Dual-lumen natural orifice translumenal endoscopic surgery (NOTES): a new method for performing a safe anastomosis.

BACKGROUND: Bowel anastomosis is one of the most challenging and difficult tasks to perform during natural orifice translumenal endoscopic surgery (NOTES). The difficulty is mainly due to the technical limitations of the endoscopic instruments available. Currently, endoscopic clips, T-bar sutures, or cumbersome suturing devices are used. A dual-lumen NOTES approach can facilitate bowel resection in a pig model by allowing the use of laparoscopic staplers through the rectum. METHODS: Acute studies were performed on four 40-kg pig models. The dual-lumen NOTES approach was used to perform small bowel resection and anastomosis. An endoscope was passed into the stomach and pushed through the stomach wall into the peritoneal cavity (first lumen), and a 12-mm trocar was placed through the anterior rectal wall, allowing access to the peritoneum (second lumen). Handling of the bowel, resection, and anastomosis were performed using endoscopic instruments through the gastric lumen and laparoscopic instruments through the rectal lumen. The resected small bowel then was removed through the rectum. RESULTS: Small bowel resection and anastomosis was successfully completed in all four animals using the dual-lumen NOTES approach. The laparoscopic stapler was used one more time to close the gastrotomy through the rectal port. At autopsy, intact suture lines were noted at the bowel anastomosis and at the stomach, with no evidence of leak from either site. CONCLUSIONS: Performing a sutured anastomosis in NOTES is complex and time consuming. The use of stapling devices designed for laparoscopic procedures greatly facilitates gastrointestinal tract operations in NOTES. Using both the upper and lower gastrointestinal tract as entry sites for NOTES eliminates some of the current technical limitations of these procedures.

Pulmonary gas exchange during exercise in pigs.

Increased ventilation-perfusion (VA/Q) inequality is observed in approximately 50% of humans during heavy exercise and contributes to the widening of the alveolar-arterial O2 difference (A-aDO2). Despite extensive investigation, the cause remains unknown. As a first step to more direct examination of this problem, we developed an animal model. Eight Yucatan miniswine were studied at rest and during treadmill exercise at approximately 30, 50, and 85% of maximal O2 consumption (VO2 max). Multiple inert-gas, blood-gas, and metabolic data were obtained. The A-aDO2 increased from 0 +/- 3 (SE) Torr at rest to 14 +/- 2 Torr during the heaviest exercise level, but arterial PO2 (PaO2) remained at resting levels during exercise. There was normal VA/Q inequality [log SD of the perfusion distribution (log) = 0.42 +/- 0.04] at rest, and moderate increases (log = 0.68 +/- 0.04, P < 0.0001) were observed with exercise. This result was reproducible on a separate day. The VA/Q inequality changes are similar to those reported in highly trained humans. However, in swine, unlike in humans, there was no inert gas evidence for pulmonary end-capillary diffusion limitation during heavy exercise; there was no systematic difference in the measured PaO2 and the PaO2 as predicted from the inert gases. These data suggest that the pig animal model is well suited for studying the mechanism of exercise-induced VA/Q inequality.