Erythrocytapheresis Procedures Research Articles

Evaluation of erythrocytapheresis compared to phlebotomy in polycythaemia vera patients

IntroductionPolycythaemia vera patients can present with arterial or venous vascular occlusive events such as thrombosis or cardiovascular disease; disease-related symptoms may significantly impact on the quality of life. The aim of this study was to evaluate the efficacy and safety of erythrocytapheresis compared to phlebotomy in the treatment of polycythaemia patients. MethodsThis study reports the findings of a retrospective analysis of 40 polycythaemia vera patients diagnosed according to published guidelines and treated either with erythrocytapheresis or phlebotomy over a four-year period. The goal of treatment was to reduce blood volume and red blood cell count to near normal levels as both of which may attenuate the symptoms and complications associated with polycythaemia. Patients were treated by applying a mathematical model. ResultsUsing the model, 28 erythrocytapheresis procedures were performed. Blood laboratory values (red blood cell count, haemoglobin count and haematocrit level) were significantly reduced in patients treated with erythrocytapheresis. Moreover, among treated patients, erythrocytapheresis resulted in less work absenteeism and reduced costs due to lost production, with a lower overall procedure cost in comparison to phlebotomy. ConclusionThis model can assist in selecting the proper treatment modality for individual patients. Especially for those with high blood volumes and high achievable haematocrit levels (delta), erythrocytapheresis offers a more efficient method in red blood cell depletion compared to phlebotomy thereby, potentially reducing the number of treatment procedures required for the induction of polycythaemia vera patients as well as the interval between procedures during the maintenance phase.

Effects of Erythrocytapheresis Procedures on Delayed Bone Marrow Conversion in Sickle Cell Disease

The imaging appearances of the skeletal system have been well documented in sickle cell disease (SCD) but there is limited information about the impact of SCD treatments on skeletal abnormalities. We present two patients with SCD maintained on long-term erythrocytapheresis and the changes to their skeletal abnormalities on neuroimaging with this treatment. We observed a reversal of the bone marrow conversion process and the skull appearance was age appropriate without any radiographic findings of iron overload in the patients.

Assessment of Average Hematocrit of Red Cell Units for Erythrocytapheresis Procedure in Sickle Cell Disease

Background:Erythrocytapheresis, or red blood cell exchange (RCE) is a non-invasive procedure in which a patient's erythrocytes are removed from the bloodstream while being replaced with erythrocytes from blood donors. RCE is commonly used as a transfusion technique in patients with sickle cell disease (SCD) to help treat and prevent complications associated with sickling of erythrocytes and iron overload.The AABB consensus report (1) outlines the procedural guidelines for RCE including appropriate indications and ideal forms of vascular access. However, the guidelines make no recommendation for determining the hematocrit (Hct) of the red cell bags for the procedure.Institutions take several different approaches to determine how many red cell units to exchange. The number of units needed depends on the volume and Hct of the individual units as well as the patient's pre-procedure Hct and HbS levels, height, weight, and the desired HbS and Hct targets. Red cell units are routinely labeled with volume, but are not generally labeled with Hct. The AABB consensus report (1) states that some institutions use an estimated Hct of 56% to 57% for each unit. The report rationalizes the use of an estimated Hct for input for the RCE, by citing the approximated Hct of bags of red cells (55% to 60%) with additive solution produced from whole blood donation, based on limited data.The goal of our study was to determine the average Hct on the red cell units used for RCE.Methods:This study used a retrospective chart review to investigate the Hct of red cell units during a RCE in a calendar year. Our institution uses pre-storage leuko-reduced red blood cells units in citrate phosphate dextrose adenine (CPDA-1) and adsol preservative (AS-1), which are 21 days old or less for RCE. The average Hct of the bags of red cells infused during the procedure was determined by accessing each bag for a small sample of blood to determine the Hct. Data was excluded if the patient did not meet standard weight requirements (> 30 kg) or required additional treatment protocols including the use of washed cells or machine priming.Results:A total of 297 encounters were recorded for 30 different patients. A total of 1953 bags (approximately 517 liters of red cell units in volume) were administered. Data from the encounters were used to calculate measures of central tendency. The average calculated Hct for each encounter was 63.3%, with a median and mode Hct being 63% and 62%. The range of Hct from the bags was 54.6% to 72.9%. The average Hct of the bags ranged from 60.6% (in March) to 64.8 % (in July).Conclusions:Our study suggests a higher average Hct of transfused red cell units than stated in the AABB consensus report (1), which was based on limited data. Our findings indicate that a standardized average of 63.3%, would be appropriate for our institution. Conversely, our findings also signify that the standardized average Hct must be determined in each institution prior to their application for RCE. However, our data also reveals that it is possible to subject patients to estimates as far as 9.7% above and 9.6 % below the true average Hct of the red cell bags used. The process of determination of Hct for each of the red cell units increases the time of pre-service activities, laboratory costs, and the overall infusion center time for the patients leading to higher costs per infusion. Consequently, using a standardized average of the Hct would result in cost savings. We have therefore adopted the practice of using the standardized average of Hct of 63.3% for RCE in our patients.Reference:1. Biller E, Zhao Y, Berg M, Boggio L, Capocelli KE, Fang DC, Koepsell S, Music-Aplenc L, Pham HP, Treml A, Weiss J, Wool G, Baron BW. Red blood cell exchange in patients with sickle cell disease-indications and management: a review and consensus report by the therapeutic apheresis subsection of the AABB. 2018 Aug;58(8):1965-1972. doi: 10.1111/trf.14806 DisclosuresMunson: Terumo Medical Corporation: Consultancy, Honoraria, Speakers Bureau. Raj: Terumo Medical Corporation: Honoraria, Speakers Bureau; Global biotherapeutics: Speakers Bureau; Forma therapeutics: Consultancy.

Long-term Erythrocytapheresis Is Associated With Reduced Liver Iron Concentration in Sickle Cell Disease.

Erythrocytapheresis procedures are increasingly used in sickle cell disease. Serum ferritin and noninvasive magnetic resonance imaging measurements of liver iron concentration (LIC) are frequently used to monitor iron overload secondary to hypertransfusion. There is a paucity of data describing the impact of long-term erythrocytapheresis (LTE) on LIC. We measured magnetic resonance imaging liver and cardiac iron on LTE subjects and stratified them into 2 groups: higher LIC (>3 mg/g) and lower LIC (<3 mg/g). χ(2) and t test were used to test for differences between the 2 groups. Logistic regression and generalized linear mixed-effects models were used to test what impacted LIC. None of 29 sickle cell disease subjects maintained on LTE had high cardiac iron concentration. LIC was associated with serum ferritin (r=0.697, P<0.001) but was not associated with the total number of LTE procedures (r=-0.088, P=0.656) or total number of simple transfusions (r=0.316, P=0.108). The total number of LTE procedures was not associated with serum ferritin (r=0.040, P=0.838), the total number of simple transfusions (r=-0.258, P=0.184), or LIC group (r=-0.111, P=0.566). There was no significant correlation between duration of LTE maintenance and LIC.

Long Term Erythrocytapheresis Is Associated with Reduced Liver Iron Concentration in Sickle Cell Disease

Background:Observational studies and randomized clinical trials have demonstrated that RBC transfusions can alleviate or prevent many complications of sickle cell disease (SCD). Obligatory iron loading is most problematic for those receiving chronic simple transfusions and is managed with chelation therapy to prevent hepatic, cardiac, and endocrinologic complications. Erythrocytapheresis procedures are increasingly used in SCD as they achieve dilution of hemoglobin S without significantly raising the total hematocrit. Some guidelines for the management of iron overload use serum ferritin levels, but non-invasive measurements of liver iron concentration (LIC) using validated and widely available MRI techniques have been described. There is a paucity of data elucidating the impact of long-term erythrocytapheresis (LTE) on LIC. We evaluated LIC with MRI and serial serum ferritin measurements among a population of SCD patients maintained on LTE at a single institution.Methods:Subjects with SCD maintained on the LTE program included those with elevated TCD, history of stroke, recurrent acute chest syndrome, or frequent pain crises unresponsive to hydroxyurea therapy. Serial serum ferritin measurements were followed and chelation with deferasirox was initiated for consistent ferritin level >1000 ng/mL. MRI of liver and cardiac iron was measured on all LTE subjects with non-contrast MRI techniques. A total of n=31 subjects maintained on LTE were enrolled and stratified into two groups: high LIC, ≥5mg/g of dry tissue (n=4, 12.9%) and low LIC, <5mg/g (n=27, 87.1%). Chi-squared and t-test were used to test for differences between the two groups. Logistic regression was used to test what impacted the odds of having a high LIC, while generalized linear mixed-effects modeling was used to test what impacted LIC.Results:None of the subjects had high cardiac iron concentration. Subjects with high LIC were significantly older (17.8 vs. 13.1, p=0.032) and were more likely to be female (100% vs. 44.4%, p=0.038). The duration of LTE was not associated with high and low levels of LIC (8.25 vs. 6.15, p=0.240, Figure 1), levels of LIC (r=0.247, p=0.188, Figure 2), or serum ferritin (r=0.077, p=0.680). The total number of simple of transfusions was not associated with serum ferritin (r=-0.177, p=0.558) or LIC (r=-0.022, p=0.910). Serum ferritin was not significantly associated with LIC (r=0.296, p=0.112, Figure 3). One of the 4 patients with high LIC required chelation with deferasirox for ferritin >1000 ng/mL. Three of the 31 subjects required iron chelation with deferasirox.Conclusions:There was no significant correlation between duration of LTE and LIC. The impact of cumulative simple transfusions on LIC was obviated by maintenance LTE. These findings are consistent with reports that LTE is associated with reduced transfusional iron overload. The lack of significant association between serum ferritin and LIC suggest that validated MRI measurements of LIC may have greater sensitivity for identifying patients with iron overload and guidelines for iron chelation should consider LIC rather than serum ferritin alone. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Nitric oxide scavenging by cell-free hemoglobin may be a primary factor determining hypertension in polycythemic patients

We tested the hypothesis that hypertension associated with polycythemia vera (PV) may be related to hemoglobin released from erythrocytes (cell-free hemoglobin, fHb). We assessed hematocrit, mean arterial pressure (MAP), blood viscosity, and the level of fHb and nitrite/nitrate (NOx) in the plasma of 73 PV patients and 38 healthy controls. The effect of isovolemic erythrocytapheresis (ECP) on the considered parameters was also studied. From the whole group of PV patients a subset of subjects with normal (normotensive patients, n = 16) and elevated MAP (hypertensive patients, n = 57) can be subtracted.It was found that in comparison with healthy controls, PV patients have significantly (p ≤ 0.01) elevated Hct (0.567 vs. 0.422), blood viscosity (5.45 vs. 3.56 cP), MAP (106.8 vs. 93.8 mmHg), plasma fHb (9.7 vs. 2.8 mg/dL), and NOx levels (34.1 vs. 27.5 μM). Compared with normotensive patients, hypertensive PV patients demonstrated a higher rise in fHb (10.2 vs. 8.0) and plasma NOx levels (35.8 vs. 31.0). In PV patients, fHb positively correlates with MAP (r = 0.489), NOx levels (r = 0.461), hematocrit (r = 0.428), and viscosity (r = 0.393). Blood viscosity positively correlated with hematocrit (r = 0.894), but not with other considered parameters. In PV patients MAP poorly correlated with hematocrit, whereas the correlation between MAP and NOx altered from − 0.325 (healthy control) to + 0.268 (PV patients). ECP procedure was associated with a significant (p < 0.01) reduction of hematocrit, fHb, blood viscosity, and MAP. In the normotensive subgroup of PV patients the ECP procedure did not affect MAP. It can be concluded that accelerated scavenging of nitric oxide by fHb rather than high Hct may be a key factor determining the development of hypertension in PV patients.

An Attempt to Induce Transient Immunosuppression Pre-Erythrocytapheresis in a Girl with Sickle Cell Disease, a History of Severe Delayed Hemolytic Transfusion Reactions and Need for Hip Prosthesis

We report on a case of delayed hemolytic transfusion reaction (DHTR) occurred 7 days after an erythrocytapheresis or eritroexchange procedure (EEX) treated with rituximab and glucocorticoids in a 15-years old patient with sickle cell disease. EEX was performed despite a previous diagnosis of alloimmunization, in order to reduce hemoglobin S rate before a major surgery for avascular necrosis of the femoral head. A first dose of rituximab was administered before EEX. However, rituximab couldn’t prevent DHTR that occurred with acute hemolysis, hemoglobinuria and hyperbilirubinemia. A further dose of rituximab and three boli of methylprednisolone were given after the onset of the reaction. It is likely that the combined use of rituximab and steroids managed to gradually improve both patient’s general conditions and hemoglobin levels. Nor early or late side effects were registered in a 33-months follow-up period. This report suggests the potential effectiveness and safety of rituximab in combination with steroids in managing and mitigating the symptoms of delayed post-transfusional hemolytic reactions in alloimmunized patients affected by sickle cell disease with absolute need for erythrocytapheresis.

Long-term red blood cell exchange in children with sickle cell disease: Manual or automatic?

Little information is available on erythrocytapheresis in children with sickle cell disease, and no comparison has ever been made with manual exchanges in a long-term blood exchange program. We matched a historical cohort of five patients who received 60 erythrocytapheresis procedures with five who received 124 manual exchanges. Long-term erythrocytapheresis was feasible and well-tolerated even in children of low weight. In a long-term approach, automated exchanges were more efficient in maintaining a low HbS level, and exchanges could be spaced out. This approach appears especially useful in the cases where the HbS level must be maintained below 30%.

Short-Term Femoral Catheter Insertion: A Promising Alternative to Consistently Allow Long-Term Erythrocytapheresis Therapy in Children with Sickle Cell Anemia

Erythrocytapheresis procedures, increasingly used in the management of patients with severe complications of sickle cell disease, are limited by adequate venous access. We have successfully used short-term femoral catheter insertion, during a 6.5-year period for a total of 443 procedures, to perform long-term erythrocytapheresis in 18 consecutive children with sickle cell disease.

Utility of Impedance Cardiography for the Detection of Hemodynamic Changes in Stable Patients With Sickle Cell Disease

The study sought to assess the potential utility of impedance cardiography (ICG) to detect hemodynamic changes after erythrocytapheresis in stable children with sickle cell disease (SCD). We prospectively monitored cardiac index, systemic vascular resistance index, heart rate, and blood pressure using ICG before and after erythrocytapheresis in 26 stable children with SCD. Echocardiography was carried out in all patients to evaluate left ventricular systolic function. Hemoglobin (Hb), sickle cell hemoglobin (HbS), and ferritin levels were also measured. Of a total of 78 erythrocytapheresis procedures in 26 children with SCD, 22 (28.2%) had hypotensive episodes defined as a decrease in systolic, diastolic, or mean blood pressure by 10 mmHg. Risk factors for developing hypotension during erythrocytapheresis were identified with logistic regression analysis: lower-body surface area and decrease in cardiac index. In contrast, age, prepheresis Hb and HbS, serum ferritin levels, and left ventricular function at baseline were not associated with hypotension. This study demonstrates the feasibility of the ICG technique to detect the hemodynamic changes in children with SCD after an erythrocytapheresis procedure.

Evaluation of hemostatic balance in blood from patients with polycythemia vera by means of thromboelastography: The effect of isovolemic erythrocytapheresis

Polycythemia vera (PV) is associated with an increased frequency of thrombotic complications. This study was undertaken to evaluate the hemostatic balance in the blood of PV patients by means of thromboelastography (TEG). The effect of isovolemic erythrocytapheresis (ECP) on the hemostasis of PV patients was also studied. We assessed the coagulation status of 76 PV patients undergoing ECP and 50 of healthy controls. TEG measurements were performed immediately before and after the ECP procedure. Coagulation was triggered by recalcification in freshly collected citrated blood. We recorded clotting time (R), alpha angle, and maximum amplitude (MA) of the clot. The results presented here show that, compared with healthy controls, PV patients demonstrated an increase in alpha angle (p < 0.005) and in MA (p = 0.14). In the subgroup of PV patients with high (>440 × 109 l−1) platelet (PLT) count, differences in MA (p < 0.01) and alpha angle (p < 0.001) were more significant. Following ECP procedure, a significant (p ≤ 0.01) reduction of R time, a rise of alpha angle, and MA were observed, indicating augmentation of a hypercoagulable state. In PV patients, the rise in alpha angle positively correlated (r = 0.549) with platelet count but not with the number of erythrocytes and leukocytes. Following ECP, this correlation was reduced (r = 0.382). Dilution (with saline) of blood from PV patients and of healthy controls, to a degree similar to that used during the ECP procedure, resulted in reduction of R and rise of the alpha angle. In conclusion, TEG measurements show that the majority of PV patients demonstrate abnormal hemostasis in which a major role is played by platelets rather than plasma factors. The hypercoagulable state in PV patients is significantly augmented following the ECP and may be related to the hemodilution intrinsically included in this procedure. TEG may help to assess the thrombotic risk in individual PV patients.

Considerations on the use of adjunct red blood cell exchange transfusion in the treatment of severe Plasmodium falciparum malaria

Travelers returning to the United States from malaria-endemic areas are at increased risk of a potentially fatal infection from Plasmodium falciparum, which requires prompt and aggressive treatment. Described is a case of a 7-year-old boy who was infected by P. falciparum while in Africa and developed features of severe infection, including hyperparasitemia, altered neurologic status, and malarial hepatitis. A single automated erythrocytapheresis procedure reduced parasitemia from 14% to less than 1%. Along with intravenous quinidine, this reduced parasite level was maintained throughout the hospitalization and the patient recovered. Exchange transfusion (ET) is an effective adjunct therapy to reduce the parasite load in cases of severe P. falciparum malaria. When performed in certain defined settings, the benefits can outweigh the risks of the procedure. Discussed are the medical and technical considerations on the use of adjunctive ET for severe P. falciparum infection and a review of the literature of the use of adjunct ET in the treatment of severe P. falciparum malaria.

Alternative method to determine the hematocrit of red blood cell units: a potential use in the apheresis unit

In automated erythrocytapheresis procedures, achieving the desired-end hematocrit (Hct) requires that the COBE Spectra (CaridianBCT) machine be programmed with the mean Hct of the replacement red blood cell (RBC) units. To determine unit Hct, data derived from quality control (QC) Hct data were utilized. However, if a unit volume is outside the quality control (QC) volume parameters, the unit is accessed to measure its Hct. In this study, 21 percent of all RBC units need to be accessed to determine the Hct, which affects 47.5 percent of patient's erythrocytapheresis procedures. Spiking the unit compromises its integrity and hastens the expiration time of the unit. Nurses must wait until the patient arrives to check units outside QC parameters, thereby delaying the start time of procedures. Even if sampled units are kept refrigerated, they cannot be returned to the blood bank inventory once spiked. The goal of this study was to determine if accurate Hct levels from RBC units could be obtained from a unique segment. To determine the centrifuged Hct, samples were prepared from the RBC units and compared to that of the unique segment. The Hct of the unique segment exceeded that of the RBC unit by a small (1.2% in AS-1 units, 0.92% in AS-3 units), but statistically significant amount. The Hct from unique RBC segments closely approximates that of the original RBC unit. Unique segments can be made that will maintain the integrity and shelf life of RBC units.

Hemodynamic Monitoring during Erythrocytapheresis in Sickle Cell Disease Patients Using Impedance Cardiography

BACKGROUND: Erythrocytapheresis procedures are increasingly used in the treatment of severe acute complications of sickle cell disease (SCD). Some patients who undergo erythrocytapheresis experience dizziness during or after the procedure. There is no data in literature for hemodynamic monitoring of cardiac index (CI) and systemic vascular resistance index (SVRI) during erythrocytapheresis. We have previously shown that impedance cardiography (ICG) and invasive measures of CI by thermodilution techniques are significantly correlated in children.OBJECTIVES: We wanted to evaluate changes in CI and SVRI using ICG and to correlate these with systolic blood pressure (SBP) measurements in SCD patients while undergoing erythrocytapheresis.METHODS: Thirty one SCD patients who had 70 consecutive erythrocytapheresis procedures were included in this IRB approved study. ICG measurements (CI, SVRI, and blood pressure) were taken pre-erythrocytapheresis, 30 minutes after initiation of the procedure, one hour into erythrocytapheresis, and at the end of the procedure. ICG measurements were repeated in symptomatic patients before and after intervention with fluid administration.RESULTS: We evaluated hemodynamic data on 31 SCD patients, average age 12.8±5.2 years and 56% are female. SBP decreased below the base line during 33 procedures and increased above the baseline during 37 procedures. Among patients who had a decrease in SBP, 28/33 (84%) had decreased CI. Among them 22/28 (78%) had increased SVRI. Among patients who had an increase in SBP, 5/37 (14%) had increased CI. Among them 4/5 (80%) also had increased SVRI. Using paired t test, the changes in CI (P <0.001) and SVRI (P=0.0002) comparing to baseline are statistically significant. CI is negatively correlated with change in SVRI (Pearson correlation coefficient −0.8).CONCLUSIONS:In summary, the hemodynamic changes during erythrocytapheresis are probably multifactorial in origin and may include a combination of SVRI and CI changes. Confirmation of these findings may allow early intervention in some patients and minimize the risk of developing overt clinical symptoms during erythrocytapheresis.

False‐positive pregnancy test after passive transfusion of β‐human chorionic gonadotropin from donor red blood cells during erythrocytapheresis

Patients transfused with blood products may passively receive soluble antibodies, proteins, and other analytes that persist during the collection, processing, and transfusion of the blood product. In this report, a female patient who received transfusion of five red blood cell (RBC) units during erythrocytapheresis later demonstrated an unexpected positive result in assays for the beta-subunit of human chorionic gonadotropin (bHCG), a screening test for pregnancy. The result caused postponement of an elective surgical procedure. A follow-up test 1 week later was negative. To investigate the possibility of passive transfusion of the hormone from a donor RBC unit, a sample from each of the units transfused was assayed for the level of bHCG. One of the 5 units transfused to the patient had a high level of bHCG. The observed bHCG level in the recipient was found to be comparable to the predicted level, given the donor's plasma bHCG level and accounting for the dilution factors in the preparation of the RBC unit and the erythrocytapheresis procedure and the in vivo t((1/2)) of the hormone. The donor, who was unaware of her pregnancy status at the time of donation, harbored a high bHCG level that caused the positive test result in the recipient patient's serum and urine. If an unexpected analyte or serology is detected in a recipient of a blood transfusion, it is important to consider the possibility of passive transfusion of the analyte.

Oxygen saturation and hemoglobin A content in patients with sickle cell disease undergoing erythrocytapheresis.

Severe hypoxia occurs in patients with acute chest syndrome, and erythrocytapheresis has been shown to improve oxygenation. Patients with sickle cell anemia also have decreased baseline oxygen saturation values, but the effect of erythrocytapheresis on steady-state oxygenation has not been well studied. We investigated the changes in oxygen saturation versus hematocrit, fraction of hemoglobin A, and transfusion volume during 71 prophylactic erythrocytapheresis procedures performed in 5 stable patients with sickle cell anemia. Each patient had a history of either acute chest syndrome or stroke, but no serious events occurred while enrolled in the chronic exchange program. The oxygen saturation improved from 1% to 6% during erythrocytapheresis in each of our patients (p < 0.001) regardless of preprocedure saturation level or total hematocrit. We have shown that decreased baseline oxygen saturation in sickle cell disease is related to abnormal hemoglobin S levels, and oxygen saturation can be improved with erythrocytapheresis, independent of any change in the total hematocrit.

Erythrocytapheresis as a method for auto-transfusion. A case study in a patient with Vel-antibodies

A 60-year-old man suffering from angina had to undergo percutaneous transluminal coronary angioplasty (PTCA). In the pre-operative screening procedure anti-Vel antibodies were identified. The patient's blood group is O, rr. The prevalence of the blood group O, rr Vel(-) is 1:60,000. Compatible blood groups were not found in the patient's family. The only alternative method to give this patient the necessary units of blood was an auto-transfusion procedure. Because of the patient's clinical condition, however, it was necessary to use an erythrocytapheresis procedure, without changing his blood volume. We performed the erythrocytapheresis using the Fenwal CS-3000. Blood (920 mL) was collected, Ht 0.67 L L , this was equivalent to 3 units of packed cells compared with random donor blood. The erythrocytapheresis procedure was performed without any problem and the PTCA was done without complications or transfusion. The blood is stored in liquid nitrogen in the central laboratory of blood transfusion, Amsterdam.

Treatment of polycythemia vera by isovolemic large-volume erythrocytapheresis

Excess red blood cells (RBC) in patients with polycythemia vera (PV) are usually removed by repeated phlebotomy. In order to improve the efficacy of this treatment, we used isovolemic large-volume erythrocytapheresis (EA) by a cell separator. A retrospective analysis of our experience with 69 PV patients (206 EA procedures) is reported. EA induced a rapid, well-tolerated, and long-lasting reduction of Hct, Hb, and RBC counts, as well as an immediate disappearance or reduction of clinical symptoms of PV, while tissue oxygen tension - as measured in 8 patients - increased. Hct was reduced by EA from 56.8% +/- 5.6% to 41.9% +/- 6.6%, Hb from 17.5 +/- 2.3 to 12.7 +/- 2.4 g%, RBC counts from 7.4 +/- 0.9 to 5.4 +/- 0.9 x 10(6)/mm3. The mean volume of the apherisate was 1410 +/- 418 ml, (mean Hct 79.7% +/- 9.3%), and the actual RBC volume removed 1113 +/- 367 ml. The isovolemic procedure was well tolerated and the acceptance by patients seemed to be better than with repeated phlebotomy. In 21 patients whose Hct values (Hct before and after EA 58% +/- 5.7% and 41.5% +/- 4.9%) were regularly followed after EA the mean period with Hct less than 50% after a single EA procedure was 6.1 +/- 4.1 months (median, 6); in 14 out of these 21 patients a Hct of less than 43% after EA was reached and their mean period with Hct less than 50% after EA was 7.6 +/- 4.0 months (median, 7.5). For three patients this period was 11, 13, and 15 months, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythrocytapheresis using the haemonetics model 30 to permit surgical correction in an adult tetralogy of fallot

The Haemonetics model 30 cell separator was used for erythrocytapheresis in an adult suffering from tetralogy of Fallot complicated by severe erythrocytosis and coagulopathy. Over a two-week period, the hematocrit was reduced from 81% to 39% after three erythrocytapheresis procedures. Abnormal coagulation was also corrected. The patient uneventfully underwent total surgical correction, during which his blood loss was minimal and his recovery surprisingly smooth.