Abstract
In the course of observations on the resuscitation of the central nervous system we have had the opportunity to determine whether regular, spontaneous respiratory movements can be discharged at a stage in the resuscitation when as yet the respiratory center is unaffected by stimulation of afferent nerves. The respiratory movements, and usually the arterial blood pressure as well, were recorded and the effect of stimulation of the central ends of the vagus, brachial plexus and sometimes the sciatic determined before occlusion of the arteries supplying the brain, the bulb and the upper portion of the cervical spinal cord. These arteries (innominate and left subclavian proximal to the origin of the left vertebral) were then occluded by temporary ligatures. At intervals during the occlusion and again after releasing the vessels the nerves were stimulated, of course with the same strength of stimulus as before. Artificial respiration was kept up from the time when natural respiration ceased till it was thoroughly re-established after resuscitation.
Result. - An interval, varying in length with the duration of the occlusion and other circumstances, was found during resuscitation, when spontaneous respiration had returned and was going on with a regular rhythm while totally incapable of being influenced by stimulation of any of the afferent paths investigated. The most probable assumption is that at this stage some portion of these afferent paths to the respiratory center was still unable to conduct impulses to the center, the block being possibly (in terms of the neurone hypothesis) in the synapses in which the afferent fibers terminate in the bulb. Resuscitation of the center and the efferent paths from it had at this stage been carried to the point at which the motor impulses were able to pass down to the anterior horn cells which innervate the muscles of ordinary respiration.
Get full access to this article
View all access options for this article.