Objectives: Tonometry is widely used in the diagnosis of sepsis and splanchnic ischemia. This study was devised to analyze the predictive value of gastric tonometry for outcome of experimental viscus perforation-induced peritonitis. The impact of conventional and laparoscopic intervention on tonometric measurements was the main scope.
Methods: This randomized controlled intervention trial was performed in a University experimental laboratory, using 24 female Duroc pigs. Pigs were subjected to gastric perforation followed by a 12 h interval of peritonitis, and then to either laparoscopic or conventional surgical repair of the defect with peritoneal lavage. Gastric tonometry and cardiocirculatory monitoring were performed.
Results: Septic shock associated with peritonitis and subsequent lethal outcome was accurately predicted with gastric tonometry. Changes of gastric mucosal pH correlated significantly with decreases of MAP (r2=0.880; P<0.001) and SVR (r2=0.678; P<0.001), increase of QT (r2=0.486; P=0.013), and mortality (r=0.752; P<0.001). Mortality was significantly higher in laparoscopically treated animals compared to those subjected to the open procedure (78% vs 22%; P<0.045).
Conclusions: Gastric tonometry accurately predicted mortality in experimental peritonitis. The decline of gastric mucosal pH in the laparoscopic group was more than double that of to conventionally treated animals. This finding not only reflected the increase of systemic CO2 due to higher absorption during CO2-pneumoperitoneum, but probably also indicated a more severe form of splanchnic ischemia during laparoscopic surgery. Even though tonometry can be used to accurately predict mortality and separate the high risk group, extreme caution should be applied under conditions associated with severe peritonitis.