Of the 160 eligible patients , significant between-group differences were found in the mean total number of dressing changes ( HD , 6.091.655 changes ; PF , 5.592.036 changes ; p = 0.010 ) , and mean number of dressing changes in the sacral region ( HD , 2.500.871 ; PF , 2.050.825 ; p = 0.001 ) , with the PF group requiring significantly fewer changes than the HD group .