Acute Normovolemic Hemodilution Reduces Allogeneic Red Blood Cell Transfusion in Cardiac Surgery

Challenges in Patient Blood Management for Cardiac Surgery: A Narrative Review

About 15 years ago, Patient Blood Management (PBM) emerged as a new paradigm in perioperative medicine and rapidly found support of all major medical societies and government bodies. Blood products are precious, scarce and expensive and their use is frequently associated with adverse short- and long-term outcomes. Recommendations and guidelines on the topic are published in an increasing rate. The concept aims at using an evidence-based approach to rationalize transfusion practices by optimizing the patient's red blood cell mass in the pre-, intra- and postoperative periods. However, elegant as a concept, the implementation of a PBM program on an institutional level or even in a single surgical discipline like cardiac surgery, can be easier said than done. Many barriers, such as dogmatic ideas, logistics and lack of support from the medical and administrative departments need to be overcome and each center must find solutions to their specific problems. In this paper we present a narrative overview of the challenges and updated recommendations for the implementation of a PBM program in cardiac surgery.

Decreased Transfusion Requirements with Use of Acute Normovolemic Hemodilution in Open Aortic Aneurysm Repair

OBJECTIVES

Acute normovolemic hemodilution (ANH) is an operative blood conservation technique involving the removal and storage of patient blood after induction of anesthesia, while maintaining normovolemia with crystalloid and/or colloid replacement. Developed and used predominately in cardiac surgery, ANH has been applied to the vascular surgery population but data regarding impact on transfusion requirements in this population is limited. The objective of this study is to compare transfusion requirements and coagulopathy in patients undergoing open abdominal aortic aneurysm repair (oAAA) employing ANH to those receiving only product replacement as clinically indicated.

METHODS

This is a retrospective review of patients undergoing elective oAAA at a quaternary aortic referral center from 2017-2019. Those eligible for ANH, no active cardiac ischemia, no valvular disease, normal LV/RV function, CKD < stage 3, HCT > 38%, normal coagulation profile, were included in the study. Patient demographics and characteristics were collected as were operative variables including extent of aneurysm, clamp site, visceral/renal ischemia time, operative time, and transfusion requirements. Post-operative morbidity, mortality, and length of stay were analyzed. Patients with and without ANH were matched and compared. Continuous measures were analyzed with Wilcoxon rank sum tests and t-tests.

RESULTS

Over the study period, 209 oAAA were performed, 76 patients met inclusion criteria; 27 patients underwent ANH while 49 did not. Patients with ANH had less PRBC transfusion intraoperative (Median [25^th,75^th]: 0 [0,1] vs. 1[0,2] units, p=0.02), at 24 hours(0[0,1] vs. 1[0,2] units, p=0.008), at 48 hours (0[0,1] vs. 1[0,2], p=0.007) and throughout the admission (0[0,1] vs. 2[0,2], p=0.011). There was no difference in intraoperative platelet or cryoprecipitate transfusions. At 48-hours, ANH had significantly higher platelet counts (142 ±35.8 vs. 124±37.6 x10(3)/mcL, p=0.044), lower PTT, and lower INR. There was no difference in MI, RTOR, or mortality (1 death overall). ANH patients had shorter LOS (7.0±2.7 vs 8.8±4.8 days, p=0.041).

CONCLUSIONS

ANH during oAAA results in less intraoperative and post-operative PRBC with improved coagulation parameters and a shorter hospital LOS.

How I treat anemia in the perisurgical setting

Anemia is a common finding in the perioperative setting with significant untoward consequences including worsening of outcomes and diminished quality of life as well as increased risk of allogeneic blood transfusions. Here, we present 3 cases that illustrate how anemia can be perioperatively managed in patients undergoing cardiac, orthopedic, and oncology surgeries. Timely detection of anemia prior to high-blood loss surgeries can allow clinicians to manage it and optimize hemoglobin level, making patients better prepared for the surgery. Treatment of anemia should be guided by the etiology and may include erythropoietic agents, folic acid, B12, and iron preparations. Other blood management strategies geared toward reducing surgical blood loss such as autologous transfusion techniques and agents to optimize hemostasis are used during surgery and in the immediate postoperative period. Patients should be closely monitored following surgery for signs of ongoing bleeding in need of control. Finally, screening for and management of anemia should continue in the postoperative and postdischarge period, as persistence and recurrence of anemia can further undermine patient's outcomes.

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.

Perioperative anemia: clinical practice update

Perioperative medicine is an evolving area of medicine in which collaboration between internists, hospitalists, surgeons and anesthesiologists is the key to delivering high-quality care. Research in all areas of perioperative medicine, including perioperative anemia, is constantly evolving. Perioperative anemia is a major contributor to mortality and morbidity in the perioperative period. It is associated with an increased likelihood of postoperative wound complications, infections, delirium, increased length of stay and increased risk of readmissions. However, there is a lack of comprehensive guidelines for management of perioperative anemia. We performed an exhaustive review of contemporary literature on perioperative anemia and present evaluation and management recommendations that have the potential to impact clinical practice in the perioperative period.

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.

[The use of diuretics in chronic heart failure. Position paper of the Russian Heart Failure Society]

The document focuses on key issues of diuretic therapy in CHF from the standpoint of current views on the pathogenesis of edema syndrome, its diagnosis, and characteristics of using diuretics in various clinical situations.

Impact of Perioperative Massive Transfusion on Long Term Outcomes of Liver Transplantation: a Retrospective Cohort Study

Background: Liver transplantation (LT) is associated with a significant risk of intraoperative hemorrhage and massive blood transfusion. However, there are few relevant reports addressing the long-term impacts of massive transfusion (MT) on liver transplantation recipients. Aim: To assess the effects of MT on the short and long-term outcomes of adult liver transplantation recipients. Methods: We included adult patients who underwent liver transplantation at West China Hospital from January 2011 to February 2015. MT was defined as red blood cell (RBC) transfusion of ≥10 units within 48 hours since the application of LT. Preoperative, intraoperative and postoperative information were collected for data analyzing. We used one-to-one propensity-matching to create pairs. Kaplan-Meier survival analysis was used to compare long-term outcomes of LT recipients between the MT and non-MT groups. Univariate and multivariate logistic regression analyses were performed to evaluate the risk factors associated with MT in LT. Results: Finally, a total of 227 patients were included in our study. After propensity score matching, 59 patients were categorized into the MT and 59 patients in non-MT groups. Compared with the non-MT group, the MT group had a higher 30-day mortality (15.3% vs 0, p=0.006), and a higher incidence of postoperative complications, including postoperative pulmonary infection, abdominal hemorrhage, pleural effusion and severe acute kidney injury. Furthermore, MT group had prolonged postoperative ventilation support (42 vs 25 h, p=0.007) and prolonged durations of ICU (12.9 vs 9.5 d, p<0.001) stay. Multivariate COX regression indicated that massive transfusion (OR: 2.393, 95% CI: 1.164-4.923, p=0.018) and acute rejection (OR: 7.295, 95% CI: 2.108-25.246, p=0.02) were significant risk factors affecting long-term survivals of LT patients. The 1-year and 3-year survival rates patients in MT group were 82.5% and 67.3%, respectively, while those of non-MT group were 93.9% and 90.5%, respectively. The MT group exhibited a lower long-term survival rate than the non-MT group (HR: 2.393, 95% CI: 1.164-4.923, p<0.001). Finally, the multivariate logistic regression revealed that preoperative hemoglobin <118 g/L (OR: 5.062, 95% CI: 2.292-11.181, p<0.001) and intraoperative blood loss ≥1100 ml (OR: 3.212, 95% CI: 1.586-6.506, p = 0.001) were the independent risk factor of MT in patients undergoing LT. Conclusion: Patients receiving MT in perioperative periods of LT had worse short-term and long-term outcomes than the non-MT patients. Massive transfusion and acute rejection were significant risk factors affecting long-term survivals of LT patients, and intraoperative blood loss of over 1100 ml was the independent risk factor of MT in patients undergoing LT. The results may offer valuable information on perioperative management in LT recipients who experience high risk of MT.

Survival outcomes of acute normovolemic hemodilution in patients undergoing primary debulking surgery for advanced ovarian cancer: A Memorial Sloan Kettering Cancer Center Team Ovary study

OBJECTIVE

To describe oncologic outcomes after using acute normovolemic hemodilution (ANH) to reduce requirement for allogenic red blood cell transfusions (ABT) in patients undergoing primary debulking surgery (PDS) for advanced ovarian cancer.

METHODS

We performed a post-hoc analysis of a recent prospective trial investigating the safety and feasibility of ANH during PDS for advanced ovarian cancer. We report long-term survival outcomes. We compared demographics, clinicopathological characteristics, survival outcomes in this cohort of Stage IIIB-IVB high-grade serous ovarian cancer patients undergoing ANH (ANH group), with a retrospective cohort of all other patients (standard group) undergoing PDS during the same time period (01/2012-04/2017). Standard statistical tests were used.

RESULTS

There were no demographic or clinicopathological differences between ANH (n = 33) and standard groups (n = 360), except for higher median age at diagnosis (57 vs. 62 years, respectively; p = 0.044) and shorter operative time (357 vs. 446 min, respectively; p < 0.001) in the standard group. Cytoreductive outcomes (ANH vs. standard): 0 mm, 69.7 vs. 63.9%; gross residual disease (RD) ≤1 cm, 21.2 vs. 26.9%; >1 cm, 9.1 vs. 9.2% (p = 0.78). RD after PDS was the only independent factor associated with worse progression-free survival (PFS) on multivariable analysis (p < 0.001). Patients with BRCA mutations trended towards improved PFS (p = 0.057). Significant factors for overall survival (OS) on multivariable analysis: preoperative CA125 (p = 0.004), ascites (p = 0.018), RD after PDS (p = 0.04), BRCA mutation status (p < 0.001). After adjustment for potential confounders, ANH was not independently associated with PFS or OS [PFS: HR 0.928 (0.618-1.395); p = 0.721; OS: HR 0.588 (95%CI: 0.317-1.092); p = 0.093].

CONCLUSIONS

ANH is an innovative approach in intraoperative management. It was previously proven to decrease need for ABT while maintaining the ability to achieve complete gross resection and associated benefits.

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.

Effects of different plasma expanders on rats subjected to severe acute normovolemic hemodilution

BACKGROUND

Plasma expanders are widely used for acute normovolemic hemodilution (ANH). However, existing studies have not focused on large-volume infusion with colloidal plasma expanders, and there is a lack of studies that compare the effects of different plasma expanders.

METHODS

The viscosity, hydrodynamic radius (R_h) and colloid osmotic pressure (COP) of plasma expanders were determined by a cone-plate viscometer, Zetasizer and cut-off membrane, respectively. Sixty male rats were randomized into five groups with Gelofusine (Gel), Hydroxyethyl Starch 200/0.5 (HES200), Hydroxyethyl Starch 130/0.4 (HES130), Hydroxyethyl Starch 40 (HES40), and Dextran40 (Dex40), with 12 rats used in each group to build the ANH model. ANH was performed by the withdrawal of blood and simultaneous infusion of plasma expanders. Acid-base, lactate, blood gas and physiological parameters were detected.

RESULTS

Gel had a lower intrinsic viscosity than HES200 and HES130 (P < 0.01), but at a low shear rate in a mixture of colloids, red cells and plasma, Gel had a higher viscosity (P < 0.05 or P < 0.01, respectively). For hydroxyethyl starch plasma expanders, the COP at a certain concentration decreases from 11.1 mmHg to 6.1 mmHg with the increase of R_h from 10.7 nm to 20.2 nm. A severe ANH model, with the hematocrit of 40% of the baseline level, was established and accompanied by disturbances in acid-base, lactate and blood gas parameters. At the end of ANH and 60 min afterward, the Dex40 group showed a worse outcome in maintaining the acid-base balance and systemic oxygenation compared to the other groups. The systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) decreased significantly in all groups at the end of ANH. The DBP and MAP in the Dex40 group further decreased 60 min after the end of ANH. During the process of ANH, the Dex40 group showed a drop and recovery in SBP, DBP and MAP. The DBP and MAP in the HES200 group were significantly higher than those in the other groups at some time points (P < 0.05 or P < 0.01).

CONCLUSION

Gel had a low intrinsic viscosity but may increase the whole blood viscosity at low shear rates. R_h and COP showed a strong correlation among hydroxyethyl starch plasma expanders. Dex40 showed a worse outcome in maintaining the acid-base balance and systemic oxygenation compared to the other plasma expanders. During the process of ANH, Dex40 displayed a V-shaped recovery pattern for blood pressure, and HES200 had the advantage in sustaining the DBP and MAP at some time points.

Clotting functional stability of withdrawing blood in storage for acute normovolemic hemodilution: a pilot study

Purpose

This study was conducted to time-course changes of clotting function of withdrawing blood for acute normovolemic hemodilution (ANH).

Methods

Twelve enrolled patients who underwent ANH from August, 2018 to January, 2019. Blood was withdrawn into blood collection pack and shaken at 60–80 rpm for 24 h in room temperature. Clot formation was evaluated using rotational thromboelastometry (ROTEM™) just after blood withdrawal (control) and 4, 8, 12 and 24 h after blood withdrawal. We compared with the control value and each value of extrinsically-activated test with tissue factor (EXTEM), intrinsically-activated test using ellagic acid (INTEM) and fibrin-based extrinsically activated test with tissue factor (FIBTEM).

Results

Maximum clot firmness (MCF) of FIBTEM did not change significantly. MCF of EXTEM was significantly decreased time-dependent manner but all MCF of EXTEM were within a normal range. Maximum percent change in MCF of EXTEM was 12.4% [95% confidence interval (CI): 9.0–15.8%]. The difference in the maximum clot elasticity (MCE) between EXTEM and FIBTEM (MCE_EXTEM−MCE_FIBTEM) was significantly decrease from 8 h after blood withdrawal. Maximum percent change in MCE_EXTEM−MCE_FIBTEM was 30.2% (95% CI:17.6–42.9%) at 24 h after blood withdrawal.

Conclusion

Even though the MCE significantly decreased in a time-dependent manner, MCF of FIBTEM and EXTEM was normal up to 24 h storage. The blood of ANH can use for the purpose of hemostasis at least 8 h stored at room temperature after blood withdrawal. Future studies are needed to elucidate the clinical impact on the patient after delayed transfusion of ANH blood with regard to patient’s hemostasis.

Electronic supplementary material

The online version of this article (10.1007/s00540-020-02856-x) contains supplementary material, which is available to authorized users.

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.

Blood management in a patient with anti-Oka antibody who underwent cardiac surgery using cardiopulmonary bypass: a case report

Background

Cardiac surgery under cardiopulmonary bypass (CPB) is often associated with massive bleeding and blood transfusion. For patients requiring specific blood products, meticulous blood management is critical to reduce blood loss, as well as the need for transfusion. Here, we have described the intraoperative blood management in a patient with anti-Ok^a antibody, who underwent cardiac surgery with CPB.

Case presentation

A 79-year-old woman was scheduled for open aortic valve replacement and tricuspid valve annuloplasty under hypothermic CPB. Her blood type was A RhD(+) Ok(a−), and anti-Ok^a, an extremely rare antibody against erythrocyte antigen, was detected. Eight units of Ok(a−) frozen thawed red cells (FTRCs), and six units of red blood cells donated by three Ok(a−) individuals were collected just prior to surgery. Although she was anemic, acute normovolemic hemodilution was conducted after anesthesia induction to preserve the autologous whole blood. Four units of FTRCs were loaded in the CPB priming solution, and modified ultrafiltration was adopted during CPB to prevent further hemodilution. After CPB termination, two units of FTRCs, four units of fresh frozen plasma, and ten units of platelet concentrate were intensively transfused, facilitating surgical hemostasis and stable hemodynamics. The autologous whole blood was returned to the patient in the intensive care unit. Since the hemoglobin and hematocrit levels were maintained postoperatively, no additional transfusion was required throughout her hospital stay.

Conclusions

Multidisciplinary intraoperative blood management in a patient with anti-Ok^a antibody facilitated successful cardiac surgery using CPB, along with effective use of limited blood products.

Essential Role of Patient Blood Management in a Pandemic: A Call for Action

The World Health Organization (WHO) has declared coronavirus disease 2019 (COVID-19), the disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a pandemic. Global health care now faces unprecedented challenges with widespread and rapid human-to-human transmission of SARS-CoV-2 and high morbidity and mortality with COVID-19 worldwide. Across the world, medical care is hampered by a critical shortage of not only hand sanitizers, personal protective equipment, ventilators, and hospital beds, but also impediments to the blood supply. Blood donation centers in many areas around the globe have mostly closed. Donors, practicing social distancing, some either with illness or undergoing self-quarantine, are quickly diminishing. Drastic public health initiatives have focused on containment and "flattening the curve" while invaluable resources are being depleted. In some countries, the point has been reached at which the demand for such resources, including donor blood, outstrips the supply. Questions as to the safety of blood persist. Although it does not appear very likely that the virus can be transmitted through allogeneic blood transfusion, this still remains to be fully determined. As options dwindle, we must enact regional and national shortage plans worldwide and more vitally disseminate the knowledge of and immediately implement patient blood management (PBM). PBM is an evidence-based bundle of care to optimize medical and surgical patient outcomes by clinically managing and preserving a patient's own blood. This multinational and diverse group of authors issue this "Call to Action" underscoring "The Essential Role of Patient Blood Management in the Management of Pandemics" and urging all stakeholders and providers to implement the practical and commonsense principles of PBM and its multiprofessional and multimodality approaches.

[Role of acute hemodilution in blood transfusion rate in patients submmited to scoliosis surgery: observational retrospective study]

BACKGROUND AND OBJECTIVES

The study assessed the role of acute hemodilution in the blood transfusion rate in patients submitted to surgical treatment of scoliosis.

METHODS

Retrospective observational study performed at Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (HC-FMRP?USP). Medical charts of patients submitted to elective correction of scoliosis between January 1996 and December 2016 were analyzed. Variables assessed were: age, weight, sex, presence of comorbidities, data regarding anesthesia and surgery, lab data, adverse events and blood transfusion rate. The final sample consisted of 33 procedures performed by the same anesthesiologist and same surgeon, divided into two groups: Hemodilution Group (n = 16) and Control Group (n = 17). Indication of acute normovolemic hemodilution was determined by patient refusal of blood transfusion for religious reasons.

RESULTS

The sample was statistically homogeneous and the groups were compared in terms of the attributes analyzed. The volume of homologous blood used by the Hemodilution Group was significantly lower than the Control Group (p = 0.0016). The percentage of patients who required transfusion was 12.5% in the Hemodilution Group, while it was 70.69% (p = 0.0013) in the Control Group. Upon hospital discharge, mean values of hemoglobin and hematocrit between groups did not present significant differences (p = 0.0679; p = 0.1027, respectively).

CONCLUSIONS

Acute normovolemic hemodilution, in scoliosis correction surgeries reduces blood transfusion rates, meeting patient needs without increasing adverse events or infection rates.

The effect of hemodilution on free flap survival: A systematic review of clinical and experimental studies

BACKGROUND

Acute normovolemic hemodilution (ANH) has been proposed as a microsurgical technique to improve blood flow in free flaps.

OBJECTIVE

Here, we present the first systematic review of clinical and experimental studies on the effect of ANH.

METHODS

We performed a systematic literature search of PubMed, Medline, the Cochrane Library, Google Scholar, and ClinicalTrials.gov using search strategies and a review process in agreement with the PRISMA statement and the Cochrane Handbook for systematic reviews of interventions. PICO criteria were defined before bibliometric processing of the retrieved articles, which were analyzed with the SYRCLE RoB tool for risk of bias and the GRADE scale for level of evidence.

RESULTS

We retrieved 74 articles from the literature search, and after processing according to PICO criteria, only four articles remained, all of which were experimental. The rating for risk of bias was uncertain according to SYRCLE RoB results, and the level of evidence was low according to GRADE evaluation.

CONCLUSIONS

There is no clinical evidence for the effect of ANH on microcirculation in free flaps, and experimental studies provide weak evidence supporting the use of hemodilution in reconstructive microsurgery.

Role of acute hemodilution in blood transfusion rate in patients submitted to scoliosis surgery: observational retrospective study

Background and objectives

The study assessed the role of acute hemodilution in the blood transfusion rate in patients submitted to surgical treatment of scoliosis.

Methods

Retrospective observational study performed at Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (HC-FMRP–USP). Medical charts of patients submitted to elective correction of scoliosis between January 1996 and December 2016 were analyzed. Variables assessed were: age, weight, sex, presence of comorbidities, data regarding anesthesia and surgery, lab data, adverse events and blood transfusion rate. The final sample consisted of 33 procedures performed by the same anesthesiologist and same surgeon, divided into two groups: Hemodilution Group (n = 16) and Control Group (n = 17). Indication of acute normovolemic hemodilution was determined by patient refusal of blood transfusion for religious reasons.

Results

The sample was statistically homogeneous and the groups were compared in terms of the attributes analyzed. The volume of homologous blood used by the Hemodilution Group was significantly lower than the Control Group (p = 0.0016). The percentage of patients who required transfusion was 12.5% in the Hemodilution Group, while it was 70.69% (p = 0.0013) in the Control Group. Upon hospital discharge, mean values of hemoglobin and hematocrit between groups did not present significant differences (p = 0.0679; p = 0.1027, respectively).

Conclusions

Acute normovolemic hemodilution, in scoliosis correction surgeries, reduces blood transfusion rates, meeting patient needs without increasing adverse events or infection rates.

Patient Blood Management

Patient blood management is a highly successful and cost-effective concept that improves patient outcome by correction of anemia with hematinic medication and reduction of blood loss perioperatively by meticulous surgical techniques and individualized coagulation management.

Phlebotomy resulting in controlled hypovolaemia to prevent blood loss in major hepatic resections (PRICE-1): a pilot randomized clinical trial for feasibility

BACKGROUND

Major liver resection is associated with blood loss and transfusion. Observational data suggest that hypovolaemic phlebotomy can reduce these risks. This feasibility RCT compared hypovolaemic phlebotomy with the standard of care, to inform a future multicentre trial.

METHODS

Patients undergoing major liver resections were enrolled between June 2016 and January 2018. Randomization was done during surgery and the surgeons were blinded to the group allocation. For hypovolaemic phlebotomy, 7-10 ml per kg whole blood was removed, without intravenous fluid replacement. Co-primary outcomes were feasibility and estimated blood loss (EBL).

RESULTS

A total of 62 patients were randomized to hypovolaemic phlebotomy (31) or standard care (31), at a rate of 3·1 patients per month, thus meeting the co-primary feasibility endpoint. The median EBL difference was -111 ml (P = 0·456). Among patients at high risk of transfusion, the median EBL difference was -448 ml (P = 0·069). Secondary feasibility endpoints were met: enrolment, blinding and target phlebotomy (mean(s.d.) 7·6(1·9) ml per kg). Blinded surgeons perceived that parenchymal resection was easier with hypovolaemic phlebotomy than standard care (16 of 31 versus 10 of 31 respectively), and guessed that hypovolaemic phlebotomy was being used with an accuracy of 65 per cent (20 of 31). There was no significant difference in overall complications (10 of 31 versus 15 of 31 patients), major complications or transfusion. Among those at high risk, transfusion was required in two of 15 versus three of nine patients (P = 0·326).

CONCLUSION

Endpoints were met successfully, but no difference in EBL was found in this feasibility study. A multicentre trial (PRICE-2) powered to identify a difference in perioperative blood transfusion is justified. Registration number: NCT02548910 ( http://www.clinicaltrials.gov).

Optimizing Perioperative Blood and Coagulation Management During Cardiac Surgery

Bleeding and transfusion are common in cardiac surgery and associated with poorer outcome. Bleeding is frequently due to coagulopathy caused by the complex interaction between cardiopulmonary bypass, major surgical trauma, anticoagulation management, and perioperative factors. Patient blood management has emerged to improve outcome by the prediction, prevention, monitoring, and treatment of bleeding and transfusion. Each part of this chain has several individual modalities and when combined leads to result in a better outcome. This article reviews the hemostasis disturbances in cardiac surgery with cardiopulmonary bypass and gives an overview of the most important patient blood management strategies.

Acute normovolemic hemodilution reduced allogeneic blood transfusion without increasing perioperative complications in patients undergoing free-flap reconstruction of the head and neck

Purpose

The present case–control study was conducted to evaluate whether acute normovolemic hemodilution (ANH) can reduce the need for perioperative allogeneic blood transfusion (ABT) and affect the incidence of perioperative complications in free-flap reconstruction of the head and neck.

Methods

This single-center, retrospective, observational study included the perioperative data of 123 patients who underwent free-flap reconstruction of the head and neck following oncological surgery. Patients were divided into the following two groups according to whether they received ANH: ANH group and non-ANH group. We investigated whether ANH can reduce the need for perioperative ABT using propensity score-adjusted logistic regression analysis.

Results

Of the 123 patients, 113 patients were assessed; 57 patients were in the ANH group and 56 patients were in the non-ANH group. The rate [ANH group vs. non-ANH group, n (%): 2 (3.5%) vs. 23 (41.1%), p < 0.0001] and amount [median (IQR): 0 mL (0, 0) vs. 0 mL (0, 280), p < 0.0001] of ABT were significantly lower in the ANH group than in the non-ANH group. Propensity score-adjusted multivariate logistic regression analysis indicated that ANH use [odds ratio (OR): 0.040; 95% confidence interval (CI) 0.005, 0.320; p = 0.0024)] was one of the independent predictors of perioperative ABT. There were no significant differences in the incidences of post-operative complications between the two groups.

Conclusion

ANH use can reduce the need for perioperative ABT in patients undergoing free-flap reconstruction of the head and neck without increasing the incidence of post-operative complications.

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.

Proceedings From the Society for Advancement of Blood Management Annual Meeting 2017: Management Dilemmas of the Surgical Patient-When Blood Is Not an Option

Vigilance is essential in the perioperative period. When blood is not an option for the patient, especially in a procedure/surgery that normally holds a risk for blood transfusion, complexity is added to the management. Current technology and knowledge has made avoidance of blood transfusion a realistic option but it does require a concerted patient-centered effort from the perioperative team. In this article, we provide suggestions for a successful, safe, and bloodless journey for patients. The approaches include preoperative optimization as well as intraoperative and postoperative techniques to reduce blood loss, and also introduces current innovative substitutes for transfusions. This article also assists in considering and maneuvering through the legal and ethical systems to respect patients' beliefs and ensuring their safety.

Consensus Report on Patient Blood Management in Cardiac Surgery by Turkish Society of Cardiovascular Surgery (TSCVS), Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care (SCTAIC)

Anemia, transfusion and bleeding independently increase the risk of complications and mortality in cardiac surgery. The main goals of patient blood management are to treat anemia, prevent bleeding, and optimize the use of blood products during the perioperative period. The benefit of this program has been confirmed in many studies and its utilization is strongly recommended by professional organizations. This consensus report has been prepared by the authors who are the task members appointed by the Turkish Society of Cardiovascular Surgery, Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care to raise the awareness of patient blood management. This report aims to summarize recommendations for all perioperative blood- conserving strategies in cardiac surgery.

High Hemoglobin Level As a Limiting Factor for Extracorporeal Membrane Oxygenation

We report the case of a 47 year old male who developed acute respiratory distress syndrome after bariatric surgery, requiring a venovenous extracorporeal membrane oxygenation. An inadequate extracorporeal membrane oxygenation output flow was observed, possibly because of severe polycythemia and hyperviscosity. Management with acute normovolemic hemodilution corrected both the biologic and hemodynamic parameters. To our knowledge, this is the first reported case of acute normovolemic hemodilution to improve extracorporeal membrane oxygenation outflow. Clinicians should be aware that polycythemia and hyperviscosity may impair extracorporeal membrane oxygenation support and that acute normovolemic hemodilution may be a safe and efficient procedure to address such matter. The optimal hemoglobin level on extracorporeal membrane oxygenation deserves further investigation.

The effect of SANGUINATE® (PEGylated carboxyhemoglobin bovine) on cardiopulmonary bypass functionality using a bovine whole blood model of normovolemic hemodilution

Background:

Cardiac surgery using cardiopulmonary bypass carries a high risk of bleeding and need for blood transfusion. Blood administration is associated with increased rates of morbidity and mortality. Perioperatively, strategies are often employed to reduce blood transfusions in high-risk patients or in situations where blood transfusion is contraindicated. Normovolemic hemodilution is a blood conservation technique used during cardiac surgery that involves replacement of blood with fluids. SANGUINATE® (PEGylated carboxyhemoglobin bovine) is a novel hemoglobin-based oxygen carrier that can deliver oxygen effectively to tissues in the presence of severe hypoxia. The use of a hemoglobin-based oxygen carrier during hemodilution may augment tissue oxygen delivery and reduce blood transfusion.

Methods:

Six standardized cardiopulmonary bypass runs simulating normovolemic hemodilution using varying proportions of bovine whole blood and SANGUINATE were performed. Pump speed, flow rate, line pressures, hemoglobin concentration, oxygenation, and degree of anticoagulation were assessed at regular intervals. Membrane oxygenators and arterial line filters were inspected for evidence of clotting following each run.

Results:

Increases in the pressure drop across the membrane oxygenator were detected during runs 5 and 6. Median activated clotting time values were able to be maintained at goal during the runs, and SANGUINATE did not appear to be thrombogenic. Hemoglobin concentration decreased following the addition of SANGUINATE. Oxygenation was maintained during all runs that included SANGUINATE.

Conclusion:

SANGUINATE does not impact the performance of the cardiopulmonary bypass circuit in a bovine whole blood model. The results support further evaluation of SANGUINATE in the setting of normovolemic hemodilution and cardiopulmonary bypass.

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.

Development of a prediction model for allogenic blood transfusion in children undergoing surgery for developmental dysplasia of the hip

BACKGROUND

Blood transfusion is a common practice, but it is not without cost and risk. A model that predicts the risk of blood transfusion could guide informed preoperative blood ordering and use of blood loss preventive measures.

OBJECTIVE

This study aimed to develop a prediction model of blood transfusion in children with developmental dysplasia of the hip (DDH) undergoing surgery.

METHODS

A retrospective cohort of DDH patients from 2008 to 2017. The included patients were between 1 to 9 years old, underwent anterior open reduction and/or acetabular osteotomy with and without femoral shortening. The unit of analysis was undergoing such an operation. The outcome was allogenic blood transfusion. Potential predictors were age, sex, body mass index (BMI), international hip dysplasia institute grade, type of surgery, intervention bilaterally during the same operative session, primary versus reoperation surgery, the addition of regional anaesthesia, preoperative haemoglobin and hematocrit.

RESULTS

A total of 524 patients who met the inclusion criteria underwent 721 operative sessions. The median age (interquartile range) at operation was 23 (20-33) months. The blood transfusion rate was 11.8%. Independent predictors were lower preoperative haemoglobin, reduced BMI, simultaneous bilateral surgery and the extent of surgical treatment.

CONCLUSIONS

The developed prognostic model allows prediction for blood transfusion in DDH patients undergoing surgery.

Systematic Review and Meta-analysis: Sometimes Bigger Is Indeed Better

Clinicians encounter an ever increasing and frequently overwhelming amount of information, even in a narrow scope or area of interest. Given this enormous amount of scientific information published every year, systematic reviews and meta-analyses have become indispensable methods for the evaluation of medical treatments and the delivery of evidence-based best practice. The present basic statistical tutorial thus focuses on the fundamentals of a systematic review and meta-analysis, against the backdrop of practicing evidence-based medicine. Even if properly performed, a single study is no more than tentative evidence, which needs to be confirmed by additional, independent research. A systematic review summarizes the existing, published research on a particular topic, in a well-described, methodical, rigorous, and reproducible (hence "systematic") manner. A systematic review typically includes a greater range of patients than any single study, thus strengthening the external validity or generalizability of its findings and the utility to the clinician seeking to practice evidence-based medicine. A systematic review often forms the basis for a concomitant meta-analysis, in which the results from the identified series of separate studies are aggregated and statistical pooling is performed. This allows for a single best estimate of the effect or association. A conjoint systematic review and meta-analysis can provide an estimate of therapeutic efficacy, prognosis, or diagnostic test accuracy. By aggregating and pooling the data derived from a systemic review, a well-done meta-analysis essentially increases the precision and the certainty of the statistical inference. The resulting single best estimate of effect or association facilitates clinical decision making and practicing evidence-based medicine. A well-designed systematic review and meta-analysis can provide valuable information for researchers, policymakers, and clinicians. However, there are many critical caveats in performing and interpreting them, and thus, like the individual research studies on which they are based, there are many ways in which meta-analyses can yield misleading information. Creators, reviewers, and consumers alike of systematic reviews and meta-analyses would thus be well-served to observe and mitigate their associated caveats and potential pitfalls.

Use of Hematocrit for Short-Term Prognosis of Patients with Traumatic Brain Injury After Decompressive Craniectomy

OBJECTIVE

To discuss the effects of the hematocrit (Hct) in patients with traumatic brain injury after decompressive craniectomy (DC).

METHODS

Demographic data, inspection and treatment procedures, and 30-day prognosis were obtained for 158 patients with head injury who underwent unilateral DC in our hospital between January 2013 and June 2018. Uni- and multivariate logistic regression was applied to analyze independent risk factors for 30-day outcome. The quantitative analysis of postoperative Hct, ΔHct (postoperative Hct minus initial Hct), and their combination for the prognosis of patients with TBI was displayed graphically using receiver operating characteristic (ROC) curves. Multiple linear regression was used to explore factors influencing postoperative Hct and ΔHct.

RESULTS

Short-term mortality was 29.7%. Uni- and multivariate logistic regression analysis showed that age (odds ratio [OR], 1.064; P = 0.024), Glasgow Coma Scale score (OR, 0.711; P = 0.027), Injury Severity Score (ISS) (OR, 1.156; P = 0.047), midline shift in millimeters (OR, 1.809; P <0.001), postoperative Hct (OR, 0.743; P = 0.001), and ΔHct (OR, 1.242; P =0.048) were independent risk factors for short-term death. In ROC curves, a combination of postoperative Hct and ΔHct showed the highest sensitivity (77.5%) and highest specificity (89.4%). When using this combination to predict prognosis, we could achieve an accuracy of 94.5%. ISS (β = -0.172, P = 0.022), initial Hct (β = 0.243, P = 0.001), principal hematoma location (β = -2.628, P < 0.001), hours of operation (β = -0.884, P = 0.048), and colloid quantity (β = -0.002, P = 0.001) were independent contributing factors for ΔHct, which was similar to postoperative Hct.

CONCLUSIONS

A combination of postoperative Hct and ΔHct could better predict short-term survival of patients with TBI. Developing an appropriate treatment strategy to increase postoperative Hct and reduce the ΔHct may be good for the short-term prognosis of patients with TBI after DC.

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.

Korean clinical practice guideline for perioperative red blood cell transfusion from Korean Society of Anesthesiologists

Background

Considering the functional role of red blood cells (RBC) in maintaining oxygen supply to tissues, RBC transfusion can be a life-saving intervention in situations of severe bleeding or anemia. RBC transfusion is often inevitable to address intraoperative massive bleeding; it is a key component in safe perioperative patient management. Unlike general medical resources, packed RBCs (pRBCs) have limited availability because their supply relies entirely on voluntary donations. Additionally, excessive utilization of pRBCs may aggravate prognosis or increase the risk of developing infectious diseases. Appropriate perioperative RBC transfusion is, therefore, crucial for the management of patient safety and medical resource conservation. These concerns motivated us to develop the present clinical practice guideline for evidence-based efficient and safe perioperative RBC transfusion management considering the current clinical landscape.

Methods

This guideline was obtained after the revision and refinement of exemplary clinical practice guidelines developed in advanced countries. This was followed by rigorous evidence-based reassessment considering the healthcare environment of the country.

Results

This guideline covers all important aspects of perioperative RBC transfusion, such as preoperative anemia management, appropriate RBC storage period, and leukoreduction (removal of white blood cells using filters), reversal of perioperative bleeding tendency, strategies for perioperative RBC transfusion, appropriate blood management protocols, efforts to reduce blood transfusion requirements, and patient monitoring during a perioperative transfusion.

Conclusions

This guideline will aid decisions related to RBC transfusion in healthcare settings and minimize patient risk associated with unnecessary pRBC transfusion.