While propofol has many advantages it can cause respiratory depression (reduced breathing rate). This reduction in breathing is more common if propofol is given quickly. When your child is given propofol for their proposed procedure this is performed by a pediatric anesthesiologist who is skilled in supporting breathing should this be required. If your child does not participate in this study they will still receive propofol administered by the anesthesiologist as this is our usual practice. It would be routine to administer the propofol rapidly and then support breathing for a few minutes. This is very safe in the hands of an expert anesthesiologist but can be sometimes more risky in other settings where extensive monitoring and anesthesiologists are not available. This is the setting that propofol is used in many institutions.