Effects of hyperoxia on bacterial translocation and mortality during gut-derived sepsis

R. Gennari and J. W. Alexander
Department of Surgery, University of Cincinnati Medical Center, Ohio, USA.

BACKGROUND: While hyperoxia is commonly used for treating carbon monoxide poisoning, chronic nonhealing ulcers, acute traumatic and chronically ischemic wounds, and refractory osteomyelitis, its efficacy is unproven in numerous clinical situations, including treatment during severe sepsis. OBJECTIVE: To test the effects of hyperoxia on bacterial translocation and mortality during gut-derived sepsis in a clinically relevant model of infection. METHODS: Balb/c mice were gavaged with 10(9) Escherichia coli and subjected to a 20% burn injury. Then, the animals were randomized to receive hyperoxia for different periods of time. Survival and the extent of translocation were determined, as well as intestinal histologic features. RESULTS: Hyperoxia treatment preserved gut morphology and improved gut barrier function, decreasing the amount of bacterial translocation. Short-term (4- or 8-hour) hyperoxia (100% oxygen) treatment improved survival only on day 1 after injury but did not affect the final outcome. Short-term (8-hour) hyperoxia (100% oxygen) plus 5-day 40% oxygen environment significantly improved long-term survival. CONCLUSION: Tissue pO2 may be an important regulator of gut barrier function. Hyperoxia treatment appears to play a major role in preserving gut barrier function.