Regular donor plasmapheresis of up to 45 l of plasma per year appears to be as safe as more moderate plasmapheresis programmes, with respect to the parameters analysed in this study. Individuals donating under these conditions did not develop impaired humoral and cellular immunity, iron store depletion, or increased cardiovascular risk with regard to established biochemical risk markers. Prospective studies are required to determine more exactly than in retrospective analyses the reasons why donors withdraw from plasmapheresis programmes.

Summary We investigated the relationship between platelet function analyzer (PFA‐100TM) closure times (CT) and bleeding time (BT), platelet aggregation (PA) induced by ADP, arachidonic acid, and collagen, blood cell counts, and von Willebrand factor (VWF) in 120 well‐characterised healthy individuals. Pre‐analytical and analytical conditions were standardised comprehensively. In a substantial number of cases the differences between duplicate measurements exceeded 15%. The reference range (5th and 95th percentiles) for CT with the collagen/epinephrine (CEPI) and the collagen/ADP (CADP) cartridge was 93–223 s and 64–117 s respectively. Re‐examination of 11 individuals with CEPI‐CT above the 95th percentile revealed considerable batch‐to‐batch variation of CEPI‐CT. Males had significantly longer CADP than females (P = 0·002). CEPI and CADP‐CT measured pm were significantly longer than corresponding values determined am (P = 0·003 and P < 0·0001 respectively). Blood group O was associated with greater CEPI and CADP‐CT and lower VWF levels compared with non‐O blood groups (P = 0·008, P = 0·0003 and P < 0·0001 respectively). Linear regression analysis revealed association between CEPI‐CT, CADP‐CT and VWF (P < 0·0001), but no relationship was found between CT and BT or between CT and PA. We conclude that VWF plasma levels modulate PFA‐100TM CT to a greater extent than platelet function. Establishment of reliable reference ranges and careful standardisation of pre‐analytical and analytical conditions is a prerequisite for obtaining reliable PFA‐100TM results. Duplicate measurements are necessary.

The reasons why donors cease to participate in intensive plasmapheresis programmes are predominantly not directly related to the plasma donation itself.

Menstruating women undergoing regular plasmapheresis at short intervals are prone to develop Fe depletion. This can be prevented by regular Fe intake. Laboratory analyses in product plasma instead of serum gained from whole-blood samples could be an alternative to reduce blood loss.

Because of the proposal that infants with hypertrophic pyloric stenosis should only be treated by surgeons with an interest in paediatric surgery, we carried out a retrospective study to audit our experience in a district general hospital. Forty six infants over a five year period underwent pyloromyotomy. There were no deaths, and 36 infants (78%) made uneventful recoveries. Perforation of the duodenal mucosa occurred during the operation in 11 patients, and eight complications developed in six of these infants. There were seven wound infections, and two patients had vomiting that lasted four days or longer after their operations. There were no long term feeding problems.The results of this study show that such patients can be successfully treated in district general hospitals, and three areas merit special attention: meticulous surgical technique, the use of prophylactic antibiotics, and early graduated feeding.In a recent report from a regional centre in London, it was suggested that infants being treated in a district general hospital for hypertrophic pyloric stenosis should instead be treated by surgeons with a special interest in paediatric surgery.' An earlier study from a district general hospital in England was cited, and the proposal was made because of the high complication rate.2 These prompted the present retrospective study: our aims were, firstly, to audit our own experience at a district general hospital in treating infants with pyloric stenosis, and, secondly, to propose any necessary changes in management so that such patients may be successfullly treated by general surgeons in district general hospitals.