Oxygen uptake during peritoneal ventilation in a porcine model of hypoxemia

Objectives: Peritoneal ventilation (PV) can greatly increase PaO₂ in hypoxemic rabbits. We tested the hypothesis that the peritoneum can provide a gas exchange surface for oxygen uptake in larger animals that, like humans, have a smaller relative peritoneal surface area and corresponding blood flow. Design: Prospective, randomized, controlled animal study. Setting: University research laboratory. Interventions: In six anesthetized pigs, a modified endotracheal tube (9.0-inner diameter) was inserted into the peritoneal cavity, and the peritoneal cavity was ventilated with oxygen in helium in gas phase. Measurements of peritoneal oxygen uptake and mixed venous oxygen saturation were made over 30 mins of: a) baseline FIO₂% 0.20, no PV; b) FIO₂ 0.20, PV; c) FIO₂ 0.20, PV, dopamine 5 μg/kg/min; d) baseline FIO₂ 0.15, no PV; e) FIO₂ 0.15, PV; and f) FIO₂ 0.15, PV, dopamine 5 μg/kg/min. Measurements and Main Results: Mixed venous oxygen saturation was 61% at the baseline FIO₂ of 0.20 and 33% at an FIO₂ of 0.15 and did not increase significantly from baseline with PV or with dopamine at either FIO₂. Peritoneal oxygen uptake, measured with a waterseal spirometer, was 9.1 ±3.1 (SD) and 11.9 ± 3.0 mL/min when lung FIO₂ was 0.20 and 0.15, respectively, and 9.7 ± 2.8 and 12.2 ± 2.7 mL/min when FIO₂ was 0.20 and 0.15 and dopamine was infused, respectively. Conclusion: Peritoneal ventilation does not result in clinically significant oxygen uptake or alter mixed venous oxygen saturation in a porcine model of hypoxemia.