Anesthetic management of a dog with severe subaortic stenosis and mitral valve disease complicated with atrial fibrillation undergoing ovariohysterectomy

Abstract

The anesthetic management in patients with subaortic stenosis and mitral valve disease should involve intensive monitoring and the anesthesiologist’s main concern is to ensure oxygen delivery and tissue perfusion. Since anesthetic procedures in such patients are rare, there is no previous report about the anesthetic management. A 5.5-year old, 32-kg Boxer, suffering a severe heart disease due to a final stage subaortic stenosis and mitral insufficiency, was anesthetized for an ovariohysterectomy to remove an ovarian tumor that was producing high-volume ascites. Methadone (0.3 mg kg⁻¹) was administered intramuscularly (IM) for pre-anesthetic medication, etomidate (1.3 mg kg⁻¹) and midazolam (0.2 mg kg⁻¹) were used for the induction of anesthesia and after endotracheal intubation, anesthesia was maintained with sevoflurane vaporized in oxygen and air. Fentanyl (5–10 μg kg⁻¹ h⁻¹) and paracetamol (15 mg kg⁻¹) were administered to improve analgesia. Previous persistent atrial fibrillation was refractory to medication (digoxin, diltiazem, and pimobendan) and continued during the anesthetic procedure. Dobutamine (1.5–5 μg kg⁻¹ minute⁻¹) helped to maintain mean arterial blood pressure above 60 mmHg. Epidural morphine (0.1 mg kg⁻¹) and incisional bupivacaine (2 mg kg⁻¹) were administered at the end of surgery to provide postoperative analgesia. Anesthesia was otherwise uneventful, and recovery was considered excellent.

Keywords: Anesthesia, Atrial fibrillation, Dog, Mitral, Subaortic stenosis