Background: To study the effects of oxygen supplementation on the metabolic and anaerobic changes caused by tourniquet application in limb surgeries using blood gas analysis. Methodology: This study was conducted with 60 adult patients in the 18–65 age group of ASA physical status I and II undergoing limb surgeries using tourniquet are randomly assigned to one of two groups 1 and 2 containing 30 patients each. Group 1: 30 patients received nasal oxygen 3 l/min after tourniquet application. Group 2: 30 patients received preoxygenation for 5 min before tournquiet in addition to 3 l/min nasal oxygen during tourniquet. Arterial blood samples are collected before and 3 min after tourniquet respectively and analyzed forblood gases and lactate levels. Results: Patients who received preoxygenation showed reduced metabolites and reduced serum lactate when compared to the group which was not preoxygenated. This difference in serum lactate was found to be statistically significant (p-value < 0.0001). Similarly the ph of the group which was preoxygenated within the normal limit while the group not preoxygenated shown acidotic pH, the difference in p was also found to be statistically signicant (p-value < 0.0001). Conclusion: The effect of oxygen supplementation in reducing the anaerobic metabolism was studied in patients Undergoing limb surgeries using tourniquet. It was foundthat the patients who received preoxygenation showed reduced serum Lactate levels and normal pH when compared to those who were not preoxygenated. Hence it is concluded that preoxygenation reduces anaerobic metabolism in surgeries done under tourniquet.

Keywords: Tourniquet; Blood gas analysis; Lactate Levels; Oxygenation.