Prediction of Intraoperative Blood Loss during Total Knee Arthroplasty in HCV+ and HCV- Patients with Hemophilia A.

We examined HCV+ and HCV- hemophilia A patients with knee arthropathy and hematocrit above 38.5%. The mean density of erythrocytes was studied by the phthalate method, intraoperative blood loss was assessed gravimetrically. The volume of blood loss in HCV+ patients with manifest adhesive process and chronic synovitis varied from 300 to 1900 ml, in patients with moderate adhesive process from 400 to 1500 ml. The volume of blood loss in HCV- patients was 300-800 ml. A positive correlation between the blood loss volume and mean density of erythrocytes was detected. Blood loss >1000 ml during total knee arthroplasty can be expected in patients with hemophilia A with HCV and high mean density of erythrocytes. Blood loss >1000 ml is unlikely in HCV- and HCV+ patients with the mean density of erythrocytes not surpassing the normal values.

Effect of Hematocrit and Erythrocyte Density on Intraoperative Blood Loss in Hemophilia A Patients During Total Knee Arthroplasty.

Intraoperative blood loss during total knee arthroplasty in patients with hemophilia varies over a wide range (from 300 to 3000 ml). The reasons have not been clarified yet. We studied the dependence of intraoperative blood loss during total knee arthroplasty in patients with hemophilia A on hematocrit and mean erythrocyte density. Intraoperational blood loss ≥1000 ml was observed in patients with hematocrit <38.5%. In patients with hematocrit >38.5% this parameter depended on the mean erythrocyte density: in patients with increased erythrocyte density, the risk of intraoperational blood loss ≥1000 ml was higher. The increase in erythrocyte density can serve as an indicator of pathological processes, including the processes modulating hemostasis. It can also be assumed that erythrocytes with higher density change blood flow, which affects platelet adhesion to the damaged endothelium. Hematocrit below the threshold level and mean density of erythrocytes above the normal level can be regarded as risk factor for increased intraoperational blood loss.

[The method of analysis of distribution of erythrocytes by density: practical guidelines].

The article describes the phthalate method of analysis of distribution of erythrocytes by density and demonstrates its possibility. The distribution of erythrocytes by density is implemented using centrifugation of blood in micro-hematocrit capillaries in presence of compounds of dimethyl- and dibuthylphthalates of known density. The acquisition of such clinically reliable parameters of distribution of erythrocytes by density as mean density of erythrocytes, width of distribution of erythrocytes by density, light and heavy fraction of erythrocytes and maximum of curve of distribution of erythrocytes by density is described. The causes of deviation of distribution of erythrocytes by density from standard values under various pathological conditions are considered. The syndrome of dehydration of erythrocytes is described in details. The simple and accessible method of acquisition of distribution of erythrocytes by density is described. It is demonstrated that analysis of distribution of erythrocytes by density makes it possible to determine character of changes occurring with erythrocytes. The monitoring of parameters of distribution of erythrocytes by density allows evaluating dynamics of pathological process and effectiveness of therapy.

Filtration method for studies of the kinetics of hypo-osmotic pore closure in erythrocyte.

Filterability of erythrocytes through small (3 µ) pores decreases with decreasing osmolarity of suspension medium because of hypo-osmotic swelling of cells. After appearance of lytic pores, erythrocyte filterability increases for some time, while after recovery of membrane integrity it decreases again. We suggest filtration method for studies of the kinetics of hypo-osmotic lytic pores closure. The dynamics of changes in erythrocyte filterability was studied in 2 patients with paroxysmal nocturnal hemoglobinuria and 6 donors (Ht 0.01%, Na phosphate buffer 5 mM, pH 7.4, 35 mOsm, 24°C). The method can be used for studies of erythrocyte membrane characteristics in various diseases and for evaluation of the membranotropic effects of drugs, infusion media, hemolysins, ethanol, etc.

[Density-specific distribution of erythrocytes in different types of anemia].

AIM: To study density-specific distribution of erythrocytes (DSDE) in different types of anemia. MATERIAL AND METHODS: DSDE was determined in anemic patients by fractionation of the whole blood in hematocritic capillaries in the presence of mixtures of dimethyl- and dibutylphthalates with known density. RESULTS: Parameters are proposed which characterize DSDE changes typical for each type of anemia: mean erythrocyte density (MED)--mean density of total erythrocytic population; DSDE width (W)--a characteristic of erythrocytic population heterogeneity; light fraction of erythrocytes (LEF)--% of the cells with density less than 1.086 g/ml (hypochromic cells and reticulocytes); dense fraction of erythrocytes (DEF)--% of cells with density over 1.112 g/ml (hyperchromic cells forming as a result of erythrocyte dehydration). DSDE parameters for different types of anemia differed: reduced MED was typical for iron deficiency anemia (IDA) and paroxysmal nocturnal hemoglobinuria (PNH), increased DEF was seen in microspherocytic anemia (MSA), autoimmune hemolytic anemia (AHA), deficiency of glucose-6-phosphate dehydrogenase, increased LEF was observed in reticulocytosis in all anemia types except MSA, DSDE W was larger in MSA, AHA, PNA. CONCLUSION: DSDE is determined by proportion of erythropoiesis and sequestration of erythrocytes as well as pathological impacts leading to impairment of membrane permeability for cations and erythrocytic metabolism. Informative value of DSDE parameters makes them effective for diagnostic screening of anemias and control over course of different diseases.

Detection of stages of autoimmune hemolytic anemia by evaluating erythrocyte deformability and density.

Study of erythrocyte density and deformability in patients with hemolytic anemia, including long-term monitoring of 5 patients, helped us to characterize the pathological processes leading to changes in the erythrocyte population at different terms of the disease and to detect its main stages (agglutination, pathological dehydration, combination of pathological dehydration and microvesiculation, hemolytic crisis, and remission).

Determination of the content of nonfilterable cells in erythrocyte suspensions as a function of the medium osmolality.

The results of most filtration assays for deformability of erythrocytes do not distinguish whether the entire population or only its small fraction exhibits abnormal rheological properties. We developed a simple filtration method for determination of the percentage of nonfilterable cells in erythrocyte suspension using membrane filters with mean pore diameter of 3.1 microns. This method makes it possible to detect even minor abnormal subpopulations in erythrocyte suspensions. The flow rate of buffer depends on the number of free pores of a filter. The plot of the number of pores clogged by nonfilterable cells vs the total number of erythrocytes that were allowed to pass through the filter had a linear portion, with a slope representing the relative content, Z%, of nonfilterable cells in the suspension. We determined Z% for various medium osmolalities u and used the data to derive the distribution of erythrocytes in ucr (ucr is the maximum value of u at which an erythrocyte cannot pass through a pore of a given filter because of geometric limitations). The distribution of ucr in suspension of normal erythrocytes has a maximum of about 200 mOsm/kg and a half-width of about 20 mOsm/kg. The distributions of ucr are altered in normal erythrocyte suspensions at decreased pH values, in cryopreserved and ATP-depleted erythrocyte suspensions and in erythrocytes from a xerocytosis patient.

A modification of the filtration method for studying the content of nonfilterable cells in erythrocyte suspension.

The results of filtration assays provide estimates of the deformability of erythrocytes averaged over the entire suspension. These assays do not distinguish whether the entire population or only its small fraction exhibits abnormal rheological properties. We developed a simple method using a filtrometer to determine the percentage of non-filterable (under given conditions) cells in the erythrocyte suspension. Membrane filters made of a polyethylene terphthalate film had the mean pore diameter of 3.1 microns and the length of cylindrical micropores of 7 microns. The buffer flow rate tb depends on the number of free pores in a filter. The plot of the number of pores clogged by non-filterable cells versus the total number of erythrocytes passed through the filter had a linear portion whose slope represents the relative content Z of non-filterable cells in the suspension. We determined Z for various medium osmolarities u. These data were used to derive the distribution of erythrocytes in ucr, the value of u at which an erythrocyte cannot pass through a pore of a given filter because of geometric limitations. The distribution maximum corresponded to 190-200 mOsm/kg for erythrocytes from the normal blood. This means that normal erythrocytes have the median values of their surface area and area-to-volume ratio of 155-151 microns2 and 1.72-1.68 microns-1, respectively. The half-width of the distribution was approximately 30 mOsm/kg. This finding suggests that the normal blood contains a certain fraction of erythrocytes with a decreased area-to-volume ratio. Our results showed that the distribution is altered in various forms of anemia and in ATP-depleted erythrocyte suspensions.