebral reflex, jaw tone, end-tidal CO2 (about 35-45 mmHg), SpO2 (greater than 95%), blood pressure (MAP above 60 mmHg), and temperature.
- Endotracheal tube size is estimated by weight and checked for a leak; inflate the cuff only until a seal is heard, then secure the tube.
Worked example
During isoflurane maintenance, a dog's heart rate rises from 90 to 140 beats/min, jaw tone increases, and the palpebral reflex returns. These signs suggest a light plane. Check the vaporizer and breathing circuit, verify the tube is not kinked, and deepen anesthesia only after confirming there is no surgical pain or hypovolemia driving the response.
Traps that cost marks
Extubating before swallowing returns; overinflating the cuff; relying on a single monitor; skipping the pre-use machine leak test; and forgetting active warming, since hypothermia prolongs recovery and shifts drug metabolism.