Intraperitoneal microdialysis for detection of splanchnic metabolic disorders

Due to its high oxygen demand the gastrointestinal tract is very susceptible to hypoxia or ischemia, which may result in local and systemic dysfunction. Early detection of any profound disorders (e.g., after abdominal surgery) remains an important target for the surgeon. This study investigates whether in vivo microdialysis monitoring of the intraperitoneal space adequately reflects hypoxic conditions.

Hypoxic hypoxia by ventilation was induced in 14 rats under general anesthesia with FIO(2) of 0.1 (40 min) followed by reoxygenation with FIO(2) of 0.21. Hemodynamic and blood gas monitoring including blood lactate was performed. Microdialysis catheters were placed in the peritoneal cavity, and lactate, pyruvate, and glycerol were measured out of the ascites.

A significant decrease in mean arterial pressure and increase in blood lactate level during the hypoxic period was observed. Hypoxia induced an immediate and significant elevation in the intraperitoneal lactate/pyruvate ratio to 446+/-137% of the baseline values, and glycerol subsequently increased during reoxygenation to 389+/-109%. Values for the blood compartment showed less profound or no significant differences.

Biochemical monitoring of the intraperitoneal space by in vivo microdialysis, such as after laparatomy can measure metabolic changes in the gastrointestinal tract produced by hypoxia/ischemia. The surgeon may thus detect postoperative complications at an earlier stage than with routine monitoring devices.