Model to determine resistance and leakage-dependent flow on flow performance of laparoscopic insufflators to predict gas flow rate of cannulas.
OBJECTIVE
To characterize insufflator CO2 gas flow performance to predict gas flow rate with standard cannulas.


METHODS
Prospective, observational study (Canadian Task Force classification II-2).


METHODS
Laboratory of university clinic.


METHODS
None. Intervention. Gas flow (L/min) and average pressure (mm Hg) inside an abdomen model were measured at 12 mm Hg nominal pressure during steady state.


RESULTS
An abdomen box model for laboratory measurements was designed with different entrance and exit diameters simulated with hole disks from 0.5 to 7.6 mm. With a computer-based data-acquisition model, five insufflators (Olympus 9L and 16L, Storz 10L and 30L, HiTec 16L) were evaluated with 150 disk combinations. Flow performance in three-dimensional profiles showed different flow rates for all insufflators depending on resistance and leakage combination, maximum flow rate, and insufflation principle. Maximum flow was reached without resistance only in the insufflation system at high leakage rates. Low-pressure principle is more affected by resistance. Cannula flow rates at 12 mm Hg and 15 L/minute leakage ranged from 4.8 (Origin) to 6.0 L/minute (Storz HiCap) for Olympus 9-L insufflators and from 5.4 (Origin) to 15.10 L/minute (Storz HiCap) for Storz 30-L Thermoflator. Reusable cannulas have more flow efficacy than disposable ones, especially with high-flow insufflators, because of larger diameter at insufflation supply.


CONCLUSIONS
Gas flow depends not only on maximum flow of insufflators but also on resistance of cannulas and leakage rate. With this model it is possible to predict the real, available flow of insufflator-cannula combinations for the first time. Improved resistance of all components can save insufflation time.
Department of Obstetrics and Gynecology, Christian-Albrechts University, Michaelisstrasse 16, 24105 Kiel, Germany.
V R
VR
Jacobs
J E
JE
Morrison
C
C
Mundhenke
K
K
Golombeck
W
W
Jonat
D
D
Harder
D006801:Humans; D007327:Insufflation / Q000295:instrumentation*; D010535:Laparoscopy; D008962:Models, Theoretical; D011446:Prospective Studies