Evaluating intra-abdominal pressures in a porcine model of acute lung injury by using a wireless motility capsule.

BACKGROUND: Intra-vesical pressure measurement as the reference standard for assessing intra-abdominal pressures is mainly indirect and discontinuous. We therefore evaluated a motility capsule for continuous intra-abdominal pressure measurement in an animal model with a high probability for capillary leakage and intestinal edema. MATERIAL/METHODS: Motility capsules were inserted into the stomachs of 8 anesthetized and ventilated pigs. Stomach pH, pressure, and temperature data were wirelessly transmitted to a recorder attached to each animal's abdomen. Intra-gastric pressures measured by the capsule were compared to intra-vesical pressures measured by a pressure transducer system. RESULTS: The intra-abdominal pressures ranged from 3 to 15 mmHg (7.8 ± 2.4 mmHg [mean ± SD]) measured via the bladder. The capsule pressure recordings ranged from 1 to 3 mmHg (1.7 ± 0.5 mmHg [mean ± SD]). Bland-Altman analysis revealed an unacceptable bias between the 2 methods. The test bias was 6.2 (± 1.4) mmHg and the limits of agreement were from 3.3 to 8.9 mmHg. CONCLUSIONS: Pressures in the stomach as measured by motility capsule underestimated the intra-vesical pressures. Discrepancies between gastric and intra-vesical pressures could be caused by gastric dilatation or different position of the 2 devices to the zero reference point.

Gastric pH and motility in a porcine model of acute lung injury using a wireless motility capsule.

BACKGROUND: Evaluation of gastric pH and motility in a porcine model of acute lung injury using a novel, wireless motility capsule. MATERIAL/METHODS: A motility capsule was applied into the stomach of 7 Pietrain pigs with acute lung injury induced by high volume saline lavage. Wireless transmission of pH, pressure and temperature data was performed by a recorder attached to the animal's abdomen. Gastric motility was evaluated using pH and pressure values, and capsule location was confirmed by autopsy. RESULTS: Gastric pH values were statistically significantly different (P<0.003) in the animals over time and ranged from 1.15 to 9.94 [5.73 ± 0.47 (mean ± SD)] with an interquartile range of 0.11 to 2.07. The capsule pressure recordings ranged from 2 to 4 mmHg [2.6 ± 0.5 mmHg (mean ± SD)]. There was no change in pressure patterns or sudden rise of pH >3 pH units during 24 hours. All animals had a gastroparesis with the capsules located in the stomach as indicated by the pressure and pH data and confirmed by necropsy. CONCLUSIONS: The preliminary data show that Pietrain pigs with acute lung injury have a high variability in gastric pH and severely disturbed gastric motility.