An insufflating surgical instrument adapted for penetrating an abdominal wall to insufflate an abdominal region of a patient, comprising: a cannula comprising a wall forming a lumen extending along an axis between the proximal end and a distal end and adapted for connection to a source of fluid under pressure at the proximal end； and a trocar insertable into and removable from the lumen of the cannula； the trocar comprising: a shaft having a wall forming a lumen extending between a proximal end and a distal end； and an insufflation channel operably connected to allow fluid transfer from the cannula to the trocar； and a tip at the distal end of the shaft adapted to penetrate tissue and enclosing the distal end of the shaft to prevent surgical instruments from extending through the tip, the tip having at least one vent hole having a first, closed position during penetration of the abdominal wall and a second, opened position to expel the fluid under pressure to insufflate the abdominal region after penetration of the abdominal wall.
