1 Intensive Care Unit, the Pulmonary Section, Medicine Department, and the Instituto Universitario, Buenos Aires, Argentina. Electronic address: p_maskin@yahoo.com.
2 Internal Medicine, Medicine Department, Centro de Educación Médica e Investigaciones Clínicas (CEMIC), Buenos Aires, Argentina.
3 Intensive Care Unit, the Pulmonary Section, Medicine Department, and the Instituto Universitario, Buenos Aires, Argentina.