Hyperoxia during one lung ventilation: Inflammatory and oxidative responses

Background It is common practice during one lung ventilation (OLV) to use 100% oxygen, although this may cause hyperoxia- and oxidative stress-related lung injury. We hypothesized that lower oxygen (FiO2) during OLV will result in less inflammatory and oxidative lung injury and improved lung function. Methods Twenty pigs (8.88?+/-?0.84?kg; 38?+/-?4.6 days) were assigned to either the hyperoxia group (n?=?10; FiO2?=?100%) or the normoxia group (n?=?10; FiO2?<?50%). Both groups were subjected to 3?hr of OLV. Blood samples were tested for pro-inflammatory cytokines and lung tissue was tested for these cytokines and oxidative biomarkers. Results There were no differences between groups for partial pressure of CO2, tidal volume, end-tidal CO2, plasma cytokines, or respiratory compliance. Total respiratory resistance was greater in the hyperoxia group (P?=?0.02). There were higher levels of TNF-a, IL-1 beta, and IL-6 in the lung homogenates of the hyperoxia group than in the normoxia group (P?=?0.01, 0.001, and 0.001, respectively). Myeloperoxidase and protein carbonyls (PC) were higher (P?=?0.03 and P?=?0.01, respectively) and superoxide dismutase (SOD) was lower in the lung homogenates of the hyperoxia group (P?=?0.001). Conclusion Higher myeloperoxidase, PC, and cytokine levels, and lower SOD availability indicate a greater degree of injury in the lungs of the hyperoxia animals, possibly from using 100% oxygen. In this translational study using a pig model, FiO2?=?50% during OLV reduced hyperoxic injury and improved function in the lungs. Pediatr Pulmonol. 2012. 47:979986. (c) 2012 Wiley Periodicals, Inc.