title: A versatile dual-channel carbon dioxide (CO2) insufflator for various CO2)applications. The prototype.
abstract: BACKGROUND
  Carbon dioxide (CO2), with its rapid absorptive nature, has been proven superior to atmospheric air as an insufflating agent in various clinical settings. However, CO2 insufflation has not gained wide clinical acceptance, mainly because there has been no suitable feeding system. The authors therefore have developed a versatile "dual-channel" CO2 insufflator that facilitates wider use of CO2. The objectives of this study were to introduce the authors' prototype insufflator, to evaluate its safety and performance, and to validate CO2 application using the prototype.
  
  
  METHODS
  The prototype insufflator provides one CO2 inlet connected to a regular CO2 gas cylinder and two CO2 outlets positioned on the front and back of the device, respectively. The CO2 gas fed from the cylinder is pressure-regulated and divided into two independent conduits inside the device. The front outlet feeds CO2 gas for pneumoperitoneum at an electronically controlled pressure and flow rate. The back channel supplies CO2 gas at a fixed flow rate, allowing manual control of insufflation for various purposes. The device was evaluated with canine models.
  
  
  RESULTS
  The prototype was safe and performed well. The CO2 application (colonoscopy in this series) using the back channel was feasible while intact CO2 pneumoperitoneum was simultaneously maintained via the front channel. There were no device malfunctions. The serial abdominal x-rays indicated that intraluminal CO2 insufflation such as that used for CO2 colonoscopy caused less residual intestinal gas than conventional air insufflation.
  
  
  CONCLUSIONS
  The dual-channel CO2 insufflator enabled two different modes of CO2 insufflation at the same time from a single CO2 cylinder. The authors are now improving the prototype to allow safer and wider usage of CO2 in the operating room.
authors.affiliation: Department of Surgery E1, Osaka University Graduate School of Medicine, 2-2, Yamadaoka, Suita Osaka, 565-0871, Japan. knakajima@surg1.med.osaka-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Nakajima
authors.forename: K
authors.initials: K
authors.lastname: Yasumasa
authors.forename: S
authors.initials: S
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: A
authors.initials: A
authors.lastname: Nishitani
authors.forename: R
authors.initials: R
authors.lastname: Nezu
authors.forename: T
authors.initials: T
authors.lastname: Nishida
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000008:administration & dosage*; D003113:Colonoscopy; D004285:Dogs; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D007327:Insufflation / Q000009:adverse effects / Q000295:instrumentation*; D011028:Pneumoperitoneum, Artificial / Q000009:adverse effects / Q000295:instrumentation*; D011860:Radiography, Abdominal; D015203:Reproducibility of Results
chemical_list: D002245:Carbon Dioxide