Anesthesia
A medically induced state of controlled unconsciousness, analgesia, and muscle relaxation. In dogs, general anesthesia is required for surgery, dental procedures, and some diagnostic imaging. Pre-operative assessment reduces risk, particularly in senior dogs.
Anesthesia is the medically controlled induction of unconsciousness, pain suppression (analgesia), and muscle relaxation. General anesthesia is required for surgical procedures, dental cleanings, and imaging studies that require absolute immobility (MRI, CT, some radiographic positioning).
General Anesthesia vs. Sedation
| General Anesthesia | Sedation | |
|---|---|---|
| Consciousness | Absent | Reduced (drowsy) |
| Pain control | Complete | Variable |
| Airway control | Intubated, ventilated | Patient maintains own airway |
| Muscle relaxation | Complete | Partial |
| Recovery time | 1-4 hours | 30-60 minutes |
| Risk level | Higher | Lower |
Sedation is appropriate for minor procedures (wound repair, radiographs, ultrasound, FNA biopsies). General anesthesia is required for surgery, dentistry, and any procedure involving significant pain or the need for absolute immobility.
Modern Anesthetic Protocols
Veterinary anesthesia has advanced significantly. Modern protocols use a balanced, multimodal approach:
- Pre-medication: sedative + analgesic (e.g., dexmedetomidine + hydromorphone) — reduces anxiety, provides pain control, reduces the dose of induction and maintenance agents
- Induction: injectable agent (propofol or alfaxalone) to achieve unconsciousness for intubation
- Maintenance: inhaled anesthetic (isoflurane or sevoflurane) delivered through endotracheal tube — allows precise depth control
- Monitoring: continuous pulse oximetry, capnography, ECG, blood pressure, temperature — modern monitoring reduces adverse event rates substantially
- Recovery: active warming, continued monitoring, pain assessment
Pre-Operative Bloodwork
Pre-anesthetic bloodwork is essential for identifying occult disease that increases anesthetic risk:
- CBC: detects anemia (reduced oxygen-carrying capacity), thrombocytopenia (bleeding risk), and infection
- Serum chemistry panel: evaluates kidney function (affects drug clearance), liver function (affects drug metabolism), glucose, and electrolytes
- Additional tests for senior dogs: thyroid panel, coagulation profile, cardiac biomarkers
The American Animal Hospital Association (AAHA) recommends pre-anesthetic bloodwork for all patients, with expanded panels for dogs over 7 years.
Senior Dog Risks
Anesthetic risk increases with age, primarily due to:
- Decreased organ reserve: kidneys and liver metabolize and clear anesthetic drugs less efficiently
- Cardiac disease: undiagnosed heart disease — particularly mitral valve disease — increases cardiovascular complications
- Thermoregulation: senior dogs lose body heat faster under anesthesia
- Recovery: prolonged emergence from anesthesia is more common in geriatric patients
These risks are manageable with proper pre-operative assessment. The senior dog screening protocol should be completed before elective anesthesia in any dog over 7 years.
Brachycephalic Considerations
Brachycephalic breeds (Bulldogs, Pugs, French Bulldogs, Boston Terriers) have inherently compromised airways. Anesthetic management requires:
- Pre-oxygenation before induction
- Rapid intubation (these dogs desaturate quickly)
- Delayed extubation (remove the endotracheal tube only when the dog is fully awake and swallowing)
- Extended recovery monitoring
Anesthetic mortality in brachycephalic breeds is approximately 2-4x higher than in non-brachycephalic breeds, though absolute risk remains low (<1%) with experienced teams.
Communicating with Your Veterinarian
Before any anesthetic procedure, discuss your dog’s complete medication list, fasting instructions, and any previous anesthetic reactions. Ask about the monitoring equipment available, who will be dedicated to anesthetic monitoring during the procedure, and what the post-operative pain management plan includes.