Colonic Anastomotic Leak Model in Swine.

INTRODUCTION: Anastomotic leaks (ALs) are serious postoperative complications. Current experimental studies designed to investigate leaks are based on acute intraoperative dehiscence of the anastomosis. Clinically, however, AL usually happens later in the postoperative course. Presented here is a clinically relevant colonic AL model in swine. METHODS: Seventeen Yorkshire pigs were divided into 2 groups: the control group (n = 6) and the experimental group (n = 11). An enterotomy was performed on the descending colon and an end-to-end handsewn anastomosis was created in the groups. The proximal and distal ends of the suture were exteriorized and tied to a plastic tube. Subsequently, the suture was cut and pulled to induce breakdown of the anastomosis in the experimental group 3-4 h postoperatively. Study endpoints included behavioral changes, clinical assessment, laboratory indicators, and macroscopic indicators of leakage. RESULTS: Leaks were successfully created in 8/11 of the experimental group animals and confirmed through exploratory relaparotomy. Seven of the experimental pigs showed complete anastomotic breakdown and one showed partial rupture. Fecal peritonitis and enteric spillage were observed macroscopically within the abdomen of the experimental pigs, confirming the presence of a leak. The remaining (3/11) experimental pigs did not experience those findings due to either a tamponade/containment by the abdominal wall or surrounding organs. Statistical significance (p < 0.05) was achieved between the experimental and control cohorts for laboratory and clinical indicators including fever, leukocytosis, and decreased blood potassium. CONCLUSION: This animal model generated postoperative induced leak in approximately three-quarters (8/11) of experimental pigs, allowing control over the time of leak onset to simulate clinical settings.

Continuous pH monitoring using a sensor for the early detection of anastomotic leaks.

Anastomotic leaks (AL) and staple line leaks are a serious post-operative complication that can develop following bariatric surgery. The delay in the onset of symptoms following a leak usually results in reactive diagnostics and treatment, leading to increased patient morbidity and mortality, and a clinical and economic burden on both the patient and the hospital. Despite support in literature for pH as a biomarker for early detection of AL, the current methods of pH detection require significant clinician involvement and resources. Presented here is a polyaniline (PANI)-based pH sensor that can be connected inline to surgical drains to continuously monitor peritoneal secretion in real time for homeostatic changes in pH. During this study, the baseline peritoneal fluid pH was measured in two pigs using the PANI sensor and verified using a benchtop pH probe. The PANI sensor was then utilized to continuously monitor the changes in the pH of peritoneal effluent, as a gastric leak was simulated. The inline sensors were able to detect the resulting local changes in drainage pH within 10 min of leak induction. The successful implementation of this sensor in clinical practice can both enable high efficiency continuous monitoring of patient status and drastically decrease the time required to detect AL, thus potentially decreasing the clinical and economic burden incurred by gastric leaks.