Differential detection of plasma hydroperoxides in sepsis

OBJECTIVE:To determine whether plasma lipid hydroperoxides may be a useful marker for sepsis. DESIGN:Exploratory, open-labeled study. SETTING:Critical care unit at a university medical center. PATIENTS:Twelve patients with sepsis syndrome requiring hemodynamic monitoring with pulmonary artery catheters. Seven patients were diagnosed with pulmonary infections and five patients had intra-abdominal infections. INTERVENTIONS:Fatty acid hydroperoxide was measured in the fresh arterial plasma (radial artery) and mixed venous plasma (pulmonary artery) from each patient. Hydroperoxide was determined using a sensitive assay based on activating the cyclooxygenase reaction of prostaglandin H synthase. MEASUREMENTS AND MAIN RESULTS:The mean difference between the amount of fatty acid hydroperoxide measured in the plasma draining involved regions (arterial plasma for pulmonary sepsis, mixed venous plasma for intra-abdominal sepsis) compared with the paired, uninvolved regions was 0.45 ± 0.14 μM (mean ± SEM; p < .005). CONCLUSIONS:Increased lipid hydroperoxides in blood-draining septic foci are markers of oxyradical release associated with severe infection, although they are not specific for infectious conditions, being released also from nonseptic regions of surgical trauma. Assays for hydroperoxides may be useful when relatively free of other tissue trauma.