1. Department of Anesthesiology, Faculdade de Medicina, Universidade Estadual Paulista (UNESP); CEP 18618-970 Botucatu Brazil
2. Departments of Veterinary Surgery and Anesthesiology; Clinical Veterinary Sciences
3. Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista (UNESP); CEP 18618-970 Botucatu Brazil
4. Department of Small Animal Clinical Sciences, College of Veterinary Medicine; University of Florida; Gainesville FL 32610