Abstract
Background
Blood transfusion is an important part of the medical care service. As there has not been a regional study about blood requests for operations, this study was done to assess blood ordering for various types of elective urological surgery.
Materials and methods
In a descriptive, retrospective, cross-sectional study, blood requests for all patients undergoing elective urological surgery in Razi Hospital (Rasht, Iran) during the first 6 months of 2010 were studied. The patients’ data (age, sex, weight, type of surgery, haemoglobin level before and after surgery, number of units of blood cross-matched and number of units transfused in the operating theatre and in the 3 days after surgery) were collected from their clinical records. Patients with a history of coagulopathy or anticoagulant drug use were excluded. The cross-match to transfusion ratio (C/T ratio), transfusion index (TI) and transfusion probability (T%) were calculated. The level of statistical significance was set at P =0.05.
Results
Of the 435 patients studied, 327 (75.1%) were male and 108 (24.9%) were female. The mean age of patients was 51.74±19.33 years. The mean number of units of blood requested for each operation was 2.8±1.2, whereas the mean number transfused was 0.59±0.24; the difference was statistically significant (P<0.05). The relationships between pre-operative haemoglobin concentration and both blood requested and blood used were also statistically significant (P =0.038 and P <0.001, respectively). Calculated for all the operations, the C/T ratio was 14.16, the TI was 0.11 and the T% was 8.85%. Overall, only 8.5% of the patients (n=37) need blood transfusion in the operating theatre and only 10.8% (n=47) required transfusion within the 72 hours after surgery.
Discussion
The amount of blood requested and cross-matched for elective urological surgery is much greater than the real level of consumption. An appropriate, standard blood order guideline would reduce costs and staff workload.
Keywords: C/T ratio, transfusion probability, transfusion index, cross-matched blood, blood transfusion
Introduction
The amount of blood requested and cross-matched is usually determined based on routine, habit and previous experience of clinicians1–2. Requests for large amounts of blood stem from the fear of not having sufficient blood available during surgery or from not having specific patterns and guidelines for blood requests3. The consequence of requesting large amounts of cross-matched blood pre-operatively is that a lot of the blood is not used and after 2 or 3 days these blood products can no longer be used for other patients4–6. Furthermore, the cost of production, storage and separation of products, hospital transfer, screening tests for blood safety and the typing and cross-matching add to the importance of appropriate application and use of blood products7. It has been suggested that in surgeries usually requiring less than 0.5 units of blood, performing compatibility testing before surgery is not necessary and that it is sufficient to determine the patient’s ABO and Rh group and perform a type & screen8. A better estimate of the need for transfusions may be obtained from parameters such as the cross-match to transfusion ratio (C/T ratio), transfusion probability (T%) and transfusion index (TI)9–11. The C/T ratio, the most important parameter for estimating the need for blood during surgery, was introduced in 1975 by Henry and Boral12. They suggested that a C/T ratio lower than 2.5 is a significant indicator of the need for blood transfusion during surgery8,12. The T% was described for the first time by Mead et al. in 1980 and a value greater than 30% indicates considerable requirement of blood9. The average number of units used per patient is calculated by the TI and, according to Henry and Boral, for operations that usually require less than 0.5 units of blood, blood compatibility testing before surgery is not necessary and it is sufficient to determine the patient’s ABO and Rh groups and perform an antibody screen8,12. Given the considerable advantages of decreasing unnecessary blood requests and the absence of regional guidelines on blood orders for different types of surgery, we decided to study the amount of cross-matched blood requested prior to surgery and the transfusion rates associated with surgery, determining the C/T ratio, T%, and TI for elective urological operations in Razi Hospital, Rasht (Iran) during the first half of 2010 and comparing these with global standards. The purpose is to use the results of this study to improve the blood order pattern for surgery at our hospital.
Materials and methods
All patients undergoing elective urological surgery at Razi hospital, Rasht during the first 6 months of 2010 whose blood request was recorded in their clinical records were studied.
After confirmation from the hospital authorities, the following data were extracted from the patients’ clinical records: age, sex, weight, type of surgery, levels of haemoglobin before and after surgery, the number of cross-matched blood units requested and the number of blood units transfused in the operating theatre and in the 3 days following surgery.
Patients who had a history of coagulopathy or anticoagulant drug use were excluded. Data were analysed using the Statistical Package for the Social Sciences (SPSS, ver. 16). The C/T ratio, TI and T% were calculated for each patient and analysed by the t-test and Kruskal-Wallis test.
Results
Of 472 patients who underwent elective urological surgery in Razi hospital, Rasht, and for whom blood was requested, 26 patients (5.5%) were excluded because of incomplete information in their clinical records. Eleven patients (2.23%) were excluded because of a history of coagulopathy or anticoagulation drug use. Consequently, 435 patients (92.16%) were included in this study. Of these 435 patients, 327 patients (75.1%) were male and 108 (24.9%) were female. The mean age of the patients was 51.74±19.33 years. The mean number of units of blood requested for each operation was 2.8±1.12, while the mean number of units transfused was 0.59±0.24; the difference was statistically significant (P <0.05). Cross-matching was not done for 2.3% of the patients, despite the request for blood. Only 8.5% of patients required blood transfusions in the operating theatre and only 10.8% of patients (47 patients) required blood in the 72 hours following surgery (Table I). The Kruskal-Wallis test was used to determine the statistical significance of differences between the amount of blood requested in different groups and the pre-operative haemoglobin (P =0.038) The amount of blood requested was highest for patients with a Hb level <7 g/dL and lowest for those with a Hb >10 g/dL. In addition, by using Kruskal-Wallis test, it was determined that there was a statistically significant difference between the amount of blood transfused in different groups and pre-operative haemoglobin levels (P <0.001). Similarly, the maximum number of units of blood transfused was among patients with a Hb <7 g/dL and the minimum number was among patients with a Hb >10 g/dL (Table II).
Table I.
Number and percentages of requests for blood, cross-matched blood and transfused blood.
| Patients for whom blood was requested | Patients for whom blood was cross-matched | Patients transfused in the operating theatre | Patients transfused during the 72 hours after surgery | Total number of patients receiving blood | |||||
|---|---|---|---|---|---|---|---|---|---|
| Yes | No | Yes | No | Yes | No | Yes | No | ||
| Number | 435 | 425 | 10 | 37 | 398 | 47 | 388 | 78 | 357 |
| Percentage | 100 | 97.7 | 2.3 | 8.5 | 91.5 | 10.8 | 89.2 | 17.9 | 82.1 |
Table II.
Mean number of units of blood requested and transfused according to the haemoglobin level before surgery.
| Haemoglobin level (g/dL) | Number of patients | Average of blood units | Standard deviation | Statistical estimation | |
|---|---|---|---|---|---|
| Units of blood requested | ≤7 | 5 | 3.8 | 0.44 | P <0.038 |
| 7.1–10 | 34 | 3.08 | 1.48 | ||
| ≥10 | 396 | 2.76 | 1.09 | ||
| Units of blood transfused | ≤7 | 5 | 1.2 | 1.3 | P <0.001 |
| 7.1–10 | 34 | 0.91 | 0.99 | ||
| ≥10 | 396 | 0.17 | 0.48 |
For all types of surgery the C/T ratio was higher than 2.5: the highest ratio (65) was for percutaneous nephrolithotomy, while the lowest was for open stone surgery (6.27). The overall ratio was 14.16. The overall TI was 0.11, while the overall T% was 8.8 (Table III).
Table III.
C/T ratio, TI and T% according to type of surgery.
| Type of surgery | N. of patients | N. of units of blood ordered | N. of cross-matched units | N. of units transfused in operating theatre | N. of patients transfused in operating theatre | N. of patients with cross-matched blood | C/T ratio | TI | T% |
|---|---|---|---|---|---|---|---|---|---|
| Adrenal surgery | 2 | 6 | 5 | 0 | 0 | 2 | - | 0 | 0 |
| Kidney surgery | 29 | 108 | 66 | 7 | 5 | 29 | 9.42 | 0.24 | 17.24 |
| Open nephrolithotomy | 45 | 127 | 69 | 11 | 8 | 44 | 6.27 | 0.25 | 18.18 |
| PNL* | 38 | 120 | 65 | 1 | 1 | 38 | 65 | 0.02 | 2.63 |
| TUL** | 90 | 193 | 108 | 4 | 4 | 86 | 27 | 0.04 | 4.65 |
| Internal uretherotomy | 4 | 6 | 4 | 0 | 0 | 4 | - | 0 | 0 |
| Pyeloplasty + ureteral reimplantation | 8 | 15 | 9 | 1 | 1 | 7 | 9 | 0.14 | 14.2 |
| TUR-BT*** and other bladder operations | 22 | 79 | 37 | 5 | 3 | 21 | 7.4 | 0.23 | 14.28 |
| TURP**** | 49 | 150 | 73 | 4 | 3 | 49 | 18.25 | 0.08 | 6.14 |
| Cystoscopy and ureteroscocpy | 38 | 83 | 56 | 2 | 2 | 37 | 28 | 0.05 | 5.4 |
| Open prostatectomy | 24 | 70 | 42 | 2 | 2 | 24 | 21 | 0.08 | 8.33 |
| Radical surgery | 8 | 39 | 22 | 4 | 1 | 8 | 5.5 | 0.5 | 12.5 |
| External genital surgery | 10 | 16 | 11 | 0 | 0 | 10 | - | 0 | 0 |
| Laparoscopic surgery | 13 | 38 | 19 | 3 | 3 | 12 | 6.33 | 0.25 | 25 |
| Prostate or kidney biopsy | 7 | 21 | 13 | 0 | 0 | 7 | - | 0 | 0 |
| Miscellaneous | 6 | 13 | 9 | 1 | 1 | 6 | 9 | 0.16 | 16.7 |
| Performing two operations simultaneously | 42 | 134 | 72 | 3 | 3 | 41 | 24 | 0.07 | 7.31 |
| Total operations | 435 | 1218 | 680 | 48 | 37 | 418 | 14.16 | 0.11 | 8.85 |
Legend
Percutaneous nephrolithotomy,
Transurethral lithotripsy,
Transurethral resection of bladder tumour,
Transurethral resection of prostate.
Discussion
The importance of blood transfusions for the survival of patients in appropriate cases is clear to everyone. Without blood and blood donations, thousands of operations could not be carried out safely13. However, despite the importance of appropriate use of blood, there is evidence of significant differences in clinical patterns of blood requests and usage among hospitals, physicians and clinicians, showing that most blood and many of its products are not used appropriately14. Three decades of studies have shown that requests for blood exceed its real use, leading to financial waste and unnecessary work by personnel15–17. In our study, cross-matching was performed for 97.5% of patients although only 8.5% (37 of a total of 435 patients) required a blood transfusion in the operating theatre and 10.8% (47 of a total of 435 patients) in the 72 hours following surgery. In a study by Palmer et al. in 2003 it was shown that only 16% of patients for whom blood was cross-matched prior to surgery actually required blood transfusion during their operations6. In 2002, Muizuddin et al. indicated that 95.1% of reserved blood is unused18. In our study about 2.8±1.12 units of blood were requested for each operation, but only 0.59±0.24 units were actually administered. It seems that two reasons for the difference between the amount of blood requested and cross-matched and the blood-consumption rate in our study were lack of adherence to relevant guidelines and surgeons’ fear of the lack of availability of blood products in an emergency situation, resulting in unnecessary and greater than standard blood requests. Based on the Scottish Intercollegiate Guidelines for operations such as transurethral resection of bladder tumour (TUR-BT), transurethral resection of prostate (TURP) and pyeloplasty, typing and screening is sufficient. It is recommended that two units of blood are reserved for prostatectomy and laparoscopy, whereas blood does not need to be ordered for external genital surgery13. In our study, 3.6 units of blood were requested for TURP, 3.59 for TUR-BT and other bladder operations, 1.87 for pyeloplasty and re-implant surgery, 2.91 for prostatectomy, 2.92 for laparoscopic surgery and 1.6 for external genital surgery. Another study showed a similar pattern of blood management: 2.2 units of blood requested for a real use of only 0.23 units13. We found a statistically significant relationship between average blood order and level of haemoglobin prior to surgery (P =0.038). Most requests for blood were for patients with a haemoglobin level of 7 g/dL or below. Various studies have shown that one of the factors most strongly determining the amount of blood requested is the level of haemoglobin before surgery13,19. We found that there is significant relationship between blood units transfused during and after surgery and the haemoglobin concentration before and after surgery (P <0.001). In addition, other studies showed that patients with a haemoglobin below 6 g/dL usually require blood transfusion6.
The C/T ratio is the most important ratio for estimating the probability of requiring blood during surgery. Several researchers have shown that a C/T ratio of less than 2.5 indicates a considerable requirement of blood transfusion during surgery8. In our study the C/T ratio for all types of urological surgery was 14.16, which indicates a high level of cross-matched blood in comparison to transfused blood. Even higher C/T ratios have been found by other researchers: Khalili et al. reported a C/T ratio of 21.5 in 364 patients20, while Couture et al. found a C/T ratio of 41.4 in 301 patients studied in 20012.
In our study the transfusion probability (T%) for all operations was 8.85%. In the study by Khalili et al. the T% was 4.7%20, whereas it was 6.8% in a study by Muizuddin et al18. Since a T% higher than 30% indicates considerable requirement for blood12, the low T% in our study and in other similar studies indicates that the patients investigated had a low probability of requiring blood transfusion.
Finally, based on the number of transfusions for each patient, the total TI for all types of surgery was 0.11. According to another study, it is not necessary to perform compatibility testing before surgery for patients with a TI of less than 0.5; for these patients determining Rh and ABO group and performing a type & screen (antibody separation) is sufficient13. These results are compatible with those of other studies including that by Khalili et al., in which the TI was 0.120. In the study by Muizuddin the TI was only 0.0618 and in our study the TI was more than 0.5 which shows inappropriate compatibility testing before surgery. In spite of research done on the amount of blood transfused in surgical patients, the patterns of use differ and do not match universal standards, and surgeons request transfusion of blood on the basis of their own habits. It is, therefore, essential to do local studies to assess these habits and produce local guidelines.
In conclusion, in our hospital the amount of blood requested and cross-matched for patients undergoing elective urological surgery is much greater than the amount actually used. Because of the high rate of unnecessary cross-matching of blood prior to surgery, the lack of most cross-matched blood usage and the increased workload and financial costs, changes in the pattern of blood requests for elective urological operations and preparation of relevant clinical guidelines will be necessary.
Footnotes
The Authors declare no conflicts of interest.
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