1. Instituto Nacional de Cancerología, Ciudad de México, Mexico
2. Instituto de Salud Pública, Universidad Veracruzana, Xalapa, Veracruz, Mexico
3. Department of Pediatrics, Division of Critical Care Medicine, Children’s National Health System, Washington, District of Columbia, United States
4. Centro de Alta Especialidad “Dr. Rafael Lucio”, Xalapa, Veracruz, Mexico