[1] Inst Nacl Enfermedades Resp, Neumol Adultos, Mexico City, DF, Mexico
[2] Inst Nacl Nutr & Ciencias Med Salvador Zubiran, Inst Continua, Dept Urgencias & Atenc, Mexico City, DF, Mexico
[3] Inst Politecn Nacl, Escuela Super Med, Secc Estudios Posgrad & Invest, Mexico City, DF, Mexico
[4] Hosp Gen Reg IMSS 6, Unidad Cuidados Intens Resp, Ciudad Madero, Mexico
[5] Inst Nacl Cancerol, Unidad Cuidados Intens Resp, Mexico City, DF, Mexico
[6] Ctr Med Nacl IMSS La Raza, Dept Anestesiol, Mexico City, DF, Mexico
[7] Hosp Gen San Juan Del Rio, Unidad Cuidados Intens Resp, Queretaro, Mexico