Prospective validation of a point score system for predicting blood transfusion following hip or knee replacement

A Novel Scoring System Predicting Red Blood Cell Transfusion Requirements in Patients Undergoing Invasive Spine Surgery

Background: Access to blood products is crucial for patient safety during the perioperative course. However, reduced donations and seasonally occurring blood shortages pose a significant challenge to the healthcare system, with surgeries being postponed. The German Blood Transfusion act requires that RBC packages become assigned to an individual patient, resulting in a significant reduction in the available blood products, further aggravating shortages. We aimed to develop a scoring system predicting transfusion probability in patients undergoing spine surgery to reduce assignment and, thus, increase the availability of blood products. Methods: The medical records of 252 patients who underwent spine surgery were evaluated and 18 potential predictors for RBC transfusion were tested to construct a logistic-regression-based predictive scoring system for blood transfusion in patients undergoing spine surgery. Results: The variables found to be the most important included the type of surgery, vertebral body replacement, number of stages, and pre-operative Hb concentration, indicating that surgical specification and the extent of the surgical procedure were more influential than the pre-existing patient condition and medication. Conclusions: Our model showed a good discrimination ability with an average AUC [min, max] of 0.87 [0.6, 0.97] and internal validation with a similar AUC of 0.84 [0.66, 0.97]. In summary, we developed a scoring system to forecast patients' perioperative transfusion needs when undergoing spine surgery using pre-operative predictors, potentially reducing the need for RBC allocation and, thus, resulting in an increased availability of this valuable resource.

How do I/we forecast tomorrow's transfusion? A focus on recipients' profiles

Red blood cell (RBC) transfusion is a life-saving medical intervention and has an essential role in the management of surgical patients. However, blood donations and supply levels are decreasing, therefore there is an unmet need for the accurate prediction of the transfusion probability for surgical patients. Multiple methods have been established to predict the need for RBC transfusion. Maximum surgical blood order schedules are widely used in the clinical setting. However, these lists are not designed to accurately predict RBC utilization for an individual case as factors such as preoperative haemoglobin level, total body blood volume, comedications are not considered. Artificial intelligence and related technologies based on machine learning modelling are valuable alternatives to predict transfusion probability taking into account patient individual risk factors including among others comorbidities, laboratory parameters, use of oral anticoagulation, ASA score, surgeon's ID or applied blood saving measures. Overall, forecasting the need for a RBC transfusion can facilitate personalized medicine, quality assurance, decrease blood wastage, decrease costs, and increase patient safety. Furthermore, transfusion prediction models could facilitate blood management strategies before surgery.

Immediate intravenous iron administration improves anaemia recovery following total knee arthroplasty: A propensity-matched analysis

BACKGROUND AND OBJECTIVES

Patients who undergo total knee arthroplasty (TKA) have a risk of postoperative anaemia. This observational study evaluated whether single-dose intravenous ferric carboxymaltose (FCM) administered immediately after TKA facilitates the correction of anaemia.

MATERIALS AND METHODS

We retrospectively analysed 722 patients who underwent primary TKA. The FCM group receiving 1000 mg intravenous FCM within one postoperative hour was compared with the non-FCM group that did not receive the medication. A propensity score matching with multiple logistic regression analysis was used to minimize intergroup differences in the baseline characteristics and postoperative blood loss. The rate and severity of postoperative anaemia were compared between the groups, along with haemoglobin (Hb) value, transfusion rate and complications.

RESULTS

After propensity score matching, 231 patients were included in each group. In the FCM group, the rate of anaemia at postoperative day (POD) 7 (p = 0.021) and postoperative week (POW) 5 (p < 0.001) and the transfusion rate were significantly lower (p = 0.008). The rate of moderate to severe anaemia at POW-5 was also significantly lower in the FCM group (p < 0.001). In patients without preoperative anaemia (n = 322), the transfusion rate and rate and severity of anaemia at POD-7 and POW-5 were significantly lower in the FCM group than in the non-FCM group.

CONCLUSION

Postoperative intravenous FCM administration facilitated recovery of surgery-related anaemia by improving Hb and may reduce the need for transfusion in TKA patients. Preoperative non-anaemic patients could also benefit from accelerated recovery by intravenous iron treatment.

Preoperative prediction of Bleeding Independently associated with Mortality after noncardiac Surgery (BIMS): an international prospective cohort study

BACKGROUND

Diagnostic criteria for Bleeding Independently associated with Mortality after noncardiac Surgery (BIMS) have been defined as bleeding that leads to a postoperative haemoglobin <70 g L^-1, leads to blood transfusion, or is judged to be the direct cause of death. Preoperative prediction guides for BIMS can facilitate informed consent and planning of perioperative care.

METHODS

In a prospective cohort study of 16 079 participants aged ≥45 yr having inpatient noncardiac surgery at 12 academic hospitals in eight countries between 2007 and 2011, 17.3% (2782) experienced BIMS. An electronic risk calculator for BIMS was developed and internally validated by logistic regression with bootstrapping, and further simplified to a risk index. Decision curve analysis assessed the potential utility of each prediction guide compared with a strategy of identifying risk of BIMS based on preoperative haemoglobin <120 g L^-1.

RESULTS

With information about the type of surgery, preoperative haemoglobin, age, sex, functional status, kidney function, history of high-risk coronary artery disease, and active cancer, the risk calculator accurately predicted BIMS (bias-corrected C-statistic, 0.84; 95% confidence interval, 0.837-0.852). A simplified index based on preoperative haemoglobin <120 g L^-1, open surgery, and high-risk surgery also predicted BIMS, but less accurately (C-statistic, 0.787; 95% confidence interval, 0.779-0.796). Both prediction guides could improve decision making compared with knowledge of haemoglobin <120 g L^-1 alone.

CONCLUSIONS

BIMS, defined as bleeding that leads to a postoperative haemoglobin <70 g L^-1, leads to blood transfusion, or that is judged to be the direct cause of death, can be predicted by a simple risk index before surgery.

CLINICAL TRIAL REGISTRATION

NCT00512109.

The Effect of Intraoperative Ferric Carboxymaltose in Joint Arthroplasty Patients: A Randomized Trial

This study assessed the efficacy of intraoperative high-dose intravenous iron therapy in facilitating recovery from postoperative anemia and reducing the transfusion rate in patients with total knee and total hip arthroplasty. This prospective randomized controlled study involved 58 subjects. Group F received 1000 mg intravenous ferric carboxymaltose and Group C received normal saline. The changes in hemoglobin (Hb), hematocrit, iron metabolism variables, transfusion rates, and the arterial partial pressure of oxygen and the fraction of oxygen (PaO2/FiO2) ratio were recorded. There were 29 patients of each group. The change in Hb levels from baseline to 1 month post-surgery was higher in Group F than in Group C (0.3 ± 1.0 g/dl vs. -0.8 ± 0.8 g/dl, p < 0.001). Functional iron deficiency occurred more frequently in Group C (0% vs. 48.3%, p < 0.001) after the operation. The incidence of postoperative anemia, transfusion rate and P/F ratio did not significantly differ between the two groups. This study suggests that intraoperative high-dose ferric carboxymaltose during lower limb total arthroplasty can facilitate the recovery from postoperative anemia. Although it could not prevent the occurrence of postoperative anemia or the administration of transfusion, this treatment seemed to overcome surgery-related decrease of iron availability.

Bleeding impacting mortality after noncardiac surgery: a protocol to establish diagnostic criteria, estimate prognostic importance, and develop and validate a prediction guide in an international prospective cohort study

INTRODUCTION

Various definitions of bleeding have been used in perioperative studies without systematic assessment of the diagnostic criteria for their independent association with outcomes important to patients. Our proposed definition of bleeding impacting mortality after noncardiac surgery (BIMS) is bleeding that is independently associated with death during or within 30 days after noncardiac surgery. We describe our analysis plan to sequentially 1) establish the diagnostic criteria for BIMS, 2) estimate the independent contribution of BIMS to 30-day mortality and 3) develop and internally validate a clinical prediction guide to estimate patient-specific risk of BIMS.

METHODS

In the Vascular Events In Noncardiac Surgery Patients Cohort Evaluation (VISION) study, we prospectively collected bleeding data for 16 079 patients aged 45 years or more who had noncardiac inpatient surgery between 2007 and 2011 at 12 centres in 8 countries across 5 continents. We will include bleeding features independently associated with 30-day mortality in the diagnostic criteria for BIMS. Candidate features will include the need for reoperation due to bleeding, the number of units of erythrocytes transfused, the lowest postoperative hemoglobin concentration, and the absolute and relative decrements in hemoglobin concentration from the preoperative value. We will then estimate the incidence of BIMS and its independent association with 30-day mortality. Last, we will construct and internally validate a clinical prediction guide for BIMS.

INTERPRETATION

This study will address an important gap in our knowledge about perioperative bleeding, with implications for the 200 million patients who undergo noncardiac surgery globally every year. Trial registration: ClinicalTrials.gov, no NCT00512109.

Preoperative haemoglobin cut-off values for the prediction of post-operative transfusion in total knee arthroplasty

PURPOSE

The purpose of this study is to determine preoperative haemoglobin cut-off values that could accurately predict post-operative transfusion outcome in patients undergoing primary unilateral total knee arthroplasty (TKA). This will allow surgeons to provide selective preoperative type and screen to only patients at high risk of transfusion.

METHODS

A total of 1457 patients diagnosed with osteoarthritis and underwent primary unilateral TKA between January 2012 and December 2014 were retrospectively reviewed. Logistic regression analyses were applied to identify factors that could predict transfusion outcome.

RESULTS

A total of 37 patients (2.5 %) were transfused postoperatively. Univariate analysis revealed preoperative haemoglobin (p < 0.001), age (p < 0.001), preoperative haematocrit (p < 0.001), and preoperative creatinine (p < 0.001) to be significant predictors. In the multivariate analysis with patients dichotomised at 70 years of age, preoperative haemoglobin remained significant with adjusted odds ratio of 0.33. Receiver operating characteristic curve identified the preoperative haemoglobin cut-off values to be 12.4 g/dL (AUC = 0.86, sensitivity = 87.5 %, specificity = 77.2 %) and 12.1 g/dL (AUC = 0.85, sensitivity = 69.2 %, specificity = 87.1 %) for age above and below 70, respectively.

CONCLUSIONS

The authors recommend preoperative haemoglobin cut-off values of 12.4 g/dL for age above 70 and 12.1 g/dL for age below 70 to be used to predict post-operative transfusion requirements in TKA. To maximise the utilisation of blood resources, the authors recommend that only patients with haemoglobin level below the cut-off should receive routine preoperative type and screen before TKA.

LEVEL OF EVIDENCE

IV.

Development and validation of a predictive score for perioperative transfusion in patients with hepatocellular carcinoma undergoing liver resection

BACKGROUND

Liver resection is a major surgery requiring perioperative blood transfusion. Predicting the need for blood transfusion for patients undergoing liver resection is of great importance. The present study aimed to develop and validate a model for predicting transfusion requirement in HBV-related hepatocellular carcinoma patients undergoing liver resection.

METHODS

A total of 1543 consecutive liver resections were included in the study. Randomly selected sample set of 1080 cases (70% of the study cohort) were used to develop a predictive score for transfusion requirement and the remaining 30% (n=463) was used to validate the score. Based on the preoperative and predictable intraoperative parameters, logistic regression was used to identify risk factors and to create an integer score for the prediction of transfusion requirement.

RESULTS

Extrahepatic procedure, major liver resection, hemoglobin level and platelets count were identified as independent predictors for transfusion requirement by logistic regression analysis. A score system integrating these 4 factors was stratified into three groups which could predict the risk of transfusion, with a rate of 11.4%, 24.7% and 57.4% for low, moderate and high risk, respectively. The prediction model appeared accurate with good discriminatory abilities, generating an area under the receiver operating characteristic curve of 0.736 in the development set and 0.709 in the validation set.

CONCLUSIONS

We have developed and validated an integer-based risk score to predict perioperative transfusion for patients undergoing liver resection in a high-volume surgical center. This score allows identifying patients at a high risk and may alter transfusion practices.

Oral ferrous sulfate does not increase preoperative hemoglobin in patients scheduled for hip or knee arthroplasty

BACKGROUND

Low hemoglobin (Hb) concentrations before lower limb joint replacement are associated with the need for blood transfusions and increased mortality. To optimize preoperative Hb, blood conservation protocols often recommend oral iron supplements, even in nonanemic patients.

OBJECTIVE

To investigate the impact of ferrous sulfate on the change in Hb prior to hip or knee arthroplasty and evaluate the effect of oral iron on hematocrit, mean corpuscular volume (MCV), ferritin, and transferrin saturation, as well as its tolerability and treatment adherence.

METHODS

We conducted a prospective, observational cohort study of adults with Hb concentrations between 10 and 15 g/dL who received iron supplementation prior to hip or knee arthroplasty. Systemic inflammatory diseases, vitamin B(12) or folate deficiency, and current use of iron supplements, intravenous iron, or erythropoietin were exclusion criteria. All participants were prescribed ferrous sulfate 300 mg 3 times daily for a minimum of 3 weeks. Complete blood cell counts and iron studies were performed before therapy and surgery.

RESULTS

Eighty-seven patients with a mean (SD) Hb of 13.47 (0.84) g/dL were included in the study. Preoperative Hb decreased after treatment with iron (-0.14 [0.53] g/dL, p = 0.015). Hematocrit also declined (-0.6% [1.8%], p = 0.002), whereas ferritin increased (25.8 [38.6] ng/mL, p < 0.001). No significant change was seen in MCV and transferrin saturation. The most common adverse effects were constipation (33.3%), heartburn (13.8%), and abdominal pain (12.6%). The adherence rate was 67.1%.

CONCLUSIONS

Oral ferrous sulfate supplementation is not an effective method to increase preoperative Hb in patients scheduled for hip or knee arthroplasty, and its use is associated with adverse effects.

Association of allogeneic red-blood cell transfusion with surgeon case-volume

BACKGROUND

Surgeon case-volume predicts a variety of patient outcomes. We hypothesize that surgeon case-volume predicts RBC transfusion across different surgical procedures.

METHODS

We performed a cohort study of 372,670 in-patient surgical cases in the 52 non-federal hospitals in Maryland between 2004 and 2005. The main outcome measure was relative risk of receiving a transfusion.

RESULTS

Overall, 13.9% of patients received a transfusion. Patients seen by the highest case-volume surgeons (>161 cases/y) were more likely to receive a transfusion (16% versus 11%, P < 0.01) compared with middle case-volume surgeons (89-161 cases/y). After adjusting for confounders, the highest case-volume patients were still at increased risk of transfusion [relative risk (RR) 1.10, 1.07-1.14]. This result was true across many surgery types.

CONCLUSIONS

Surgeon case-volume is independently associated with the likelihood of RBC transfusion across a broad range of surgical procedures. Future efforts should be directed towards studying and standardization of transfusion practices.

An individualized pre-operative blood saving protocol can increase pre-operative haemoglobin levels and reduce the need for transfusion in elective total hip or knee arthroplasty

We have prospectively evaluated the efficacy of an individualized pre-operative blood saving protocol in elective total hip arthroplasty (THA) or total knee arthroplasty (TKA). The primary aim was to obtain a pre-operative haemoglobin (Hb) level of > or =14 g dL(-1). A reduction in requirements for allogeneic transfusion was considered the second aim. Several strategies are available for increasing pre-operative Hb levels and reducing red blood cell (RBC) transfusions following THA or TKA, but the success of these programmes depends on selecting the most appropriate treatment for each patient. Three hundred and five patients with an indication of elective THA or TKA were individually assigned to the following strategies according to Hb and ferritin levels and medical conditions: (a) no pre-operative intervention, (b) oral iron therapy, (c) intravenous (i.v.) iron therapy, (d) recombinant human erythropoietin alpha with i.v. iron and (e) pre-operative autologous donation (PAD) plus oral iron. Eighty-two percent of the patients reached a pre-operative Hb level of > or =14 g dL(-1) compared with 62% of patients with Hb levels of > or =14 g dL(-1) at the baseline visit. Treatment with PAD showed a significant reduction in the pre-operative Hb levels. The rate of RBC transfusion was 18.8% compared with 31.5% of matched historic group (P < 0.001). In conclusion, all patients scheduled to undergo THA or TKA should be candidates for an individualized pre-operative blood salvage programme.

Autologous blood donation and subsequent blood use in patients undergoing total knee arthroplasty

Autologous blood donation is designed to avoid complications from allogeneic blood, leaving units of blood in the general blood supply. It is unclear how efficient these programmes are in accomplishing these goals. It is unclear if autologous donation provokes increased need for any transfusion following surgery and whether it can be avoided in low-risk surgeries. Of 430 patients undergoing unilateral primary knee replacement arthroplasty over 12 months in our hospital, 309 had autologous donations and 121 did not. Of the 121 patients who did not donate, 36% completed surgery without transfusion, whereas only 17% of those who had autologous donations did so (P < 0.05). Age less than 65 years, higher baseline and postoperative haemoglobin levels were associated with lower transfusion rates. Patients who had autologous donations were approximately four times more likely to be transfused. As the number of autologous units donated increased, transfusions following surgery increased. Autologous donation did reduce allogeneic blood transfusions. Therefore, autologous blood donation for unilateral total knee arthroplasty is associated with overall increased transfusion rates, but with reduced need for allogeneic blood, independent of other clinical factors associated with transfusion. Therefore, there is need for reconsideration of these programmes relative to specific surgeries.

Autologous Blood Donation

Preoperative autologous blood donation has become accepted as a standard practice in elective surgery. Subsequent improvements in blood safety and evolving surgical techniques resulting in less blood loss have caused a national decline in preoperative autologous blood donation by approximately 50%. Nevertheless, the continuing emergence of new pathogens and the potential for severe blood inventory shortages continue to give preoperative autologous blood donation an important role in blood conservation strategies.

Predicting Allogeneic Blood Transfusion Use in Total Joint Arthroplasty

Total joint arthroplasty (TJA) patients often receive allogeneic blood transfusion. In this study we sought to create and validate a clinical prediction rule for transfusion in TJA using data that are easily available when scheduling the procedure. Logistic regression modeling was applied to retrospective data from all TJA procedures performed in Edmonton, Alberta in 2000 (n = 1875). The area under the receiver operating curve for the resulting model in the training and validation data sets was 0.80 and 0.76 respectively. By assigning a simple score based on six independent predictors (age, gender, weight, hemoglobin, ASA operative risk classification and whether revision surgery was planned), it was possible to classify a given subject's risk of receiving allogeneic transfusion. We conclude that accurate prediction of transfusion risk in TJA is possible using a rule based on simple preoperative clinical and laboratory data. Such prediction could allow transfusion prevention strategies to be applied selectively to those at greatest risk.

Autologous blood donation

Although preoperative autologous blood donation is employed in elective surgery, this is declining because of the increasingly safe allogeneic blood supply. However, it continues to be used because of the public's perception of allogeneic blood risks and increasing blood shortages. Patients may donate a unit of blood (450 +/- 45 ml) as often as twice weekly, up to 72 hours before surgery. Preoperative autologous blood is most beneficial in procedures that cause significant blood loss. It has been determined that preoperative autologous blood donation is poorly cost-effective; the use of this procedure must be based on evidence that it is safe and of value for the patient.

Effects of blood transfusion on clinical and functional outcomes in patients with hip fracture

BACKGROUND

Anemia and transfusion are common among elderly patients requiring surgery. The effects of transfusion on morbidity and mortality are controversial. The influence of transfusion on risk-adjusted mortality, readmissions, and functional mobility was examined.

STUDY DESIGN AND METHODS

A consecutive cohort of 551 patients undergoing surgery for hip fracture at four hospitals was prospectively studied. Outcomes were death, readmission, and functional independence measure-locomotion scores within 60 days of discharge. The trigger Hb level was defined as the lowest value before the first postoperative transfusion. Multivariate analyses adjusted for a validated, hip-fracture-specific risk model and predictors of transfusion.

RESULTS

Overall, 54.4 percent of patients received transfusions after surgery. Seventy-two percent of patients with a lowest postoperative Hb level of less than 10.0 g per dL received transfusions compared to 19.6 percent of those whose lowest measurement was at least 10.0 g per dL (p < 0.0001). In the 60 days after discharge, 3.8 percent of patients died and 16.9 percent were readmitted. Transfusion was associated with lower risk-adjusted odds of readmission (OR, 0.54; 95% CI, 0.30-0.97), but it did not influence mortality or mobility functioning. In subgroups analyses, the benefit of transfusion on readmission rates appeared to be concentrated among patients with a trigger Hb level of less than 10.0 g per dL. For patients with a trigger Hb level of at least 10.0 g per dL, transfusion did not affect risk-adjusted rates of death or readmission, but was associated with better risk-adjusted functional mobility scores (p < 0.01).

CONCLUSIONS

Postoperative transfusion reduced the risk of readmission but did not decrease mortality or improve mobility. Randomized controlled trials of different transfusion strategies will be needed to clarify the true benefits and risks of transfusion in surgical patients.

Identifying patients for blood conservation strategies

BACKGROUND

Generally, only the type of operation is used to estimate the need for perioperative homologous blood transfusion. This study quantified the extent to which the estimation could be improved if, in addition, simple patient characteristics were taken into account.

METHODS

Retrospective data on 24 509 consecutive adult surgical patients were used to derive and validate three models to predict perioperative homologous transfusion. The first model was a univariable model with type of operation as the only predictor. The second and third models were a full and a simplified multivariable logistic regression model. The performance of the multivariable models was tested in two validation sets: in similar patients who had operations in the same general hospital (internal validation) and in patients who had operations in a university hospital (external validation). The areas under the receiver-operator characteristic (ROC) curve were compared with that found in the derivation set.

RESULTS

There were no important differences in characteristics between the derivation and validation sets. The ROC area of the model including surgery only was 0.92 (99 per cent confidence interval (c.i.) 0.91 to 0.94) and that of the full and simplified multivariable models 0.95 (99 per cent c.i. 0.94 to 0.96) and 0.94 (99 per cent c.i. 0.93 to 0.95) respectively. The latter two were significantly different from the first one. In the external validation set the ROC area of the simplified model was 0.84 (95 per cent c.i. 0.83 to 0.86). Patients who had a preoperative haemoglobin level lower than 13 g/dl and underwent major invasive surgery had the highest risk (43 per cent) of transfusion.

CONCLUSION

A simple algorithm using type of operation and haemoglobin concentration was effective in identifying patients likely to need perioperative homologous blood transfusion.

Validation of a clinical prediction rule to reduce preoperative type and screen procedures

BACKGROUND

We have developed a prediction rule for the occurrence of perioperative red blood cell transfusion to help to reduce the number of unnecessary preoperative type and screen procedures. We evaluated the robustness of this prediction rule in patients from another hospital.

METHODS

The rule was retrospectively applied to 1282 consecutive patients ('validation set') who underwent similar surgical procedures to the patients in the derivation study. The outcome was similarly defined as any allogeneic transfusion on the day of surgery or during the first postoperative day. The predictive value of the rule was assessed using a Receiver Operating Characteristic curve (ROC) and compared with the results of the derivation study. Subsequently, the number of correctly predicted transfusions was compared.

RESULTS

The patient characteristics did not differ between the two sets, except for the incidence of transfusion (derivation study: 18%; present study: 8%). In the validation set, the ROC area of the prediction rule was 0.78 (95% confidence intervals [CI]: 0.73-0.82), which was within the CI of the ROC area found in the derivation study (0.75; 95% CI: 0.72-0.79). In total, 35% of the type and screen procedures could be omitted (derivation study: 50%), with 13% missed transfused patients (derivation study: 20%).

CONCLUSIONS

After comparing the results of this validation study with that of the derivation study, the prediction rule was robust and may work in other clinics as well.

The reduction of preoperative autologous blood donation for primary total hip or knee arthroplasty: the effect on subsequent transfusion rates

We conducted this quality assurance observational study to examine the effects of a change in policy regarding preoperative autologous blood donation (PABD) and indications for perioperative blood transfusion in patients undergoing primary total hip or knee arthroplasty. Two successive time periods, each including 182 successive patients treated by the same medical team and with standardized anesthesia, were compared. The first study had the following standard transfusion policy: 3 U of PABD collected (n = 119) and liberal autologous transfusion (AT). The second study introduced a specific indication for PABD, on the basis of estimated red blood cell reserve and a life expectancy of more than 10 years; 2 U of PABD was collected (n = 81), and criteria were identical for AT and allogeneic transfusion. We mainly compared the incidence of AT; allogeneic and overall transfusions; the inclusion, admission, and discharge hematocrit values; and the wastage of PABD units. This novel policy increased the number of untransfused patients by a factor of 10 (5.5% vs 56.6%) (P < 0.0001), decreased the number of PABD patients by 30% with a 2.4-fold reduction in AT (30% vs 80%) (P < 0.0001), and did not change allogeneic requirements (13% vs 15%). Although fewer autologous units were collected (172 vs 426), the wastage was higher in Study 2 (46% vs 12%) (P < 0.0001). We conclude that incorporation of patients' individual factors improves the efficiency of transfusion for total hip and total knee arthroplasty surgeries.

IMPLICATIONS

We compared two transfusion policies for primary total hip or knee arthroplasties: first, a standard preoperative autologous donation with a liberal autologous transfusion policy; and second, a more restrictive indication for autologous donation that was based on patients' individual factors, with identical criteria for autologous and allogeneic transfusion. We found that this change of policy reduced autologous donation and transfusion with no increase in allogeneic transfusion.

A reduction in type and screen: preoperative prediction of RBC transfusions in surgery procedures with intermediate transfusion risks

In many patients, a 'type and screen' procedure is routinely performed before surgery. However, most patients are not transfused after all. Can we predict, which surgical patients will and will not be transfused, to reduce the number of these investigations? We studied 1482 consecutive surgical patients with intermediate risk for transfusion. Multivariate logistic regression modelling and the area under the Receiver Operating Characteristic curve (ROC area) were used to quantify how well age, gender, surgical procedure, emergency or elective surgery and anaesthetic technique predicted transfusion, and whether the preoperative haemoglobin concentration had added predictive value. Gender, age > or =70 yr, and type of surgery were independent predictors of transfusion, with a ROC area of 0.75 (95% CI: 0.72-0.79). Validating this model with an easily used prediction rule in a second patient population yielded a ROC area of 0.70 (95% CI: 0.63-0.77). With this rule type and screen could correctly be withheld in 35% of these patients. In the remaining 65% of the patients, a further reduction in type and screen investigations of 15% could be achieved using the preoperative haemoglobin concentration. Using a simple prediction rule, preoperative type and screen investigations in patients who have to undergo surgery procedures with intermediate transfusion risk can be avoided in about 50%. This may reduce patient burden and hospital costs (on average: 3 million US$ per 100 000 procedures).

Transfusion practice in elective orthopaedic surgery

. The transfusion requirements of 2233 patients who underwent total hip or knee joint arthroplasty procedures at nine Canadian hospitals during 1995-1996 were evaluated. Although 64% of patients were eligible for participation in an autologous blood donation (ABD) programme, only 8% predonated blood. Patients who were eligible for ABD were younger (62 years vs. 70 years) and had fewer medical illnesses (18% vs. 44%) than those who did not predonate. The rate of allogeneic transfusion was 9.0% (95% confidence interval 4.9-13.1%) in patients who predonated as compared with 24.1% (95% confidence interval 22.2-25.9%) in those who did not. Risk factors for the occurrence of an allogeneic transfusion were type of procedure (primary or revision hip arthroplasty), lower baseline haemoglobin, lower body weight, older age and presence of rheumatoid arthritis (P < 0.001). Only patients without risk factors were predicted to have a less than 10% risk of receiving an allogeneic transfusion. Use of preventive strategies was minimal. Two models designed to predict the occurrence of an allogeneic transfusion were evaluated. If allogeneic transfusion rates are to be reduced, eligible patients should be encouraged to participate in ABD programmes. For patients who are ineligible, other preventative strategies should be introduced.

Blood conservation in patients undergoing non-cardiac surgery

Concerns about the safety, inventory, and cost of allogeneic blood have led to a renewed interest in blood conservation. Autologous blood collection techniques, including preoperative autologous donation, acute normovolemic hemodilution, and perioperative blood recovery are routinely used as alternatives to allogeneic transfusion. In the future, these techniques may be combined with pharmacological strategies, such as presurgical erythropoietin therapy or red cell substitutes, to reduce further the need for allogeneic blood.

A study of an educational intervention to decrease inappropriate preoperative autologous blood donation: its effectiveness and the effect on subsequent transfusion rates in elective hysterectomy

BACKGROUND

Decreasing the overcollection of preoperative autologous blood is difficult to achieve. The purpose of this study was to determine whether an educational intervention designed to outline the risks of preoperative autologous collection can decrease such donations and, if so, to determine how this decrease will affect subsequent transfusion rates.

STUDY DESIGN AND METHODS

An educational intervention consisting of a didactic presentation to the Department of Gynecology staff about the risks and benefits of autologous blood was implemented. Written material with similar information was given to patients. Subsequently, the percentage of patients donating autologous blood, the number of autologous units donated, and the rates of transfusion in patients eligible for autologous donation who were admitted for elective abdominal or vaginal hysterectomy were measured. These rates were compared to those in similar patients admitted in the 2 years before the educational intervention.

RESULTS

After an educational intervention, the proportion of patients donating autologous blood decreased from 53 percent to 26 percent (p<0.01), and the number of units collected per patient decreased from 0.86 to 0.31 (p<0.01); this resulted in a savings of 80 autologous donations per year. Despite no difference in estimated blood loss (p = 0.46), the overall transfusion rate decreased from 10 percent to 3.7 percent (p = 0.03), while the allogeneic transfusion rate demonstrated no significant change (1.1% vs. 2.2%; p = 0.40).

CONCLUSIONS

Unnecessary preoperative autologous donations by elective hysterectomy patients can be decreased by educating physicians and patients about the risks of preoperative autologous blood donation. Decreasing such unnecessary donations can decrease the subsequent autologous transfusion rate, with its attendant risks, without increasing the risk of allogeneic transfusion.