[1] Rigshosp, Cochrane Anaesthesia Review Grp, DK-2100 Copenhagen, Denmark
[2] Rigshosp, Copenhagen Trial Unit, DK-2100 Copenhagen, Denmark
[3] Rigshosp, Dept Paediat & Obstet Anaesthesia, DK-2100 Copenhagen, Denmark
[4] Univ Copenhagen, Hvidovre Hosp, Dept Paediat, DK-2650 Hvidovre, Denmark
[5] Herlev Univ Hosp, Dept Anaesthesiol, DK-2730 Herlev, Denmark
[6] Copenhagen Univ Hosp, Rigshosp, Ctr Clin Intervent Res, Copenhagen Trial Unit,Dept 3344, Copenhagen, Denmark