Preparation of pooled cryoprecipitate for treatment of hemophilia A in a home care program

Cryoprecipitate is used infrequently in home therapy for patients with hemophilia A since freezer storage is required and resuspension and pooling of thawed cryoprecipitate is cumbersome. We evaluated procedures for preparation of cryoprecipitate in an "open system" so that four to six bags of cryoprecipitate could be pooled after production and refrozen for home therapy. Factor VIII activity for pooled cryoprecipitate was 132 +/- 30 (mean +/- SD), 125 +/- 45, and 145 +/- 47 units per bag pooled in three separate studies. Cultures from cryoprecipitate pools and individual cryoprecipitate bags did not show contamination in the "open system" or with the water bath thawing procedure. The mean increment in factor VIII activity per unit per kg infused was 0.02 units per ml and the mean half-life was 10.5 hours in three patients with hemophilia A. Pooled cryoprecipitate was shown to be clinically efficacious and acceptable for use in home care programs for hemophilia A.     

Variations in cryoprecipitate production

Several variables influencing the recovery of Factor VIII in the cold- precipitated protein fraction were examined. The actual rate at which the physical-chemical conversion of plasma from a solid to a liquid state occurs does not seem to affect the yield. Rather, it is the amount of time immediately postthaw and prior to centrifugation that determines the Factor VIII activity in the cryoprecipitate. With prolonged periods at 4 C the Factor VIII activity leaves the cold precipitate and lifts into the supernatant. Even distribution of the plasma layer and close attention to the thawing procedure facilitate Factor VIII recovery.     

Evaluation of factor VIII-rich cryoprecipitate and the plasma fibronectin-rich, heparin-precipitable fraction prepared from single- donor plasma units

A plasma fibronectin-rich component was prepared by heparin-induced 4 degrees C precipitation of fresh or stored (21 days at 4 degrees C), single-donor plasma. The recovery of plasma fibronectin was 45 percent at a concentration of 0.05 mg heparin per ml (7.5 units/ml) and 75 percent at 0.1 mg per ml (15 units/ml). The biologic activity of plasma fibronectin, as assessed by the spreading of Chinese hamster ovary cells or attachment of monocytes to gelatin-coated surfaces, was similar to that of plasma fibronectin concentrates made from fresh or stored plasma. Only 20 to 30 percent of the factor VIII activity in fresh plasma was recovered in cryoprecipitate produced after the heparin-induced precipitate containing fibronectin was removed. Cryoprecipitate prepared from the supernatant plasma that remains after heparin-induced cold precipitation in the presence of CaCl2 (5 mM) contained approximately 50 percent less factor VIII. The relatively low recovery of factor VIII in cryoprecipitate prepared from fibronectin-depleted plasma makes cryoprecipitation an unsuitable method of producing fibronectin-rich and factor VIII-rich components effectively from a single unit of fresh plasma. However, heparin-induced cold precipitation provides an efficient method for preparing plasma fibronectin concentrates from small plasma pools or single units of stored or fresh plasma.     

冷沉淀的临床应用分析

目的了解冷沉淀在临床的应用情况。方法收集我院2009年1月-2011年1月冷沉淀输注情况,将冷沉淀的使用情况按专业科室分别归类。结果冷沉淀的使用主要集中在胸外ICU、血液内科,消化内科及普外科。其中血液内科、胸外ICU的用量最多。结论冷沉淀的止血功效逐渐被临床认识并在各类痰病中得到大量应用。     

Determinants of factor VIII recovery in cryoprecipitate

Many aspects of the production of cryoprecipitate were studied to determine which methods resulted in the greatest recovery of Factor VIII. The following recommendations resulted: 1) blood should be mixed with anticoagulant throughout phlebotomy; 2) blood should be centrifuged within a few hours of collection; 3) larger satellite bags should be used to contain the usual volume of plasma, for example, 200 ml of plasma should be frozen in a 600-ml capacity bag; 4) plasma should be centrifuged as soon as thawing is complete; 5) cryoprecipitate should be refrozen on dry ice; 6) cryoprecipitate should be stored at or below -30 C.; and 7) prolonged storage of frozen plasma or cryoprecipitate should be avoided. Variations in Factor VIII content from one bag of cryoprecipitate to another, under uniform production conditions, depends largely on two donor-specific attributes which tend to remain constant from time to time, namely, the donor's plasma Factor VIII level and the cryoprecipitability of his Factor VIII.     

Fibrinogen content of low-volume cryoprecipitate

Single-donor cryoprecipitate is the most convenient and reliable source of fibrinogen. A change by the regional Red Cross Blood Service to the production of low-volume cryoprecipitate led the authors to reexamine the fibrinogen content of cryoprecipitate units. The average fibrinogen content of individual low-volume (4 ml) units (n = 23) was 101 +/− 48 mg; in the 10-unit pools (n = 9 pools), content was 89 +/− 13 mg. Both measurements were considerably lower than previously published. By contrast, the mean fibrinogen content of regular-volume (15 ml) cryoprecipitate units (n = 8) was 142 +/− 50 mg. The fibrinogen was stable for at least 4 hours after thawing, and it survived refreezing and thawing.     

In vivo stability of cryoprecipitate fibrinogen

Because of its lower hepatitis risk, cryoprecipitate has been advocated as a substitute for commercial fibrinogen. Previous literature on cryofibrinogen has demonstrated a short blood t1/2, rendering it unsuitable for therapeutic use. The in vivo clearance of 131I- cryoprecipitate was compared with that of 125I-standard fibrinogen. A small amount of cryoprecipitate was rapidly cleared and apparently was cryofibrinogen. However, the bulk of the cryoprecipitate was cleared with a normal half life, as was cryoprecipitated that was in 10-bag pools. The data indicated cryoprecipitate was an effective in vivo form of fibrinogen and thus the preferred fibrinogen source because of its combining normal t1/2 with single donor procurement.     

B-mode sonography of blood clots

Systematic evaluation of blood clot echogenicity was performed with five different transducer frequencies in two experiments. In the first experiment, blood clots were insonified at five different time periods; from immediately after clotting up to 96 hours after clotting. In the second experiment, blood clots of four different hematocrits (48 to 20%) and clots of hemolysed blood were insonified. The clots, with normal hematocrits, were highly echogenic when imaged with 5, 7.5 and 10-MHz transducers immediately and 24 hours after clotting. The echo intensity decreased over the following days until it almost disappeared at 96 hours after clotting. Clot echogenicity was not observed with 2.25 and 3.5-MHz transducers, except at the interface between retracted clot and serum. Clot echogenicity decreased in proportion with the hematocrit. Hemolysed blood clots were not echogenic. It is concluded from this study that fresh blood clots are echogenic soon after thrombosis with high resolution imaging and this echogenicity diminishes with time. Ultimately, with organization and lamination, echogenicity will recur.     

Prepooled cryoprecipitate for treatment of hemophilia A

Lyophilized factor VIII concentrates, because of their convenience, are the most commonly used products for providing antihemophilic factor to patients with hemophilia A. Heightened concerns about associated complications indicate that cryoprecipitate usage will increase in the immediate future. We present a protocol for making cryoprecipitate more usable by "prepooling" individual units of cryoprecipitate in an "open" system. Our experience indicates this approach is safe, effective and acceptable to patients, including those on home therapy programs.     

The effects of temperature variations on cryoprecipitate

The effect of temperature on Factor VIII levels in blood and cryoprecipitate was assessed. Freshw collected units of blood required several hours to reach 4 C, but this delay seemed of little importance since equal amounts of cryoprecipitated Factor VIII were recovered from blood stored either at 22 C or at 4 C. Freezing at -80, -60, or −40 C produced identical yields of Factor VIII, whereas freezing at −20 C resulted in significantly lower recoveries. This might be expected if one considers the physiochemical changes that occur during the freezing process.     

Preparation of factor VIII concentrates by cryoprecipitate sedimentation

A new method for factor VIII concentrate preparation is proposed. The method is the collection of cryoprecipitate after sedimentation at 4 C in a jacketed glass vessel. The final product is standardized (4.0 +/- 0.3 factor VIII units per ml) and can be infused in hemophilic patients regardless of their ABO blood type. Factor VIII recovery (52.2 +/- 6.4%) is comparable to other processes.     

An adverse pulmonary reaction to cryoprecipitate in a hemophiliac

An adult with classif Hemophilia A experienced a very severe reaction to transfusion with cryoprecipitate which was manifested as an adverse pulmonary reaction with marked hypoxemia in spite of oxygen therapy. The patient had neither leukoagglutinins nor lymphocytoxic, anti-platelet, or anti-Gm antibodies. His IgA level was normal. The possibility that debris in the cryoprecipitate from leukocytes and platelets contributed to the reaction is discussed.