Audit of Platelet Use

Transcription

1 South West Regional Transfusion Committee Audit of Platelet Use Report by Regional Transfusion Team

2 Acknowledgements Thanks to all transfusion laboratory staff who provided the data for this audit report. Thanks to Sandra Hodgkins who was largely responsible for data entry, and analysis. For information about the report contact: Janet Birchall Maggi Webb Consultant Haematologist Transfusion Laboratory Manager NBS Bristol North Devon Hospital Southmead Rd Raleigh Park Bristol Barnstaple BS10 5ND EX31 4JB Tel: Tel:

3 Contents Page Number Background 1 Aim of Study 1 Method 1 Results 2-9 Discussion 9 10 Summary 11 References 12 Appendices 13

4 Use of Platelets Audit The South West Regional Blood Transfusion Committee Background Although the use of red cells in England has declined steadily since 2000 platelet use has increased. Quarterly platelet issue figures identify that in the South West there has been an increase of 22.5% between April 02 March 05 compared with a 7.5% increase nationally over the same time period. Aim of Study 1. To determine which patients are being transfused platelets. 2. To identify why platelets are being transfused Method To try and achieve maximum participation from Trusts/hospitals in the South West region, the study was kept simple and involved blood bank staff only. An Excel spreadsheet was used for data collection, with each request entered on a separate line. The following data was required: Date of request Demographic details - the age of the patient User details - directorate specialty (see appendix 1) Clinical details - clinical summary (see appendix 2) - whether the platelets were required for prophylaxis or bleeding - the type of operation (if relevant) - the platelet count prior to issue - the number of adult therapeutic doses requested and the number actually given The study period was from 14th November until 11th December 2005, i.e. over a 4- week period. One Trust with a very high platelet use requested that their data collection be limited to a 2-week period, given the significant workload that this would involve. This was agreed and their result was doubled prior to inclusion in the analysis. 1

5 Results Out of 28 Trusts/Hospitals in the South West Region, 22 returned information. 1 Trust confused the data collection period and collected data over the month of November. 2 Trusts provided limited clinical data and one of these failed to provide any data on demographic or user details. All available data from these 3 Trusts was included in the analysis. The number of platelets identified as being requested and used by each Trust was compared with issue data from the National Blood Service over the audit time period. In 1 Trust, the number of platelets identified as used was significantly greater than those issued. On discussion with the main contact, the data supplied was considered inaccurate therefore all data from this Trust was excluded from further analysis. In total data from 21 hospitals was used for this analysis. Using NBS issue data it can be estimated that the audit captured 86% (1323/1535) of all platelets issued. Overall 1323 units of platelets were requested and 1226 units (93%) used for the initial request. Use of Platelets by each Trust/Hospital Table 1 identifies and per Trust/hospital. 4 hospitals requested more than 100 units and 2 of these requested more than 200 units. N.B: If the hospital who recorded usage over a 30-day period in November has been limited to 28-days, their usage would have reduced by 21 units of platelets but their position as the second largest user would not have changed. All 3 private hospitals which provided data used either 1 unit of platelets or none. Table 1 Regional Use of Platelets 300 Number of Platelets A B C D E F G H I J K L M N O P Q R S T U Hospital 2

6 Platelet Use by Age Table 2 identifies the number of platelets used by age category. Both platelets requested and platelets used increase according to age, with the largest number used by patients aged 65 years or above. Table 2 Platelet Use by Age 600 Number of Platelets by age < 16, 16-<40 40-< age UK Age Platelet Use by User (Specialty) Table 3 identifies the number of platelets used by each Specialty - see appendix 1 for list of Specialties. Cardiac surgery, haematology and oncology used more than 100 units of platelets each during the study period. The largest user was haematology, with 779 (59% of total) platelets being requested and 715 (58% of total) used. Oncology requested 149 (11% of total) and used 139 (11% of total). Cardiac surgery requested 111 (8% of total) and used 105 (9% of total). Table 3 Platelet Use by Specialty Number of Platelets Specialty 3

7 Platelet Use by Clinical Summary Table 4 identifies platelets requested / used according to clinical summary. The category associated with the highest use was post chemotherapy followed by bone marrow failure, surgery, bone marrow transplant and MDS. This is compatible with table 2 which identifies the highest specialty use by haematology, oncology and cardiac surgery. Although the highest single category of platelet use by clinical summary was other 165 of these cases, were haematological malignancy where the exact reason for the platelet request was unknown. Table 4 Platelet Use by Clinical Summary Number of Platelets DIC BMT PCX Prophylactic or Therapeutic Use PCX / BMT BMF BMF/MDS BMS MDS MDS / PCX Clinical Summary MDS / SUR NAT SUR OTHER UK When prophylactic or therapeutic use of platelets was known, 75% of all platelets were used for prophylaxis (prophylactic 904, prophylactic 838; therapeutic 310, therapeutic 289) see Table 5. The vast majority of prophylactic use was by haematology (676 and 621 ). Oncology accounted for 128 platelets requested and 118 used. Cardiac surgery was the highest single users of platelets for therapeutic use, with 94 and 92. The second largest user in this category was haematology, with 58 and 51. ITU requested 27 units and used 24 and oncology and general medicine requested and used 20 units of platelets each. 4

8 Table 5 Prophylactic vs Therapeutic Use 1000 Number of Platelets Prophylaxis Bleeding Unknown Use When Prophylactic or Therapeutic use Indicated 25% Prophylaxis Bleeding 75% 25% Prophylaxis Bleeding 75% 5

9 Prophylactic Use by Platelet Count When the platelet count was known 635 units (73%) were requested when the platelet count was measured at more than 10, compared with 235 units (27%) when the platelet count was known to be 10 or less, see Table 6. When the platelet count was more than 10 the main clinical indications were post chemotherapy, other (most use occurred in haematological malignancy), bone marrow failure, bone marrow transplant and MDS - see table 7. Table 6 Prophylactic Use by Platelet Count Number of Platelets Platelets < 10 Platelets > 10 Platelet count UK Platelet Count Prophylactic Use When the Platelet Count was Known 27% Platelets < 10 Platelets > 10 73% 6

10 29% Platelets < 10 Platelets > 10 71% Table 7 Prophylactic Use When Platelet Count >10 Number of Platelets BMF BMF/MDS BMS BMT MDS MDS/SUR MDS/PCS OTHER PCX Clinical Summary PCX/BMT SURGERY NOT KNOWN 7

11 Therapeutic use by Platelet Count 310 units of platelets were requested and 289 used to control bleeding see table 8. When the platelet count was know 150 (53%) were requested when the previously available platelet count was more than 50x10 9 /L. Out of these 70/150 (47%) were requested for cardiac surgery and 56/150 (37%) for other surgical patients. Table 8 Therapeutic Use by Platelet Count Number of Platelets Platelets < 50 Platelets > 50 Unknown Platelet Count Therapeutic Use When the Platelet Count was Known 53% 47% Platelets < 50 Platelets > 50 8

12 53% 47% Platelets < 50 Platelets > 50 Discussion The results of this study are compatible with data collected by the RTC in May 2005 indicating that platelet use per hospital in the South West region is very different but consistent. 4 hospitals requested more than 100 units, and 3 hospitals used more than 100 units over a 4 week period. One hospital which was identified as a large platelet user in May did not contribute data to this audit as their information was identified as unreliable. The high platelet use in patients of 65 years or older is of concern as the age profile of the population is increasing. The vast majority of platelets were used by haematology (58%). Oncology and cardiac surgery were the next highest users, however combined they used around a 1/3rd of those used by haematology. 75% of all platelets were given to prevent bleeding rather than treat bleeding. BCSH Guidelines recommend prophylactic transfusion without additional risk factors at a platelet count of 10x10 9 /L or less. This threshold is based on level 1b evidence (at least one randomised controlled trial). Despite this, 73% of all prophylactic platelets used in this study, where the platelet count was known, were associated with a recorded platelet count of greater than 10x10 9 /L. This could be explained by: a) use in patients with additional risk factors for bleeding such as sepsis, coagulopathy, or before an invasive procedure. Surgery was the clinical summary in 5% of requests when the platelet count was greater than 10 and therefore did not account for significant use in this category. b) use in patients when the count is predicted to fall - the platelet units are short dated or a further hospital attendance for an outpatient would be inconvenient. Use in this category is more likely if the patients platelet count is not routinely available to the transfusion laboratory prior to requesting delivery of blood products from the NBS. c) lack of adherence to BCSH Guidelines. 9

13 BCSH Guidelines recommend transfusion of platelets when bleeding occurs if the patients platelets are dysfunctional or to achieve a count of greater than 50x10 9 /L (higher at around 100x10 9 /L in CNS bleeding or patients with multiple trauma). When the count was known, more than ½ of platelets were given when the last recorded count was higher than 50x10 9 /L. 47% of these were used during cardiac surgery and 37% for other surgical procedures. Dysfunctional platelets, lack of an immediately available platelet count, a desire for a higher threshold platelet count and availability of platelets are likely to be significant factors for requests in this category. The use of near patient testing should be considered when quantitative or qualitative platelet problems are suspected. To further investigate platelet use according to counts, data from the 4 largest users was considered, see table 9. These Trusts/hospitals were chosen for this analysis to reduce bias caused by individual patients. The results illustrate significantly different use - in Trust/hospital F only 49% of all prophylactic platelets were requested when the platelet count was more than 10x10 9 /L compared to 80% in the other 3 Trust/hospitals. In Trust /hospital M a much smaller number of platelets were used when the platelet count was greater than 10x10 9 /L than requested, 21(75%) v 36 (80%). These findings are likely to represent platelet use in categories b) and c) above rather than true differences in the patients risk factors for bleeding between the Trusts/hospitals although verification would require further audit. It is worth noting that Trust /hospital F is close to an NBS centre and therefore platelet supply. Therapeutic use was also different between these users however the data is likely to be less reliable as the numbers in some are small. Table 9: Prophylactic and Therapeutic use by Platelet Count in the 4 largest Trust/hospital users Platelets requested M C F L Req % Req % Req % Req % Proph < Proph > Proph UK Bleed < Bleed > UK Platelets used M C F L Used % Used % Used % Used % Proph < Proph > Proph UK Bleed < Bleed > UK

14 Summary The results of this study indicate that: patients aged 65 years or older use most platelets. The increasing age profile of the population will require platelet collection by the National Blood Service, and the cost to Trusts / hospitals to increase unless platelet use alters. Almost 60% of all platelets are requested and used by haematology. Conservative use by staff in this specialty will have a significant effect on total platelet use and influence use by other specialties. 75% of all platelets are used for prophylaxis and 73% of these at pre-transfusion counts of greater than 10x10 9 /L. - Each Trust / hospital should have guidelines for appropriate platelet transfusion which are widely disseminated and monitored for compliance by regular audit. - Platelet counts, from patients at risk of requiring prophylactic platelet transfusions, should be available prior to the transfusion laboratory requesting delivery from the NBS. - A randomised controlled trial to assess the risks and benefits of not having a threshold platelet count in non haemorrhagic patients is required. More platelets were used to treat bleeding when the last measured count was greater than 50x10 9 /L. - Consideration should be given to the use of near patient testing to assess the need for platelets. - Guidelines for appropriate use should be widely disseminated and monitored for compliance by regular audit. 11

15 References: Benjamin RH & Anderson KC (2002) What is the proper threshold for platelet transfusion in patients with chemotherapy-induced thrombocytopenia? Critical Reviews in Oncology/Hematology, 42, British Committee for Standards in Haematology (BCSH) (2003). Guidelines for the sue of platelet transfusions. British Journal of haematology, 122, Eikenboom JCJ, van Wordragen R & Brand A (2005) Compliance with prophylactic platelet transfusion trigger in haematological patients. Transfusion Medicine, 15, Friedmann AM, Sengul H, Lehmann H, Schwartz C & Goodman S (2002) Do basic laboratory tests or clinical observations predict bleeding in thrombocytopenic oncology patients? Transfusion Medicine Reviews, 16, Stansworth SJ, Hyde C, Heddle N, Rubella P, Brunskill S & Murphy MF (2004) Prophylactic Platelet Transfusion for Haemorrhage after Chemotherapy and Stem Cell Transplantation. John Wiley & Sons, Ltd, Chichester, UK. The Cochrane Database of Systematic Reviews 2004, art No: CD pub2, doi: 10,1002/ CD pub2. 12

16 Appendix 1 Specialty Code Specialty Code General Surgery 1 Vascular Surgery 2 Urology 3 Plastics/burns 4 Cardiac Surgery 5 Neurosurgery 6 Orthopaedics/Trauma 7 ITU 8 A/E 9 SCBU 10 Obstetrics 11 Gynaecology 12 General Medicine 13 Haematology 14 Oncology 15 Renal 16 Cardiology 17 Neurology 18 Rheumatology 19 Care of the Elderly 20 Paediatric Medicine 21 Other (please specify) 22 Appendix 2 Clinical Summary Disseminated Intravascular Coagulation Bone Marrow Transplant Post Chemotherapy Bone marrow failure due to infiltration by disease Bone marrow failure due to sepsis Myelodysplastic syndrome Neonatal alloimmune thrombocytopenia Surgery (please state operation) Other (please specify) DIC BMT PCX BMF BMS MDS NAT SUR Code 13