Measurements of intraperitoneal pressure and the development of a feedback control valve for regulating pressure during flexible transgastric surgery (NOTES)

Background: High intraabdominal pressures during laparoscopy (greater than 15 mm Hg) are dangerous. Pressures developed during translumenal endosurgery when using flexible endoscopes without feed-back regulation are unknown. Objective: To measure and control intraabdominal pressures during transgastric endosurgery. Design: In a blinded study, intraabdominal pressures during unregulated transgastric cholecystectomy and tubal ligation were measured by using Veress needles in 5 pigs (group 1). The accessory channel valve of a double-channel gastroscope was modified to allow measurement and control of intraabdominal pressures with a laparoscopic insufflator. This was tested prospectively in another blinded study in 5 pigs (group 2) that underwent identical procedures to those in group 1, with independent Veress needle pressure measurements. Setting: This ethically approved study was performed in an experimental surgical operating theater. Interventions: Transgastric cholecystectomy (n = 4) and tubal resection (n = 6). Main Outcome Measures: Intraabdominal pressure measurements during transgastric endosurgery, with and without feed-back control. Results: The mean (standard deviation) number of pressure measurements per procedure greater than 20 mm Hg was 11 +/- 1.41 in group 1 and 0 +/- 0 in group 2 (P < .05). Most episodes of high pressure were undetected by the endoscopist, who was blinded to the pressure measurements. Conclusions: Unacceptably high intraabdominal pressures were common during translumenal endosurgical procedures. Feedback pressure regulation through a modified valve prevented overinflation.