Traube-Hering Waves

TRAUBE-HERING WAVES (Traube, Hering). If artificial respiration is stopped in a curarized dog with severed vagus nerves, the blood pressure in the arterial system begins to rise immediately. Despite the fact that the animal lies completely motionless and shows no signs of chest wall movement, the rise in blood pressure takes the form of a curve on which, in addition to the usual pulse fluctuations, long, regularly alternating waves appear, the height of which can reach 50 mm of mercury. The phenomenon lasts 2-3 minutes, after which the blood pressure begins to fall until the moment the left ventricle stops, and during this final period the waves in question gradually disappear. If, after the drop in blood pressure has begun, artificial respiration is applied again, the picture repeats itself, and the same rhythmically repeating rises appear on the pressure curve (third-order waves), on which, in turn, weak pressure fluctuations caused by artificial respiration can be distinguished (second-order waves), and finally pulse fluctuations (first-order waves). The first of these, first described by Traube and studied in more detail by Hering, were named Traube-Hering waves. Conducting the experiment on a curarized dog in which only faint traces of respiratory muscle activity remained—so faint that their movements did not cause the slightest fluctuation of a manometer inserted into the trachea—Hering noted that the waves occurred synchronously with respiratory movements, in other words, had, in his opinion, the respiratory center as their pulsing point; on the other hand, when the heart was excluded from the general vascular system and artificial circulation was used, he was able to ascertain that the heart plays no role in the origin of these waves. Based on these data, Hering concludes that the vascular system possesses its own respiratory movements (Athembewegungen), proceeding synchronously with the movements of the respiratory muscles. Both types arise due to nerve impulses originating from the respiratory center, which is periodically excited by fluctuations in the gas composition of the blood.