Supplemental systemic oxygen support with peritoneal oxygenation using a continuous low-pressure oxygen flow system (PEROX)

Background

In a continuous peritoneal oxygen flow model, we studied its influence on hemodynamic stability, arterial and mixed venous gases, comparing its effects in normal and in oleic-acid-induced ARDS lungs.

Methods

Four pigs were anesthetized, mechanically ventilated and invasively monitored with a Swan-Ganz and femoral catheter. A continuous infusion of dobutamine (2 μ g/kg/hour) was maintained. Arterial pressure, cardiac output, pulmonary compliance, PCWP, and arterial and mixed venous gases were measured every hour. Baseline measures were taken and three laparoscopic trochars were introduced in the abdomen. A continuous oxygen flow of 5–6 l/min was maintained for 8 hours with a sustained intra-abdominal pressure of 5–6 mmHg using a continuous low-pressure flow system (PEROX). At the fifth hour an oleic acid (OA) dose (0.2 mg/kg) was injected into the pulmonary circulation. Afterwards, lungs were histopathologically studied to evaluate the presence of ARDS. A two-way ANOVA with replication was used for the sequential analysis of data.

Results

PEROX demonstrated efficiency to maintain normal oxygenation indexes even though the presence of ARDS after the injection of OA was confirmed with a histopathological study and a significant difference in the pulmonary compliance (P = 0.032). This is evident because no statistical difference was observed in oxygen indexes and variables during the 4 hours posterior to the injection of OA (Fig. 1).

Figure 1

Oxygen indexes and values before and after lung injury with oleic acid.

Conclusion

This experimental model demonstrated that peritoneal oxygenation could be an effective gas interchange-supporting alternative in ARDS. The mechanism of action could be an increase of the mixed venous oxygenation.