Restoration of vital functions of animals revived with a donor circulation after prolonged circulatory arrest

Anesthetized dogs were revived by means of an artificial donor circulation after circulatory arrest lasting 15–20 min. In group 1 the donor's blood was injected toward the heart of the resuscitated dog, whereas in group 2 it was injected toward the heart and brain. In donor-aided resuscitation (especially in group 2) the vital functions were restored more quickly and the number of surviving animals was greater than when other methods of resuscitation were used. Despite the outwardly full recovery of the animals after prolonged circulatory arrest, various degrees of injury took place to their brains, depending both on the duration of clinical death and on the methods of resuscitation.Laboratory of Experimental Physiology of Resuscitation, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. A. Negovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 9, pp. 271–273, September, 1977.     

Changes in the duration of the ventricular complex of the electrocardiogram during interruption and restoration of the work of the heart

Summary ECG changes were studied in the agonal condition and during resuscitation of dogs. After quick death the ventricular complex usually shortened to 0.15–0.20 sec during the first minutes of the clinical death, while in re-establishment of the heart work it was increased to 0.25–0.35 sec. In a prolonged agony and clinical death the ventricular complex was not shortened as much, while in resuscitation it was prolonged to 0.4–0.55 sec.Various changes which take place in the length of the ventricular complex in the processes of dying and resuscitation may be explained by the relationship of two factors: the velocity of the spread of excitation and the number of the myocardial elements which are excited.Presented by Active Member Acad. Med. Sci. USSR, V. N. Chernigovskii     

An experimental study of the portal circulation in the agony period and during resuscitation from clinical death

Summary An inquiry was made into the regularities of the portal system of animals after fatal blood loss and resuscitation following clinical death. The mechanisms capable of providing blood accumulation in the portal circulation at the initial period of revivial were revealed. The following factors which could prevent normalization of the vital activity were noted: a) aggregation of erythrocytes obstructing some small blood vessels, b) possibility of fat drops penetrating into the circulation during agony, c) blood thickening in the portal circulation, inhibiting its movement along the capillary bed and oxygen exchange.(Presented by Active Member AMN SSSR A. V. Lebedinskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 55, No. 5, pp. 33–36, May, 1963     

Some aspects of ammonia formation in the brain of dying animals and during recovery after resuscitation

The dynamics of some indices of nitrogen metabolism in the brain was studied in dogs after lethal blood loss and in the postresuscitation period. The investigation showed that the main source of ammonia in the brain during the development of the organism and in the state of clinical death is glutamine. In the recovery period after resuscitation, however, glutamine becomes a remover of ammonia and the main source of ammonia becomes the labile amino groups of proteins.Department of Pathological Physiology, Erevan Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. A. Negovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 6, pp. 686–688, June, 1977.     

Changes in respiration during acclimatization in the interior of Antarctica

Summary Observations were made at the Soviet antarctic station, Vostok. Tachypnea and considerable hyperventitation were observed during the first days after arrival at the station. With acclimatization, the frequency of respiration restored to the normal, pulmonary ventilation decreased, reaching the lowest level during the polar night period (however, even during that period it is 1 1/2 times greater than the normal value); the depth of respiration increased considerably. During the whole period of stay in Antarctica every individual had Cheyne-Stokes respiration, especially during sleep. Dyspnea increased considerably, even during slight physical strain. Composition of alveolar an became stabilized at a new level corresponding to a partial oxygen pressure of 53–56 mm Hg and to CO₂ pressure of 26–29 mm Hg. The blood oxygenation during quiet respiration was 80–87%, increasing with voluntary hyperventilation to 85–94%. Hypoxemia rose considerably with voluntary breath holding and physical strain.Presented by Active Member AMN SSSR, A. V. Lebedinskii Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 57, No. 1, pp. 20–23, January, 1964     

The role of interoceptors in the regulation of oxygen saturation of arterial blood

Summary Studies were made of the oxygen saturation in arterial blood in animals during exposure to 7500 m in a chamber. The study was carried out after the photoelectrical method by means of continous oxyhemometry in rabbits and cats with denervation of carotid sinus zones, as well as in controls. In the controls the saturation diminished, to 55–62% and increased somewhat after 8–10 minutes' exposition to altitude. In the experimental animals the diminution of oxygen saturation was more pronounced, reaching 40–50% and remained within this range during the whole period of exposure.The experiments demonstrated that the dynamics and the degree of oxygen saturation of arterial blood in case of hypoxia depend on the function of the carotid sinus zones.Presented by Active Member of the Academy of Medical Sciences USSR V. N. Chernigovsky     

The dynamic of thermal fields of the brain of rats in the late post-resuscitation period under stress

The temperature topography of the cerebral cortex of rats following clinical death and resuscitation was investigated with the technique of thermoencephaloscopy. Complete restoration of the neurological status of the animals was achieved over the course of one to two days. Marked disturbances in the background thermal maps and the thermal reactions of the cerebral hemispheres induced by a stressor were identified in the remote post-resuscitation period (up to two months). A pathological mosaicism of the thermal characteristics was detected under the conditions of relative rest, as were disturbances in the dynamics of the temperature reactions of the brain and in the character of the interhemispheric asymmetries under stress. The individual character of the post-resuscitation pathology which is found both in the baseline thermal maps as well as following a functional load is emphasized. The results of the investigation point to the importance of an individual approach in the rehabilitation therapy of the post-resuscitation illness.Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 42, No. 2, pp. 351–356, March–April, 1992.     

Relationship of changes in the central hemodynamics to the development of posthypoxic cerebral edema in the postresuscitation period

A syndrome of low cardiac output developed between the first and third hours after resuscitation in 16 dogs subjected to circulatory arrest for 15 min. In half of the cases its development was preceded by an increase in the cardiac output in the initial period of resuscitation. Without hyperperfusion at the beginning of resuscitation, the animals died 9–23 h after the beginning of the experiment. Among the surviving animals, edema of the cerebral cortex always developed in dogs with a reduced cardiac output 24 h after resuscitation, but no cerebral edema was observed in dogs with a high cardiac output.Laboratory of Experimental Physiology of Resuscitation, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. A. Negovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 3, pp. 266–268, March, 1977.     

On the restoration of the neuroreflex regulation of the cardiovascular system during resuscitation after clinical death

Summary Investigations carried out by the author have demonstrated that in reviving the organism after clinical death the activity of the vagus center is restored subsequent to the appearance of respiration. Up to that time the cardiovascular system was under a preponderant effect of the sympathetic nervous system. In the next few days following the revival, the heart reactions to external stimuli were inadequate. This may be due to an incomplete central nervous system restoration. Cardiac reaction to external stimuli normalized in 1–4 weeks.(Presented by Active Member, AMS USSR, V. V. Parin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 52, No. 10, pp. 34–38, October, 1961     

Correlation between the central hemodynamics of dogs in the early postresuscitation period and the outcome of resuscitation

Changes in the central hemodynamics were compared with the outcome of resuscitation in 18 dogs after circulatory arrest lasting 12 min caused by ventricular fibrillation. In nine animals resuscitated with evidently complete neurological recovery moderate hypertension was observed in the first 10 min after the beginning of the resuscitation measures: The mean arterial pressure (MAP) was 175.0±8.9 mm Hg. In most of the dogs which died subsequently MAP in this period was not higher than initially, but two animals showed severe hypertension (MAP about 200 mm Hg). In this same period differences also were found in other parameters of the central hemodynamics. Moderate hypertension in the first 10 min of the postresuscitation period evidently leads to rapid recovery of an adequate level of the peripheral blood flow in tissues and organs and, as a result, it aids the survival of animals after a long period of circulatory arrest.Research Laboratory of General Resuscitation, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. A. Negovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 11, pp. 530–532. November, 1979.     

Structure of the respiratory cycle during extinction and restoration of vital functions

Summary Acute experiments on dogs were made to study by means of electromyography the structure of the respiratory cycle of the main and accessory respiratory muscles at various stages of extinction of the vital functions during death from blood loss and in the first 1.5–3 h of resuscitation after a 3–5 min clinical death. Dying of the animals is accompanied by disturbances in the reciprocal relations between the inspiratory and expiratory centers, as a result of which in the agonal state the expiratory and accessory respiratory muscles contract during inspiration. The mechanisms ensuring an active expiration are more sensitive to hypoxemia; during dying the expiratory muscles are excluded from the respiratory activity earlier and are restored to function later than the inspiratory muscles. Normalization of the activity of the expiratory muscles depends on the restoration of the parts of the brain stem on the border between the medulla oblongata and the pons Varoli. As evidenced by EMG data, the degree of pulmonary ventilation corresponds to the structure of the respiratory cycle much more than to its pneumographic characteristics.(Presented by Academician V. V. Parin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 59, No. 5, pp. 35–40, May, 1965.     

The pathogenesis of histamine shock

Summary Experiments were performed on animals revived after clinical death by V. A. Negovskii's method, with a view to studying their reaction to shock-producing doses of histamine. It appeared that in these animals the sensitivity to histamine was decreased and varied, depending on the period of brain function restoration. Histamine inhibited the normalization of arterial blood pressure in animals after clinical death, notwithstanding the fact that the initial phase of the action of the preparation was weak. Preliminary adrenalectomy fails to enhance the manifestations of the first (reflex) phase of histamine reaction. Another characteristic feature of the adrenalectomized animals is intensification of the second (humoral) phase, and these animals die sooner following administration of the preparation. This is evidence of the enhanced effect of the direct action of the drug on the vessels when secretion of corticoids is deficient. During the resuscitation of the animal after clinical death and in the treatment of prolonged terminal states, in view of the possible liberation of histamine as a result of the marked anoxia it is evidently desirable to administer adrenal cortical hormone preparations.The participation of two components—reflex and humoral—in the pathogenesis of histamine shock must be recognized. The reflex component is associated with stimulation of receptors, and the humoral with the direct action of histamine on the vessels.(Presented by Active Member AMN SSSR V. N. Chernigovskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 50, No. 9, pp. 69–76, September, 1960     

Restoration of higher nervous activity in dogs resuscitated after 30-minute clinical death in conditions of hypothermia

Summary The characteristic features of recovery of the function of the brain cortex after resuscitation was studied in 4 dogs. For that purpose a system of conditioned reflexes was previously developed. These reflexes were formed according to a stereotype, consisting of 5 positive (metronome −120 light, bell, metronome −120) and one inhibitory (metronome −60) stimulants. The acid-defense method was used in these experiments. The possibility of complete recovery of the previously developed conditioned reflexes after a 30-minute clinical death, caused by acute blood loss in condition of hypothermia was proved in these animals. Various disturbances of relationship between the fundamental nervous processes took place during the process of recovery. These disturbances were either in the form of extreme exhaustion of the functions of the highest portions of the central nervous system, or gave the picture of various degree hypnotic condition. Presented by Prof. V. N. Chemigovsky. Active Member of the AMNSSSR     

Structural basis of impairment of the external respiratory function in the post-resuscitation period

External enhancement of free-radical processes followed by considerable tissue accumulation of toxic lipid peroxidation products in an early postresuscitation period is the main pathochemical mechanism which causes lung air-blood barrier disturbance. The basis of animal respiratory insufficiency morphogenesis after clinical death is ventilation failure (dis- and atelectasis), circulation disorder (edema, hemorrhage) being secondary. However, morphological examination of lungs of animals after four-minutes clinical death from an acute blood loss and resuscitation showed that it is the severity of circulation disorders that determines the animals condition in the postresuscitation period.     

Resuscitation of animals after long periods of clinical death during isolated cooling of the brain

Summary A study was made of the possibility of restoring the vital functions in dogs following prolonged periods of clinical death in conditions of isolated cooling of the brain. As established, dynamics of the restoration of cardiac activity and respiration in animals after a 30 min clinical death in isolated cooling of the brain (body temperature 32.9°C to 29.5°C, brain temperature from 4 to 8.6°C lower) did not differ materially from the results obtained with the general body chilling. However, subsequent restoration in these animals (especially after one hour of clinical death) occurs with much greater difficulty than following general chilling. This may be attributed to the accumulation of suboxidized metabolites in the body during prolonged severe hypoxia in conditions of high body temperature, these metabolites exerting an unfavorable effect on the subsequent restoration process in revived animals. Along with this, as shown by autopsy data, severe hypoxia in such conditions leads to a marked rise in vascular permeability, which in a great proportion of the cases served as a direct cause of the animal's death as a result of massive hemorrhages into the internal organs.(Presented by Active Member AMN SSSR V. V. Parin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 54, No. 10, pp. 33–36, October, 1962     

The effect of the resistance to respiration on the functional state of the respiratory center in dogs in chronic experimental conditions

Summary Three adult dogs were used in 97 chronic experiments to study the influence of resistance to respiration on the functional state of the respiratory center. Resistance to respiration was produced by using a respiratory mask for 5–10–30 min. In a number of experiments, the animals were given morphine in 0.01 g doses. The pneumogram and electrocardiogram were registered in the second standard lead.Respiration with resistance was accompanied by a slow-down in the rhythm of respiratory movements and an increase in the amplitude; in 68 experiments out of 97, these changes were noted also in the period of after-effect. At the same time, in the process of training of the animals changes in the amplitude of respiratory movements arrived first, and duplication in their rhythm came on later. Morphine reduced the reaction of the respiratory center under the influence of increased resistance to respiration.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 60, No. 8, pp. 14–17, August, 1965     

Hyperoxic Vasoconstriction in the Brain Is Mediated by Inactivation of Nitric Oxide by Superoxide Anions

The hypothesis that decreases in brain blood flow during respiration of hyperbaric oxygen result from inactivation of nitric oxide (NO) by superoxide anions (O_{2 –}) is proposed. Changes in brain blood flow were assessed in conscious rats during respiration of atmospheric air or oxygen at a pressure of 4 atm after dismutation of O_{2 –} with superoxide dismutase or suppression of NO synthesis with the NO synthase inhibitor L-NAME. I.v. administration of superoxide dismutase increased brain blood flow in rats breathing air but was ineffective after previous inhibition of NO synthase. Hyperbaric oxygenation at 4 atm induced decreases in brain blood flow, though prior superoxide dismutase prevented hyperoxic vasoconstriction and increased brain blood flow in rats breathing hyperbaric oxygen. The vasodilatory effect of superoxide dismutase in hyperbaric oxygenation was not seen in animals given prior doses of the NO synthase inhibitor. These results provide evidence that one mechanism for hyperoxic vasoconstriction in the brain consists of inactivation of NO by superoxide anions, decreasing its basal vasorelaxing action.     

Response of rats to hyperbaric oxygen after preliminary adaptation to hypoxia

Preliminary adaptation of rats to hypoxia under conditions increasing resistance to many stressproducing agents not only had no protective effect against exposure to hyperbaric oxygen at pressures up to 6 kgf/cm² but, conversely, lowered the resistance of the animals. The latent period of onset of seizures in the adapted rats was shortened especially if exposure to hyperbaric oxygen began 1 or 2 days after the end of adaptation to hypoxia, and was a little shorter in the experiments carried out after 3–4 days. The responses returned completely to normal 1 month after the end of adaptation to hypoxia. The possible causes of development of the phenomena are discussed.I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR Leningrad. (Presented by Academician V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 3, pp. 265–267, March, 1978.     

Intravital microscopy of the lung tissue in small laboratory animals

A method of biomicroscopy of the lungs using a modified experimental lung fixing device is suggested. It enables intravital investigation of the microcirculation of the lung tissue to be carried out not only during artificial respiration, but also during spontaneous breathing of the animals.Department of Pathological Physiology, Vladivostok Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR A. D. Ado.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 2, pp. 245–246, February, 1978.     

Analysis of the pattern of energy expenditure of rats in different age periods

Summary A study was carried out of the characteristics of oxygen consumption at different age periods in rats kept in a respiratory chamber at a temperature corresponding to that in their natural habitat. The experiments were carried out on 407 animals. In albino rats the oxygen consumption increases after birth both per unit of weight and per unit of body surface, reaching the maximum at the time of assuming the standing posture (11th–17th day after birth) –104.6 ml/kg weight and 323.6 ml/m² body surface per minute. During subsequent postnatal development oxygen consumption both per unit of weight and per unit of body surface gradually decreases. At the same time, a progressive decrease in oxygen consumption occurs per unit of body weight up to the adult period, reaching 35.0 ml/kg per min. The oxygen consumption per unit of body surface falls only until one month of age, after which it increases again. It is concluded that change in oxygen consumption reflecting the energy expenditure rate in the postnatal ontogenetic process does not conform to the surface energy rule.Presented by Active Member AMN SSSR V. V. Parin Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 59, No. 3, pp. 25–29, March, 1965