The state of haemodynamics, as we mentioned above, largely determines the severity of the disturbances of metabolic processes. Analysis of the results from observing 280 patients suffering from massive blood loss or severe multiple injuries has shown that normalization of the level of arterial pressure does not yet mean that all is well.
In spite of massive transfusion therapy compensating, even overcompensating, the supposed degree of blood loss hypovolaemia, reduction of cardiac output, disturbances of peripheral and microcirculation last for a long time in the postreanimation period. The development of hypoxia in these cases is a result of the discrepancy between the increased organism’s demand for oxygen and the limited possibilities of meeting it. The more massive and prolonged the loss of blood, the greater is the reduction in the volume of circulating blood.
For patients brought out from a state of III degree shock the volume of circulating blood after compensation of loss, as determined by Evan’s blue method using the Gregersen technique in Koziner and Rodionova’s modification, was 10.8 per cent lower than normal, and for those brought out of IV degree shock it was 35.1 per cent lower. This significant decrease in the volume of circulating blood from normal may be due to the prolonged bleeding in certain types of lesions and to storage of blood.
Dynamic study of blood filling of the tissues by means of rheovasography has shown that blood supply to the tissues is sharply reduced in patients who have suffered massive blood loss, prior to its replacement even after stabilization of arterial pressure, and the tone of the peripheral vessels is increased. As blood loss is made good, blood supply to the tissues becomes normal, but spasm continues in the peripheral vessels for three to five hours, even a full 24 hours after operation. Vasospasm is then replaced in most patients by a reduction of tone.
The time needed for normalization of peripheral resistance largely depends on the degree of the preceding loss of blood. Thus, in patients who have suffered a loss of not more than 2000 ml of blood, the tone of peripheral vessels was normalized in three to five days when blood and blood substitutes were transfused daily. Most patients losing more than 2000 ml of blood had lowered tone of peripheral vessels even on the eighth or ninth day. The spasm of peripheral vessels occurring in the early stages of the treatment of terminal states in the opinion of many authors is largely due to overstimulation of the sympathico-adrenal system. Elucidation of the causes of so long a reduction in peripheral resistance in spite of treatment is an urgent problem requiring solution.
In patients brought round from a state of traumatic shock, unlike those with massive loss of blood not complicated by traumatic lesions, peripheral vasospasm lasted much longer, owing to centralization of circulation. Evidence of this is the much greater degree of systolic blood filling of tissues of the head compared with the hand. Investigation of regional blood supply to the various organs has shown that the most severe and prolonged impairment of circulation occurred in pulmonary tissue and in the liver.
Our Laboratory’s findings coincide with those of other authors who have studied circulation by other methods. Compensatory centralization of circulation, directed to protecting the activity of vital organs is usually observed in conditions of hypovolaemia; and if treatment is delayed or inadequate, can lead to severe lesions of the liver and kidneys.
For that reason, it is necessary in order to get the most rapid improvement of haemodynamics, and consequently also to prevent the development of respiration and hepatic-renal insufficiency, to try for the earliest possible restoration of the volume of circulat ing blood and normalization of the tone of the peripheral vessels, in addition to measures directed to stabilizing arterial blood pressure. That quite justifiably lends the greatest importance to transfusion therapy. But the problem of the volume and quality of the transfused solutions is still far from being solved.
It is apparently not sufficient with patients brought out of a terminal state to determine the volume of transfusion therapy from the level of arterial blood pressure or from the haematocrit index. Study of the features of peripheral circulation and volume of circulating blood showed that it is important to take into account the degree of blood loss both during the trauma and the treatment. There are indications in the literature that the deficit in the volume of circulating blood is 40 to 50 per cent in cases of III degree shock, so that the minimum quantity of liquid to be administered is two or three litres. As to IV degree shock no definite recommendations yet exist.
In the opinion of Blazha and Krivda, there are no clear limits for the dose of blood needed when blood pressure is near zero. Observations made in the reanimation department of the Hospital have shown that arterial pressure is stabilized at an adequately high level in patients admitted in states of III degree shock after they had received on average 3540 ml. With IV degree shock cases this happened after an average of 4700 ml of liquid had been transfused; owing to the reduction in the volume of circulating blood, however, transfusion therapy was subsequently indicated as well, under control of rheovasography. The impression obtained was that compensation of blood loss did not depend on the volume of the haemorrhage alone. The character and volume of the surgical intervention, the duration of bleeding, and the background on which it occurred were all most important.
To normalize metabolic processes the transfusion of crystalloid and protein preparations is indicated in combination with blood. The proteins contained in plasma maintain osmotic pressure and play a not inconsiderable role in the blood’s buffer and coagulation systems. The importance of protein among the plasma substitutes must be emphasized, since its curative properties are no worse than those of plasma in the treatment of shock and hypoproteinaemia of various aetiology. A highly effective anti-shock remedy is concentrated albumin solution prepared from retroplacentary serum. This preparation has a good haemodynamic and antitoxic effect.
It seems to us appropriate here to recall that the patient needs transfusion of blood not only in order to restore the correlation between the volume of his circulating blood and the capacity of the vessels, but also in order to improve his blood’s oxygen transport properties. For that reason the main means of compensating blood loss is, after all, haemotransfusion.
It must, however, be kept in mind that massive doses of citrated donor’s blood have a negative effect on several of the organism’s important functions. Much better results can be achieved by way of direct transfusion from the donor, which gives more rapid and stable normalization of haemodynamics, blood composition, and its coagulating properties. In our opinion, when treating anaemia in the first day or two, the composition of the transfusion media should include up to 44 or 48 per cent blood. In connection with the fact that the anaemia, however, lasts for some time, and can even progress, haemotransfusion is indicated, later as well, depending on the haemoglobin indices and the erythrocyte count.
In order to get more rapid replacement of blood loss and restoration of the volume of circulating blood when treating III-IV degree shock and massive blood loss, it sometimes becomes necessary to carry out massive transfusion into two veins; this, however, can overload the right heart. To avoid that complication, intravenous transfusion should be carried out under control of central venous pressure, and where appropriate switched to intra-arterial injection.
For dynamic measurement of central venous pressure it is best to catheterize the subclavian vein using Aubaniac’s method. This method is also used in the reanimation department for protracted transfusional therapy and for taking blood for biochemical analysis. Periodic introduction of heparin into the catheter avoids the formation of thrombi and enables this system to be used for many days.
The most rapid possible normalization of peripheral circulation is no less important. To eliminate vasospasm and improve the rheological properties of the blood, blood substitutes with a haemodynamic effect are administered, a 10 per cent solution of mannitol, ganglionic blocking drugs. It is advisable, however, to introduce these solutions after the blood loss has been made good under control of arterial pressure.
If there is severe hypovolaemia, the elimination of peripheral vasospasm can sometimes lead to an undesirable lowering of arterial pressure as a result of a disparity between the volume of circulating blood and the capacity of vascular bed. In order to prevent intravascular formation of thrombi and, of course, to improve microcirculation, heparin is introduced as a prophylactic measure from the second day. With sharply marked hyperfibrinogenaemia and delayed fibrino lytic activity, the dose of heparin is increased to 40 000 units per day and is supplemented by fibrinolysine under coagulogrammetric control.
As to the treatment of pareses and paralysis of the peripheral vessels, this is a problem requiring further study: intravenous transfusions and hormone therapy do not always give positive results with it, and one gets the impression that timely elimination of hypovolaemia gives much better results.
Taking into account the unfavourable influence that intoxication of the organism has on haemodynamics, detoxication therapy is applied at the same time as the administration of drugs that have a direct effect on circulation, using for this purpose Haemodesum, sorbitol, lactasol, and, with uncompensated acidosis, as mentioned above, sodium bicarbonate.