Positive direct antiglobulin reaction in a patient population.

This study was undertaken to ascertain the incidence, the associated clinical diseases, and the serologic characteristics and significance of positive direct antiglobulin tests (DAT) in a hospital population. Forty-one (0.9%) of 4,664 medical-surgical patients had positive DAT's on admission. Eight of these 41 people also had antibodies in their sera. Twelve patients were taking alpha-methyldopa and one cephalothin, seven had malignant tumors, nine had immunologic disease, and 12 had miscellaneous conditions. Elution of antibodies from the erythrocytes of 36 patients was attempted: 17 eluates failed to react with panel cells; anti-K antibody was found in the eluates from two patients who had recently received transfusions; five eluates showed no blood-group specificity; and 12 agglutinated all panel cells. Eleven of the last 12 eluates, after absorption with Rh-negative cells, were tested with Rh cells of various phenotypes, and weaker or negative results with Rhnull cells were obtained with seven absorbed eluates. Three of the 41 patients had mild to overt hemolysis.

Evaluation of erythrocyte washing using the Haemonetics Model 102 Cell Washer.

The Haemonetics Model 102 Cell Washer was evaluated for efficiency of leukocyte removal and erythrocyte recovery. Groups of 25 units of blood were washed using five different protocols, including the methods recommended by the manufacturer. Mean erythrocyte recovery ranged from 83% to 91% and median residual leukocytes ranged from 1% to 4% for the five protocols. The mean erythrocyte recovery for units washed with 30 sec of increased pump speed was 95%, while it was 84% for units washed with 90 sec of increased pump speed (P less than 0.001). The median residual leukocytes was 1% for units washed after buffy coat removal and 4% for all other units (P less than 0.001). There was no other significant difference among the different protocols. These findings could not be explained on the basis of age of units, prewash erythrocyte mass, or prewash total leukocytes.

Rapid estimation of the glycerol concentration of frozen-thawed red cells prepared by the agglomeration technique.

The glycerol concentration of frozen-thawed red cells must be less than 2 percent to prevent hemolysis upon transfusion. Three methods were investigated for monitoring the glycerol concentration of frozen-thawed red cells prepared by the agglomeration technique. The supernatant osmolality and glycerol concentration were determined on 47 units of frozen-thawed red cells prepared by agglomeration, and were found to be linearly related (r = 0.83, p less than 0.001). The supernatant refractive index was determined on 29 of the same units. There also was a linear relationship between the refractive index and the glycerol concentration (r = 0.74, p less than 0.001). The relationships were different from those previously reported for red cells prepared by other methods. The simulated transfusion test was done on red cells from three units whose glycerol concentration had been artificially elevated. The simulated transfusion test was found to be sensitive to glycerol concentrations above 2 percent. All three of the methods evaluated can be used to estimate the glycerol concentration of frozen-thawed red cells prepared by the agglomeration technique.

Long-term plateletpheresis of a donor.

A 25-year-old woman underwent plateletpheresis 101 times over a 33-month period. The equivalent of 5.8 to 7.5 units of platelet concentrate was removed during each pheresis. Two machine-related complications occurred, resulting in the loss of one unit of blood and 150 milliliters of plasma. Other complications included a mild anemia consistent with iron deficiency. The donor's platelet count decreased but remained in the normal range. There were no significant changes in the serum proteins or immunoglobulins. Serum hepatic enzymes became elevated and were consistent with a mild, subclinical hepatitis. These returned toward normal during continued pheresis.

The complications of therapeutic plasma exchange.

We reviewed a series of 181 patients who were treated with therapeutic plasma exchange ( TPE ) a total of 1,389 times. Complications were associated with 22 (1.6%) of the procedures and involved 20 (11%) of the patients. Six of the complications were of a technical nature and did not affect the medical conditions of the patients. 8 patients developed the following serious medical problems: unexplained death during the post- TPE period, myocardial infarction, pulmonary embolus, loss of consciousness, myocardial ischemia, cerebral ischemia and chest pain. Although these problems were temporally associated with TPE none of them could be attributed to the TPE with certainty. The remaining eight medical complications were of a less serious nature.

Parathyroid response during therapeutic plasma exchange.

Significant hypocalcemia is infrequently encountered during therapeutic plasma exchange. An increase in parathyroid hormone secretion during the procedure may be responsible for maintaining the calcium levels.

Coagulation defects in rabbits after infusion of dispersed fluorochemicals.

Coagulation parameters were studied in rabbits during and after intravenous infusion of suspensions of dispersed fluorochemicals. Blood samples from rabbits given dispersed perfluorobutyltetrahydrofurane or perfluorotributylamine showed thrombocytopenia, prolongation of activated partial thromboplastin time, and decreases in Factors X and XI. The possible presence of an inhibitor of coagulation was suggested by the prolongation of prothrombin time when measured with serial dilutions of thromboplastin reagent. These abnormalities were not found in whole blood or platelet-rich plasma after incubation in vitro with dispersed fluorochemical.

Effects of Intersept micropore filtration of blood on microaggregates and other constituents.

Micropore filtration (Intersept) of whole, stored blood was examined in two studies. In Study A, 1 unit of 14-day-old blood flowed by gravity across the filter. In Study B, the filter was preloaded by passage of 2 units of blood, and the effects on a third, consisting of 21-day-old blood, flowing under 150 mm Hg pressure, were examined. Filtration did not significantly alter erythrocyte count, total hemoglobin, plasma hemoglobin, erythrocyte fragility, plasma sodium, potassium, albumin, or globulin in either study, although some platelets and leukocytes were removed. Microaggregates, assessed by Coulter counting, screen filtration pressure, total screen proteins, wet and dry weights of material retained, and scanning electron microscopy, were satisfactorily removed over the whole range of particle sizes. Comparison with the Bentley PFS-127, Fenwal 4C2417, Pall Ultipore, and Swank IL200 filters led to the conclusion that the Intersept is the most efficient filter available at the present time for removing microaggregates during massive blood transfusion.

Cytapheresis in a patient with Sezary syndrome.

A patient with Sezary syndrome underwent cytapheresis on the IBM 2997 cell separator. Four procedures were performed over a 12-day period. A total of 8.3 x 10(10) Sezary cells were removed. The patient's skin lesions and lymphadenopathy regressed. Transient thrombocytopenia occurred, requiring platelet transfusion. Although a significant number of platelets were removed by pheresis, this was not sufficient to explain the thrombocytopenia. The patient subsequently died of causes unrelated to the cytapheresis.

An evaluation of the Bentley PFF-100 transfusion filter.

The effects of a new transfusion filter (Bentley PFF-100) on stored whole blood have been examined. Six filters were preloaded by passage of two units of outdated type-specific bank blood and the effects of filtration on a third unit of 21-day-old blood flowing under 19.95 kPa (150 mm Hg) pressure were measured. Filtration did not significantly alter erythrocyte or leukocyte count, total or plasma haemoglobin, red cell fragility, plasma sodium, potassium, albumin, or globulin. Platelet counts were reduced by 31%. Removal of microaggregates, assessed by Coulter counting, screen filtration pressure, total screen protein, wet and dry weight of material retained and scanning electron microscopy, was shown to be effective over the entire range of particle size. In comparison with other transfusion filters previously examined in this laboratory, the Bentley PFF-100 filter combines the feature of moderately efficient microaggregate removal with rapid blood flow rate. Compared to its predecessor, the Bentley PF-127, this new filter design has improved flow characteristics without loss of efficiency of microaggregate removal.

Evaluation of the Swank IL-201 transfusion filter.

The effects of a new transfusion filter (Swank IL-20U) on stored, whole blood have been examined. Six filters were preloaded by passage of two units of outdated, type-specific bank blood, and the effects of filtration on a third unit of 21-day-old blood flowing under 150 mm Hg pressure were measured. Filtration did not significantly alter erythrocyte or leukocyte count, total or plasma hemoglobin, red-cell fragility, and plasma sodium, potassium, albumin, or globulin. Platelet counts were reduced by 33%. Removal of microaggregates, assessed by Coulter counting, screen filtration pressure, total screen protein, wet and dry weight of material retained, and scanning electron microscopy, was shown to be effective over the entire range of particle size. In comparison with other transfusion filters previously examined in this laboratory, the Swank IL-201 filter combines the features of efficient microaggregate removal with moderate blood-flow rate. Compared to its predecessor, the Swank IL-200, this new filter design has improved flow characteristics without loss of microaggregate removal efficiency. In view of the similarity of performance demonstrated for several of the available filters, it seems likely that relative cost will constitute an important determinant of filter selection.

Effects of Fenwal 4C2423 transfusion microfilter on microaggregates and other constituents of stored blood.

The effects of a new micropore transfusion filter (Fenwal 4C2423) on stored whole blood have been examined. Five filters were preloaded by passage of two units of outdated type specific bank blood, and the effects of filtration on a third unit, consisting of 21-day-old blood, flowing under 150 mmHg pressure, were measured. Filtration did not significantly alter red blood cell count, total hemoglobin, red blood cell fragility, plasma sodium, potassium, albumin, or globulin. Some platelets and white blood cells were removed and a small amount of hemolygis of erythrocytes (less than 0.1%) was observed. Removal of microaggregates, assessed by Coulter counting, screen filtration pressure, total screen porteins, wet and dry weights of material retained, and scanning electron microscopy, was shown to be excellent over the entire range of particle size. Comparison of the Bentley PFS-127, Fenwal 4C2417, Johnson & Johnson Intersept, Pall Ultipore, and Swank IL200 filters led to the conclusion that the Fenwal 4C2423 was both a significant improvement over the previous Fenwal design and comparable to the most efficient of these filters for both the removal of microaggregates during massive blood transfusion and for the blood flow rates obtained.