DYNAMICS OF FUNCTIONAL CONDITION OF KIDNEYS IN THE EARLY PERIOD AFTER SKELETAL INJURY OF DIFFERENT SEVERE COMPLICATED BY BLOOD LOSS

Abstract

In modern conditions, the rise in the frequency of terrorist attacks and local armed conflicts has become an urgent problem. Under these conditions, a significant frequency of acute blood loss and mechanical damage to the limbs is noted, which in 80–90 % of cases are the main cause of death of the injured and wounded. Timely and correct imposition of the arterial tourniquet contributes to significant survival of the wounded in conditions of massive external bleeding from the extremities, but does not deprive further systemic disorders caused by the severity of blood loss and injuries of the skeletal bones.

The aim of the study – to learn the dynamics of the functional state of the kidneys in the early period after the application of skeletal injury of varying severity, complicated by blood loss.

Materials and Methods. The experiments were performed on 60 non-linear white rats-males weighing 180–200 g, which were on the standard diet of the vivarium. All animals were divided into 4 groups: control (6 animals) and three experimental ones (18 animals each). In the control group, rats were only anesthetized (sodium thiopental, 40 mg×kg^-1). In the first experimental group, thiopenenatonatrial anesthesia was used to simulate skeletal injury by applying a dosed strike on the thigh, which caused a closed fracture, in the second – an additional 20–22 % blood volume loss was modeled with the introduction of autologous blood into the abdominal cavity at the rate of 0.5 ml per 100 g of animal weight. In the third group, the adjacent thigh was additionally broken. After 1, 3 and 7 days in experimental animals, the functional state of the kidneys was determined by the water load method. After a two-hour urine sampling and diuresis determination under thiopental-sodium anesthesia, rats were taken out of the experiment by the method of total bleeding from the heart. In the urine and serum determined the concentration of creatinine. Calculated glomerular filtration rate (GFR) and creatinine excretion.

Results and Discussion. Under the influence of skeletal injury (closed hip fracture) in the acute period (1 day) and the period of early manifestations of traumatic disease (3–7 days) in traumatized rats diuresis, GFR and creatinine excretion are significantly reduced. The revealed violations reached a maximum after 3 days and improved up to 7 days, not reaching the values of the control group, which indicated an increase in the kidney processes of sanogenesis. Additional blood loss with simultaneous modeling of hematoma in the abdominal cavity contributed to a significant deterioration of the studied parameters: diuresis, GFR, creatinine excretion significantly decreased. On the one hand, the detected violations are based on a decrease in the effective filtration pressure in the kidney, on the other hand – a combination of compensatory reactions in response to acute blood loss, aimed at retaining water and sodium ions, which as a result reduces diuresis. However, the greatest violations occurred with the simultaneous fracture of the adjacent thigh. In this case, the leading role played by systemic disorders caused by severe trauma, in particular the factors that formed the body's systemic response to inflammation. The results aim to ensure that the kidney plays a key role in the processes of homeostatic regulation in conditions of severe injury, which requires new approaches to the correction of systemic disorders in conditions of severe skeletal injury, aimed at strengthening the mechanisms of sanogenesis.

Conclussions. Under conditions of isolated skeletal injury (fracture of the femur), diuresis is significantly reduced by up to 3 days compared with the control group, the glomerular filtration rate and creatinine excretion slow down. Up to 7 days, the kidney function improves, but the studied parameters do not reach the level of the control group. Additional blood loss (20–22 % of the circulating blood volume) and modeling of hematoma in the abdominal cavity (0.5 ml per 100 g of animal weight) against the background of a closed hip fracture is accompanied by a deepening of the kidney function, which is manifested by a large decrease in diuresis, glomerular velocity filtering and excretion of creatinine than an isolated hip fracture. The indicators reach a maximum after 3 days and remain at the same level for up to 7 days. In conditions of fracture of both hips, blood loss and hematoma modeling in the abdominal cavity, functional disorders of the kidneys from 1 to 7 days are aggravated and after 7 days significantly exceed other research groups that simulated an isolated hip fracture or additionally simulate blood loss and hematoma.