Analysis of oxygen and carbondioxide under artificial respiration in rats and mouse

The provision and control of ventilation in artificial respiration is of special importance. The application of artificial respiration as well as the difficulty in measurements of respiratory gases is profound in small laboratory animals. The purpose of this study is to develop an artificial respiratory valve and mechanical artificial respiratory apparatus for measuring experimental "indirect calorimetry? in laboratory animals.Wistar rats and BALB-c mice were used throughout the experiments. Following urethane anesthesia application and surgical tracheotomy was done, and artificial respiration with room air was applied under general anesthesia. Expired breathing air has been accumulated in a separate compartment via a specially designed valve. Expiratory air oxygen and carbon dioxide concentrations were measured and recorded on the computer. Using the computer records, "ventilation" and "oxygen intake" and "carbon dioxide output" were calculated.The results obtained from the rats clearly show the success of our application. However a depression in circulation developed in mice, which thought to happen due to the dose of urethane anesthesia. In parallel, the variances of the biphasic respiratory parameters were monitored which is revealed to be free from the performance of the experimental rig.The "breathing cylinder piston valve" mechanism which is developed for the experimental artificial respiration model provided a sensitive measurement of the respiratory gases causing a low dead space volume and turned out to be a successful application for the small laboratory animals. Test results demonstrated the efficacy of this respiratory machine with the first time used -invented- gas collection unit. Therefore, the experimental arrangement referred in this study can be used for indirect calorimetric measurements under artificial respiration in many more scientific experimental animal models and in functional assessment of lung damage models.