Too Light Anesthetic Plane
Possible cause
Low level of (empty) isoflurane and O2
Excited animals during induction
Endotracheal leaks
Apnea
Esophageal intubation
Endobronchial intubation
Treatment
Check isoflurane and O2 level
Use effective premedication
Change defective endotracheal tube
Breathing for patients if apnea occurs
Check positioning of endotracheal intubation
Post anesthesia airway obstruction
Signs
Stridor
Excessive abdominal breathing
Cyanosis
Possible causes
Upper airway swelling (trauma, prolonged head-down position, allergic reaction, etc.)
Soft palate entrapment (i.e., brachycephalic breeds)
Foreign bodies in the trachea
Laryngeal paralysis
Possible treatment
For airway swelling, steroid, (e.g., dexamethasone [0.25 mg/kg]) should be given.
For brachycephalic breeds, maintain a gradual recovery and wait until the animal becomes very awake and tolerates the endotracheal tube in the trachea. Once extubated, monitor animals closely for 15–30 min.
Examine and/or clean oral cavity before extubation.
Hypothermia
Possible causes
Anesthetic drugs interfere with thermoregulation
Use of non-rebreathing circuits with high O2 flow
Large surgical prep area and very long procedures
Cold fluid administration or cold fluid lavage
Treatments
Provide heat sources (e.g., circulating heating pads, Bair Huggers, etc.)
Use rebreathing circuits when possible
Minimize excessive clipping area
Reduce surgical and anesthesia time when possible
Administer warm fluid (IV or lavage fluid)
Keep OR room > 70°F (21°C)
Monitor body temperature throughout surgery
Prolonged Recovery
Possible causes
Deep anesthetic plane
Hypothermia
Hypoglycemia
Effects of anesthetics
Existing diseases
Treatment
Communicate with surgeon and lighten anesthetic plane 15–20 min before finishing surgery if possible.
For hypothermia, please see hypothermia.
Check glucose level and treat accordingly.
Treat existing diseases in advance when possible. Drug dosages may need to be reduced depending on patients' health status and other factors.
References
1. Greene SA. Veterinary Anesthesia and Pain Management Secrets. Philadelphia, PA: Hanley & Belfus; 2002:1–43.
2. Seymour C, Duke-Novakovski T. BSAVA Manual of Canine and Feline Anaesthesia and Analgesia. 2nd ed. Gloucester, UK: British Small Animal Veterinary Association; 2007.