title: Gastric transmural pressure measurements in vivo: implications for natural orifice transluminal endoscopic surgery (NOTES).
abstract: BACKGROUND
  The success of natural orifice surgery depends on a reliable, secure closure of the opening in the gut. Forces that might be exerted on the gastric wall to disrupt closure have not been measured in humans or animals.
  
  
  OBJECTIVE
  To determine how transmural gastric pressure gradients vary under different experimental conditions.
  
  
  METHODS
  In vivo porcine model.
  
  
  METHODS
  Animal laboratory.
  
  
  METHODS
  Eleven laboratory pigs.
  
  
  METHODS
  Pressure transducers were placed in the abdomen and stomachs of the test animals. Simultaneous pressure measurements were obtained to determine the stresses applied to the gastric wall during various maneuvers.
  
  
  METHODS
  Continuous intra-abdominal and intragastric pressures in vivo. Transgastric pressure gradients (DeltaP) were computed in real time by subtracting gastric pressure from abdominal pressure.
  
  
  RESULTS
  In all cases, the measured gastric pressures were nearly identical to those measured in the abdominal cavity because the stomach is entirely contained within the abdomen. The transmural gastric pressure gradients were near zero during a variety of experimental conditions.
  
  
  CONCLUSIONS
  Anesthetized animal model, not engaged in usual activities. Relatively low pressures generated during a cough sequence and a Valsalva maneuver compared with reported values in the literature.
  
  
  CONCLUSIONS
  Estimates of gastric pressures that must be tolerated by gastric closure devices after natural orifice transluminal endoscopic surgery procedures have been greatly overestimated. Absolute gastric pressure is counteracted by external (intra-abdominal) pressure such that the net transmural gastric pressure gradient remains near zero under a variety of conditions.
authors.affiliation: Division of Gastroenterology, Department of Medicine, Tufts University School of Medicine, Baystate Medical Center, Springfield, Massachusetts 01199, USA. david.desilets@bhs.org
authors.forename: David J
authors.initials: DJ
authors.lastname: Desilets
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Mader
authors.forename: John R
authors.initials: JR
authors.lastname: Romanelli
authors.forename: David B
authors.initials: DB
authors.lastname: Earle
mesh_terms: D034861:Abdominal Wall / Q000503:physiopathology; D000818:Animals; D016099:Endoscopy, Gastrointestinal / Q000379:methods*; D011312:Pressure; D013270:Stomach / Q000601:surgery*; D013552:Swine; D014159:Transducers