[1] Univ Valencia, Hosp Clin, Unidad Cuidados Intens Resp, Valencia 46010, Spain
[2] Hosp Cruces, Baracaldo, Bizkaia, Spain
[3] Univ Zaragoza, Hosp Clin, Zaragoza, Spain
[4] Hosp Txagorritxu, Vitoria, Alava, Spain
[5] Hosp Virgen Rocio, Seville, Spain
[6] Hosp Ramon & Cajal, E-28034 Madrid, Spain
[7] Hosp Badalona Germans Trias & Pujol, Badalona, Barcelona, Spain
[8] Hosp La Fe, E-46009 Valencia, Spain