Ballistocardiogram recording in acute experiments on dogs

Summary

The construction of the ballistocardiogram described in this article provides reliable attachment to the movable part of the electromagnetic pickup on the dog's symphysis pubis. Thus the precise reproduction of the oscillations of its body is obtained. The operation which is required for this is very simple and does not take much time.

Position of the animal on the back gives wide possibilities for surgical interventions. Stability of this position is achieved by placing sand bags around the body. Intravenous barbamyl anesthesia caused deep sleep, slow respiration and good relaxation of mus cles. In surgical interventions on the thorax, ballistocardiogram records were taken during temporary stop of artificial respiration. Moderate hyperventilation necessary for ballistocardiography excluded the possibility of spontaneous respiratory motions during the experiments. Similarity of ballistocardiograms of dogs with those of human beings gives the opportunity of studying some aspects of ballistocardiography on dogs.