Blood loss correction in surgery

Blood loss in surgery is an inevitable aspect of surgical intervention. In this case, not only the localization of the surgical intervention is important, but also the volume, diagnosis, presence of concomitant pathology, and the initial state of blood parameters. Therefore, it is necessary to predict the volume of expected blood loss, the risk of bleeding, and the compensatory capabilities of the body. All of the above affects the prognosis and outcome of the disease for a given patient. Hence, the high importance of the strategy of timely and accurate correction of the blood condition in the perioperative period.

Increased blood loss is typical for a number of surgical fields. In particular, this includes neurosurgery, cardiac surgery, oncology, urology, obstetrics, and traumatology. Therefore, there are certain aspects that must be taken into account when compensating and correcting blood homeostasis during surgical interventions.

Successful solution of this task is determined by the need to focus on a number of key positions, in this situation - this is timely compensation of blood loss with observance of the physiological ratio of plasma and formed cellular composition of blood in order to maintain oncotic balance between the volume of the vascular and extravascular bed, prevention of damage to the vascular wall, prevention and treatment of coagulation disorders. Each nosological unit has its own characteristics and mechanisms of damage that require consideration when choosing the tactics of the transfusiologist.

One of the most accessible and widespread procedures is the use of frozen autogenous erythrocytes. The possibility of long-term storage of cryopreserved autogenous erythrocytes can improve the results of planned surgical interventions in patients with increased requirements for the quality of transfused media. The component principle of transfusion therapy is quite applicable to autogenous transfusions. Fractionation of the prepared autoblood to obtain autogenous red blood cell mass (auto EM) and fresh frozen autoplasma (auto FFP) significantly enhances the therapeutic effect of their use in replenishing surgical blood loss. Preparation of fresh frozen autoplasma in the blood transfusion department (or office) of a medical institution by the plasmapheresis method allows accumulating it in the required quantities and using it both to compensate for the intravascular volume and to replenish the deficiency of plasma coagulation factors. The presence of 1-3 doses of autogenous fresh frozen plasma provides additional opportunities for the correction of acute coagulation disorders in the case of massive intraoperative blood loss and/or intraoperative return of erythrocytes. Thawed and washed erythrocytes are areactogenic, lack plasma proteins, leukocytes and platelets, therefore their transfusions are especially indicated for reactive, alloimmunized patients.

ESMO (European Society for Medical Oncology) recommendations for red blood cell transfusion: decrease in hemoglobin to less than 80 g/l, ASCO (American Society for Clinical Oncology) - presence of clinical cardiac signs of anemia (tachycardia), when adapting to low hemoglobin levels (80 g/l) there may be no tachycardia, here it is not the established reference values that are assessed, but the condition of the patients.

The clinical use of erythropoietin has ushered in a new era of transfusion medicine with the incorporation of pharmacological agents into blood conservation strategies. Recombinant human erythropoietin may play a significant role in elective surgeries with significant blood loss, including complex revision and bilateral total joint replacements. Preoperative use of erythropoietin (Epoetin alfa) increases the possibility of preoperative autologous blood collection and perioperative red blood cell mass.

Clinical recommendations for working with erythropoietins indicate the advantages of using them at a hemoglobin level of 90 to 110 g / l, at lower values, preliminary transfusion of red blood cell mass with subsequent administration of erythropoietins is necessary, since the red blood cells introduced with red blood cell mass are destroyed and the patient again returns to anemia. There is a tactic of early intervention, that is, the earlier (at hemoglobin 90-110 g / l) the introduction of erythropoietins is started, the better, without waiting for the hemoglobin indicator to decrease to 80-90 g / l, especially in cardiovascular pathology, or in the presence of cardiac symptoms of anemia (tachycardia). Intravenous administration of erythropoietins not only helps to increase the effectiveness of the treatment of anemia, but also reduces the incidence of thrombosis. There is a relationship between thrombosis and anemia. Organ hypoxia increases the incidence of thrombosis. However, treatment with erythropoietins alone is a factor in the development of thrombosis. It is necessary to connect intravenous iron on the 7-10th day of treatment with erythropoietins, since the iron does not have time to leave the depot into the blood, and the patient's own iron in the blood is already used up, thus, a functional iron deficiency occurs. A plateau is formed - hemoglobin seems to freeze, which is regarded as the ineffectiveness of treatment with erythropoietins, and the therapy is stopped. The main purpose of erythropoietins is not to restore the hemoglobin level, but to eliminate other possible causes of anemia. If the level of endogenous erythropoietin reaches 1 IU, then its introduction from the outside does not solve the problem, with its deficiency, this is an absolute indication for its introduction. The problem of anemia is not only a problem of decreasing hemoglobin, but also the survival of red blood cells. This is especially true for cancer patients. The possible concern that erythropoietins are pro-oncogenes is unfounded, due to the lack of substrate and expression receptors for this substrate in erythropoietins.

Thus, three apologists for the treatment of perioperative blood loss are substantiated: red blood cell mass, erythropoietins and intravenous iron.

However, one of the most easily implemented, cheap and effective methods of blood conservation is acute isovolemic hemodilution (AIHD). The isovolemic hemodilution method is currently widely and successfully used in various fields of surgery, including neurosurgery, where significant blood loss is predicted based on a set of clinical and radiological data - a large tumor volume, proximity to large vessels, pronounced accumulation of contrast agent (computer tomography, magnetic resonance imaging), the presence of the tumor's own vascular network (cerebral angiography), intraventricular tumors, as well as patients with extensive cranioplasty reconstructions. This method allows to significantly reduce the volume of actual surgical blood loss and, accordingly, the necessary transfusion load on the patient.

This problem is especially relevant in neurosurgical interventions in children - low absolute values of the BCC and tolerance to blood loss, rapid development of circulatory decompensation, systemic hemodynamic and metabolic disorders. In children, due to the massiveness of blood loss, a combination of isovolemic hemodilution and the method of hardware reinfusion of autoerythrocytes (Cell Saver Fresenius CATS) was used. This method allows to significantly reduce the volume of actual surgical blood loss and, accordingly, the necessary transfusion load on the patient.

Hemotransfusion remains one of the main methods of treating acute blood loss today, as it is the only transfusion medium containing hemoglobin.

Of the four main types of blood transfusion (transfusion of preserved blood, direct transfusion, reinfusion and autohemotransfusion), direct blood transfusion is currently prohibited according to the order of the Russian Ministry of Health No. 363. Blood reinfusion reduces the risk of blood transfusion complications, eliminates the risk of the patient becoming infected with blood-borne infections, and expands the possibilities for carrying out extensive surgical interventions. Autohemotransfusion or reverse transfusion of previously prepared blood has been increasingly recognized in obstetric practice in recent years. This includes both the procurement of autologous plasma (collection usually begins 1-2 months before abdominal delivery using plasmapheresis) and cryopreservation of erythrocytes by creating an autologous blood bank before pregnancy.

Natural carriers of blood gases include erythrocyte mass and erythrocyte suspension: one dose of donor erythrocytes increases hemoglobin by 10 g/l, and hematocrit by 3-4%. The following hemogram values indicate an adequately replenished volume of circulating erythrocytes, ensuring effective oxygen transport: hematocrit - 27%, hemoglobin - 80 g/l.

Currently, preference is given to erythrocyte suspension, since when using erythromass in the treatment of acute blood loss, the level of 2,3-diphosphoglycerate in it drops sharply by the 2-3rd day of storage; under conditions of generalized endothelial damage, which occurs in decompensated shock, it very quickly appears in the interstitial space; the risk of developing acute lung injury syndrome (ALIS) when using it in the case of massive blood loss will increase by 2-3 times compared to whole blood.

Plasma and albumin play a special role in replenishing the BCC. The advantages of plasma include the fact that it is a universal hemocoagulation corrector. A negative aspect is the contamination of the patient's plasma with microclots, blood cell aggregates and their fragments, which increase the blockade of microcirculation and dysfunction of target organs; an increase in the concentration of coagulation-active phospholipid matrices in plasma, which maintain hypercoagulation even against the background of intensive anticoagulant therapy; as well as an increase in the level of antiplasmin and tissue plasminogen activator.

Albumin has high oncotic activity, well maintaining colloid-osmotic pressure, which determines the high hemodynamic effect of the drug. The ability of the drug to bind various substances, including bilirubin (in this regard, albumin with increased sorption capacity is especially effective), determines its transport function and makes it indispensable for the elimination of foreign substances and decay products, and the effect of 100 ml of a 20% albumin solution corresponds to the oncotic effect of approximately 400 ml of plasma. It should be remembered that the use of albumin in the case of sharply impaired vascular permeability due to a change in the reflection angle as a result of severe hypoproteinemia can lead to pulmonary edema and worsening hypovolemia due to fluid migration into the interstitium.

Of the blood substitutes-oxygen carriers, the most important are hemoglobin solutions without stroma (erygem) and fluorocarbons (perftoran, perfukol). Their use is still constrained by such practical shortcomings as low oxygen capacity, short circulation time in the body and reactogenicity. In the conditions of the ever-increasing threat of AIDS, as well as numerous shortcomings of preserved blood, the future in transfusiology belongs to oxygen carriers.

When treating hypovolemia with colloids or crystalloids, it is advisable to adhere to the following rule: colloidal solutions should make up at least 25% of the infused volume.

Additional hemodynamic and inotropic support with adrenomimetics dopamine and dopamine provides a positive effect on renal blood flow and minimizes microcirculatory disorders; it is also necessary to include a short course of glucocorticoids, and, if indicated, fibrinolysis inhibitors, recombinant blood clotting factors (Novoseven).

It is important to consider the need for a fine individual combination of optimal methods of treating anemia during surgery for the patient, which consists in the ability to continuously respond dynamically. Thus, correction of blood loss in the perioperative period is a rather delicate score in the skillful hands of a blood transfusion specialist, in whose role most often turns out to be an anesthesiologist-resuscitator, while maintaining the constants of classical blood transfusion, which do not interfere with, but organically combine with the freedom of creative experimentation.

Doctor of Medical Sciences, Professor Ziyatdinov Kamil Shagarovich. Correction of blood loss in surgery // Practical Medicine. 8 (64) December 2012 / Volume 1

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