[1] Tecnol Monterrey, Sch Med, Mexico City, DF, Mexico
[2] Amer British Cowdray Med Ctr IAP, Dept Anesthesiol, Mexico City, DF, Mexico
[3] Univ Nacl Autonoma Mexico, Fac Med, Forens Sci, Mexico City, DF, Mexico
[4] Emergency Med Regulat Ctr, Mexico Citys Hlth Secretariat, Mexico City, DF, Mexico