Internationally used propofol starting doses in newborns vary between 1.0 to 2.5 mg/kg and are repeated if necessary. The current study will start with propofol doses of 1.0 mg/kg in every age group. If the study starting dose is insufficient, the patient will receive additional propofol doses (1.0 mg/kg) until adequate sedation is acquired. No patient will be intubated before adequate sedation is reached. This is possible because propofol is very fast acting (1-2 minutes).