Left ventricular volume studies in tranquilized dogs with local anesthesia.

• It has become apparent that the use of general anesthesia for some types of hemodynamic investigations introduces changes which may limit application of the results to normal physiology. The importance of this point has been emphasized by Rushmer and his colleagues and studies of unanesthetized animals have been published by several authors in recent years. Certainly most cardiovascular experiments in animals are more difficult without general anesthesia and some are impossible. However, those requiring only catheterization of the vascular system can be accomplished with local anesthesia, and in the untrained animal are facilitated by the use of a tranquilizing drug.