J.Jpn. Surg. Soc.. 59(3): 368-381, 1958
EXPERIMENTAL STUDY ON THE CHANGES PRODUCED BY ANOXIC ANOXIA IN THE RESPIRATION, BLOOD PRESSURE AND ELECTROCARDIOGRAM
I. CHANGES IN THE RESPIRATION, BLOOD PRESSURE AND ECG
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Second Surgical Clinic, Faculty of Medicine, Kyushu University, Fukuoka (Director: Prof. Masanobu TOMODA) Yukio MIZUNOE |
1. In dogs in progressive anoxic anoxia, there was a progressive increase in the rate and amplitude of the respiration, and when they reached maximal values, they decreased suddenly, ending in respiratory standstill preceded in many cases by a few terminal gasps.
2. The blood pressure gradually rose in the first half to the first two thirds of the time from the beginning to the respiratory standstill. The crisis was followed by a great rise of the pulse pressure and an abrupt fall of the blood pressure, the heart beat becoming slower at the sametime. There was a remarkable fall in the minimal blood pressure level after the crisis.
3. The heart rate, rising, as a rule, concurrently with the blood pressure, reached its maximum level immediately before the highest blood pressure was reached, and began to fall by degrees afterwards. The rapid fall of the blood pressure was synchronized with the marked bradycardia, the heart rate decreasing to one-third to one half of its maximum value or, in rare cases, a condition of temporary respiratory standstill arising as a result.
4. In ECG taken from dogs before the crisis the R-R, P-Q, and Q-T intervals were shortend and T was invariably increased in amplitude. T was kept high in amplitude from the time the heart rate was highest or nearly so after the termination of the crisis. Arrhythmia was noted about the time when the heart rate began to fall from its highest level downwards; it gradually gave place later to bradycardia. The sinus rhythm was depressed after the crisis and with the shift of the pacemaker to a lower center there set in either a nodal rhythm or a ventricular automatism.
5. In unanesthetized rabbits in progressive anoxic anoxia, the blood pressure was increased and the heart rate was more or less decreased for some time to be raised later with a crisis. The crisis was followed by an extreme bradycardia, an increased pulse pressure, nodal rhythm or ventricular automatism. In ether-anesthetized rabbits in heart progressive anoxic anoxia, the crisis had no effect on the blood pressure or on the heart rate, but the changes in the blood pressure and in the ECG produced after the crisis were the same in nonanesthetized and anesthetized rabbits.
(author's abstract)
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