Renal consequences of intraabdominal hypertension in a porcine model. Search for the choice indirect technique for intraabdominal pressure measurement.

OBJECTIVE: To study the effects on the renal system in a porcine model of intraabdominal hypertension, and to determine the indirect technique of choice for determination of the intraabdominal pressure.
MATERIAL AND METHODS: 30 pigs were used divided in two groups according with increased intraabdominal pressure values (20 mmHg and 30 mmHg). In both groups pressures were registered 8 times, summing up to 3 hours, with a CO₂ insufflator. Three different measures of the intraabdominal pressure were taken: a direct transperitoneal measure, using a catheter of Jackson-Pratt connected to a pressure transducer, and two indirect measures, a transvesical by means of a Foley to manometer system, and a transgastric by introducing in the stomach a catheter connected to a pressure monitor with electronic hardware. Mean arterial pressure was calculated, along with the cardiac index, production of urine and serum creatinine.
RESULTS: There was a greater correlation between the transvesical and the transperitoneal intraabdominal pressures (R(2)=0,95). Average transgastric intraabdominal pressure was inferior to the transperitoneal indicator in all taken measurements. The average arterial pressure descended in both groups, with earlier significant differences observed at 30 mmHg (p<0,020). Urine production was lower at 30 mmHg compared with the 20 mmHg group (9,63 ± 1,57 versus 3.26 ml ± 1,73). Serum creatinine increased in both groups being pathological at 30 mmHg after 1h 20 min, with existing differences between early pressures (p<0,027).
CONCLUSIONS: This study revealed marked renal affectation with higher severity at 30 mmHg pressures. The transvesical technique showed a greater correlation with the direct measurement technique used, defining this as the method of choice for determination of intraabdominal pressure.