[1] Royal Brompton Hosp, London SW3 6NP, England
[2] Leicester Royal Infirm, Dept Child Hlth, Leicester LE1 5WW, Leics, England
[3] Hop Robert Debre, F-75935 Paris, France
[4] Klinikum Saarbrucken, D-66119 Saarbrucken, Germany
[5] Ulleval Hosp, Barn Afd, N-0407 Oslo, Norway
[6] Neonatal & Paediat Intens Care Unit, I-37126 Verona, Italy
[7] Great Ormond St Hosp Children, London WC1N 3JH, England
[8] Sahlgrens Univ Hosp, Drottning Silvias Barnsjukhus, S-41685 Gothenburg, Sweden
[9] Karolinska Inst, Dept Physiol & Pharmacol, S-17177 Stockholm, Sweden
[10] Kinderspital, CH-4005 Basel, Switzerland
[11] Karolinska Inst, Astrid Lindgren Childrens Hosp, Dept Paediat Anaesthesia & Intens Care, S-17176 Stockholm, Sweden
[12] Hosp Gen Univ Gregorio Maranon, Serv Neonatol, Madrid 28009, Spain
[13] Akad Sjukhuset, S-75185 Uppsala, Sweden
[14] Liverpool Womens Hosp, Neonatal Unit, Liverpool L8 7SS, Merseyside, England