Alloimmunization and erythrocyte autoimmunization in transfusion-dependent thalassemia patients of predominantly Asian descent

BACKGROUND Cell salvage has been used in obstetrics to a limited degree because of a fear of amniotic fluid embolism. In this study, cell salvage was combined with blood filtration using a leukocyte depletion filter. A comparison of this washed, filtered product was then made with maternal central venous blood. METHODS The squamous cell concentration, lamellar body count, quantitative bacterial colonization, potassium level, and fetal hemoglobin concentration were measured in four sequential blood samples collected from 15 women undergoing elective cesarean section. The blood samples collected included (1) unwashed blood from the surgical field (prewash), (2) washed blood (postwash), (3) washed and filtered blood (postfiltration), and (4) maternal central venous blood drawn from a femoral catheter at the time of placental separation. RESULTS Significant reductions in the following parameters were seen when the postfiltration samples were compared to the prewash samples (median [25th-75th percentile]): squamous cell concentration (0.0 [0.0-0.1 counts/high-powered field (HPF)] vs. 8.3 counts/HPF [4. 0-10.5 counts/HPF], P < 0.05); bacterial contamination (0.1 [0.0-0. 2] vs. 3.0 [0.6-7.7] colony-forming units (CFU)/ml, P < 0.01); and lamellar body concentration (0.0 [0.0-1.0] vs. 22.0 [18.5-29.5] thousands/microl, P < 0.01). No significant differences existed between the postfiltration and maternal samples for each of these parameters. Fetal hemoglobin was in higher concentrations in the postfiltration sample when compared with maternal blood (1.9 [1.1-2. 5] vs. 0.5% [0.3-0.7] ). Potassium levels were significantly less in the postfiltration sample when compared with maternal (1.4 [1.0-1.5] vs. 3.8 mEq/l [3.7-4.0]). CONCLUSIONS Leukocyte depletion filtering of cell-salvaged blood obtained from cesarean section significantly reduces particulate contaminants to a concentration equivalent to maternal venous blood.

Amniotic Fluid Removal during Cell Salvage in the Cesarean Section Patient

Numerous approaches are used to avoid transfusion of allogeneic blood Primary methods include, but are not limited to, erythropoietin and iron supplementation, pre-operative autologous donation, acute normovolaemic haemodilution, haemoglobin-based blood substitutes and infusible oxygen-carrying fluids, and the use of cell salvage systems While currently unavailable in North America and Europe because of an increased risk of myocardial infarction and death1,2, research continues in the areas of haemoglobin-based blood substitutes and infusible oxygen-carrying liquids

Of the accepted strategies mentioned above, cell salvage offers the medical community a safe, resource-saving, and relatively inexpensive method to avoid allogeneic red cell transfusion Currently, incorrect information and misconceptions regarding the use of cell salvage systems frequently portray them as expensive, ineffective, and inappropriate for use in certain clinical situations In addition to addressing these misconceptions, this article will discuss indications and contraindications for the use of such systems

Intra-operative cell salvage: a fresh look at the indications and contraindications.

The safety of intraoperative autologous blood collection and autotransfusion during cesarean section

The aim of this study was to assess blood salvage during Caesarean section. In 15 Caesarean sections, red cells lost were collected and washed with a Dideco machine and tested for the presence of fetoplacental material, bacterial contamination, free haemoglobin and fetal blood cells. Successive patients were allocated randomly to one of two groups. In group 1 (n = 34), intraoperative blood was salvaged, while group 2 served as a control. The mean amount of blood salvaged in group 1 was 363 (SD 153) ml. Blood was salvaged following these guidelines: identification of blood group of the mother and fetus; avoidance of aspirating blood from the umbilical cord; commencement of salvage after removing the fetoplacental unit; completely filling the centrifugation bowl with red cells; washing the cells using at least 1000 ml of physiological solution per bowl; and mixing the contents of the bowl, completely eliminating the buffy coat where fetal cells are located. In group 1, the use of homologous blood transfusions was significantly lower (one of 34 (2.9%) patients compared with eight of 34 (23.5%); P = 0.01), haemoglobin concentrations during the first 4 days after operation were significantly higher and postoperative hospital stay was significantly shorter. Duration of hospital stay was significantly shorter in group 1 (5.3 (1.9) vs 7.3 (4) days; P = 0.003). Mean base haemoglobin concentrations were significantly lower in group 1 (10.7 (1.4) vs 11.7 (1.5) g dl-1; P > 0.0001), while after surgery mean haemoglobin concentrations were significantly higher approximately 3 h after operation compared with the control group (10.2 (1.5) vs 8.6 (1.2) g dl-1; P < 0.0001). On the first day, haemoglobin concentrations were 9.8 (1.5) vs 8 (1.4) g dl-1 (P < 0.0001), on the second day 9.8 (1.4) vs 7.7 (1.4) g dl-1 (P < 0.0001), on the third day 10.1 (1.5) vs 7.5 (1.3) g dl-1 (P < 0.0001) and on the fourth day 10.4 (1.5) vs 8.1 (1.4) g dl-1 (P < 0.0001).

Blood salvage during caesarean section.

Etude rhéologique et cytologique du sang autologue recueilli par le « Cell Saver 4au cours de césarienne

Recombinant human erythropoietin (rhu EPO) is the choice treatment of dialytic anemia; however, this therapy has side effects due to the increased number of blood components involved. It seemed to us worth assessing, by hemorheological study, the impact of such a treatment on blood flow properties, already impaired in this type of patients. This study was designed to measure the evolution of hemorheological parameters in 16 hemodialysed patients before and after 2.3 and 6 months of treatment with rhu EPO. Hemorheological work-ups included: erythrocyte filtration with a hemorheometer; blood and plasma viscosities (LS30), ATP and 2.3 DPG, RBC aggregation (Sefam erythroaggregameter), RBC morphology under a scanning electron microscope; blood counts and full biochemical work-ups were performed to explore renal function. The results showed, besides a significant increase in hemoglobin: normalized rigidity index, reflecting the better deformability of erythrocytes; a moderate increase in blood viscosity with uncorrected hematocrit, becoming significant after 6 months of treatment. This increase however did not reach the values that could be expected with the increased hematocrit (it was probably balanced by improved erythrocyte deformability, which is confirmed by the fact that with corrected hematocrit, blood viscosity decreases during treatment). Studying erythrocyte aggregation in hemodialysed patients reveals, in the absence of any treatment, a decrease in aggregation time and a higher dissociation threshold, which reflects a tendency to erythrocyte hyperaggregation enhanced by erythropoietin.(ABSTRACT TRUNCATED AT 250 WORDS)

Improvement of hemorheologic parameters in hemodialyzed patients treated with human recombinant erythropoietin

Study of hemorheological parameters in patients with chronic renal failure and evolution of those parameters in the course of dialysis treatment

In autoimmune haemolytic anaemia, the presence of antibodies on the erythrocyte membrane results in haemolysis through an immune process, but does it not alter the rheological properties of red blood cells (RBC), thus adding a mechanical factor to haemolysis? This study was designed to examine the rheological properties of erythrocytes sensitized with IgG-type antibodies. The study involved 20 patients with anaemia and positive direct antiglobulin test, including 12 with straightforward haemolysis, 10 samples sensitized in vitro, and 20 controls. The following haemorheological parameters were studied: erythrocyte filtration, blood and plasma viscosities, titration of adenosine triphosphate (ATP) and 2-3-DPG, erythrocyte morphology under scanning electron microscopy. The results showed increased erythrocyte rigidity (P less than 0.025) as well as higher blood viscosity compared to controls with similar haematocrit values, and unaltered ATP and 2-3-DPG (consistently with scanning electron microscope observations). These haemorheological disorders were more noticeable in patients with clear-cut haemolysis, and there was a correlation between the increase in erythrocyte rigidity indices and the haemolytic parameters, especially haptoglobin (P less than 0.001). The in vitro study confirmed the results obtained ex vivo. To conclude, the mechanical properties of antibody-coated erythrocytes are impaired, which may promote the immunological mechanism favouring haemolysis in the spleen.

Is there a mechanical factor of haemolysis in patients with positive IgG-type direct antiglobulin test?

Resume Dans les anemies hemolytiques auto-immunes, la presence d'anticorps sur la membrane erythrocytaire conduit a une hemolyse selon un processus immunologique, mais ne modifie-t-elle pas les proprietes rheologiques des hematies, participant ainsi a l'hemolyse par un processus mecanique? Le but de ce travail a ete d'etudier les proprietes rheologiques d'hematies sensibilisees par des anticorps de type IgG. L'etude a porte sur 20 patients porteurs d'anemie avec test de Coombs direct positif, dont 12 presentent une hemolyse franche, 10 echantillons sanguins sensibilises in vitro, et 20 sujets temoins. Les parametres hemorheologiques suivants ont ete mesures: filtration erythrocytaire, viscosites sanguine et plasmatique, dosage de l'ATP et du 2,3 DPG, morphologie des hematies en microscopie electronique a balayage (MEB). Les resultats montrent une augmentation des index de rigidite erythrocytaire (p

F. Durand

Papers

Etude rhéologique et cytologique du sang autologue recueilli par le « Cell Saver 4au cours de césarienne

Improvement of hemorheologic parameters in hemodialyzed patients treated with human recombinant erythropoietin

Study of hemorheological parameters in patients with chronic renal failure and evolution of those parameters in the course of dialysis treatment

Is there a mechanical factor of haemolysis in patients with positive IgG-type direct antiglobulin test?

Existe-t-il un mécanisme physique d'hémolyse chez les patients porteurs d'une anémie hémolytique autoimmune?