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Biomedical subjects

P H Pinkerton

Publications and source records attributed to P H Pinkerton.

At least 19 recordsLinked to original sources
PubMed2001

Reporting of near-miss events for transfusion medicine: improving transfusion safety.

BACKGROUND: Half of the reported serious adverse events from transfusion are a consequence of medical error. A no-fault medical-event reporting system for transfusion medicine (MERS-TM) was developed to capture and analyze both near-miss and actual transfusion-related errors. STUDY DESIGN AND METHODS: A prospective audit of transfusion-related errors was performed to determine the ability of MERS-TM to identify the frequency and patterns of errors. RESULTS: Events and near-miss events (total, 819) were recorded for a period of 19 months (median, 51/month). No serious adverse patient outcome occurred, despite these events, with the transfusion of 17,465 units of RBCs. Sixty-one events (7.4%) were potentially life-threatening or could have led to permanent injury (severity Level 1). Of most concern were 3 samples collected from the wrong patient, 13 mislabeled samples, and 22 requests for blood for the wrong patient. Near-miss events were five times more frequent than actual transfusion errors, and 68 percent of errors were detected before blood was issued. Sixty-one percent of events originated from patient areas, 35 percent from the blood bank, and 4 percent from the blood supplier or other hospitals. Repeat collection was required for 1 of every 94 samples, and 1 in 346 requests for blood components was incorrect. Education of nurses and alterations to blood bank forms were not by themselves effective in reducing severe errors. An artifactual 50-percent reduction in the number of errors reported was noted during a 6-month period when two chief members of the event-reporting team were on temporary leave. CONCLUSION: The MERS-TM allowed the recognition and analysis of errors, determination of patterns of errors, and monitoring for changes in frequency after corrective action was implemented. Although no permanent injury resulted from the 819 events, innovative mechanisms must be designed to prevent these errors, instead of relying on faulty informal checks to capture errors after they occur.

Blood Transfusion↗
PubMed2000

An evaluation of the process and costs associated with targeted lookbacks for HCV and general notification of transfusion recipients.

BACKGROUND: The Commission of Inquiry on the Blood System in Canada recommended that hospitals notify patients who received blood between 1978 and May 1990 of the risks of contracting HIV (up to the end of 1985 only) and HCV infection. The commission also recommended that patients should be informed of any transfusion received. STUDY DESIGN AND METHOD: General notifications for HIV and HCV for this period were begun in mid-1994. Notification after discharge of transfusions received after May 1990 was begun in 1997. Targeted HCV lookback was performed from 1995 to 1999. RESULTS: Of 21,016 transfusion recipients from January 1978 to May 1990 identified in the general look-back process and believed still alive, 13,549 (64%) were presumed contacted, by registered mail. The overall contact rate for the ongoing notifications (transfusions after May 1990) cannot be accurately determined, as registered mail was not used and a reply not requested. The total cost for these two processes was CAN$373,481, or $13 per patient believed contacted. Most (56%) of this cost was for the conversion to electronic form of paper transfusion records for the period 1978 through early 1984. In the targeted HCV lookback program 1995 through 1999, 94 percent of 256 recipients of specific components identified as likely to have transmitted HCV either were contacted or had died. Of 84 living recipients, 47 (56%) are HCV positive. The last documented potential seroconversion occurred after a transfusion in November 1991, during the period of first-generation EIA testing. If the targeted HCV lookback had been restricted to transfusions after 1987, as the FDA recommended, we would have failed to identify 39 living patients, of whom 21 are HCV positive. The cost per HCV-positive patient notified in the targeted HCV lookback was CAN $4,174. CONCLUSION: The cost of compliance with the com-mission's recommendations was CAN$569,636. Over 28,000 of 36,773 transfusion recipients were notified or presumed notified, and 272 targeted HCV lookbacks to 256 recipients were performed. Performance of this task required the existence of transfusion records back to 1978, conversion of paper records to electronic form, and adequate secretarial and financial support.

Blood Transfusion↗
PubMed2000

Screening for azathioprine toxicity: a pharmacoeconomic analysis based on a target case.

The risk of azathioprine-induced myelosuppression can be predicted by detecting patients with intermediate or low thiopurine methyltransferase (TPMT) activity. Population studies have shown that 89% of whites have high TPMT activity, 11% have intermediate TPMT activity, and 0.3% have low TPMT activity. Three specific mutations in the TPMT gene that cause decreased TPMT activity have recently been identified. Patients homozygous for the TPMT mutations have low TPMT activity, and patients heterozygous for TPMT mutations have intermediate TPMT activity. This has led to the development of a technique for TPMT genotype analysis that will identify patients at risk of azathioprine-induced myelosuppression. We report a case of a patient with bullous pemphigoid who experienced azathioprine-induced myelosuppression and who was later found to be homozygous for TPMT mutant alleles. Using the cost of treatment required for this patient and the estimated population prevalence of TPMT mutations, we examined the cost impact of screening for TPMT mutations in all patients being considered for azathioprine therapy. We calculated that screening is cost-neutral assuming patients homozygous for TPMT mutations experience myelosuppression, and that it is cost-beneficial assuming patients heterozygous for TPMT mutations also experience myelosuppression while receiving azathioprine. Screening patients for TPMT mutations will reduce the risk of azathioprine-induced myelosuppression, and our study suggests that it may also be a cost-attractive strategy.

Adult↗
PubMed2000

A gel technology system to determine postpartum RhIG dosage.

Failures of Rh immune globulin (RhIG) prophylaxis occur when the dose is too small. We report a test using a gel technology (GT) method to replace the Kleihauer-Betke (K-B) test to assess fetomaternal hemorrhage (FMH) and assist in determining the minimum necessary dose of RhIG. Cord blood (O, D+) was mixed with adult blood (O D-) to mimic an FMH of 10 mL, 20 mL, 28 mL, and 40 mL. Test samples were incubated with anti-D at known concentrations and centrifuged. The supernatant was titrated against D+ and D- red cells using GT and an interpretation of the required RhIG dose was made. Results were compared with the K-B test. Results were easily discernible and interpretations leading to determination of recommended RhIG dosage were reproducible. Correlation to standard K-B testing was confirmed. Elapsed time for result availability by GT testing was 60 minutes, with a direct technical time requirement of 30 minutes. The GT system is easier, objective, and quantitative, and compares well to the standard K-B test. A single procedure will allow assessment of the extent of FMH in the great majority of cases. This technique works well in determining the appropriate dose of anti-D required to treat D- patients with D+ newborns. There are potential cost savings in decreased use of RhIG, less direct technical time required, and more rapid availability of results.

Journal Article↗
PubMed1998

Changes in red-cell transfusion practice in a tertiary care hospital during the 1990s--a 7-year study.

Use of red cells for transfusion in a tertiary care hospital has been studied over a 7-year period from 1990-1991 to 1996-1997. In this time, red-cell use has declined by 18% while new patients or admissions to programmes in oncology, trauma or cardiac bypass surgery have increased by 57%, 66% and 73%, respectively. This reduction in red-cell transfusion has been achieved by a combination of less patients (proportionately) receiving red cells and less red cells being transfused to individual recipients. When the trends are analysed for red-cell use in four elective surgical procedures there is a significant reduction in both the proportion of patients transfused and the mean number of units used per patient undergoing the procedure. Autologous presurgical blood deposit met about 45% of the blood requirement for those four procedures. A similar decreasing trend in units per patient and proportion of patients transfused red cells was seen for 'first-time' coronary artery bypass surgery. The question arises as to how far this trend may go before adverse effects of undertransfusion become apparent.

Arthroplasty, Replacement, Hip↗
PubMed1997

Assessment of an instrument for automated reagent and specimen dispensing in blood banking.

We have evaluated a semi-automated computer controlled dispensing device in conjunction with microtube technology for the performance of routine blood grouping and antibody screening procedures. A total of 787 specimens have been tested, 78 with unexpected antibodies previously identified by manual microtube methods. All were tested in duplicate in different order; there was complete agreement in blood group (ABO, RhD) determinations and the unexpected antibodies were found in the appropriate microtube location in all duplicate sets of results. We conclude that the device accurately and reproducibly dispenses cells, sera and reagents. The savings of technologists' time over traditional manual tube methods exceed 75%, excluding the time to perform elements common to both methods. The combination of automation and microtube technology offers the opportunity for substantial savings in technologist time with accuracy in reagent and specimen dispensing.

Automation↗
PubMed1996

Transfusion practice in a Canadian hospital. Use of a major European study of transfusion practice for comparison as a form of audit.

Blood transfusion practices in a Canadian hospital have been compared, as a form of audit, to those reported in a multi-hospital study in Europe, to identify possible deviations from desirable practice. Blood product use for four surgical procedures: laparatomic cholecystectomy, total hip replacement, coronary artery bypass graft (CABG) and abdominal aortic aneurysmectomy (AAA), was determined from this hospital's blood bank data base, and is compared to use for the same procedures in European hospitals. Blood product use here is less than in the majority of European centres, in respect of red cells for all four procedures and plasma for CABG and AAA. Platelet use in association with CABG and AAA is greater than the majority of European centres reporting data. As a consequence, platelet use here will be subjected to closer review.

Blood Transfusion↗
PubMed1996

Autologous blood transfusion in radical hysterectomy.

The application of a hospital-based presurgical autologous blood deposit programme to support of radical hysterectomy is described over 4 years (1991-95), during which 48 patients participated in the autologous blood programme, and 63 did not to do so. All but one of the autologous donors received autologous blood but only two received allogeneic blood. Forty-three of the autologous nondonors received no transfusion and 20 received allogeneic blood. These differences are highly significant. For the 48 autologous donors, 91% of the blood requested was collected, and of that 91% was used, for a "wastage' rate of 9%. The mean blood use was significantly greater in the autologous donors. Blood loss was not significantly different between the two groups. The data confirm the validity of the autologous blood order schedule of 2 units for radical hysterectomy.

Blood Loss, Surgical↗
PubMed1995

SBH-1, a novel Reed-Sternberg-like cell line capable of inducing tumors in SCID mice: immunophenotypic, cytogenetic, and cytokine expression profiles.

A new cell line, SBH-1, with the morphologic, immunophenotypic, and karyotypic features consistent with those of Reed-Sternberg (RS) and Hodgkin (H) cells, has been established from the pleural effusion of a patient. The cytologic appearance of SBH-1 cells is characteristic of multinucleate RS and mononuclear H cells, all containing inclusion-like nucleoli. The SBH-1 cells express CD30, CD15, CD25, CD71, CD45, CD20, CD22, and bcl-2 protein and are negative for epithelial membrane antigen. Cytogenetic analysis showed multiple clonal abnormalities with breakpoints at 14q32, 6q21, and 11q23. The Ig heavy chain genes and both Ig light chain genes were rearranged in SBH-1 cells, whereas the bcl-2 gene was in germline configuration. Messages for the cytokines interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha, and transforming growth factor-beta and the cytokine receptors IL-2R, IL-4R, IL-6R, and IL-7R were detected by reverse transcription-polymerase chain reaction analysis. Xenotransplantation of SBH-1 cells into severe combined immunodeficient (SCID) mice led to local and disseminated tumor growth. The cytologic, histologic, and immunohistochemical features of SBH-1 cells in SCID mouse tumors were typical of RS and H cells. The SBH-1 cell line will be useful in the study of RS and H cell biology, inasmuch as it represents a cell line obtained from a previously untreated patient.

Aged↗
PubMed1995

Transfusion practice in urological surgery: modifications in association with the introduction of an autologous blood donor programme.

The transfusion records of 122 urological patients who had deposited one or more units of autologous blood were analysed. The 95 patients undergoing radical prostatectomy were arbitrarily divided into two cohorts (the first 47 patients enrolled, and the last 48 enrolled) to assess changes in use of blood. The avoidance of allogeneic transfusion in radical prostatectomy was 64% in the first cohort studied, and increased to 81% in the second. There was a significant decline in the mean absolute amounts of blood used from 4.47 to 2.54 units per patient from the first to second cohorts. Introduction of an autologous blood donor programme has been associated with a reduction in total blood use for radical prostatectomy, and a decrease in the number of patients exposed to allogeneic blood. The validity of an autologous blood-order schedule of 3 units for radical prostatectomy is supported.

Blood Transfusion, Autologous↗
PubMed1995

Use of autologous blood in support of orthopaedic surgery using a hospital-based autologous donor programme.

The use of autologous blood in support of orthopaedic surgery has been assessed for 296 patients; 150 underwent hip arthroplasty, 69 underwent knee arthroplasty, 37 underwent spinal procedures and 40 underwent miscellaneous operations. Overall, 87% of patients received no allogeneic blood and 23% of the autologous blood collected was not used. For hip and knee arthroplasty, there appears to be an increased willingness to transfuse patients when autologous blood is available, and a decreased proportion of patients receiving more than 3 units for hip arthroplasty and 2 units for knee surgery, when compared with an audit of blood use when almost all blood used was allogeneic. Wastage of autologous blood in support of spinal surgery was 66%, prompting a review of ordering practices. Assessment of avoidance of allogeneic transfusion by the standard schedule of 3 units for hip arthroplasty and 2 units for knee arthroplasty appears justified by the calculation that collection of an additional unit in each case would avoid allogeneic transfusion in 11 (5%) more patients with the unnecessary collection of 208 units.

Blood Transfusion, Autologous↗
PubMed1995

Blood bank audit.

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Blood Banks↗