Reactive oxygen species are associated with tissue inflammation and injury. Our laboratory has demonstrated that ethane, a stable product of lipid peroxidation, in exhaled breath can be used to measure total body oxidative stress. Herein patients were studied who underwent outpatient surgery, laproscopic bilateral tubal ligation (BTL, n = 10) and anterior cruciate ligament (ACL, n = 10) repair of the knee. These surgical procedures were expected to involve mild degrees of ischemia and reperfusion. In each of these cases propofol, an intravenous anesthetic with antioxidant properties, was used. Breath ethane was measured as a biomarker of oxidative stress that occurred at reperfusion of ischemic tissue. Data were analyzed by one-way analysis of variance. Clinically relevant concentrations of propofol were unable to completely block the increase in oxidative stress following reperfusion in either of these minor surgeries. Breath ethane increased significantly after reperfusion in both the BTL (p = 0.03) and the ACL (p = 0.005) patients. Also, the increase in oxidative stress was related to the time of ischemia.