Greater Volume of Acute Normovolemic Hemodilution May Aid in Reducing Blood Transfusions After Cardiac Surgery

Practical training concept for perfusionists at the heart and diabetes center Nordrhein-Westfalen

BACKGROUND

Increasing regulations and requirements of advisory bodies, in particular the Joint Federal Committee and the Medical Service of the health insurance funds, make it necessary to employ only demonstrably well-trained perfusionists. The minimum requirement for this staff is EBCP certification. Currently there is limited availability of such specialists on the German market. Therefore, the qualification of young people in this area is of central importance. The aim of this paper is to strengthen the training of perfusionists at our centre, to standardise the process and to provide the respective student with a "roadmap" to their internship.

MATERIAL & METHODS

The structure is based on a rough division of the 24 weeks of internship. This is described in detail in the following and is backed up with the learning objectives for the respective time periods.

RESULTS

At our centre, practical training has been standardized and clear responsibilities have been defined. Furthermore, as a centre of maximum care in the field of cardiac surgery, we can offer students the necessary number of perfusions in just six months to meet the requirements of the ECBP for practical training. According to this concept, 20 perfusionists have been successfully trained in the last 8 years. All of them have passed the exams and have been certified according to EBCP.

CONCLUSION

The aim of the practical semester is for the student to be in a position at the end of the semester to independently supervise simple cardiac surgery procedures with the aid of the Extra- Corporal Circulation (ECC) and to carry this out in accordance with the currently valid guidelines and directives (1-8) and the departmental procedural instructions based on them. Great emphasis is placed to the students becoming aware of their competence to act, knowing their limits and being able to assess when these limits have been reached and the involvement of experienced colleagues is necessary to ensure patient safety.

Low-Volume Acute Normovolemic Hemodilution Does Not Reduce Allogeneic Red Blood Cell Transfusion in Cardiac Surgery in the Modern Era of Patient Blood Management: A Propensity Score-Matched Cohort Study

OBJECTIVES

Patients undergoing cardiac surgery often require blood transfusions, which are associated with increased morbidity and mortality. Patient blood management (PBM) strategies, including acute normovolemic hemodilution (ANH), have been implemented to minimize allogeneic transfusion requirements. Older studies suggested that ANH is associated with reduced transfusions; however, its effectiveness in the modern era of PBM remains unclear.

DESIGN

This was a retrospective cohort study.

SETTING

The study was held at a single university hospital.

PARTICIPANTS

542 patients who underwent elective cardiac surgery with cardiopulmonary bypass (CPB) using low-priming-volume circuits between January 2017 and March 2022.

INTERVENTIONS

Patients who received ANH were matched with those who did not receive ANH, using propensity scores.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the proportion of patients who received perioperative red blood cell (RBC) transfusion. Of the 542 eligible patients, 49 ANH cases were propensity-score matched to 97 controls. The median ANH volume was 450 mL (IQR, 400-800 mL). There was no significant difference in perioperative RBC transfusion rates between the 2 groups (24.5% in the ANH group vs 30.9% in the control group, p = 0.42). The odds ratio for perioperative RBC transfusion in the ANH group versus the control group was 0.72 (95% CI, 0.32-1.55, p = 0.42).

CONCLUSIONS

Low-volume ANH was not associated with a significant reduction in perioperative allogeneic RBC transfusion during cardiac surgery with CPB using low-priming-volume circuits. The benefits of low-volume ANH in reducing the requirement for RBC transfusion in the modern era of PBM may be smaller than reported previously.

Effect of acute normovolemic hemodilution in patients undergoing cardiac surgery with remimazolam anesthesia

PURPOSE

The reduced effects of allogeneic transfusion with acute normovolemic hemodilution (ANH) have been reported. Harvesting a large volume of blood may maximize the effect in patients with low body weight, and the prevention of hypotension is important. Remimazolam is an anesthetic with few circulatory responses. Our aim was to evaluate whether high-volume ANH reduces the need for transfusion in cardiac patients under remimazolam anesthesia.

METHODS

In this retrospective single-center study, we enrolled cardiopulmonary bypass (CPB) patients who received remimazolam anesthesia. Changes in hemodynamic parameters were assessed. The numbers of blood transfusions and chest tube outputs were also evaluated.

RESULTS

In a total of 51 patients, ANH was performed in 27 patients with a mean body mass index of 23.2 (ANH volume: 740 ± 222 mL). No significant differences were observed in mean blood pressure during blood collection. The intraoperative amount of red blood cell (RBC) transfusion was significantly lower in the ANH group than in the control group (431 ± 678 and 1260 ± 572 mL, p < 0.001). The avoidance rates of RBC were 66.7 and 4.2%, respectively. The multivariate analysis result revealed that ANH correlated with RBC, with an odds ratio of 0.067 (95% confidence interval 0.005-0.84, p < 0.05). The postoperative bleeding at 24 h was significantly lower in the ANH group (455 ± 228 and 797 ± 535 mL, p < 0.01).

CONCLUSION

In patients undergoing CPB, ANH reduced intraoperative transfusion amount and postoperative bleeding. Hemodynamic changes during blood collection were minimal under remimazolam anesthesia and high-volume ANH was feasible.

Intraoperative Transfusion of Autologous Blood Protects from Acute Kidney Injury after Pediatric Congenital Heart Surgery

Background

Acute kidney injury (AKI) is a common complication after pediatric cardiac surgery. And autologous blood transfusion (ABT) is an important predictor of postoperative AKI. Unlike previous studies, which mainly focused on the correlation between ABT and AKI, the current study focuses heavily on the causal relationship between them, thus providing guidance for the treatment of patients during hospitalization to reduce the occurrence of AKI.

Methods

A retrospective cohort of 3386 patients extracted from the Pediatric Intensive Care database was used for statistical analysis, multifactorial analysis, and causal inference. Characteristics that were correlated with ABT and AKI were categorized as confounders, instrumental variables, and effect modifiers, and were entered into the DoWhy causal inference model to determine causality. The calculated average treatment effect (ATE) was compared with the results of the multifactorial analysis.

Results

The adjusted odds ratio (OR) for ABT volume was obtained by multifactorial analysis as 0.964. The DoWhy model refute test was able to indicate a causal relationship between ABT and AKI. Any ABT reduces AKI about 15.3%-18.8% by different estimation methods. The ATE regarding the amount of ABT was -0.0088, suggesting that every 1 mL/kg of ABT reduced the risk of AKI by 0.88%.

Conclusions

Intraoperative transfusion of autologous blood can have a protective effect against postoperative AKI.

Large volume acute normovolemic hemodilution in patients undergoing cardiac surgery with intermediate-high risk of transfusion: A randomized controlled trial

STUDY OBJECTIVE

To investigate whether large volume acute normovolemic hemodilution (L-ANH), compared with moderate acute normovolemic hemodilution (M-ANH), can reduce perioperative allogeneic blood transfusion in patients with intermediate-high risk of transfusion during cardiac surgery with cardiopulmonary bypass (CPB).

DESIGN

Prospective randomized controlled trial.

SETTING

University hospital.

PATIENTS

Patients with transfusion risk understanding scoring tool ("TRUST") ≥2 points undergoing cardiac surgery with CPB in the Second Affiliated Hospital of Zhejiang University from May 2020 to January 2021 were included.

INTERVENTIONS

The patients were randomly assigned with a 1:1 ratio to M-ANH (5 to 8 mL/kg) or L-ANH (12 to 15 mL/kg).

MEASUREMENTS

The primary outcome was perioperative red blood cell (RBC) transfusion units. The composite outcome included new-onset atrial fibrillation, pulmonary infection, cardiac surgery associated acute kidney injury (CSA-AKI) class ≥2, surgical incision infection, postoperative excessive bleeding, and resternotomy.

MAIN RESULTS

Total 159 patients were screened and 110 (55 L-ANH and 55 M-ANH) were included for final analysis. Removed blood volume of L-ANH is significantly higher than M-ANH (886 ± 152 vs. 395 ± 86 mL, P < 0.001). Perioperative RBC transfusion was median 0 unit ([25th, 75th] percentiles: 0-4.4) in M-ANH group vs. 0 unit ([25th, 75th] percentiles: 0-2.0) in L-ANH group (P = 0.012) and L-ANH was associated with lower incidence of transfusion (23.6% vs. 41.8%, P = 0.042, rate difference: 0.182, 95% confidence interval [0.007-0.343]). The incidence of postoperative excessive bleeding was significantly lower in L-ANH vs. M-ANH (3.6% vs. 18.2%, P = 0.029, rate difference: 0.146, 95% confidence interval [0.027-0.270]) without significant difference for other second outcomes. The volume of ANH was inversely related to perioperative RBC transfusion units (Spearman r = -0.483, 95% confidence interval [-0.708 to -0.168], P = 0.003), and L-ANH in cardiac surgery was associated with a significantly reduced risk of perioperative RBC transfusion (odds ratio: 0.43, 95% confidence interval: 0.19-0.98, P = 0.044).

CONCLUSIONS

Compared with M-ANH, L-ANH during cardiac surgery inclined to be associated with reduced perioperative RBC transfusion and the volume of RBC transfusion was inversely proportional to the volume of ANH. In addition, LANH during cardiac surgery was associated with a lower incidence of postoperative excessive bleeding.

Comparison of the effects of autologous and non-autologous blood transfusions on the advantages, disadvantages, extubation time and bleeding after coronary bypass

Purpose

Blood transfusion; is considered an organ transplant. In coronary bypass surgery, large volumes of homologous blood transfusion may be required due to excessive bleeding. The large number of use of homologous blood transfusion in open heart surgery and the awareness of its various harmful effects have prompted researchers to conduct research on the use of autologous blood. With autologous transfusion, blood diseases, incompatibility, immunosuppression and organ damage can be prevented and the patient can be extubated earlier in the postoperative period.

Methods

Between January 2020 and January 2016, a total of 176 patients, 56 in the treatment group (with autologous blood transfusion) and 120 in the control group, whose information could be reached from hospital records were investigated retrospectively.

Results

No statistical difference was found between the mean intubation SO2 and PO2 values of the groups. On the contrary, considering the mean intubation times in the intensive care unit of both groups, the patients who underwent autologous blood transfusion were extubated at a statistically significant earlier time.

Conclusion

Autologous blood transfusion is a safe method in selected patients as well. Thanks to this method, patients are protected from complications associated with homologous blood transfusion. It is believed that performing autologous blood transfusion in selected patients undergoing open-heart surgery can decrease the number of postoperative transfusions, frequency of transfusion-related complications (especially in the lungs), and mean intubation times.

Management of Combined Cardiac Surgery Using Cardiopulmonary Bypass With Acute Normovolemic Hemodilution in a Jehovah's Witness: A Case Report

Combined cardiac surgery under cardiopulmonary bypass (CPB) has a high risk of requiring blood transfusion. Performing this surgery on Jehovah's Witnesses (JWs) is challenging as they strictly refuse allogeneic blood transfusions due to their religious beliefs. A 73-year-old female JW patient underwent combined surgery involving coronary artery bypass grafting and mitral valvuloplasty under CPB. Preoperative hematopoiesis maintained the hemoglobin (Hb) level at >12 g/dL preoperatively; the Hb level was maintained at >7 g/dL during CPB for effective acute normovolemic hemodilution (ANH). Compared with the values obtained immediately after CPB weaning, the Hb level and coagulation functions (measured using viscoelastic tests) improved after autologous transfusion at the end of the surgery. When cardiac surgery under CPB is performed on JWs, ANH can be useful for maintaining postoperative Hb levels and coagulation factors. Sufficient preoperative hematopoiesis and determination of an appropriate volume for intraoperative ANH may be important for effective ANH.

Effects of acute normovolemic hemodilution on allogeneic blood transfusion & coagulation in orthognathic surgery: A randomized study

BACKGROUND

Acute normovolemic hemodilution (ANH) is one of the important techniques predominantly used in cardiac, hepatic, and vascular surgery for decreasing allogeneic blood transfusion. However, the effect of ANH in orthognathic surgery has been rarely studied. Therefore, this study aims to assess the ANH-mediated reduction in the allogeneic red blood cell transfusion for orthognathic surgery patients.

STUDY DESIGN AND METHODS

In this single-center study, 18-80 years old patients were recruited. Patients with hemoglobin ≥11 g/dL and normal coagulation function were randomly divided into ANH or standard treatment group.

RESULTS

Ninety six patients underwent ANH, and 101 patients received standard treatment. No differences in demographic or major pre-operative characteristics were observed between the two groups. One patient in the ANH and three patients in the standard treatment group received allogeneic blood [3(2.97%) vs. 1(1.16%), control vs. ANH, p = .395]. Multivariate logistic regression analysis revealed that ANH treatment was not associated with transfusion of allogeneic blood (p = .763). After retransfusing autologous blood, PT and APTT in the ANH group significantly increased compared to standard treatment group (PT: -1.73 ± 1.09 vs. -2.15 ± 1.06, p = .035; APTT: -6.39 ± 5.76 vs. -8.16 ± 5.70, p = .031; control vs. ANH). No significant differences between the two groups were observed for changes in coagulation parameters at first postoperative day. However, platelet counts in the ANH group decreased compared to the standard group. No significant difference in major adverse outcomes was observed between the two groups.

CONCLUSION

ANH did not reduce the incidence of allogeneic transfusion in patients undergoing orthognathic surgery.

Intraoperative blood collection without fluid replacement for cardiac surgery - A retrospective analysis

BACKGROUND

Transfusion rates in cardiac surgery are high.

AIM

To determine if intraoperative autologous blood removal without volume replacement is associated with fewer homologous blood transfusions without increasing acute kidney injury.

SETTING AND DESIGN

Retrospective, comparative study.

MATERIALS AND METHODS

Adult patients undergoing cardiac surgery, excluding those who underwent ventricular assist device surgery, heart transplants, or cardiac surgery without cardiopulmonary bypass were excluded, who had 1-3 units of intraoperative autologous blood removal were compared to patients without blood removal for determination of volume replacement, vasopressor support, acute kidney injury, and transfusions.

RESULTS

Autologous blood removal was associated with fewer patients receiving homologous transfusions: intraoperative red cell transfusions fell from 75% (Control) to 48% (1 unit removed), 40% (2 units), and 30% (3 units), P &lt; 0.001. Total intraoperative and postoperative homologous RBC units transfused were lower in the blood removal groups: median (interquartile range) 3 (1, 6) in Control patients and 0 (0, 2), 0 (0, 2) and 0 (0, 1) in the 1, 2, and 3 units removed groups, P &lt; 0.001. Similarly, plasma, platelet, and cryoprecipitate transfusions decreased. After adjustment for confounders, increased amounts of autologous blood removal were associated with increased intravenous fluids, only when 2 units were removed, and trivially increased vasopressor use. However, it was not associated with acidosis or acute kidney injury.

CONCLUSIONS

Intraoperative autologous blood removal without volume replacement of 1-3 units for later autologous transfusion is associated with decreased homologous transfusions without acidosis or acute kidney injury.

Management of Bombay Rh negative with clinically significant anti-S for CABG surgery

The Bombay Rh D negative is the rarest of the rare in blood groups. A 65-year-old male patient with coronary artery disease was admitted for CABG. During grouping, forward showed no agglutination in A, B, D, and H, and reverse showed agglutination in A, B, and O cell. The blood group was confirmed as Bombay Rh D negative. Four units of PRBC was requested for the surgery as it was cardiothoracic surgery. We checked our inventory and rare donor list for Bombay-negative blood. Acute normovolemic hemodilution was done for 2 units preoperatively with saline replacement. Autologous platelet apheresis was done for this patient. During routine cross-match, one unit was incompatible. The patient had naturally occurring anti-S, which was reactive at 37°C and clinically significant. A total of 4 PRBC (Packed Red Blood Cell), 1 Single Donor Platelet (SDP), 12 Fresh Frozen Plasma (FFP), and 9 cryoprecipitate were transfused throughout the hospital stay. The patient was Bombay Rh negative with anti-S with major surgery, which was re-explored twice; the patient was managed successfully in spite of all these difficulties with cooperation from different blood banks from all over India.

Acute normovolemic hemodilution in combination with tranexamic acid is an effective strategy for blood management in lumbar spinal fusion surgery

Background

The retrospective study was designed to compare the effectiveness and safety of acute normovolemic hemodilution (ANH), tranexamic Acid (TXA), and a combination of ANH and TXA in lumbar spinal fusion surgery.

Methods

Data of 120 patients underwent multi-level posterior spinal fusion for treating degenerative lumbar disease between June 2013 and December 2017 was collected, retrospectively. Four treatment strategies were enrolled, including ANH, TXA, a combination of ANH and TXA, and without any patient blood management. Intraoperative blood loss, hemoglobin and PCV at the end of surgery and at the postoperative first day, and postoperative drain collection, and intraoperative and postoperative transfusion and rate of transfusion were also collected.

Results

Intraoperative blood loss and postoperative drain collection of the TXA group, ANH combined with TXA group were statistically lower than those in the control group and ANH group (P < 0.05). Intraoperative and postoperative transfusion amount and rate of intra-operative allogenic transfusion of the ANH group, TXA group, and ANH combined with TXA group were statistically lower than those of the control group (P < 0.05). Hemoglobin and PCV at postoperative the first day in the ANH group, TXA group, and ANH combined with TXA group were significant higher than those in the control group (P < 0.05). The combination of TXA and ANH group achieved the lowest intraoperative blood loss, postoperative drain collection and allogenic transfusion rate.

Conclusion

A combination of TXA and ANH might be an effective strategy for reducing the rate of transfusion and blood loss in patients underwent lumbar spinal fusion surgery.

Cardiac Surgery and Blood-Saving Techniques: An Update

Cardiac surgery is typically attributed with a significant risk of intraoperative blood loss and allogeneic blood transfusions. Intraoperative blood loss, allogenic blood transfusions, high dose anticoagulation requirement, and interactions with cardiopulmonary bypass (CPB) have all been linked to cardiac surgeries. To reduce unnecessary transfusions and their negative effects, it is recommended to follow evidence-based multidisciplinary strategies, which are collectively termed patient blood management (PBM). This review highlights the most recent blood conservation strategies in adult cardiac surgery, which can be employed pre-operatively, intra-operatively, and postoperatively, to enhance red cell mass and attenuate the utilization of packed red blood cells (PRBCs) and other blood products.

Risk and Safety Perceptions Contribute to Transfusion Decisions in Coronary Artery Bypass Grafting

Variability persists in intraoperative red blood cell (RBC) transfusion rates, despite evidence supporting associated adverse sequelae. We evaluated whether beliefs concerning transfusion risk and safety are independently associated with the inclination to transfuse. We surveyed intraoperative transfusion decision-makers from 33 cardiac surgery programs in Michigan. The primary outcome was a provider's reported inclination to transfuse (via a six-point Likert Scale) averaged across 10 clinical vignettes based on Class IIA or IIB blood management guideline recommendations. Survey questions assessed hematocrit threshold for transfusion ("hematocrit trigger"), demographic and practice characteristics, years and case-volume of practice, knowledge of transfusion guidelines, and provider attitude regarding perceived risk and safety of blood transfusions. Linear regression models were used to estimate the effect of these variables on transfusion inclination. Mixed effect models were used to quantify the variation attributed to provider specialties and hematocrit triggers. The mean inclination to transfuse was 3.2 (might NOT transfuse) on the survey Likert scale (SD: .86) across vignettes among 202/413 (48.9%) returned surveys. Hematocrit triggers ranged from 15% to 30% (average: 20.4%; SE: .18%). The inclination to transfuse in situations with weak-to-moderate evidence for supporting transfusion was associated with a provider's hematocrit trigger (p < .01) and specialty. Providers believing in the safety of transfusions were significantly more likely to transfuse. Provider specialty and belief in transfusion safety were significantly associated with a provider's hematocrit trigger and likelihood for transfusion. Our findings suggest that blood management interventions should target these previously unaccounted for blood transfusion determinants.

The Role of Race on Acute Kidney Injury Following Cardiac Surgery

BACKGROUND

Acute kidney injury (AKI) frequently complicates cardiac surgery and is more common among Black patients. We evaluated determinants of race-based differences in AKI rates.

METHODS

Serum creatinine-based criteria was used to identify adult cardiac surgical patients developing post-operative AKI in the PERForm registry (7/1/2014-6/30/2019). Patient characteristics, operative details and outcomes were compared by race (Black versus White) after excluding patients with pre-operative dialysis, missing pre- or post-operative creatinine, or other races. A mixed effect model (adjusting for demographics, comorbidities, surgical factors) used hospital as a random effect to predict post-operative stage 2 or 3 AKI. Propensity score analyses were conducted to evaluate robustness of the primary analyses.

RESULTS

The study cohort included 34,520 patients (8% Black). More Black than White patients were female (43 versus 27%, p<.001), had hypertension (93 versus 87%, p<.001) and diabetes (51 versus 41%, p<.001). AKI >Stage 2 occurred among 1,780 (5%) patients, more often among Black than White patients (8 versus 5%, p<.001). Intra-operatively, Black patients had lower nadir hematocrits (23 versus 26, p<.001), and were more likely to be transfused (22 versus 14%, p<.001). After adjustment, Black (compared to White) race independently predicted odds for post-operative AKI (adjOR 1.50, 95% CI 1.26-1.78). The multivariable findings were similar in propensity score analyses.

CONCLUSIONS

Despite accounting for differences in risk factors and intra-operative practices, Black patients had a 50% increased odds for developing moderate-severe post-operative AKI compared to White patients. Additional evaluations are warranted to identify potential targets to address racial disparities in AKI outcomes.

Effects of whole blood storage in a polyolefin blood bag on platelets for acute normovolemic hemodilution

Acute normovolemic hemodilution (ANH) is a potential transfusion method for platelets, as well as for red blood cells. However, previous studies have shown that whole blood storage in ANH decreases platelet aggregability by 14.7–76.3% and that this decrease is not recovered by reinfusion. We investigated whether a new whole blood storage method for 6 h using a polyolefin bag, based on the platelet concentrates storage method, would maintain platelet function better than the conventional method using a polyvinyl chloride bag. We demonstrated that storage of whole blood in a polyolefin bag maintained ADP-induced aggregation rates at more than twofold higher than those in a polyvinyl chloride bag, and also significantly suppressed P-selectin expression, a platelet activation marker (ADP-induced aggregation rates: 24.6 ± 5.1% vs. 51.7 ± 11.5%, p = 0.002; P-selectin expression; 50.3 ± 8.4MFI vs. 31.6 ± 9.3MFI, p = 0.018). These results could be attributed to the high gas permeability of polyolefin, which lowered PCO₂ and maintained a high pH with or without agitation. There were no significant changes in platelet count and red blood cell parameters due to the storage methods. Our results suggest that ANH using polyolefin bags is advantageous in improving hemostatic function compared to the conventional method.

Optimising bloodless cardiovascular surgery for Jehovah's Witnesses and beyond

Emerging evidence suggests surgical outcomes of patients undergoing cardiovascular surgery that refuse autologous transfusion is comparable to those who accept whole blood product transfusions. There are several methods that can be used to minimize blood loss during cardiovascular surgery. These methods can be categorised into pharmacological measures, including the use of erythropoietin, iron and tranexamic acid, surgical techniques, like the use of polysaccharide haemostat, and devices such as those used in acute normovolaemic haemodilution. More prospective studies with stricter protocols are required to assess surgical outcomes in bloodless cardiac surgery as well as further research into the long-term outcomes of bloodless cardiovascular surgery patients. This review summarizes current evidence on the use of pre-, intra-, and post-operative strategies aimed at the subset of patients who refuse blood transfusion, for example Jehovah's Witnesses.

Intra-operative autologous blood donation for cardiovascular surgeries in Japan: A retrospective cohort study

Intra-operative autologous blood donation is a blood conservation technique with limited evidence. We evaluated the association between intra-operative autologous blood donation and decrease in peri-operative transfusion in cardiovascular surgery based on evidence from a Japanese administrative database. We extracted the data of patients who had undergone cardiovascular surgery from the Diagnosis Procedure Combination database in Japan (2016–2019). Based on the surgery type, we examined the association of intra-operative autologous blood donation with the transfusion rate and amount of blood used in cardiac and aortic surgeries using multilevel propensity score matching. We enrolled 32,433 and 4,267 patients who underwent cardiac and aortic surgeries and received 5.0% and 6.7% intra-operative autologous blood donation with mean volumes of 557.68 mL and 616.96 mL, respectively. The red blood cell transfusion rates of the control and intra-operative autologous blood donation groups were 60.6% and 38.4%, respectively, in the cardiac surgery cohort (p < .001) and 91.4%, and 83.8%, respectively, in the aortic surgery cohort (p = .037). The transfusion amounts for the control and intra-operative autologous blood donation groups were 5.9 and 3.5 units of red blood cells, respectively, for cardiac surgery patients (p < .001) and 11.9 and 7.9 units, respectively, for aortic surgery patients (p < .001). Intra-operative autologous blood donation could reduce the transfusion rate or amount of red blood cells and fresh frozen plasma for patients undergoing index cardiovascular surgery and could be an effective blood transfusion strategy in cardiovascular surgery for Japanese patients.

The Year in Coagulation: Selected Highlights from 2020

This is the second annual review in the Journal of Cardiothoracic and Vascular Anesthesia to cover highlights in coagulation for cardiac surgery. The goal of this article is to provide readers with a focused summary from the literature of the prior year's most important coagulation topics. In 2020, this included a discussion covering allogeneic transfusion, antiplatelet and anticoagulant therapy, factor concentrates, coagulation testing, mechanical circulatory support, and the effects of coronavirus disease 2019.

Prepump autologous blood collection is associated with reduced intraoperative transfusions in aortic surgery with circulatory arrest: A propensity score-matched analysis

OBJECTIVE

To evaluate the effect of autologous whole blood (AWB) collection on intraoperative/postoperative allogeneic blood transfusion rate in complex aortic surgery with hypothermic circulatory arrest.

METHODS

This retrospective study included adults who underwent aortic surgery with hypothermic circulatory arrest at a single institution between 2014 and 2019. Out of 509 cases (414 patients), 110 (22%) received the AWB protocol. We performed propensity-score matching, including 35 preoperative and procedural variables, which resulted in 95 well-matched pairs, to compare outcomes in patients who received AWB protocol versus those who did not. Study outcomes were percentage of patients who received transfusion of allogeneic blood products intraoperatively and postoperatively.

RESULTS

Mean volume of collected autologous blood was 826 ± 263 mL. Intraoperatively, fewer AWB patients received red blood cell concentrate (33% vs 49%; P = .02), plasma (35% vs 62%; P = .0002), platelets (61% vs 81%; P = .003), and cryoprecipitate (43% vs 56%; P = .08) compared with non-AWB patients. During the entire hospital stay, the differences in transfusion rate between the 2 groups were: red blood cells (58% vs 62%; P = .6), plasma (49% vs 66%; P = .01), platelets (72% vs 82%; P = .09), and cryoprecipitate (56% vs 63%; P = .3).

CONCLUSIONS

Pre-pump autologous blood collection may reduce the need for intraoperative transfusion of allogenic non-red-cell blood products in patients undergoing complex aortic surgery with hypothermic circulatory arrest. A larger study is needed to clarify the influence of this association on patient outcomes and resource utilization.

Impact of Preoperative Platelet Count on Bleeding Risk and Allogeneic Transfusion in Multilevel Spine Surgery

STUDY DESIGN

This was an observational cohort study of patients receiving multilevel thoracic and lumbar spine surgery.

OBJECTIVE

The aim of this study was to identify which patients are at high risk for allogeneic transfusion which may allow for better preoperative planning and employment of specific blood management strategies.

SUMMARY OF BACKGROUND DATA

Multilevel posterior spine surgery is associated with a significant risk for major blood loss, and allogeneic blood transfusion is common in spine surgery.

METHODS

A univariate logistic regression model was used to identify variables that were significantly associated with intraoperative allogeneic transfusion. A multivariate forward stepwise logistic regression model was then used to measure the adjusted association of these variables with intraoperative transfusion.

RESULTS

Multilevel thoracic and lumbar spine surgery was performed in 921 patients. When stratifying patients by preoperative platelet count, patients with pre-operative thrombocytopenia and severe thrombocytopenia had a significantly higher rate of transfusion than those who were not thrombocytopenic. Furthermore, those with severe thrombocytopenia had a higher rate of red blood cells, fresh frozen plasma, and platelet transfusion than those with higher platelet counts. Multivariate logistic regression found that preoperative platelet count was the most significant contributor to transfusion, with a platelet count ≤100 having an adjusted odds ratio (OR) of transfusion of 4.88 (95% confidence interval [CI] 1.58-15.02, P = 0.006). Similarly, a platelet count between 101and 150 also doubled the risk of transfusion with an adjusted OR of 2.02 (95% CI 1.01-4.04, P = 0.047). The American Society of Anesthesiologists classification score increased the OR of transfusion by 2.5 times (OR = 2.52, 95% CI 1.54-4.13), whereas preoperative prothrombin time and age minimally increased the risk.

CONCLUSION

Preoperative thrombocytopenia significantly contributes to intraoperative transfusion in multilevel thoracic lumbar spine surgery. Identifying factors that may increase the risk for transfusion could be of great benefit in better preoperative counseling of patients and in reducing overall cost and postoperative complications by implementing strategies and techniques to reduce blood loss and blood transfusions.

LEVEL OF EVIDENCE

2.

Adult cardiopulmonary bypass in Australian and New Zealand public hospitals: A survey of practice

A telephone survey of cardiac anaesthetists and perfusionists at the 29 public hospitals providing adult cardiac surgical services in Australia and New Zealand was carried out between December 2019 and January 2020. The aim was to investigate current practice with regard to selected contentious elements of anaesthetic and perfusion management during cardiopulmonary bypass; primarily relating to bypass circuit priming, blood conservation methods and point-of-care coagulation testing. There was a 100% response rate. The average number of adult public cardiopulmonary bypass cases per hospital was 508 (160-1400). For cardiopulmonary bypass cases, ten hospitals (34%) routinely used a cell saver and the remainder used a cell saver selectively. Residual blood remaining in the cardiopulmonary bypass circuit was processed using a cell saver routinely in four hospitals (14%) and selectively in 23 (79%). Acute normovolaemic haemodilution was rarely used. Retrograde autologous priming was used routinely in seven hospitals (24%) and selectively in 16 (55%). All hospitals had access to point-of-care coagulation testing. The majority of hospitals targeted an activated clotting time of 480 s (range 400-500 s) prior to commencing cardiopulmonary bypass. There was marked geographic variation in access to fibrinogen concentrate. The cardiopulmonary bypass circuit prime solution was primarily a balanced crystalloid in most hospitals; however, there was significant variation regarding the addition of human albumin, mannitol, sodium bicarbonate and other medications. Many of the interventions examined were used on a case-by-case basis. These findings support the need for further research to define more evidence-based practice of these interventions.

Controversies in the Clinical Practice of Patient Blood Management

Patient blood management (PBM) has been proposed as a standard of care in modern perioperative medicine. PBM-related interventions usually are implemented as bundles, but randomized controlled trials on the implementation of PBM as a bundle are missing. This special article focuses on the current evidence and controversies in the clinical practice of PBM and on emerging data related to specific PBM-related interventions in patients undergoing cardiac surgery. Strong evidence for many PBM-related interventions is limited because of missing studies or the poor quality of published findings and study endpoints. Restrictive blood transfusion and timely interventions to maintain hemoglobin concentration and to reduce blood loss potentially might result in improved patient outcome, although the latter has yet to be proven.

Acute normovolemic hemodilution in major orthopedic surgery

BACKGROUND

With increasing concerns regarding the newer emerging pathogens, alternatives to allogeneic blood transfusion are being explored and acute normovolemic hemodilution (ANH) is one of them.

METHODS

A prospective study was conducted in patients aged 18-65 years with preoperative hemoglobin >12 g/dl undergoing total knee replacement or total hip replacement. Patients in whom hemodilution was performed were included in the ANH group whereas patients undergoing treatment as per the routine hospital protocol were included in the control group.

RESULTS

Preoperative hemoglobin was similar in both ANH and control groups (12.7 ± 0.7 vs 12.6 ± 0.6, p = 0.56). Allogeneic blood requirement was significantly less in the ANH group as compared to the control group (4 vs 15, p = 0.001). Postoperative complications were significantly lower in ANH group as compared to control group (7 vs 16, p = 0.01).

CONCLUSIONS

ANH can be an alternative approach to meet the need of safe blood especially in resource constrained countries, like India where risk of transfusion transmitted infections are still high and where there is high demand of blood and acute shortage of blood in hospitals.

Effect of acute normovolemic hemodilution on coronary artery bypass grafting: A systematic review and meta-analysis of 22 randomized trials

BACKGROUND

Efficacy of minimal acute normovolemic hemodilution (ANH) in avoiding homologous blood transfusion during cardiovascular surgery remains controversial. Postoperative bleeding and transfusion remain a source of morbidity and cost after open heart operations. To better understand the role of acute normovolemic hemodilution (ANH) in coronary artery bypass grafting (CABG), we compared ANH with standard intraoperative care in a systematic review including a standard pairwise meta-analysis of randomized controlled trials (RCTs).

METHODS

We searched the Cochrane Library, PubMed, EMBASE, Web of Science and Chinese National Knowledge Infrastructure (CNKI) up to April 1, 2020. The primary outcome was to assess the incidence of ANH-related number of allogeneic red blood cell units (ARBCu) transfused. Secondary outcomes included the rate of allogeneic blood transfusion and estimated total blood loss.

RESULTS

A total of 22 RCTs including 1688 patients were identified for the present meta-analysis. Of these studies, 19 were about CABG with on-pump and three with off-pump. Our pooled result indicated that patients received ANH experienced fewer ARBCu transfusions, with a standardized mean difference (SMD) of -0.60 (95%CI -0.96 to -0.24; P = 0.001). The rate of allogeneic blood transfusion in ANH group was significant reduced when compared with controls, with a relative risk (RR) of 0.65 (95%CI 0.52 to 0.82; P = 0.0002). In addition, less postoperative estimated total blood loss was present, with a SMD of -0.53 (95%CI -0.88 to -0.17; P = 0.004).

CONCLUSIONS

The present meta-analysis indicated that ANH could reduce the number of ARBCu transfused in the CABG surgery setting. In addition, ANH could also reduce the rate of ARBCu transfusion and estimated total blood loss for CABG patients.

Transfusion of Red Blood Cells, Fresh Frozen Plasma, or Platelets Is Associated With Mortality and Infection After Cardiac Surgery in a Dose-Dependent Manner

BACKGROUND

It is unclear whether transfusion of platelets or fresh frozen plasma, in addition to red blood cells, is associated with an increased risk of mortality and infection after cardiac surgery.

METHODS

Patients who underwent valve surgery and/or coronary artery bypass grafting from January 1, 2011 to June 30, 2017 and September 1, 2013 to June 30, 2017 at 2 centers performing cardiac surgery were included in this retrospective study. After stratifying patients based on propensity score matching, we compared rates of mortality and infection between patients who transfused red blood cells, fresh frozen plasma, or platelets with those who did not receive such transfusions. We also compared outcomes between patients who received any of the 3 blood products and patients who received no transfusions at all. Multivariable logistic regression was used to assess associations between transfusion and outcomes.

RESULTS

Of 8238 patients in this study, 109 (1.3%) died, 812 (9.9%) experienced infection, and 4937 (59.9%) received at least 1 type of blood product. Transfusion of any blood type was associated with higher rates of mortality (2.0% vs 0.18%; P < .01) and infection (13.3% vs 4.8%; P < .01). Each of the 3 blood products was independently associated with an increase in mortality per unit transfused (red blood cells, odds ratio 1.18, 95% confidence interval [CI], 1.14-1.22; fresh frozen plasma, odds ratio 1.24, 95% CI, 1.18-1.30; platelets, odds ratio 1.12, 95% CI, 1.07-1.18). Transfusing 3 units of any of the 3 blood products was associated with a dose-dependent increase in the incidence of mortality (odds ratio 1.88, 95% CI, 1.70-2.08) and infection (odds ratio 1.50, 95% CI, 1.43-1.57).

CONCLUSIONS

Transfusion of red blood cells, fresh frozen plasma, or platelets is an independent risk factor of mortality and infection, and combination of the 3 blood products is associated with adverse outcomes after cardiac surgery in a dose-dependent manner.

Society of Cardiovascular Anesthesiologists Clinical Practice Improvement Advisory for Management of Perioperative Bleeding and Hemostasis in Cardiac Surgery Patients

Bleeding after cardiac surgery is a common and serious complication leading to transfusion of multiple blood products and resulting in increased morbidity and mortality. Despite the publication of numerous guidelines and consensus statements for patient blood management in cardiac surgery, research has revealed that adherence to these guidelines is poor, and as a result, a significant variability in patient transfusion practices among practitioners still remains. In addition, although utilization of point-of-care (POC) coagulation monitors and the use of novel therapeutic strategies for perioperative hemostasis, such as the use of coagulation factor concentrates, have increased significantly over the last decade, they are still not widely available in every institution. Therefore, despite continuous efforts, blood transfusion in cardiac surgery has only modestly declined over the last decade, remaining at ≥50% in high-risk patients. Given these limitations, and in response to new regulatory and legislature requirements, the Society of Cardiovascular Anesthesiologists (SCA) has formed the Blood Conservation in Cardiac Surgery Working Group to organize, summarize, and disseminate the available best-practice knowledge in patient blood management in cardiac surgery. The current publication includes the summary statements and algorithms designed by the working group, after collection and review of the existing guidelines, consensus statements, and recommendations for patient blood management practices in cardiac surgery patients. The overall goal is creating a dynamic resource of easily accessible educational material that will help to increase and improve compliance with the existing evidence-based best practices of patient blood management by cardiac surgery care teams.

Impact of Pre-bypass Autologous Blood Collection on Blood Transfusion Rates

Pre-bypass acute autologous donation (PAAD) is a method of blood conservation that reduces exposure of blood to the cardiopulmonary bypass (CPB) circuit and may prevent the contact activation of platelets and clotting factors. The purpose of this study was to evaluate the impact of PAAD on product transfusion rates in cardiac surgical patients. This is a retrospective study of patients undergoing cardiac surgery between 2015 and 2017 for either a coronary artery bypass (CABG), valve replacement, or a combined valve/CABG procedure. PAAD was performed by removing blood from the venous line of the bypass circuit immediately before the institution of CPB. The amount of PAAD volume was determined during the surgical time-out. This was based on patient size, baseline hemoglobin, and type of case. Poisson logistic regression was used to determine whether PAAD was a significant predictor for blood product transfusion. After obtaining institutional review board approval, we reviewed 236 records on (n = 154, 65.3%) who received PAAD and (n = 82, 34.7%) with no blood withdrawal before CPB. The median PAAD volume in the PAAD group was 750 mL. Patients undergoing PAAD had a 14.3% red blood cell (RBC) transfusion rate (.27 ± .91 units), and without PAAD, the RBC transfusion rate was 62.2% (1.56 ± 1.79 units). The significant (p < .05) odds ratios (ORs) for RBC transfusion were as follows: baseline hemoglobin .617 (.530-.719), PAAD .998 (.997-.999), CPB time 1.009 (1.003-1.015), age 1.034 (1.013-1.055), and BSA odds ratio (OR) .326 (.124-.857). PAAD could not be used in all patients. However, using the OR in the Poisson logistic regression model, a one-unit reduction in RBC transfusion is predicted for each 500 mL of PAAD. PAAD was also associated with a significant reduction in fresh frozen plasma and platelet transfusion.

Platelet function, but not thrombin generation, is impaired in acute normovolemic hemodilution (ANH) blood

STUDY OBJECTIVE

We investigated the coagulation changes that might occur in acute normovolemic hemodilution (ANH) blood over several hours during cardiac surgery requiring cardiopulmonary bypass.

DESIGN

This study was a prospective observational study.

SETTING

This study took place at a university teaching hospital.

PATIENTS

This study included 26 patients, either ASA 3 or 4 and without known coagulation disorders, undergoing cardiac surgery. Patients were included if the use of cardiopulmonary bypass was expected to reach 2.5 h.

INTERVENTIONS

ANH blood was collected into CPDA-1 collection bags before systemic heparinization. Samples were taken directly from the bags at time of collection and reinfusion to assess changes in platelet and thrombin generation parameters.

MEASUREMENTS

Whole blood from citrated tubes was used immediately for rotational thromboelastometry and platelet aggregometry analyses. Thrombin generation was assessed using calibrated automated thrombography with platelet poor plasma.

MAIN RESULTS

Despite no significant change in platelet count over the ANH storage period, there was significant degradation in platelet function as measured by thrombin receptor activating peptide stimulation on Mulltiplate™ analysis and maximum clot formation on ROTEM™ EXTEM. Notably, there was no change in the ability to generate thrombin.

CONCLUSIONS

Little data exists regarding the quality of coagulation factors in autologous blood. Our study confirms ANH collection results in decreased platelet aggregation with TRAP stimulation; however, this is not appreciated with ADP stimulation. Thrombin generation capacity remains preserved.

Myocardial oxygen balance during acute normovolemic hemodilution: A novel compartmental modeling approach

BACKGROUND

Hemodilution was introduced initially as a blood conservation technique to reduce allogeneic blood transfusion in patients undergoing surgical procedures. Although the technique has been approved by the National Institute of Health consensus panel, limits of hemodilution under anesthetic conditions have not been established as they have in animal models.

METHODS

A novel multi-compartmental modeling approach has been proposed that includes the effect of anesthesia to quantify the effect of hemodilution on myocardial oxygen balance during myocardial ischemia.

RESULTS

The results showed that isovolemic hemodilution would cause detrimental effects around a hematocrit of 15%. Even though the fall in oxygen content caused by the decrease in hemoglobin concentration was compensated by an increase in coronary blood flow induced by hypoxic vasodilation and decreased viscosity, the endocardial tissue received less oxygen compared to the epicardial regions, and this sub-endocardial ischemia eventually led to cardiac failure. Statistical analysis also showed that the type of acellular replacement fluid failed to affect the heart rate, the stroke index or the cardiac index during hemodilution, and supplemental oxygen improved the endocardial oxygen supply.

CONCLUSION

The model validates the clinical conclusions that sub-endocardial ischemia causes cardiac failure under extreme hemodilution conditions and the model can also be easily integrated into other human simulators.

Feasibility of autologous intraoperative blood collection and retransfusion in small children with complex congenital heart defects undergoing cardiopulmonary bypass

INTRODUCTION

Allogeneic blood product transfusion is common in pediatric patients undergoing cardiopulmonary bypass although it is associated with an increased risk for adverse events. Furthermore, numerous donor exposures may affect future blood transfusion needs and human leukocyte antigen matching for patients who may ultimately require cardiac transplantation. Autologous intraoperative blood collection and retransfusion is a known method of blood preservation, but has not been extensively practiced in pediatric patients. In this study we assess the feasibility of this blood conservation technique in small children with complex congenital heart defects undergoing cardiopulmonary bypass.

METHODS

After Institutional Review Board approval, we retrospectively reviewed the medical records of children weighing <10 kg who underwent cardiopulmonary bypass over a 2-year period. Eighteen patients underwent autologous intraoperative blood collection and retransfusion and comprised the study group. Eighteen control patients were chosen by a 1:1 matched design using preoperative hematocrit, surgical procedure, and body weight. Multiple corresponding demographic and surgical variables, transfusion data, and clinical outcomes were compared.

RESULTS

Patient demographics, operative parameters and preoperative laboratory, and coagulation values were similar between the two groups. Despite the removal of autologous blood, study patients did not require more inotropic support prior to cardiopulmonary bypass. They also did not experience a significant increase in bleeding as measured by 24-hour postoperative chest tube output. Study patients were exposed to significantly fewer donor units intraoperatively and within the first 24 hours postoperatively.

DISCUSSION

The use of autologous intraoperative blood collection and retransfusion is a feasible option for small children with complex congenital heart defects undergoing cardiopulmonary bypass. Study patients received significantly fewer donor exposures without an increase in postoperative bleeding. Children who require multiple cardiac surgeries or eventually transplantation could benefit from this blood conservation technique.