Specific resistance of Veress needles, disposable and reusable trocars is limiting CO2 gas flow performance in pelviscopy and laparoscopy

An efficient insufflation technique is essential for laparoscopy. Up to now physicians have had to rely on their experience and intuition when putting together an insufflation system. Comparable, objective data about the insu fflation properties of all insufflation components used has not been availa ble. In this study, details of the insufflation properties of disposable an d reusable Veress needles and trocars and Luer lock connectors and the part icular meaning of flow resistance for function and efficiency of the entire insufflation system have been measured and compared. In an independent lab oratory study a computer-based data acquisition measurement model was devel oped. Specific pressure dependent flow and resistance curves of insufflatio n components from manufacturers such as Auto Suture, Deride, Ethicon, HiTec , Olympus, Origin, Richard-Allan, Volzer, Wiest, Wolf and Storz were evalua ted by measurement of physical parameters pressure, CO2 gas flow and resist ance. Through the introduction of reference values, different insufflation properties for all studied components were characterised for the first time and can be compared. Despite similar type of construction, remarkable diff erences of CO2 gas flow were found in Veress needles (0.85-2.38 L min(-1)), disposable (3.91-9.61 L min(-1)) and reusable trocars (5.27-21.07 L min(-1 )) at reference pressure of 12 mmHg, if used for insufflation only. It furt her decreased after insertion of a 10 mm optic for disposable (1.53-7.08 L min(-1)) and reusable trocars (1.22-14.03 L min(-1)). All insufflation comp onents have different flow properties, due to the space left for insufflati on. The largest resistance is usually the diameter size at the insufflation supply (1.5-4.3 mm). In general, disposable trocars are not useful for hig h flow insufflation (> 10 L min(-1) at P-Ref = 12 mmHg). Only two reusable trocars studied deliver high flow with a 10 mm optic inserted (HiTec 1013, Olympus A 5359). Resistance, especially of disposable trocars, needs to be improved by enlarging the insufflation diameter. Resistance-optimised insuf flation components are more efficient, faster and could save time and money . Users need to demand resistance-improved products from manufacturers, who should publish reference values about specific flow and resistance propert ies of their products.