[1] Hosp Clin Univ Chile Santiago, Dept Med, Crit Care Unit, Santiago, Chile
[2] Univ Chile, Sch Med, Fac Med, Santiago, Chile
[3] Hosp Clin Univ Chile, Dept Anesthesiol & Perioperat Med, Santiago, Chile
[4] Hosp Clin Univ Chile, Dept Otorhinolaryngol, Santiago, Chile
[5] Hosp Clin Univ Chile, Head & neck Surg, Dept Surg, Santiago, Chile
[6] Hosp Clin Univ Chile, Dept Nursing, Santiago, Chile