Understanding challenges in feline anesthesia is important and will assist anesthetists in preparing for complications that can sometimes occur. Experience in treating complications is a crucial factor. A few common examples of complications and appropriate managements in feline anesthesia are listed below.
Apnea: Apnea can be due to high doses of anesthetic drugs. Most anesthetics suppress respiration in a dose dependent manner, which most commonly occurs right after induction. Anesthetists should confirm that it is not a life-threatening situation. Patients should be intubated, and ventilation should be provided via anesthetic machine with 100% O2. However, if apnea is due to recent hyperventilation (PaCO2 < 40 mm Hg), reduction of assist ventilation should be done.
Airway obstruction: An example of a clinical sign is stridor or abdominal breathing, especially during the postoperative period. Common causes are laryngeal spasm, mucous blockade, and endotracheal tube kinks. Cats can have strong laryngeal spasms, so it is prudent to monitor animals closely after extubation. If this may be the case, emergency re-intubation kits and tracheostomy kits should be prepared. Mucous blockade and endotracheal tube kinks can often be seen due to the small size of endotracheal tube lumen. Therefore, patency of endotracheal tube (ETCO2 wave form, breathing pattern, etc.) should be monitored. If needed, an armoured endotracheal tube can be used.
Hypotension: Hypotension is a common problem during anesthesia. Several anesthetics such as isoflurane, acepromazine, dexmedetomidine, etc., cause dose-dependent vasodilation leading to hypotension. During anesthesia, blood pressure should be monitored. Mean arterial blood pressure should be kept > 65–70 mm Hg. When hypotension is encountered, depending on causes, action should be taken - such as decreasing anesthetic drugs, lightening an anesthetic depth, administrating fluid and/or inotropic drugs. If blood loss is the cause of hypotension, fluid (3x of the loss) and/or blood transfusion should be performed.
Hypothermia: This is a common problem in small patients, especially if a nonrebreathing circuit is used. Body temperature should be monitored. A heating pad should be provided. The surgical preparation area should be minimized, and warm lavage fluid should be used.
Other complications should also be considered; e.g., prolonged recovery, cardiac arrhythmias, human errors, and anesthetic machine errors.
1. Thurmon JC, Tranquilli WJ, Benson GJ. Essentials of Small Animal Anesthesia & Analgesia. Baltimore, MD: Lippicott Williams & Wilkins; 1999.
2. Greene SA. Veterinary Anesthesia and Pain Management Secrets: Patient Management. Philadelphia, PA: Hanley & Belfus, Inc.; 2002:1–43.