Operative laparoscopy needs a space to be made inside the abdominal cavity. This can only be achieved by suspension or by positive pressure. The endoscopic insufflator makes it possible to create this positive pressure, and does indeed enable the operating space to remain open. But it would be too limiting to consider these devices from the visibility point of view only, for they can also be exploited for their action on hemostasis and dissection. With this in mind we feel that the endoscopic surgeon ought to be perfectly familiar with his apparatus and not simply limit himself to adjusting the pressure and flowrate at the beginning of the operation. This hyper pressure in the abdomen is not without consequences for the patients' homeostasis and can indeed require an operation to be halted or converted to laparotomy. So knowledge of the biomedical aspects of his equipment will also enable the surgeon to increase the safety of his operations.