Impact of intraoperative high‐volume autologous blood collection on allogeneic transfusion during and after cardiac surgery: a propensity score matched analysis

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.

Role of Cardiac Anesthesiologists in Intraoperative Enhanced Recovery After Cardiac Surgery (ERACS) Protocol: A Retrospective Single-Center Study Analyzing Preliminary Results of a Yearlong ERACS Protocol Implementation

INTRODUCTION

Enhanced recovery after cardiac surgery (ERACS) has been gaining rapid acceptance after multiple studies have demonstrated promising results in improved outcomes of enhanced recovery after surgery in other surgical fields (eg, colorectal, orthopedic, thoracic, etc). Cardiac surgery has several unique challenges, including sternotomy, cardiopulmonary bypass and associated coagulopathy, blood transfusion, and postoperative intensive care requirement. Nonetheless, selective cardiac surgical patients can still benefit from ERACS. Guidelines for perioperative care in cardiac surgery, previously published by the ERACS Society, are weighted heavily in preoperative and postoperative management without much focus on intraoperative care provided by anesthesiologists. To address this gap and to explore anesthesiology's contribution in achieving ERACS, the study authors' cardiac anesthesiology division, in collaboration with cardiac surgery, introduced the ERACS protocol in their institution in February 2020.

METHODS

The cardiac anesthesiology division, in collaboration with cardiac surgery, introduced the ERACS protocol consisting of multimodal opioid-sparing analgesia, including the introduction of regional blocks, hemostasis management protocol, reversal of neuromuscular blockade, and administration of antiemetics in the authors' institution in February 2020. They have conducted a retrospective chart review study comparing patients who have received ERACS measures with a similar historic cohort who underwent cardiac surgery prior to initiation of an ERACS protocol. The primary outcomes of the study were to determine patients' time to extubation, postoperative opioid consumption, intensive care unit (ICU) length of stay (LOS), and incidence of postoperative complications (eg, postoperative nausea vomiting [PONV], bleeding, ICU readmission, delirium.

RESULTS

The ERACS patients showed reduced opioid consumption (intraoperative fentanyl; postoperative fentanyl, as well as oxycodone, in the first 6 hours postoperatively), lesser mechanical ventilation (2.5 hours less), shorter ICU stays (5 hours less), shorter hospital LOS (1 day), and lesser incidence of PONV. None of the ERACS patients required blood transfusion. The study authors performed an anonymous survey among the anesthesiologists and ICU providers to assess providers' satisfaction, which showed 92% of survey takers agreed that the ERACS protocol should be continued for future cardiac patients, and 61% of survey takers reported superior pain control in ERACS group of patients while managing those patients.

DISCUSSION

The ERACS is achievable after the careful implementation of a series of measures. It does not signify only fast-track extubation and opioid-sparing analgesia, and must be implemented in the entire perioperative period beginning from preoperative clinic to postoperative rehabilitation. Cardiac anesthesiologists play a vital role in execution of intraoperative ERACS measures. Both providers and patients themselves are key stakeholders. A larger randomized prospective trial is warranted to solidify the inference.

Medicare and Medicaid insurance status is associated with increased allogeneic red blood cell transfusion in cardiac surgery patients: 2007-2018

BACKGROUND AND AIM

Allogeneic red blood cell (RBC) transfusion and health insurance status are independently associated with perioperative morbidity. The aim of this study was to evaluate the effect of insurance status on allogeneic and autologous transfusion risk in cardiac surgery patients.

METHODS

We conducted a retrospective observational study of data spanning 2007-2018 from six states from the State Inpatient Databases. Patients were cohorted by medical insurance type. Rates and risk-adjusted odds ratios (aOR) were calculated for allogenic and autologous RBC transfusions. Interactions between insurance and race/ethnicity were assessed.

RESULTS

A total of 710,296 cardiac surgery patients were included. Allogeneic infusions occurred in 34.7% of Medicare patients, 31.9% of Medicaid patients, 24.7% of privately insured patients, and 26.1% of uninsured patients. Autologous rates were 2.3%, 2.5%, 3.4%, and 2.6% for Medicare, Medicaid, privately insured, and uninsured patients, respectively. Medicare and Medicaid patients were more likely to receive allogeneic RBC than privately insured patients (Medicare: aOR: 1.42, 99% confidence interval [CI]: 1.40-1.44, p < .001, Medicaid: aOR: 1.18, 99% CI: 1.14-1.21, p < .001). Nonwhite Medicare patients showed higher odds of allogeneic transfusion compared with White patients with private insurance (Black Medicare: aOR 1.74, 99% CI: 1.65-1.83, p < .001, Hispanic Medicare: aOR 1.92, 99% CI: 1.84-2.00, p < .001).

CONCLUSION

Cardiac surgery patients with Medicare and Medicaid insurance demonstrate increased risk of allogeneic RBC transfusion; nonwhite patient groups are particularly vulnerable. Further research is needed to understand the causes and implications of these disparities, and to help ensure equitable care across patient groups.

Hemodilution in high-risk cardiac surgery: Laboratory values, physiological parameters, and outcomes

BACKGROUND

Acute normovolemic hemodilution (ANH) is a blood conservation strategy in cardiac surgery, predominantly used in coronary artery bypass graft (CABG) and/or valve procedures. Although higher complexity cardiac procedures may benefit from ANH, concerns for hemodynamic instability, and organ injury during hemodilution hinder its wider acceptance. Laboratory and physiological parameters during hemodilution in complex cardiac surgeries have not been described.

STUDY DESIGN AND METHODS

This observational cohort (2019-2021) study included 169 patients who underwent thoracic aortic repair, multiple valve procedure, concomitant CABG with the aforementioned procedure, and/or redo sternotomies. Patients who received allogeneic blood were excluded. Statistical comparisons were performed between ANH (N = 66) and non-ANH controls (N = 103). ANH consisted of removal of blood at the beginning of surgery and its return after cardiopulmonary bypass.

RESULTS

Intraoperatively, the ANH group received more albumin (p = .04) and vasopressor medications (p = .01), while urine output was no different between ANH and controls. Bilateral cerebral oximetry (rSO₂ ) values were similar before and after hemodilution. During bypass, rSO₂ were discretely lower in the ANH versus control group (right rSO₂ p = .03, left rSO₂ p = .05). No differences in lactic acid values were detected across the procedural continuum. Postoperatively, no differences in extubation times, intensive care unit length of stay, kidney injury, stroke, or infection were demonstrated.

DISCUSSION

This study suggests hemodilution to be a safe and comparable blood conservation technique, even without accounting for potential benefits of reduced allogenic blood administration. The study may contribute to better understanding and wider acceptance of ANH protocols in high-risk cardiac surgeries.

Intra-operative intravascular effect of the difference in colloid solutions during acute normovolemic hemodilution

Background

Acute normovolemic hemodilution (ANH) is used to reduce the risk of peri-operative allogeneic blood transfusion. Although crystalloid and/or colloid solutions have been used for volume replacement during ANH, no studies have examined the differences among solutions on the volume status, electrolytes, acid-base balance, and hemodynamic status during surgery with ANH.

Methods

We retrospectively compared the effect of Ringer’s lactate with 3% dextran-40 (Saviosol®, DEX group) and 6% hydroxyethyl starch 130/0.4 in 0.9% sodium chloride (Voluven®, HES group) on blood hemoglobin serum electrolytes and estimated blood volume before induction of anesthesia (baseline), after ANH and after blood transfusion following surgery in patients undergoing open gynecological surgery (n = 111 and 67, respectively). The primary outcomes were the changes in hemoglobin and electrolytes after ANH.

Results

There were no differences in hemoglobin or electrolytes between the two groups at baseline. Postoperative hemoglobin was significantly higher (11.0 ± 1.5 g/dL vs 9.9 ± 1.3 g/dL) (mean ± SD) in the DEX group than in the HES group (p = 0.03). Postoperative potassium was significantly decreased from the baseline both in the DEX group (137.9 ± 2.5 mmol/L vs 136.3 ± 2.7 mmol/L) and in the HES group (138.3 ± 2.0 mmol/L vs 137.8 ± 2.5 mmol/L) (p < 0.001 for both); however, it was significantly higher than in the DEX group after surgery (p < 0.001). Estimated blood volume after surgery was significantly increased after ANH in both groups; however, it was larger in the HES group than in the DEX group.

Conclusions

Postoperative hemoglobin and potassium were significantly higher, and estimated blood volume was significantly smaller in the DEX than in the HES group.

Effects of acute normovolemic hemodilution on post-cardiopulmonary bypass coagulation tests and allogeneic blood transfusion in thoracic aortic repair surgery: An observational cohort study

BACKGROUND AND AIM

Perioperative blood transfusion is associated with increased morbidity and mortality. Acute normovolemic hemodilution (ANH) is a blood conservation strategy associated with variable success, and rarely studied in more complex cardiac procedures. The study aim was to evaluate whether ANH improves coagulopathy and reduces blood transfusions in thoracic aortic surgeries.

METHODS

Single-center observational cohort study comparing ANH and standard institutional practice in patients who underwent thoracic aortic repair with cardiopulmonary bypass (CPB) from 2019 to 2021.

RESULTS

A total of 89 patients underwent ANH and 116 standard practice. There were no significant differences between the groups in terms of demographic or major perioperative characteristics. In the ANH group coagulation tests before and after transfusion of autologous blood showed decreased INR and increased platelets, fibrinogen, all with p < 0.0005. Coagulation results in the ANH and control groups were not statistically different. The average number of transfused allogeneic products per patient was lower in the ANH versus control group: FFP 1.1 ± 1.6 versus 1.9 ± 2.3 (p = 0.003), platelets 0.6 ± 0.8 versus 1.2 ± 1.3 (p = 0.0008), and cryoprecipitate 0.3 ± 0.7 versus 0.7 ± 1.1 (p = 0.008). Reduction in red blood cell transfusion was not statistically significant. The percentage of patients who received any transfusion was 53.9% in ANH and 59.5% in the control group (p = 0.42). There was no significant difference in major adverse outcomes.

CONCLUSIONS

ANH is a safe blood conservation strategy for surgical repairs of the thoracic aorta. Laboratory data suggests ANH can improve some coagulation values after separation from CPB, and significantly reduce the number of transfused FFP, platelets and cryoprecipitate.

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.