S1422

Carbon Dioxide Insufflation for More Comfortable ERCP:

A Randomized Controlled TrialMichael Bretthauer, Birgitte Seip, Geir Hoff, Mariann Kordal,Lars AabakkenBackground: Carbon dioxide (CO2) insufflation during colonoscopy has beenshown to substantially reduce post-procedure abdominal pain. The effect of CO2on pain after endosocopic retrograde cholangiopancreatography (ERCP) has notbeen investigated. The present study aimed to determine the effect of CO2insufflation on pain during and after ERCP when compared to standard airinsufflation. Additionally, we investigated a possible negative effect of the body’spCO2 level by CO2 insufflation. Methods: 118 consecutive ERCP patients at twoNorwegian centres were randomised to either CO2 or air insufflation during theprocedure. Both endoscopists and patients were blinded with regard to type of gasused. Patients were asked to rate their intensity of pain on a 100-mm visualanalogue scale (VAS) during and at 1, 3, 6 and 24 hours after the ERCP, usinga questionnaire. Trans-dermal pCO2 was measured continuously in all patientsduring the procedure. Results: 116 patients were eligible for analysis, 58 in eachtreatment group. 91 patients responded to the questionnaire (78%). The meanamount of post-procedure pain (in mm on VAS) was significantly reduced in theCO2 group compared to the air group, at both one hour (5 mm vs. 20 mm, p !0,001), three hours (7 mm vs. 21 mm, p ! 0,001), six hours (10mm vs. 22 mm, p Z0,003) and 24 hours (4 mm vs. 20 mm, p ! 0,001) after the procedure. There wereno differences in pCO2 values between the two treatment groups. Conclusions:CO2 insufflation during ERCP significantly reduces post-procedure abdominal pain.No side-effects have been observed. CO2 should be used instead of air insufflationin ERCP.

Abstracts

762

Design, Development, and Testing of a Remote-Controlled,

Stereoscopic (Three-Dimensional) Imaging, Self-Propelled,

Wireless Capsule EndoscopeEric Allison, Zsolt Kiraly, George S. Springer, Jacques Van DamBackground: Wireless capsule endoscopy (WCE) has become an importantminimally-invasive method of examining the human digestive system. Limitations ofthe currently-utilized WCE system include the inability to examine an organ in realtime, inability to examine and re-examine a particular lesion, inability to examinethe stomach, and an inability to direct the capsule from one location to another. Wedesigned and tested (in vitro) a WCE equipped with a remotely-controlledpropulsion system capable of transporting the capsule to a desired location. Anovel optical system wirelessly transmitted stereoscopic (three-dimensional) videoimages that enabled operators to direct the capsule in real time. Methods: To date,stereoscopic images have generally been created either by polarizing the videostreams from dual cameras or by filtering video streams using complementarycolors. To overcome the limitations of these techniques, video images from dualcameras were merged and transmitted into a single stream to a computer anddisplayed on a video monitor as alternating images. Video was reconstructed withthe aid of shutter glasses synchronized to reassemble the images at a rate beyondthe limit of human perception. A propulsion system was created using acousticthrusters mounted at strategic locations on the capsule operating at their naturalfrequency. The force developed by each thruster was T Z P/c where P is the powerinput to the thruster and c is the speed of sound in the liquid surrounding thethruster. Results: For ease of manipulation, the prototype WCE was created in a sizeapproximately 5 times that of the currently clinically used capsule (130 mm �50 mm). The WCE consisted of 2 color cameras (OmniVision OV7910 CMOSelement); 6 light emitting diodes to provide illumination (LEDs; LEDtronicsLF200CW6K-27), thrusters for propulsion (10 mm diameter lead zirconate titanate[PZT] piezoelectric crystals), a logic board that processed the signals from thecameras and controlled the LEDs, a transmitter that sent signals from the cameras,and an internal rechargeable battery. The maximum speed of the capsule was100 mm/s. Model tests in a water tunnel and subsequent analysis of the datashowed that a 30 mm � 10 mm capsule could travel at speeds up to 200 mm/s. Inbench top tests, operators successfully steered the capsule through a fluid-filledmedium by way of a joystick. Conclusions: We successfully developed and tested invitro, a three-dimensional imaging, self-propelled, steerable WCE capable of realtime imaging in large gastrointestinal organs such as the stomach. Onceappropriately sized, clinical trials are warranted.

763

Deconstructing the Endoscope: Intragastric, Transgastric

and Laparoscopic Wireless Endosurgery Using Manipulable

Attached and Free Capsule ImagersPaul Swain, Sandy Mosse, Keiichi Ikeda, Maria Bergstrom, Per-Ola ParkIntroduction: Wireless capsule endoscopy (WCE) might be usefully deployed to aidendosurgery. Spacial separation of the imager and the axis of the tools ofendosurgery in flexible endoscopy might offer improved views of less accessibletargets and free precious intra-esophageal space for the passage of mechanicaldevices. The use of extra cameras during laparoscopy or transgastric surgery mightallow new angles of view improving efficacy and safety. Methods: Studies usingGivenImaging capsules (SB and Eso) and a real-time imager (Sony U70) were madein 9 pigs weighing 28-45 Kg during flexible endoscopic, transgastric andlaparoscopic endosurgical procedures. Methods of attachment of WCE to thestomach (submucosal and full thickness) were tested using new endoscopic sewingmethods. Capsules were also placed with a PEG-like method allowing the capsuleto be raised, lowered and rotated and angled to examine a specific site in thestomach or small intestine. WCE were passed through and beyond esophagealovertubes to allow manipulable imaging leaving the total overtube inner diameteravailable for endosurgical device passage. Capsule endoscopes were placed in theperitoneal cavity at laparoscopy to allow continuous wireless views of targetstructures including gallbladder, diaphragm and liver with simultaneouslaparoscopic imaging using a Storz laparoscopic system. Transabdominal andperitoneal attachment was used for stabilization and remote manipulation. Results:Intragastric: WCE sewn to the stomach wall or held by thread passed through theabdominal wall were able to capture multiple images of specific targets forendotherapy including lower esophageal junction, ulcers and biliary orifice. Somesimple methods of remote articulation of attached and free capsule were tested.WCE attached to, or freely observing, the end of esophageal overtubes were able toview instruments manipulating the cardia without retroflexion. Transgastric:Capsules passed through transgastric incisions allowed simultaneous views of bothsides of the gastric incision during suturing maneuvers. Laparoscopic: wirelessimaging allowed imaging of biliary manipulations, and liver biopsy with or withoutthe use of the conventional laparoscope image and imaging of subhepaticstructures inaccessible to laparoscopy. Conclusions: Wireless endosopy with andwithout attachment and manipulation capacities allowed spatial separation ofimaging and therapeutic functions of flexible endoscopy. Multiple simultaneousviews of structures during transgastric and laparoscopic surgery using wireless andconventional endoscopes gave useful views which could not be obtained withconventional endoscopes.

S1423

Pulsed Fluoroscopy to Reduce Radiation Exposure During ERCP:

A Prospective Randomized TrialLance T. Uradomo, Eric M. Goldberg, Peter E. DarwinBackground: Endoscopic retrograde cholangiopancreatography (ERCP) exposespatients and staff to potentially harmful ionizing radiation. Measures should beemployed to limit the dose to the minimum required to perform theprocedure.Aim: To determine whether ‘‘pulsed’’ fluoroscopy reduces radiationexposure and fluoroscopy time compared to continuous fluoroscopy. Methods:Subjects: Adult patients presenting to a single, university-based endoscopy unit forERCP. Subjects were randomized into two groups: 1) Pulsed fluoroscopy, wherea timer terminates x-ray exposure 3 seconds after the foot-operated switch isdepressed; 2) Continuous setting, where x-ray exposure continues for as long as theswitch is depressed. All procedures were performed by one of two attendinggastroenterologists. Following each procedure, fluoroscopy time (FT) and patientand procedure-related data were recorded. A scoring system rated duct cannulationas easy (!5 touches), moderate (6-15 touches), or difficult (O15 touches).Radiation dosimetry badges were also positioned during each case to estimateexposure to 1) patients, 2) sedation nurse, and 3) endoscopist. These wereanalyzed in a blinded fashion by the university radiation safety department. Results:A sample size of 99 ERCPs in each group was calculated prior to initiation of thestudy. A total of 199 procedures were performed: 99 in the pulsed group and 100using continuous fluoroscopy. By simple linear regression, longer FTwas predictedby moderate or difficult cannulations (p Z 0.008), lithotripsy (p ! 0.001), stentplacement (p Z 0.007), sphincterotomy (p ! 0.001), and longer overall procedurelength (p ! 0.001). Procedures by one endoscopist also had significantly longer FT(p Z 0.04). The difference in mean FT between groups was not statisticallysignificant (314 versus 284 seconds for continuous and pulsed fluoroscopy,respectively; p Z 0.34). The difference in radiation dose between groups was alsonot significant. However, when controlling for the above factors using a multiplelinear regression model, a strong association between lower FT and the pulsedsetting was found (p Z 0.019). DiscussionFluoroscopy time and radiation exposureare dependent on numerous patient, operator, and procedure-related factors. Thisstudy found that, after controlling for the impact of certain significant factors,pulsed fluoroscopy significantly decreases fluoroscopy times. A possiblemechanism of this effect is that the pulsed setting serves as a constant reminder tothe endoscopist to limit fluoroscopy.

AB104 GASTROINTESTINAL ENDOSCOPY Volume 63, No. 5 : 2006 www.giejournal.org