4001734 P group propofol group 15 1481264 PRO propofol group 2 363906 PP propofol group 1 1469168 PPF propofol group 1 3201641 PRO group propofol group 1 349922 Pg propofol group 1 2136984 Prop group propofol group 1 3310517 prop propofol group 1