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Study Shows That $250 Million Could Be Saved Continued...

Experimental Method
Jacobs selected a number of standard insufflation and surgical components with a variety of different specifications from different manufacturers like Storz, Olympus, Wolf, Ethicon or Auto Suture and many others. The pressure reducer on the carbon dioxide supply was slowly opened to the maximum, then closed. Then a 10 mm optic, the device used by the surgeon to look inside the abdomen, was introduced into the trocar, further constricting gas flow. In both cases, flow resistance was measured as pressure drop and as resistance (pressure drop divided by flow rate) with gas flow rate serving as the independent variable. Polynomial regression curves were then calculated with Origin to convert the cloud of measurements into a function and a reference pressure (PRef) of 12 mmHg was defined. The regression curves and reference pressure made it possible to easily compare the performance of different insufflation components.

While there are many technical graphics programs available, Jacobs said that Origin 5.0 is clearly the best suited for this project. The first and most important reason is the customizability of this program. One can make essentially any imaginable change to the visual display of data using Origin. Every aspect of the screen object is independently available. It is possible to use whatever fonts, orientations, sizes, and colors needed to visually express relationships in complex datasets. A second strength is its ability to handle very large multiple datasets quickly and efficiently. This is in sharp contrast to some other commercial data analysis packages. The third strength lies in Origin's LabTalk scripting language. Using LabTalk, computational and graphical tools specific to whatever analysis is being done can be easily created, since the language was created for researchers to use. Creating sets of instructions for complex and tedious manipulation of raw data to extract the critical information and display it in a transparent manner is a breeze. These scripts can then be called at the push of a single on-screen button.

Study Results
The study showed a wide variation among the performance of different insufflation systems and that many of the combinations studied did not provide adequate gas flow. An interesting conclusion is that the smallest diameter in the system left for insufflation determines the resistance and the flow properties of the entire insufflation system. This can either be the insufflation diameter at the trocar supply, the connector used to attach the gas supply to the trocar, the diameter of the Veress needle or the inner lumen in the trocar left for insufflation after optic insertion. Different trocar sizes have the same flow properties if they have the same diameter at the stop cock. After the insertion of a 10 mm optic, disposable and reusable 10 mm trocars have massively reduced flow values.

Figure 3

Figure 3: Gas flow regression curves of disposable trocars: 1. Origin, 2. Richard Allan (5 nd 12 mm), 3. Ethicon, 4. Auto suture and 5. Richard Allan (10 mm).


Figure 4

Figure 4: Gas flow regression curves for reusable trocars: 1. Storz 26020, 2. Storz 30104T, 3. Olympus A 5675, 4. Wolf, 5. Storz, 6. Olympus A 5359 and 7. HiTec.

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