title: Tonometry as a predictor of inadequate splanchnic perfusion in an intra-abdominal hypertension animal model.
abstract: BACKGROUND
  The gastrointestinal system is the most sensitive to the presence of intra-abdominal hypertension. We aimed to assess the early prognostic value of gastric air tonometry as a predictor of inadequate splanchnic perfusion and determine its relation with abdominal perfusion pressure (APP).
  
  
  METHODS
  Twenty-five Large White swine were used for this study. A control group and two study groups were included, in which intra-abdominal pressure (IAP) was elevated with Co2 to 20 and 30 mmHg during 5 h. We measured the intramucosal gastric pH (pHim) and determined gastric luminal PCO2 (PgCO2) and PgCO2gap (gastric luminal CO2-arterial CO2) to evaluate gastric acidity. APP was indirectly obtained through IAP and mean arterial pressure. Additionally, histopathologic samples of small intestine were obtained and analyzed.
  
  
  RESULTS
  pHim showed a decrease in IAP groups, with statistical significance in the 30 mmHg group, 90 min after stabilization period (P < 0.01). Serum lactate showed delayed alteration when compared with pHim, with significant increase, 180 min after stabilization (P < 0.05). The values of PgCO2 and PCO2gap were increased in IAP groups, being statistically significant in the 30 mmHg group, 120 and 150 min, respectively, after stabilization. In increased IAP groups, there was a time progressive decrease of APP, with statistically significant differences observed between groups at 20 min (P < 0.001). The histopathology study revealed parenchymal injury of the intestine at 30 mmHg.
  
  
  CONCLUSIONS
  Tonometry is sensitive to the increase in IAP and relates to the reduction of APP generated by splanchnic hypoperfusion.
authors.affiliation: Department of Laparoscopy, Jesús Usón Minimally Invasive Surgery Center (JUMISC), Cáceres, Spain. Electronic address: lcorreaccmijesususon@gmail.com.
authors.forename: Laura
authors.initials: L
authors.lastname: Correa-Martín
authors.forename: Gregorio
authors.initials: G
authors.lastname: Castellanos
authors.forename: Mónica
authors.initials: M
authors.lastname: García-Lindo
authors.forename: Idoia
authors.initials: I
authors.lastname: Díaz-Güemes
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Sánchez-Margallo
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D007421:Intestine, Small / Q000098:blood supply / Q000473:pathology; D059325:Intra-Abdominal Hypertension / Q000175:diagnosis* / Q000503:physiopathology*; D008365:Manometry / Q000379:methods*; D011237:Predictive Value of Tests; D013152:Splanchnic Circulation / Q000502:physiology*; D013552:Swine
keywords: Abdominal compartment syndrome; Histologic examination; Intraabdominal hypertension; Porcine model; Tonometry