1. Discipline of Anesthesiology, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo 05403-010, Brazil
2. Instituto da Criança e do Adolescente, Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo 05403-000, Brazil
3. Department of Anatomy, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria 0085, South Africa
4. Department of Anesthesia and Pain Management, Seattle Children’s Hospital, University of Washington, Seattle, WA 98195, USA
5. Department of Medicine, Universidade Nove de Julho (UNINOVE), São Paulo 03155-000, Brazil