The Influence Of Transgastric Natural Orifice Transluminal Endoscopic Surgery Cholecystectomy On The Circulatory And Respiratory Function In Rabbits

Background:The successful clinical application of laparoscope and digestive endoscopyhave already initiate a new era in the field of minimally invasive surgery, along withthe vigorous development of new technologies and innovative ideas emerge in anendless stream, Since the natural orifice transluminal endoscopic surgery came out,surgeons clever use of the body’s natural anatomy of the channel and skillfullycombined the endoscopic surgery and the flexible endoscopic technique, guided abrand new direction for the development of minimally invasive interventionaldiagnosis and treatment. The purpose of NOTES is not only realizing the aim of trulyno scar on abdominal wall, but more importantly accelerating postoperative recoveryas well as reducing pain and interference in physiological internal environment ofbody. Similar to laparoscopy, NOTES also require the establishment of artificialpneumoperitoneum to expose visualization and operation field in lumen. Althoughcarbon dioxide is currently the most widely used distending medium, which yet hasbeen largely reported having negative effect on systematic and organic functions ofnormal body. Moreover, the application carbon dioxide is limited by the lack ofpneumoperitoneum endoscopic equipment of carbon dioxide within the fact that air asdistending gas was already extensively applied in therapeutic endoscopic surgery ofstomach and enterocoel, of which the category, difficulty and the duration of thesurgery continuously extend. The application value of the aerial distending mediumshould be reexamined the feasibility of the application.Objective:The project aims at observing the varying pattern of circulatory and respiratoryindexes of rabbit under different surgical procedures and pneumoperitoneum medium(air and carbon dioxide), then comparing and discussing the strengths and weaknessesof the transgastric natural orifice transluminal endoscopic cholecystectomy andtraditional laparoscopic cholecystectomy, as well as their influences on physiologicalinternal environment of body, through building experimental rabbit pneumoperitoneum models then respectively implementing these two surgeries.Methods:1. Grouping and preparation of animals:24healthy Japanese white rabbits,either male or female, weighing2.5～3.5kg was chosen for the experiment. Theywere randomly separated into two groups, which equally consist of12rabbits, as theair pneumoperitoneum rabbit model and carbon dioxide pneumoperitoneum rabbitmodel. The former one was applied in transgastric natural orifice transluminalendoscopic surgery group (NOTES Group), while the latter one in traditionallaparoscopic cholecystectomy group (LC Group). The experimental animals shouldbe fed for one week after purchase to adapt new environment, then fed with crudefibre food for three days just before surgery. They were preoperatively forbidden toeat for24hours and to drink for8hours.2. Surgical procedures: The general anesthesia, trachea cannula, vascularcatheter and assistant breathing machine were used in the surgery.①NOTES Group:The endoscope (choledochofiberscope) was placed through mouth. Metal guide wirepre-cut the lesser curvature side of stomach fanterior wall, and then balloons weresent step by step along the guide wire. After3～5times of gas injection, balloondilatation made the gastric wall stoma expand to3.5～4.0mm, where the endoscopeentered enterocoelia and artificial pneumoperitoneum was made by air injection.Afterwards the endoscope searched in the enterocoelia to seek the gallbladder. Ifnecessary, laparoscopic instruments should be transumbilically placed to assist toremove the gallbladder under the endoscope. The gallbladder was finally taken outfrom mouth through endoscope. Gastric wall stoma was closed up by omentumtamponade and biogum bonding.②LC Group: The veress needle was placed throughthe2mm small incision of umbilical region. After carbon dioxide pneumoperitoneumwas made, laparoscope was placed and so did the5mm trocars respectively at1～2cm off the edge of xiphoid process and on the plane of the second pair of nipple offthe edge of right rib arch. The gall bladder was removed with conventional approachand taken out through the incision below the xiphoid process. The incision ofabdominal wall was intermittently sutured by silk thread.3. Observation indexes: The timings below were chosen as observation time phases for record cardiopulmonary parameters: after cervical cathetering wasaccomplished (T1), after pneumoperitoneum was steadily built (T2), after the body ofgallbladder was retrograde separated to the cystic duct (T3), after the gallbladder wasstripped from the gallbladder bed and cystic duct was occlusived (T4) andimmediately after the surgery finished (T5). Circulatory indexes: Heart rate (HR),Systolic arterial pressure (ASBP), Diastolic arterial pressure (ADBP), Mean arterialpressure (MAP) and Central venous pressure (CVP). Respiratory indexes: Arterialblood pH (pH), Arterial CO2partial pressure (PaCO2), Arterial O2partialpressure(PaO2), Arterial oxygen saturation (SaO2) and Blood bicarbonate (HCO3).Furthermore, the duration of surgery, surgical success rate, complications and bloodloss volume of each group should be recorded. The animals were planned to beexecuted two days after surgery. Ptomatopsia was to examine whether there was anysurrounding organ injury, hemorrhage and bile leakage, abscess and peritonitis andperitoneal adhesion.Results:1. All the experimental animals that were brought into the statistical standardwere successfully operated NOTES or LC. There was no severe complication foundduring or after the surgery.2. Though the duration of surgery in NOTES Group was longer than LC Group(85.5±14.5min vs61.8±7.2min), the difference was statistically significant(P <0.05),there was no significant difference of the circulatory indexes (HR, ASBP, ADBP,MAP and CVP) and the respiratory indexes (PaO2、SaO2and HCO3) between thetwo surgery groups(P>0.05). Moreover, there were significant differences of pH andPaCO2between the two groups (P <0.05), that LC Group showed slight respiratoryacidosis, but the indexes of NOTES Group in different time phases of the wholeprocess were steadier than LC Group. In the meantime under effective artificialmonitoring, the intratracheal pressures between the two groups were relatively steady.3. The experimental animals were restored to drink and eat one day aftersurgery, which survived well and no bad consequence was found. There was nocomplication found as surrounding organ injury, hemorrhage and bile leakage,abscess and peritonitis in autopsy. There was no significant difference of average marks of abdominal adhesion between NOTES Group and LC Group (P>0.05).Pelvic adhesion was not observed in either group, abdominal adhesions were mainlyfound at the closed stoma on anterior gastric wall in NOTES Group as well as thesurrounding region of gallbladder bed in LC Group.Conclusion:1. A brand new cholecystectomy animal (rabbit) model of NOTES is built.2. There was no significant difference of the introoperative influence onorganism stability of circulatory function between the transgastric natural orificetransluminal endoscopic cholecystectomy under air pneumoperitoneum andlaparoscopic cholecystectomy under carbon dioxide pneumoperitoneum. Additionally,the stability of NOTES Group was better than LC Group. It is supposed that in a shortmoment under air pneumoperitoneum, NOTES, whose invasion was less thanlaparoscopic surgery.3. The safety of surgery could be enhanced by necessary assistant laparoscopein order to make up current insufficiency of flexible endoscope.