[Intra-abdominal hypertension: effects on the splanchnic circulation. Preliminary study in a model of ascites]

Intra-abdominal hypertension is defined as a rise in intra-abdominal pressure leading to progressive dysfunction of the abdominal organs.

To evaluate the effects of intra-abdominal hypertension on the splanchnic circulation in a porcine animal model with a view to determining the diagnostic method of choice.

A total of 10 swine were divided into 2 groups: a control group and a group with an ascites pressure of 20mmHg. Transvesical and transperitoneal intra-abdominal pressures were registered, and the correlation between the measurements obtained was determined. Concentrations of lactic acid, alanine aminotransferase, glucose and gastric mucosal pH were also obtained. We registered the mean arterial and abdominal perfusion pressures, and the correlation of the latter with gastric mucosal pH and lactic acid concentrations. The parameters were registered for a total of 3hours.

We observed a high correlation between transvesical and transperitoneal measurements of intra-abdominal pressure (R(2)=0.98). In the 20mmHg pressure group, lactic acid concentrations increased significantly at 180min (p<0.011). Gastric mucosal pH differed significantly between the 2 groups from the beginning of the study (p=0.004) and significantly decreased from 120min onward. Mean arterial and abdominal perfusion pressures gradually decreased during the trial, with early significant changes in the abdominal perfusion pressure (p=0.001), and a good correlation with the remaining study parameters. There were no significant changes in hepatic indicators.

We believe the transvesical approach to be the technique of choice to determine intra-abdominal pressure. Abdominal perfusion pressure is a sensitive marker of intra-abdominal hypertension, and gastric mucosal pH is the first parameter to be affected.