[1] Sismanogle Athens Hosp, Dept Internal Med 2, Athens 15126, Greece
[2] Univ Athens, Sch Med, Dept Internal Med 4, Athens 12462, Greece
[3] Protemaida Hosp, Intens Care Unit, Ptolemaida, Greece
[4] Univ Athens, Sch Med, Dept Crit Care 2, Athens 12462, Greece
[5] Nafplion Gen Hosp, Dept Surg, Naflpion 21100, Greece
[6] G Gennimatas Athens Hosp, Dept Internal Med 1, Athens 11527, Greece
[7] Nikaia Gen Hosp, Dept Internal Med 1, Nikaia, Greece
[8] Korgialeneion Benakeion Hosp Athens, Intens Care Unit, Athens 11526, Greece
[9] Univ Ioannina, Sch Med, Dept Crit Care, GR-45110 Ioannina, Greece
[10] Laikon Athens Gen Hosp, Intens Care Unit, Athens 11527, Greece
[11] Thriassio Elefsina Gen Hosp, Dept Internal Med 1, Magoula 19600, Greece
[12] Tzaneion Hosp Piraeus, Intens Care Unit, Piraeus, Greece
[13] Univ Thessaloniki, Dept Med 3, Thessaloniki 54635, Greece
[14] Univ Thessaloniki, Sch Med, Dept Surg 2, Thessaloniki 54635, Greece
[15] Univ Patras, Sch Med, Dept Internal Med 1, Rion 26504, Greece
[16] Hosp Dresden Neustadt, Dept Anaesthesiol & Intens Care Med, D-1129 Dresden, Germany