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

New insights in cardiovascular anesthesia: a dual focus on clinical practice and research

Accumulation of the results of basic and clinical research has advanced the safety and quality of management in cardiovascular anesthesia. To address recent developments in this field, a symposium was held during the 71th Japanese Society of Anesthesiologists annual meetings in 2024, focusing on new advancements in both clinical and basic research in cardiovascular anesthesia. During this symposium, four experts reviewed recent findings in their respective areas of study, covering the following topics: clinical reliability and concerns regarding volatile anesthetics during cardiopulmonary bypass; novel basic and clinical findings regarding the cardioprotective effects of dexmedetomidine; advancements in optimizing blood and hemostasis management during cardiovascular surgery; and innovative strategies for managing postoperative cognitive disorders following cardiovascular and thoracic surgery. Each expert summarized recent novel findings, clinical reliability and concerns, as well as future directions in their respective topics. We believe that this special article provides valuable insights into both clinical practice and basic research in cardiovascular anesthesia while also inspiring anesthesiologists to pursue further research in this field.

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.

Postoperative mortality analysis on nationwide data from diagnosis procedure combination database in Japan

INTRODUCTION

The present study aimed to investigate the postoperative mortality due to all surgeries at the prefectural level using a nationwide diagnosis procedure combination (DPC) database in Japan and to evaluate the data according to temporal changes and regional differences.

METHODS

Data were provided in accordance with the guidelines indicated on the Ministry of Health, Labor and Welfare, Japan. The number of cases and in-hospital mortality were calculated for each representative surgery for each hospitalization according to fiscal year of discharge from 2011 to 2018 and according to prefecture. Values of ≥10 in each aggregated data cell were presented.

RESULTS AND DISCUSSION

The aggregated result data contain 474,154 records, with about 2,000 different surgical codes. More than 10 mortalities were recorded in only 16,890 data cells, which can be used in the mortality analysis. In the analyses of artificial head insertion, cerebral aneurysm neck clipping, coronary artery and aortic bypass grafting, and tracheotomy, regional differences and a declining trend were observed in some categories.

CONCLUSION

In addition to considering categories that can be used in the analysis, careful consideration must be given to the inclusion of background context such as the quality of care.

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.