1. Pediatric Sedation Unit, Department of Pediatrics, Maastricht University Medical Centre, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
2. Dutch Institute for Health Care Improvement CBO, P.O. Box 20064, 3502 LB Utrecht, The Netherlands
3. Department of Anesthesiology, University Medical Centre, P.O. Box 85500, 3508 GA Utrecht, The Netherlands