AGONY (Greek agonia — fight, an agony) — last stage of dying. characterized by rise in activity of compensatory mechanisms, the vital forces of an organism directed to fight against fading.
The AGONY is preceded by a preagonal state, in time to-rogo the frustration of a hemodynamics and breath causing development dominate hypoxias (see). Duration of this period is varied significantly by me depends on the basic pathological process, and also on safety and character of compensatory mechanisms. So, at the sudden cardiac standstill caused by fibrillation of ventricles (e.g., at a coronary disease, defeats by electric current), the preagonal period is practically absent. Contrary to it during the dying from blood loss, at traumatic shock, the progressing respiratory insufficiency of various etiology and some other morbid conditions it can last within many hours. A transitional stage from a preagonal state to And. the so-called terminal pause which is especially expressed during the dying from blood loss is. The terminal pause is characterized by the sudden termination of breath after a sharp tachypnea. At this moment on EEG bioelectric activity disappears, lid reflexes die away, on an ECG ectopic impulses appear. Oxidizing processes are oppressed in glycoclastic amplify. Duration of a terminal pause makes of 5 — 10 sec. up to 3 — 4 min. then there comes the AGONY
the Clinical picture of an agony
the Clinical picture of an agony consists of symptoms of deep oppression of the vital functions of an organism owing to a sharp hypoxia. Disappearance of painful sensitivity, loss of consciousness, a mydriasis, fading pupillary, corneal, tendon and cutaneous reflexes concern to them. The major sign And. disturbance of breath is. Agonal breath is characterized or the weak rare respiratory movements of small amplitude, or, on the contrary, a short maximum breath and a bystry full exhalation with a big amplitude of respiratory movements and with a frequency of 2 — 6 in a minute. At extreme stages of dying muscles of a neck and a trunk participate in the act of a breath. The head at each breath overturns, the mouth widely reveals, dying as if swallows air. At the seeming activity efficiency of external respiration in time And. very low. The minute volume of lung ventilation makes apprx. 15% of initial.
Characteristic sign And. the so-called terminal fluid lungs is. Possibly, it is connected not only with the hypoxia increasing permeability of alveolar walls in and with weakening of blood circulation in lungs, and also with disturbance of microcirculation in them.
Fading of cordial activity is considered as «the last chord of life» and differs depending on a type of dying.
Directly after a terminal pause efficiency of cordial reductions increases a little that causes a nek-swarm increase in arterial pressure (to 20 — 30 mm of mercury., sometimes above). On an ECG the sinus automaticity is recovered, the rhythm becomes frequent, topical activity in whole or in part stops. Centralization of blood circulation and some podjy arterial pressure can for the short period (several seconds, and sometimes and minutes) obuslo to twist recovery of consciousness. These signs, and also deep agonal breath do not speak about improvement of a condition of the patient in comparison with the preagonal period at all. On the contrary, they demonstrate approach And. are also the indication to the emergency resuscitation measures (see below).
By the end And. the rhythm of cordial reductions is slowed down to 40 — 20 in a minute, arterial pressure decreases (20 — 10 mm of mercury.). On an ECG disturbances of atrioventricular and intra ventricular conductivity are noted, ectopic activity appears and amplifies. Nevertheless the sinoatrial rate can remain not only during the period And., but also the first minutes of clinical death. In this case an initial part of the ECG ventricular complex is not exposed to essential changes. Naturally gradual shortening of an electrical systole that at simultaneous lengthening of an interval of PQ leads to a symmetric arrangement of teeth P and T concerning a tooth of R. In time And., especially in its last phase, the cerebrate rigidity and the general tonic spasms are quite often observed. The involuntary urination and defecation are often noted. Body temperature usually decreases.
At different types of dying duration And. and its manifestations can differ.
During the dying from traumatic shock (see), blood losses (see) integuments and visible mucous membranes become voskovidnobledny, the nose is pointed, the cornea of eyes loses transparency, pupils sharply extend, tachycardia is characteristic. Period And. from 2 — 3 to 15 — 20 min. proceed.
For mechanical asphyxia (see) in an initial stage of dying increase in level of arterial pressure and reflex delay of a cordial rhythm, multiple premature ventricular contraction is typical. On an ECG quickly there is a disturbance of conductivity, a peculiar deformation of a final part of a ventricular complex («huge teeth of T»). Arterial pressure critically decreases just before the termination of cordial activity. Integuments become sharply cyanochroic, spasms, paralysis of sphincters develop. Period And. usually short — 5 — 10 min.
At the dying caused cardiac tamponade (see), arterial pressure progressively decreases also in time And. its increase, as a rule, is not observed. On an ECG amplitude of teeth nachal sharply decreases ache parts of a ventricular complex, there occurs their deformation and inverting of the tooth of T taking a tear-shaped form.
At a sudden stop of cordial activity (an asystolia or fibrillation of ventricles) sharp cyanosis of integuments of the person and neck, and then and all trunk quickly develops. The person becomes bloated. Spasms are possible. Agonal breath can continue within 5 — 10 min. after the termination of blood circulation.
During the dying from long intoxication (a cancer cachexia, sepsis, peritonitis etc.) The AGONY develops gradually, often without terminal pause and can proceed is long — of several hours to 2 — 3 days in separate observations.
During the dying under anesthetic, and also at very exhausted patients clinical signs of the AGONY can be absent.
One of the most important factors in development And. switching off of functions of the highest departments of a brain, especially its bark (neocortex) is, and at the same time — excitement is lower than more ancient structures of a brainstem located fi-lo-and ontogenetically. Owing to development of guarding braking in bark and subcrustal educations regulation of neurophysiological functions in the agonal period is carried out by the bulbar vegetative centers which activity due to the lack of the coordinating influences of a cerebral cortex has the primitive, chaotic, disorder character. Their activity causes the short-term strengthening of almost died away functions of breath and blood circulation described above, and sometimes and simultaneous recovery of consciousness.
EEG and an elektrokortikogramma testify to absence in the agonal period of biopotentials in a cerebral cortex and subcrustal educations («bioelectric silence»). Electric activity of a cerebral cortex dies away at the same time or for several seconds before fading of biopotentials in subcrustal and mezentsefalny educations. Bioelectric activity of a reticular formation of a brainstem, especially its caudal department and kernels of an amygdaloid nucleus is steadier (arkhipallium). In these educations bioelectric activity remains up to the end A. Nablyudayemye on EEG fluctuations in cortical assignments in beat of breath keep the physiological nature and arise owing to irradiation of excitement from a myelencephalon to subcrustal educations and a cerebral cortex. It should be considered as the natural phenomenon which is shown in cases rough And., when the myelencephalon sometimes is capable to awaken a cerebral cortex as if. However mentioned arterial pressure it is insufficient for maintenance of activity of the highest departments of a brain. Vegetative formations of a myelencephalon, and in particular its mesh formation, can function at low level of arterial pressure much longer. Disappearance of electric activity of a myelencephalon is a sign of approach or direct proximity of clinical death. Disturbances of the main vital functions of an organism — breath and blood circulation — carry characteristic feature for And. diskoordination.
Agonal breath forms at the expense of independent mechanisms of a myelencephalon and does not depend on influence of overlying departments of a brain. «Gasping-center», for the account to-rogo the respiratory movements during the period are carried out And., does not react to afferent impulses from receptors of easy and upper respiratory tracts. The research of electric activity of respiratory muscles showed that muscles of a breath and auxiliary respiratory muscles (muscles of a neck, a mouth floor, language) participate in the first agonal breaths. Muscles of an exhalation in the act of breath of participation do not accept. At the subsequent agonal breaths of a muscle of an exhalation are reduced along with muscles of a breath and auxiliary muscles — the reciprocal relations between the inspiratory and expiratory center are broken.
If during the AGONY arterial pressure temporarily increases in this connection lid reflexes are recovered, and on EEG polymorphic delta waves appear again, in other words, if the organism as if is returned by the preagonal period, the reciprocal relations between an inspiratory center and an exhalation are recovered and muscles of an exhalation are reduced in an expiratory phase. At long dying throughout the entire period And. muscles of an exhalation in the act of breath of participation do not accept.
In time And. amplitude of fluctuations of biocurrents of respiratory muscles several times exceeds initial that is explained by strong excitement of the inspiratory center. Reduction of expiratory muscles along with inspiratory is result of irradiation of excitement from the inspiratory center on expiratory. In time And. excitement from the inspiratory center irradiates as well on motor neurons of other skeletal muscles.
At long dying in time And. the nature of reduction of respiratory muscles changes — conjoint tetanic reduction breaks into a number of the clonic categories reproducing a rhythm of fluctuations in flashes in a setevidny formation of a myelencephalon. During the deepening And. there comes the moment when flashes in a setevidny formation remain, being the last reflection of activity of a respiratory center. At the same time signs of activity of respiratory muscles are already absent.
At the end And. the first are switched off from the act of breath of a muscle of an exhalation, then (in 60% of cases) at the same time diaphragmal and costal respiration stops and in 40% of cases costal, then diaphragmal respiration disappears at first. Muscles of a neck in 60% of observations are switched off from the act of a breath along with a diaphragm and in 40% of cases after it. A low performance of ventilation of the lungs in time And. it can be explained with the fact that muscles of an exhalation (a muscle of a front abdominal wall), being reduced along with muscles of a breath, obstruct the traffic of a diaphragm (S. V. Tolova, 1965).
At the initial stage of dying from blood loss sharp increase of the sinus automaticity against the background of quickly decreasing arterial pressure is, as a rule, observed. This compensatory reaction is connected with activation of sympaticoadrenal system in response to action of a stressful factor. Further the period of sharp delay of heart rate — the terminal pause obliged by the origin to excitement of kernels of vagus nerves in a myelencephalon begins. On an ECG the partial or full atrioventricular block, a nodal or idioventricular rhythm is found at this time. Atrial teeth if they are kept, follow usually in more accurate rhythm, than ventricular complexes, and also are distorted.
Period And., directly following a terminal pause, the nek-swarm is characterized by activation of cordial activity and breath. This last flash of life activity of an organism also has compensatory character and is caused by oppression of the center of vagus nerves. At the same time a peculiar distribution of a blood-groove — expansion of the coronary vessels and the main arteries bearing blood to a brain, a spasm of peripheral vessels and vessels of internals (centralization of blood circulation) is observed.
The analysis of electrocardiographic data allows to define the moment of a stop of blood circulation (if it precedes an apnoea) only at emergence of fibrillation of ventricles or complete cessation of bioelectric activity of heart. At preservation of activity of this or that center of the automaticity it is reliable to judge the fact of the termination And. and approach of clinical death only on the basis of a habit view of a ventricular complex it is possible only after several minutes after a stop of blood circulation, during formation two-or monophase deviations («complexes of the dying heart»).
As it was noted biochemical changes above, in a preagonal state the organism still copes with air hunger, using compensatory mechanisms of all systems providing delivery of oxygen to fabrics. However in process of dying and approach And. compensatory opportunities are exhausted, and into the forefront hypoxemic lines of exchange act. From the blood which is slowly proceeding on vessels, fabrics manage to choose almost all oxygen. In a venous blood there are only its traces. Oxygen consumption by an organism sharply falls, and fabrics test air hunger (see. Hypoxia ). The arterial blood at acute blood loss, unlike other types of dying, e.g. asphyxia, remains to the lung ventilation which is well oxygenated as a result of change of a ratio and a pulmonary blood-groove. Arteriovenous distinction on oxygen is higher initial by 2 — 3 times. Despite it, to fabrics it is delivered less and less oxygen since the amount of blood in an organism as a result of blood loss decreases. Along with it microcirculation is sharply broken.
In these conditions the oxidizing way of use of the carbohydrates which are the main source of energy is replaced glycoclastic (oxygen-free), at Krom of fabric receive much less energy during the use of the same amount of substrate (see. Anaerobiosis ). It inevitably conducts to the fact that the amount of carbohydrates begins to be reduced sharply and that is especially important in a brain and a liver. Also other energy sources — high-energy phosphatic bonds are at the same time exhausted. Transition to a glycoclastic pathway leads to significant increase in concentration milk to - you in blood of total amount of organic acids.
Owing to a lack of oxygen oxidation of carbohydrates through a tricarbonic acid cycle (to CO 2 and waters) becomes impossible. In process of exhaustion of carbohydrate reserves other energy sources, first of all fats also are involved in exchange. There is a ketonemiya.
Accumulation in blood of acids leads to development of a metabolic acidosis that in turn influences delivery of oxygen to fabrics. The metabolic acidosis is often combined with a respiratory alkalosis. At the same time in blood the maintenance of potassium ions at the expense of its exit from uniform elements increases, decrease in ions of sodium, a high level of urea is observed.
In brain fabric the amount of glucose and phosphocreatinine decreases and the amount of inorganic phosphorus increases. The amount of ATP — the universal donator of energy — is reduced while the maintenance of ADF and AMF increases. Disturbance of energy balance in the period of the AGONY leads to disturbance of synthesis of a glutamine and reduction of its quantity at the increasing content of ammonia. Also changes physical are observed. - chemical properties of proteinaceous molecules (without considerable change of their structure). There is an activation of acid hydrolases in subcellular fractions of brain fabric, increase in proteolytic activity, activity of acid phosphatase and a fabric plasminogen activator. These changes of activity of lizosomalny enzymes can be considered at a certain stage as compensatory reaction, but against the background of further deepening And. they promote destruction of a cell. During the AGONY deep disturbances of processes of hemocoagulation often are found.
Thinner biochemical changes during the period And. depends on duration of the last and the nature of dying.
the AGONY belongs to the category so-called. terminal states (see). Is also a reversible stage of dying. When the organism perishes, without having exhausted all the functionality yet (first of all in cases of so-called acute death from blood loss, shock, asphyxia etc.), it is necessary to help it to overcome the AGONY.
At emergence of clinical signs of an agony it is necessary to apply all complex of resuscitation actions immediately (for more details see. Resuscitation ), first of all artificial respiration (see) and indirect cardiac massage (see). Despite the independent respiratory dv of a zheniye remaining at the patient and existence of signs of cordial activity (often irregular), the specified events shall be held vigorously and rather for a long time — before full removal of an organism from And. and stabilization of a state. If the independent respiratory movements do not give the chance to provide full artificial ventilation of the lungs with special devices of manual action like Ambu, it is necessary to apply muscle relaxants (see) short actions with the subsequent intubation of a trachea (see. Intubation ). If the intubation is impossible or for it there are no conditions, carrying out artificial ventilation from a mouth in a mouth or from a mouth in a nose is necessary in the way. At development of a terminal fluid lungs the intubation of a trachea and carrying out artificial ventilation of the lungs under constant positive pressure is necessary.
At fibrillation of ventricles against the background of the proceeding cardiac massage the electric defibrillation is shown. If the AGONY was caused by traumatic shock or blood loss, along with intravenous transfusions intra arterial hemotransfusion and plasma substituting liquids is necessary.
All surgical manipulations in time And. it is necessary to carry out only in the presence of absolute vital the indication (obturation of a throat by a foreign body, arterial bleeding); they shall become quickly and to be minimum on volume (an applying a tourniquet on an extremity or a clip on the bleeding vessel, but not search of the last in a wound; pressing of a ventral aorta during operation, but not removal of the damaged body; konikotomiya, but not a tracheostomy etc.). At development And. during an operative measure the last shall be immediately suspended. It is possible to finish operation only after complete elimination of the menacing state and stabilization of the main vital signs (breath, pulse, arterial pressure etc.).
The patient brought from a condition of the AGONY needs careful observation and an intensive care for a long time even if the main reason which caused development of a terminal state is eliminated. The organism which transferred And., it is extraordinary labilen, and repeated development of a terminal state can occur from the most various reasons. Correction of metabolic disturbances, full elimination of a hypoxia and circulatory disturbances, prevention of purulent and septic complications are necessary. Metabolic acidosis (see), as a rule, developing the ambassador A., it has to be as fast as possible liquidated. It is impossible to stop artificial ventilation of the lungs and transfusion therapy before full elimination of signs of respiratory insufficiency and normalization of volume of the circulating blood, the central and peripheric circulation.
Success of resuscitation at the AGONY depends on the reasons which led to development of a terminal state, duration of dying and also on timeliness and correctness of the applied treatment. When therapy is late and the AGONY proceeds long, functionality of an organism and first of all c. N of page are exhausted and recovery of the dying-away vital signs becomes difficult and even impossible.
Bibliography: Negovsky V. A. Pathophysiology and therapy of an agony and clinical death, M., 1954; it. Urgent problems of resuscitation, M., 1971; Tolov and S. V. Struktura of the respiratory act in the course of fading and recovery of vital signs of an organism, Bulletin ekspsry. biol, and medical, t. 59, JM * 5, page 35, 1965; GUO about r G. V. About the death of the person (introduction to thanatology), J1., 1925; Laves W. u. Berg S. Aponie, physiologisch-chemische Untersuchungcn bei gewal teamen Todcsarten, Ltibeck, 1965.
V. A. Negovsky.