Erik Clary

Safety and efficacy of India ink and indocyanine green as colonic tattooing agents

BACKGROUND Controversy exists concerning the safety and efficacy of colonic tattooing for the intraoperative identification of polypectomy sites. The purpose of this study was to determine (1) the concentrations of India ink and indocyanine green that resulted in high-visibility tattoos without significant tissue inflammation and (2) the India ink injection volume that produces best visibility at colonoscopy, laparoscopy, and laparotomy. METHODS Twenty-two New Zealand white rabbits (2 kg) were anesthetized and injected with India ink (undiluted 1:10, 1:50, 1:100, 1:1000, 1:10,000) and indocyanine green as an undiluted, concentrated formulation (25 mL/2 mL solvent) or in a diluted form (25 mg/5 mL solvent) at various concentrations (1:10, 1:50, 1:100). Tuberculin syringes were used to create a 0.1 mL serosal bleb at two injection sites 2 cm apart. Laparotomy was repeated at days 1, 3, and 7 after injection. Additionally, 16 rabbits were injected with India ink at laparotomy and re-explored at 1 and 5 months. Twelve mongrel dogs (20 kg) were injected with 1.0 mL volumes. Re-exploration by colonoscopy, laparoscopy, and laparotomy was done at 7 days and 1 month. Tattoo visibility at re-exploration in both animal models was graded on a scale (0 = agent not seen, 1 = seen with difficulty, 2 = easily seen). Histology in the rabbit was judged by degrees of inflammation (0 = no inflammation, 2 = mild inflammation, 4 = moderate inflammation, 6 = severe inflammation). RESULTS The concentrated indocyanine green solution was easily visible only on day 1 in the rabbit. Injections of both concentrated and diluted indocyanine green caused mucosal ulceration and moderate to severe inflammation. India ink studied at 7 days, 1 month, and 5 months after injection in the rabbit model was visible at all concentrations. The undiluted and 1:10 concentrations were easily seen and showed evidence of mucosal ulceration. Tattoos produced with all other India ink concentrations were visible without gross inflammation. India ink was also studied at 7 days and 1 month in dogs. The tattoo with the 1:100 concentration at 0.5 mL was seen consistently at colonoscopy, laparoscopy, and laparotomy with only a mild submucosal reaction at 7 days. The tattoos produced with the 1:100 and 1:1000 concentrations at 0.5 mL and 1.0 mL injection volumes were easily seen by all methods of intraabdominal visualization at 1 month with similar histology. CONCLUSION Indocyanine green was an ineffective colonic tattooing agent. India ink was an effective colonic tattooing agent. Dilute concentrations that caused little to no inflammation could be visualized at 7 days and 1 month in rabbits and dogs and at 5 months in rabbits. India ink, at appropriated concentrations, appears to be a safe short- and long-term colonic tattooing agent.

Intraperitoneal immunity and pneumoperitoneum

AbstractBackground: Carbon dioxide (CO2) pneumoperitoneum has been implicated as a possible factor in depressed intraperitoneal immunity. Using in vitro functional assays, CO2 has been shown to decrease the function of peritoneal macrophages harvested from insufflated mice. However, an effective in vivo assessment is lacking. Listeria monocytogenes (LM), an intracellular pathogen, has served as a well-established in vivo model to study cell-mediated immune responses in mice. This study examines the immune competence of mice based on their ability to clear intraperitoneally administered LM following CO2 vs helium (He) insufflation. Methods: Eighty-five mice (C57Bl/6, males, 4–6 weeks old) were divided between the following four treatment groups: CO2 insufflation, He insufflation, abdominal laparotomy (Lap), and control (anesthesia only). Immediately postoperatively, each group was inoculated percutaneously and intraperitoneally with a sublethal dose (.015 × 106 org) of virulent LM (EGD strain). Half of the animals were killed on postoperative day 3 and half on day 5. Spleens and livers (sites of bacterial predilection) were harvested, homogenized, and plated on TSB agar. The amount of bacteria (1 × 106LM/spleen and liver) from each group was then compared. Statistical significance was set at p≤ 0.05. Results: Control animals had nominal bacteria on day 3 (0.016 × 106LM/spleen and liver), and the bacterial burden remained low at day 5 (0.038 × 106LM/spleen and liver) postchallenge. On day 3, the bacterial burden was significantly higher in the CO2 group (5.46 × 106LM/spleen and liver) as compared to He (0.093 × 106LM/spleen and liver) and controls. The Lap group (3.44 × 106LM/spleen and liver) had significantly more bacteria than the controls. There were no significant differences between any of the groups on day 5. Conclusions: In this animal model, CO2 pneumoperitoneum impaired cell-mediated intraperitoneal immunity significantly more than He pneumoperitoneum and controls on day 3. Also on day 3, laparotomy caused impairment of intraperitoneal immunity when compared to controls. Finally, intraperitoneal immunosuppression resolved by day 5.

Laparoscopic Nissen fundoplication for treating reflux in lung transplant recipients

Gastroesophageal reflux disease may contribute to pulmonary injury and the development of bronchiolitis obliterans syndrome in lung transplant patients. As a result, such individuals are increasingly likely to undergo corrective gastrointestinal surgery. The present study collected outcome data for 28 lung transplant patients with documented reflux who underwent an uncomplicated laparoscopic Nissen fundoplication at our institution. The results were compared to data from 63 nontransplant reflux patients who had undergone the procedure over the same time period. All Nissen fundoplications were conducted by the same surgeon. There were no intraoperative or perioperative deaths in either patient group. Operative parameters did not differ but the postoperative hospital stay was significantly greater for the lung transplant patients (P < 0.05). Seven transplant patients (25%) were readmitted within 30 days compared to two readmissions (3.2%) in the reflux group. Five transplant patients (17.9%) have died, all from pulmonary complications; on average, death occurred 15.5 months after the Nissen surgery. There have been no deaths in the reflux group. These data indicate that laparoscopic Nissen fundoplication can be performed on lung transplant recipients to treat reflux. The average hospital stay is longer and there are more frequent readmissions in this population, but this does not appear to be due to any Nissen-related morbidity.

Endoscopic components separation for abdominal compartment syndrome

BACKGROUND Sustained intraabdominal pressures of 14 to 20 mm Hg have significant pathophysiological consequences, but there is currently no satisfactory low-morbidity procedure appropriate for intervention early in the disease process of abdominal compartment syndrome (ACS). The anatomical principles of abdominal wall components separation were used to develop a percutaneous procedure that increased abdominal capacity and decreased abdominal pressure. METHODS Using a porcine model, we determined abdominal capacity changes by helium insufflation. Corn oil was then used to create an episode of sustained intraabdominal hypertension and changes in intraabdominal pressure and intestinal mucosal oxygenation were determined. RESULTS Endoscopic abdominal wall components separation (EACS) increased abdominal capacity by 1 L (from 0.89 +/- 0.39 L to 1.95 +/- 0.48 L; P <0.001). During intraabdominal hypertension, EACS decreased abdominal pressure by 31.6% (from 15.9 +/- 2.1 to 11.0 +/- 1.5 mm Hg; P <0.001). Intestinal PO(2) was increased by 61% (18.8 +/- 11.4 to 30.3 +/- 11.7; P = 0.012) CONCLUSIONS A minimally invasive procedure (EACS) is feasible and has demonstrated effectiveness in a porcine model of ACS.

A canine model of gastroesophageal reflux disease (GERD).

Background: Although a variety of antireflux procedures and medications are used to treat gastroesophageal reflux disease (GERD), reliable large-animal models of GERD that can be used to objectively compare the efficacy of these treatments are lacking. Methods: Esophageal manometry and 24-h gastroesophageal pH monitoring with event data were performed in 18 mongrel dogs with a cervical esophagopexy. We then calculated a modified DeMeester score: The Duke Canine reflux score (DCR). Thereafter, the animals underwent a 4-cm anterior distal esophageal myotomy, incision of the left diaphragmatic crus, and intrathoracic gastric cardiopexy. Postoperative 24-h pH and manometry were obtained 2 weeks later. Results: The postoperative 24-h pH results showed a significant increase in the mean DCR score (5.9 ± 4.5 vs 84.9 ± 56.1, p < 0.0002), and manometry indicated a significant decrease in mean lower esophageal sphincter (LES) pressure (7.1 ± 2.9 vs 3.2 ± 2.5 mmHg, p < 0.0001). Conclusion: This technique reliably creates a canine model of GERD.

Videoendoscopic endotracheal intubation of the rat

Mechanical ventilation is essential to the proper maintenance of anaesthesia in research animals undergoing laparoscopic research investigations with prolonged pneumoperitoneum. Ventilatory assistance is greatly aided by endotracheal intubation, which in rats can be a challenging procedure with a substantial risk of complication. The difficulty of the procedure arises primarily from the limited exposure and access to the laryngeal opening. We describe a simple and safe technique for endotracheal intubation in the rat that permits the introduction of a large-bore tube under direct visualization using equipment commonly found in the endosurgical research setting.

Laparoscopy and the internet. A surgeon survey.

BackgroundThe Internet has become an important new tool for the delivery and acquisition of medical information.MethodsA 13-item questionnaire designed to collect information on the attitudes and practices of surgeons regarding the use of the Internet as a medical resource was posted on the World Wide Web and also sent via e-mail.ResultsOver a 2-month period, 459 surgeons were enrolled in this study. Most of the respondents were identified as male surgeons (96%) between the ages of 31 and 50 years (79.25%). They accessed the Internet mainly from their homes (67.10%) and offices (17%) using 56 Kbps (34.86%) and 33.6 Kbps (21.79%) modems. These participants indicated that they use the Internet to expand their knowledge of general surgery (78.87%), learn more about technologies related to the practice of surgery (74.51%), access the Medline medical database (73.20%), and locate other resources for academic purposes (68%). Approximately half of them said that they favored the use of robotic assist devices in the operating room (53%), and most supported the use of technology for telementoring purposes (78%). Almost 80% professed an interest in video streaming technology applied to surgical education.ConclusionsThis study showed that the Internet is a useful and powerful real-time survey tool that can help us to assess the impact of the World Wide Web and related technologies on surgical education and practice. However, the respondents in this study belong to a biased group that is already familiar with the Internet and computer technology and thus may not be representative of the surgical community as a whole.

Percutaneous cervical oesophageal cannulation in the dog for the performance of prolonged oesophageal pH and manometric studies.

Traditional methods for obtaining oesophageal access in experimental animals are unsuitable for prolonged (24 h) oesophageal pH evaluation, a procedure that is commonly employed in the assessment of human patients suspected of having gastroesophageal reflux disease. In the present study, we describe a six-year experience with a technique of percutaneous oesophagostomy for the performance of serial 24 h oesophageal pH and manometric studies involving 62 dogs and a total of 208 oesophageal cannula placement procedures. The results indicate a considerable improvement over previously described techniques with respect to simplicity of surgical technique, associated morbidity, oesophagostomy management, animal conditioning, and avoidance of chemical and excessive physical restraints in animals undergoing oesophageal pH and manometric evaluation.

Celecoxib (Celebrex) increases canine lower esophageal sphincter pressure

BACKGROUND Prostaglandins inhibit the contraction of gastrointestinal smooth muscle and may decrease lower esophageal sphincter tone. The purpose of this study was to determine whether the cyclooxygenase-2 inhibitor celecoxib (Celebrex) could increase lower esophageal pressure (without affecting gastric emptying) compared to placebo and cisapride (Prepulsid), a compound previously used to treat reflux disease. MATERIALS AND METHODS Six mongrel dogs were assigned to receive celecoxib, cisapride, and placebo using a randomized cross-over design with a 1-week washout period between treatments. Prior to dosing, each dog underwent an esophagopexy to provide access to the esophagus and stomach. On the fourth day of dosing, sphincter tone was measured in awake unsedated dogs using radial manometry. In a different set of six dogs, liquid and solid gastric emptying rates were scintigraphically determined. RESULTS Celecoxib significantly increased mean and average maximum lower esophageal pressures compared to placebo without affecting the gastric emptying rate. The magnitudes of these increases were similar to that produced by cisapride. CONCLUSIONS Celecoxib had a positive effect on canine lower esophageal sphincter tone. This finding, combined with the drugs low incidence of gastrointestinal toxicity, suggests that celecoxib may warrant consideration and investigation as a pharmacotherapy for human reflux disease.