Retrograde Autologous Priming Research Articles

Abstract 12189: Gender Differences in Intra-Operative Blood Transfusions: Analysis of 54,122 Coronary Artery Bypass (CABG) Procedures

Background/Hypothesis: Women have higher morbidity and mortality associated with CABG procedures than men. The extent intra-operative red blood cell (RBC) transfusions contribute to gender differences in surgical outcomes is not established. We hypothesized that women are at increased risk for RBC transfusions due to lower pre-op hematocrit (Hct) and blood volume, but that other factors may also contribute. Methods: Consecutive, non-reoperative CABG procedures from 189 institutions (2012 -2015) were reviewed. Gender differences and odds ratios for intra-operative transfusion were evaluated with logistic regression models adjusting for age, blood volume (Nadler formula-to normalize for height and weight), procedure acuity, net extracorporeal circuit prime volume, use of retrograde autologous priming, first Hct in OR, nadir Hct on cardiopulmonary bypass (CPB), volume added on CPB, ultra-filtration volume, urine output on CPB, and procedure duration. Results: Among 54,122 patients (25.3% female), 21.9% (n=11,901) received a RBC transfusion. Compared to men, female patients were older (66 yrs vs. 64 yrs, p<.001), had lower blood volumes (4.3L vs. 5.6L, p<.001), and lower pre-op Hct (32.9% vs. 37.2%, p<.001). Transfusion rates were 3-fold higher in women vs. men (45.1% vs 13.7%, p<.001). Even after adjustment for independent predictors of intra-operative transfusion, women remained at increased risk vs men (OR = 1.3, 95% CI = 1.2 -1.4). No gender differences in transfusion rates were observed for Hct 21%-23% (Figure). Conclusions: Women have an increased risk of intra-operative RBC transfusion vs men. After adjusting for height and weight, much of this risk is due to gender differences in pre-op Hct and blood volume, however a residual significant risk remained after adjustment. Perfusion strategies aimed at gender differences may minimize unnecessary transfusions. Future study on the impact of gender on transfusion practice in cardiac surgery is warranted.

Blood conservation strategies in cardiac valve replacement

We aimed to evaluate whether blood conservation strategies including intraoperative autologous donation (IAD) could reduce perioperative blood transfusion for patients undergoing cardiac valve replacement including mitral valve replacement, aortic valve replacement (AVR), and double valve replacement (DVR).A total of 726 patients were studied over a 3-year period (2011–2013) after the implementation of IAD and were compared with 919 patients during the previous 36-month period (January 2008–December 2010). The method of small-volume retrograde autologous priming, strict blood transfusion standard together with IAD constituted a progressive blood-saving strategy.Baseline characteristics and preoperative information showed no statistically significant difference between IAD group and non-IAD group. Most of the postoperative morbidities are statistically the same in the 2 groups. Chest tube output (415.2 vs 1029.8 mL, P < 0.001) and postoperative respiratory failure (5.9% vs 8.6%, P = 0.039) favored the IAD group, whereas hematocrit levels were more favorable in the non-IAD group (30.3% vs 33.0% at the end of the operation, P < 0.001; 30.4% vs 31.5% at the time of discharge). The use of blood product transfusion was higher in the non-IAD group (22.6% vs 43.3%, P < 0.001). Binary multivariate logistic regression analysis showed that high age, non-IAD, DVR surgery, and absent smoking history are associated with a higher risk of intra-/postoperative blood transfusion.Blood conservation is effective and safe in cardiac valve replacement surgeries. The use of intraoperative autologous donation can lead to improved outcomes including a significantly lower rate of intra-/postoperative blood transfusion and postoperative complications.

Blood Conservation—A Team Sport

Cardiac surgery accounts for between 15% and 20% of all blood product utilization in the United States. A body of literature suggests that patients who are exposed to even small quantities of blood have an increased risk of morbidity and mortality, even after adjusting for pre-operative risk. Despite this body of literature supporting a restrictive blood management strategy, wide variability in transfusion rates exist across institutions. Recent blood management guidelines have shed light on a number of potentially promising blood management strategies, including acute normovolemic hemodilution (ANH) and retrograde autologous priming (RAP). We evaluated the literature concerning ANH and RAP, and the use of both techniques among centers participating in the Perfusion Measures and outcomes (PERForm) registry. We leveraged data concerning ANH and RAP among 10,203 patients undergoing isolated coronary artery bypass grafting (CABG) procedures from 2010 to 2014 at 27 medical centers. Meta-analyses have focused on the topic of ANH, with few studies focusing specifically on cardiac surgery. Two meta-analyses have been conducted to date on RAP, with many reporting higher intra-operative hematocrits and reduced transfusions. The rate of red blood cell transfusions in the setting of CABG surgery is 34.2%, although varied across institutions from 16.8% to 57.6%. Overall use of ANH was 11.6%, although the utilization varied from .0% to 75.7% across institutions. RAP use was 71.4%, although varied from .0% to 99.0% across institutions. A number of blood conservation strategies have been proposed, with varying levels of evidence from meta-analyses. This uncertainty has likely contributed to center-level differences in the utilization of these practices as evidenced by our multi-institutional database. Perfusion databases, including the PERForm registry, serve as a vehicle for perfusionist's to track their practice, and contribute to multidisciplinary team efforts aimed at assessing and improving the value of cardiac surgical care.

Intraoperative autologous based blood conservation strategies in mitral valve replacement

To evaluate whether intraoperative autologous donation (IAD) can reduce perioperative blood transfusion for patients underwent mitral valve replacement (MVR). A total of 318 patients received implementation of IAD from January 2011 to December 2013 were analyzed retrospectively, and compared with 517 patients of the previous 36-month period (from January 2008 to December 2012). The method of small-volume retrograde autologous priming, strict blood transfusion standard along with IAD together constituted a progressive blood-saving strategy. Statistical methods including Students' t-test, Pearson's χ(2) test, Kruskal-Wallis analysis and multivariate Logistic regression model were used for comparisons of the data. There were no significant difference between IAD group and non-IAD group considering preoperative patient demographics, characteristics and preoperative comorbidities. However, IAD group significantly reduced number of patients transfused with intra/post-operative packed red-blood cell (PRBC) (55(17.0%) vs. 215 (42.1%), χ(2)=53.0, P=0.000), and had significantly reduced postoperative chest tube output (150(380) ml vs. 700(660) ml, H=195.648, P=0.000), length of stay ((16±6) d vs. (20±8)d, t=9.60, P=0.000). But hematocrit were lower in IAD group (30%±5% vs.33%±4% at end of operation, t=7.76, P=0.000; 30%±4% vs. 32%±5% at discharge, P=0.000, t=3.86). Multivariate logistic aggression analysis revealed that age, IAD and smoking history were factors influencing the probability of intra or postoperative blood transfusion. Implementation of blood conservation strategies based on intraoperative autologous donation in mitral valve replacement surgery can significantly reduce intra/postoperative blood transfusion as well as postoperative complications.

Does retrograde autologous priming of the cardiopulmonary bypass circuit have an impact on haematocrit and blood transfusion in uncomplicated coronary artery bypass graft surgery? A retrospective analysis

Haemodilution occuring as a result of cardiopulmonary bypass prime volume increases the need for transfusion of allogenic blood products. Many techniques have been employed to reduce the same. Priming the CPB circuit with the patient's own blood is thought to decrease haemodilution and transfusion requirements.

Short-Term Effects and Safety Analysis of Retrograde Autologous Blood Priming for Cardiopulmonary Bypass in Patients with Cardiac Valve Replacement Surgery.

This randomized, double-blind study evaluated the short-term effects and safety of perioperative retrograde autologous priming (RAP) for cardiopulmonary bypass (CPB) in patients with cardiac replacement surgery to determine if this approach is a better substitute for crystal liquids priming in patients with valvular heart disease. We observed that RAP significantly decreased the actual priming volume, preserved the hematocrit and hemoglobin level during CPB to a certain degree, and decreased lactate accumulation in CPB period. Moreover, RAP lowered the volume of transfusion and dosage blood products. Thus, our results showed that RAP approach effectively improved tissue perfusion and lowered intraoperative Lac levels, by reducing the hemodilution, which safely and reliably improve the microcirculation perfusion.

THE ABC TRIAL - DOES ALL-BLOOD CARDIOPLEGIA PREVENT BLOOD TRANSFUSION IN CARDIAC SURGERY? A SINGLE CENTER PILOT STUDY

s S227 was classified into a high RDW group and others were classified into a control group. Thrombolysis in Myocardial Infarction (TIMI) risk scores, angiographic characteristics, inhospital percutaneous or surgical revascularization, as well as 30-days major adverse cardiac event (MACE) including death, recurrent myocardial infarction, target vessel revascularization and lethal ventricular arrhythmias were compared between the two groups. RESULTS: Among 340 patients, 31 patients (9.1%) were classified into the high RDW group and 309 patients (90.9%) were classified into the control group. Mean RDW was 18.3 2.6% in the high RDW group and 13.8 0.9% in the control group. Patients with high RDW were more likely to have hypertension (93.5% vs. 73.1%, p1⁄40.01), chronic kidney disease (51.6% vs. 30.4%, p1⁄40.02) and anemia (11.3 1.6 g/dl vs. 13.2 1.7g/dl, p<0.001). Patients with high RDW had higher TIMI risk scores (4.2 1.2 vs. 3.6 1.5, p1⁄40.017) compared to the control group. Patients with high RDW had a higher rate of 30-days MACE (12.9% vs. 2.9%, p1⁄40.001) compared to the control group, and this association remained significant after adjusting for the baseline hemoglobin levels (odds ratio 2.878; 95% confidence interval 1.66 to 24.1; p1⁄40.004). There was no significant difference in peak troponin values, the rates of inhospital revascularization, pre-procedural impaired coronary flow, and the existence of coronary thrombus between the two groups. CONCLUSION: In patients with NSTEMI, high RDW defined as greater than 1SD was significantly associated with a higher TIMI risk score and a higher rate of 30-days MACE. After adjusting for the baseline hemoglobin levels, high RDW remained significantly associated with a higher rate of 30-days MACE. 337 THE ABC TRIAL DOES ALL-BLOOD CARDIOPLEGIA PREVENT BLOOD TRANSFUSION IN CARDIAC SURGERY? A SINGLE CENTER PILOT STUDY C Deshaies, RD Stanzel, KJ Buth, AB Fagan, GM Hirsch, SB O’Blenes Halifax, Nova Scotia BACKGROUND: All-blood cardioplegia (ABC) has emerged as an alternative to standard 4:1 diluted blood cardioplegia (DBC) due to its theoretical advantages of limiting hemodilution, blood transfusion, and myocardial edema. METHODS: We performed a randomized, double blind pilot study to determine feasibility and sample size for a multicenter trial comparing both strategies. Patients were eligible if undergoing CABG, aortic, mitral or combined surgery. Exclusion criteria included pre-op mechanical support, endocarditis, previous cardiac surgery, and recent irreversible anticoagulation. Retrograde autologous priming was used in all cases. Strict transfusion criteria were followed during hospital admission. RESULTS: Of 650 cases performed at our centre between February and September 2013, 246 patients were screened and 36 of them (15%) were eligible, consented, and randomized (ABC n1⁄418; DBC n1⁄418). Comorbidities, procedure types, and cross-clamp time, were similar in each group (table 1). There was no mortality. The total volume of cardioplegia delivered in each group was similar but the amount of crystalloid in the cardioplegia was significantly less in the ABC group (73 vs. 516 mL; p < .0001) (figure 1). Nonetheless, crystalloid in the cardioplegia represented only 1% (ABC) vs. 8% (DBC; p < .0001) of the total intraoperative crystalloid administration, and 0.7% (ABC) vs. 5% (DBC; p < .0001) of the fluid received in the first 24 hours of care. Four ABC and 2 DBC patients were transfused a total of 6.75 and 5 pRBC units. There was 100% adherence to our transfusion protocol. One subject in the ABC group, who was initially transfused during his admission, also received an additional unit in a peripheral center after discharge. The drop in hemoglobin from pre-op to lowest value (g/L: 51 vs. 49; p 1⁄4 0.60), the incidence of low cardiac output (%: 16 vs. 22; p 1⁄4 0.99) and markers of myocardial injury (16-hr Tn-T: 227 vs. 327; p 1⁄4 0.08) were similar in each group. Based on the DBC transfusion rate of 11% and a power of 80%, 898 to 2892 patients per arm would be required to show a relative risk reduction between 20 and 35%. CONCLUSION: The study demonstrated the feasibility of our design. However, over 1000 subjects per group will be required to detect a clinically significant reduction in transfusion. Modification of inclusion criteria, targeting patients at high risk of transfusion, would likely reduce the necessary sample size but would negatively impact recruitment rate and generalizability of the results. S228 Canadian Journal of Cardiology Volume 3

Retrograde autologous priming (RAP) as a safe and easy method to reduce haemodilution and transfusion requirements during cardiac surgery - Comparison between RAP, standard and Miniaturised Extracorporeal Circulation -

Retrograde autologous priming (RAP) as a safe and easy method to reduce haemodilution and transfusion requirements during cardiac surgery - Comparison between RAP, standard and Miniaturised Extracorporeal Circulation -

Effects of retrograde autologous priming in adult patients undergoing cardiac surgery

Effects of retrograde autologous priming in adult patients undergoing cardiac surgery

Blood conservation strategies in cardiac surgery: more is better

Recent data show that up to 50% of heart procedures require blood transfusion, which can have adverse long- and short-term outcomes for the patient. This led to the updated 2011 Society of Thoracic Surgery (STS)/Society of Cardiovascular Anesthesiologists (SCA) guidelines in an attempt to adopt more effective blood conservation techniques. We present our results after the implementation of a more aggressive strategy for intraoperative blood conservation in cardiac surgery. Our cardiac surgery database was reviewed retrospectively, comparing outcomes from two different time periods, after the implementation of a more effective two-way blood conservation strategy beginning in March 2012: more aggressive intraoperative autologous donation (IAD) based on a newly constructed nomogram, and the use of a shorter length circuit of the cardiopulmonary bypass (CPB) which allowed for lower fluid volume as a prime. The method of retrograde autologous priming (RAP) was the same for both time periods. A total of 1126 patients (Group 1) were studied in a 12-month period (March 2012-February 2013) after the implementation of the new strategy, and compared with 3758 patients (Group 2) of the previous 36-month period (March 2009-February 2012). There was a significant reduction in the percent change of the intraoperative haematocrit between Groups 1 and 2 (14 vs 28%, P = 0.01), with an increase in the mean IAD volume (655 vs 390 ml, P = 0.02) and a reduction in the CPB priming volume (1000 vs 1600 ml, P = 0.03). Group 1 required significantly less blood transfusions in the perioperative period (29 vs 49%, P = 0.02) and had significantly reduced postoperative rates of respiratory failure (3 vs 7%, P = 0.03), pneumonia (1 vs 3.1%, P = 0.01), chest tube output (350 vs 730 ml, P = 0.01), reoperation for bleeding (1.2 vs 2.5%, P = 0.04) and length of stay (6.1 vs 8.2 days, P = 0.05). Blood conservation is safe and effective in reducing transfusions in cardiac surgery, minimizing perioperative morbidity and mortality. Aggressive IAD and low CPB prime, along with effective RAP, is the three-way blood conservation strategy that leads to improved outcomes in cardiac surgery.

State-of-the-art blood conservation strategies following repair of aortic aneurysms and acute aortic dissection

surgery poses a higher risk for bleeding diathesis. Predictors of bleeding include patient factors such as older age, emergency surgery, lower body surface area and the use of perioperative antiplatelet agents. Operative factors include prolonged cardiopulmonary bypass (CPB) time, complexity of surgery, reoperative surgery and prolonged hypothermia. Between 2% and 15% of patients require re-exploration for bleeding. Although a surgically correctable source is found in 50% to 67% of cases, bleeding and surgical re-exploration are independent predictors of adverse outcome. The use of allogeneic transfusions is associated with numerous adverse outcomes such as an increase in nosocomial infection and mortality in critically ill patients. Blood conservation strategies and steps to minimize bleeding are the desired clinical goal. Preoperative antiplatelet agents are limited when possible. Transfusion triggers use hemoglobin levels and platelet counts to guide treatment. Advanced measurements (whole body oxygen-carrying capacity, oxygen consumption, oxygen extraction ratios and oxygen delivery) represent accurate methods to estimate the need for transfusion. Intraoperative deployment of minimally invasive techniques and meticulous hemostasis reduce blood loss. Modified strategies for CPB are discussed such as using activated clotting time-guided heparinization, retrograde autologous priming of the CPB circuit, autotransfusion and cell salvage. Postoperative use of autologous transfusion strategies, and pharmacological adjuncts, such as aprotinin, lysine analogues epsilon-aminocaproic acid and tranexamic acid, are discussed. Specific correction of coagulation using fresh frozen plasma, cryoprecipitate or factor VIIa may be required. The multimodality approach to blood loss aims to optimize outcomes in highrisk aortic surgical patients.

019 * BLOOD CONSERVATION STRATEGIES IN CARDIAC SURGERY: MORE IS BETTER

Objectives: Recent data show that up to 50% of heart procedures require blood transfusion, which can have adverse long- and short-term outcomes for the patient. This led to the updated 2011 STS/SCA guidelines in an attempt to adopt more effective blood conservation techniques. We present our results after the implementation of a more aggressive strategy for intraoperative blood conservation in cardiac surgery. Methods: Our cardiac surgery database was reviewed retrospectively, comparing outcomes from two different time periods, after the implementation of a more effective two-fold blood conservation strategy beginning in March 2012: more aggressive intraoperative autologous donation (IAD) based on a newly constructed nomogram, and the use of a shorter length circuit of the cardiopulmonary bypass (CPB) which allowed for lower fluid volume as a prime. The method of retrograde autologous priming (RAP) was the same for both time periods. Results: A total of 1126 patients (group 1) were studied in a 12-month period (March 2012-February 2013) after the implementation of the new strategy, and compared to 2758 patients (group 2) from the previous 36-month period (March 2009-February 2012). There was a significant reduction in the percentage change of the intraoperative haematocrit between groups 1 and 2 (14% vs 28%, P = 0.01), with an increase in the mean IAD volume (655 ml vs 390 ml, P = 0.02) and a reduction in the CPB prime volume (1000 ml vs 1600 ml, P = 0.03). Group 1 required significantly fewer blood transfusions in the perioperative period (29% vs 49%, P = 0.02) and had significantly reduced postoperative rates of respiratory failure (3% vs 7%, P = 0.03), pneumonia (1% vs 3.1%, P = 0.01), chest tube output (350 ml vs 730 ml, P = 0.01), reoperation for bleeding (1.2% vs 2.5%, P = 0.04), and length of stay (6.1 days vs 8.2 days, P = 0.05). Conclusions: Aggressive IAD and low CPB prime, along with effective RAP, is the three-fold blood conservation strategy that leads to improved outcomes in cardiac surgery.

Effects of retrograde autologous priming in adult patients undergoing cardiac surgery

Background Adult cardiac surgery with extracorporeal circulation (ECC) is known to be associated with increased risk of blood transfusion and systemic inflammatory response leading to adverse outcomes. Modern procedures like retrograde autologous priming (RAP) may reduce these negative side effects of ECC. This randomized prospective study was initiated to assess whether RAP using specifically designed RAP bag (Terumo) has immediate effects on patient outcome.

Use of miniaturized extracorporeal circulation for implanting left ventricular assist devices in high-risk end-stage heart failure patients

Background Miniaturized extracorporeal circulation (MECC) has been implemented in clinical practice for the last decade with superior results regarding postoperative morbidity and mortality mainly in coronary procedures. We challenged this technique in high-risk patients with end-stage heart failure undergoing left ventricular assist device (LVAD) implantation. Methods Four patients with end-stage ischemic heart failure were included in this study. All patients were inotrope dependent (INTERMACS class 2) and their preoperative evaluation considered them to be high-risk for developing postoperative right ventricular failure. Hence, optimization of right ventricular function was performed preoperatively following a protocol based on intermittent administration of doses of levosimendan. Two Jarvik 2000 and two HeartWare LVADs were implanted on beating heart using MECC system. Surgical strategy included retrograde autologous priming of the circuit and avoidance of administering cardioplegia. Results

The effect of retrograde autologous priming on intraoperative blood product transfusion in coronary artery bypass grafting

Retrograde autologous priming (RAP) of the cardiopulmonary bypass (CPB) circuit could reduce the degree of haemodilution associated with priming with acellular solutions. However, there is no strong evidence to prove that the practice of RAP reduced intraoperative packed red cell (PRC) or blood product transfusion. To evaluate the effect of RAP on intraoperative PRC usage in coronary artery bypass grafting (CABG). This study is a prospective, observational study on patients who underwent first-time, isolated CABG using CPB between April 2012 and July 2012. Two groups of patients were identified: 1. Non-RAP group (n=128) and 2. RAP group (n=73). The primary outcome for the study was the amount of PRC and blood product usage between the induction of anaesthesia and the cessation of CPB. Use of PRC and blood products in the operating room was comparable in both groups. Univariate logistic regression showed that RAP was not an independent predictor of PRC or blood product transfusion (p=0.43). Multivariate logistic regression showed that CPB time, preoperative haemoglobin (Hb) levels and creatinine clearance were independent predictors of blood product transfusion. Practising RAP with mean volumes of 300 ml does not necessarily reduce PRC and other blood product transfusion requirements during CABG. In our practice, RAP was performed, aiming at displacing CPB circuit prime volume with which the perfusionist felt comfortable and dictated by haemodynamic parameters prior to commencing CPB. We presume this is the case in many units around the world. This practice, in our opinion, is not enough to achieve the benefits of RAP, if any, in the form of a reduction of packed red cell transfusion requirements. The true advantages of RAP in cardiac surgery need to be studied in a prospective, randomized, controlled trial.

Miniaturized cardiopulmonary bypass: the Hammersmith technique

BackgroundConventional Cardiopulmonary Bypass (cCPB) is a trigger of systemic inflammatory reactions, hemodilution, coagulopathy, and organ failure. Miniaturised Cardiopulmonary Bypass (mCPB) has the potential to reduce these deleterious effects. Here, we describe our standardised ‘Hammersmith’ mCPB technique, used in all types of adult cardiac operations including major aortic surgery.MethodsThe use of mCPB remains limited by the diversity of technologies which range from extremely complex, micro systems to ones very similar to cCPB. Our approach is designed around the principle of balancing the benefits of miniaturisation; reducing foreign surface area while maintaining patient safety.ResultsFrom January 2010 to March 2011, a single surgeon performed 184 consecutive operations (Euro score Logistic 8.4+/-9.9): 61 aortic valve replacements, 78 CABGs, 25 aortic valve replacement and CABG and 17 other procedures (major aortic surgery, re-do operations or double/triple valve replacements).Our clinical experience suggests that:i. Venous drainage is optimally maintained using kinetic energy.ii. Venous collapse pressure depends on the patient’s anatomy and cannula size, but most importantly on the negative pressure generated by venous drainage.iii. The patient-prime interaction is optimised with antegrade and retrograde autologous priming, which mixes the blood and prime away from the tissues and results in a reduced oncotic destabilization.iv. mCPB is a safe and reproducible techniqueConclusionThe Hammersmith mCPB is a “next generation” system which uses standard commercially available components. It aims to maintain safety margin and the benefit of miniaturised system whilst reducing the human factor demands.

Multifaceted Blood Conservation Stratergy Reduces Periopertative Transfusion Requirement in Cardiac Surgery

Fig. 1. Surgical progression of patient cohort. Discussion: Surgical outcomes of single ventricle palliation seem poor in patients with dextrocardia. Aggressive management of congenital AVVR could improve longterm prognosis (Fig. 1). http://dx.doi.org/10.1016/j.hlc.2013.03.053 2012 Poster Presentation/Panel 28 Multifaceted Blood Conservation Stratergy Reduces Periopertative Transfusion Requirement in Cardiac Surgery Benjamin M. Robinson1,4,∗, Waleed A. Ahmed1, William O’Regan2, Manish Jain1, Ajay Hirikannawar1, Hugh D. Wolfenden1, Bruce G. French1, Rebecca Dignan1,3 1Department of Cardiothoracic Surgery, Liverpool Hospital, Sydney, Australia 2 Department of Anaesthesia, Liverpool Hospital, Sydney, Australia A B S T R A C T S Heart, Lung and Circulation 481 2013;22:455–489 2012 ANZSCTS Annual Scientific Meeting 3 University of New South Wales Clinical School, Liverpool, Australia 4 The Baird Institute for Applied Heart and Lung Surgical Research, Sydney, Australia Introduction: This study aimed to evaluate the effect of a multifaceted blood conservation strategy on blood product transfusion rates in cardiac surgery. This strategy involved acute normovolaemic haemodilution, also known as autologous operative donation, low volume pump priming, retrograde autologous pump priming (RAPP) and theuse of the antifibrinolytic, tranexamic acid. Risk factors for transfusion were also evaluated. Methods: A retrospective analysis of 1582 consecutive cardiac surgery patients at Liverpool Hospital between January 2008 and June 2012 was performed. 473 patients made up the blood conservation group, commencing June 2011. Using propensity score methods, a matched cohort of historical controls was assembled. Multivariate logistic regression was used to determine the independence of risk factors for transfusion. Results:Themean age of patientswas 64.4. Themajority had coronary artery bypass grafting alone (63.1%) or single valve procedures (17.5%), while 39.6% of cases were non-elective. Increased age, prolonged cardiopulmonary bypass, elevated preoperative serum creatinine, previous cardiac surgery, low body surface area, urgent or emergency surgery and preoperative anti-platelet agent administration were independent risk factors for transfusion. The crude transfusion rates in theblood conservation groupand the remainder of the cohortwere 33.8% (95%CI; 29.5–38.1) and62.7% (95%CI; 59.9–65.6) respectively. There was a 27.4% (95% CI; 22.2–35.2) reduction in transfusion rate for the blood conservation cohort when compared to propensity score matched controls. Conclusions: A multifaceted blood conservation strategy combining antifibrinolytic use with changes in perfusion practice reduces perioperative blood product transfusion in cardiac surgery. http://dx.doi.org/10.1016/j.hlc.2013.03.054 2012 Poster Presentation/Panel 29 Management of the Empty Pleural Space with Balanced Chest Drainage to Prevent Post-Pneumonectomy Pul-

EComment. Is retrograde autologous priming effective on cerebral functions and haematocrit levels?

Vandewiele et al. presented an interesting paper on retrograde autologous priming (RAP), comprising a satisfactory number of patients [1]. RAP has been employed since the 1960s. The effects and applicability of RAP on haematocrit levels and transfusion requirements are well documented, but still it is not a routine method of cardiopulmonary bypass (CPB) priming due to controversies. This report objectively answers the questions concerning the efficacy of this procedure. In this valuable report, we think that there are a few topics to be discussed. First, there is no data on whether the same surgeon or different surgeons operated on the patient. This issue is important since it directly affects perioperative blood loss and transfusion strategies. The second topic addresses the effects of RAP on neurological complications. It is well-known that one of the major effects of maintaining adequate haematocrit levels during CPB is providing better neurological and neurocognitive functions following an operation [2]. However, the authors did not provide information on neurologic complications, such as stroke and delirium. Finally, in the study, the authors stated that they used phosporylcholine-coated CPB circuits, which has been documented to have protective effects on blood loss and hematocrit levels [3,4]. It is reported that haematocrit levels did not statistically differ between the groups on admission to intensive care unit, but the possible effects of phosporylcholine coated circuits on outcomes should also be mentioned. In conclusion, we also believe that RAP is a very effective and accurate method for maintaining adequate haematocrit levels and lowering transfusion requirements. We, the readers thank the authors for sharing their knowledge and experiences. Conflict of interest: none declared.

EReply. Is retrograde autologous priming effective on cerebral functions and haematocrit levels?

We were pleased to receive Dr Gurbuz and colleagues' comments on our study [1]. Yet, we would like to add some comments to their remarks. Firstly, we can state that there were no differences between the study and the control group concerning the surgeons performing the procedure. We agree that the surgeon himself, often directly affects the amount of blood lost intraoperatively. However, in our hospital, the transfusion strategies are the result of a team approach and they are the same for each patient, regardless of the team members present in the operating theatre. Secondly, as the effect of retrograde autologous priming (RAP) on haemodilution and transfusion requirements was the main endpoint of our study, the effect of this technique on neurological complications were not reported. As referred in our article, lower intraoperative haematocrit levels can result in postoperative end-organ dysfunction, as shown by several large observational studies [2], including both transient and permanent stroke. As RAP increases the intraoperative haematocrit, one could suggest that this technique should improve the preservation of multiple organs. However, we did not look into the direct effect of RAP on these outcome variables and we think this should be the subject of further investigation. Finally, we agree with Dr Gurbuz that the phosphorylcholine coating has been proven to protect the platelets [3] during cardiopulmonary bypass (CPB) and affects blood loss and hematocrit levels. We want to emphasize that, besides the cannulas, all CPB circuits used in our study were completely phosphorylcholine-coated. Indeed, there was no difference between the haematocrit of both groups on admission to the ICU, which means that in the RAP group, the same haematocrit was achieved with less transfusion compared to the control group. In conclusion, we would like to thank Dr Gurbuz and his colleagues for their constructive remarks and hopefully, together we can further improve blood management strategies in the future. Conflict of interest: none declared.

EComment. The impact of blood conservation on outcomes in adult cardiac surgery

We read with great interest the study by Vandewiele and associates [1]. Many studies have shown the benefits of retrograde autologous priming (RAP) on preserving the patient's haematocrit to levels that do not require transfusion. Only a study by Murphy et al. failed to reproduce similar results in a large cohort of 545 patients [2]. Since our publication in 1998 on retrograde autologous priming [3], we have developed further strategies for blood conservation that have resulted in improved outcomes. Our strategy is three-fold: retrograde autologous priming, low prime volume in the cardiopulmonary bypass (CPB) circuit, and autologous blood donation immediately in the operating room immediately after incision is made. Our preliminary data in the first 300 patients showed a dramatic reduction in the post-operative blood transfusion requirement, with 70% of our patients requiring no blood transfusion at all. In the same time period, our 30-day mortality for all open heart procedures had decreased in an all-time low of 1.38%, and the respiratory complications had dropped from 7% in 2007, to 3% in the end of 2012. This proves that the above three techniques of blood conservation are safe and desirable, leading to reduced morbidity and hospital cost. Conflict of interest: none declared.