title: Endoscope system with plasma flushing and coaxial round jet nozzle for off-pump cardiac surgery.
abstract: BACKGROUND
  To develop a new endoscope for performing simple surgical tasks inside the blood-filled cardiac atrium/chamber, that is, "off-pump" cardiac surgeries.
  
  
  METHODS
  We developed the endoscope system with plasma flushing and coaxial round jet nozzle. The "plasma flushing" system was invented to observe the interior of the blood-filled heart by displacing blood cells in front of the endoscope tip. However, some areas could not be observed with simple flushing of the liquid because the flushed liquid mixed with blood. Further, a large amount of liquid had to be flushed, which posed a risk of cardiac damage caused by excess volume. Therefore, to safely capture high-resolution images of the interior of the heart, an endoscope with a coaxial round jet nozzle through which plasma is flushed has been developed. And to reduce the volume of flushed liquid, the synchronization system of heartbeat and the endoscope system with plasma flushing has been developed.
  
  
  RESULTS
  We conducted an in vivo experiment to determine whether we could observe intracardiac tissues in swine without the use of a heart-lung machine. As a result, we successfully observed intracardiac tissues without using a heart-lung machine. By using a coaxial nozzle, we could even observe the tricuspid valve. Moreover, we were able to save up to 30% of the flushed liquid by replacing the original system with a synchronization system. And we evaluated the performance of the endoscope with the coaxial round jet nozzle by conducting fluid analysis and an in vitro experiment.
  
  
  CONCLUSIONS
  We successfully observed intracardiac tissues without using a heart-lung machine. By using a coaxial nozzle, we could even observe the tricuspid valve. And by replacing an original system to a synchronization system, we were able to save up to 30% of the flushed liquid. As a follow-up study, we plan to create a surgical flexible device for valve disease that can grasp, staple, and repair cardiac valves by endoscopic visualization.
authors.affiliation: Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan. tetsuya@atre.t.u-tokyo.ac.jp
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Horiuchi
authors.forename: Ken
authors.initials: K
authors.lastname: Masamune
authors.forename: Yuki
authors.initials: Y
authors.lastname: Iwase
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Ymashita
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsukihara
authors.forename: Noboru
authors.initials: N
authors.lastname: Motomura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ohta
authors.forename: Takeyoshi
authors.initials: T
authors.lastname: Dohi
mesh_terms: D000818:Animals; D006348:Cardiac Surgical Procedures / Q000295:instrumentation*; D047549:Coronary Artery Bypass, Off-Pump / Q000295:instrumentation*; D019723:Endoscopes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D018056:Hemorheology; D011138:Polytetrafluoroethylene; D012828:Silicones; D013193:Stainless Steel; D013552:Swine
chemical_list: D012828:Silicones; D013193:Stainless Steel; D011138:Polytetrafluoroethylene