Blood utilization in hip and knee arthroplasty: a cost-minimization study.

The non-utilization of crossmatched blood is an expensive waste of resources. We have audited blood utilization for all primary total hip and knee arthroplasty patients. We compared routine pre-operative crossmatching (Phase 1) with a policy of group, screen and save (G & S) only (Phase 2). The patient groups were similar in both phases. Pre- and post-operative haemoglobin results were not significantly different between Phase 1 and 2. No adverse transfusion reactions occurred. In Phase 1, 213 units were crossmatched pre-operatively, but only 127 (60%) were transfused. In Phase 2, 117 units were requested and all transfused. The G & S only policy proved to be a safe and practical option which improved the efficiency and cost-effectiveness of blood ordering. Based on a handling charge of 37.50 Pounds per unit of blood by the Regional Transfusion Centre, an estimated annual saving of over 8000 Pounds can be made in our directorate.

Do extra-platelet sources contribute to the plasma level of thrombospondin?

Thrombospondin, a trimeric glycoprotein contained in the platelet alpha-granules, has been proposed as a marker of in vivo platelet activation. However, it is also synthesised by a range of other cells. The extraplatelet contribution to plasma levels of thrombospondin was therefore estimated by investigating the relationship between plasma thrombospondin levels and platelet count in samples from profoundly thrombocytopenic patients with marrow hypoplasia, using the platelet-specific alpha-granule protein beta-thromboglobulin as control. Serum concentrations of both proteins were highly correlated with platelet count, but while plasma beta-thromboglobulin levels and platelet count also correlated, there was no relationship between the number of platelets and thrombospondin concentrations in plasma. Serial sampling of patients recovering from bone marrow depression indicated that the plasma thrombospondin contributed by platelets is superimposed on a background concentration of at least 50 ng/ml probably derived from a non-platelet source, and plasma thrombospondin levels do not simply reflect platelet release.

Reduced risk of non-A, non-B hepatitis after a first exposure to 'wet heated' factor VIII concentrate.

The risk of post-infusion non-A, non-B hepatitis (NANBH) in patients receiving a first exposure to unheated or conventionally 'dry heated' factor VIII concentrates approaches 100%, implying invariable contamination of these products. Amongst 18 patients who received a first treatment with a 'wet heated' commercial concentrate, five (28%) developed asymptomatic NANBH, suggesting a more efficient inactivation of NANB agent(s) by this process. 2/9 (22%) of the batches of concentrate used in the study were implicated in NANBH transmission. One of those two batches, responsible for NANBH in four patients, had been prepared from a plasma pool containing an unusually large proportion of donations with high alanine aminotransferase (ALT) levels. A resulting high level of viral contamination in this batch may have been sufficient to override the effects of the sterilization process. All patients remained anti-HIV seronegative at 17-28 months of follow-up.

Hypothyroidism as a cause of acquired von Willebrand's disease.

Three patients with bleeding tendency who met the criteria for type 1 von Willebrand's disease are described. In two patients, hypothyroidism was suspected and confirmed at presentation, and in the third hypothyroidism became apparent 4 years later. In all three, the history and clinical course after treatment with thyroxine indicated acquired von Willebrand's disease secondary to hypothyroidism. The possibility of hypothyroidism should be considered in patients presenting with von Willebrand's disease.