2011 update to the Society of Thoracic Surgeons and the Society of Cardiovascular Anesthesiologists blood conservation clinical practice guidelines

The Effect of Antifibrinolytic Use on Intraoperative Cell Salvage: Results from a National Registry of Surgical Procedures

Intraoperative cell salvage (ICS) is a critical component of any blood management program involving surgery with a high potential for blood loss. The introduction of antifibrinolytics (AF) may reduce blood loss. The purpose of this study was to evaluate the use of AF on ICS in non-cardiac surgical procedures. Following institutional review board approval, 69,935 consecutive case records between January 2016 and September 2019 from a national registry of adult surgical patients were reviewed. Procedure types were stratified into one of nine surgical categories: general (GN, n = 1,525), neurosurgical (NS, n = 479), obstetric (OB, n = 1,563), cervical spine (CS, n = 2,701), lumbar spine (LS, n = 38,383), hip arthroplasty (HA, n = 13,327), knee arthroplasty (KA, n = 596), vascular (VA, n = 9,845), or orthopedic other (OO, n = 1,516). The primary endpoint was the use of AF with the secondary endpoints ICS shed blood volume and volume available for return. The overall use of AF across all surgical procedures increased from 21.4% in 2016 to 25.4% in 2019. The greatest increases were seen in NS (4.4% to 16.2%), LS (13.7% to 23.1%), and HA (55.8% to 61.9%). For several procedure types, there was an initial increase then either a leveling off or a decline in AF use: OB initially increased from 6.2% to 10.8% in 2018, whereas GN (9.4% to 7.2%) and VA surgery declined slightly (9.9% to 5.7%). When comparing patients who did not receive AF with those who did, there were similar volumes of ICS available for return in all groups, except for LS, GN, and VA, where lower volumes were seen in the No-AF groups. The use of AF has increased each year over the 4-year period in most of the surgical categories, but several have declined. There may be a beneficial effect of AF with lower ICS volumes available for return in a few groups.

Institutional Red Blood Cell Transfusion Rates Are Correlated Following Endovascular and Surgical Cardiovascular Procedures: Evidence That Local Culture Influences Transfusion Decisions

Background

The relationship between local hospital culture and transfusion rates following endovascular and surgical cardiovascular procedures has not been well studied.

Methods and Results

Patients undergoing coronary revascularization, aortic valve replacement, lower extremity peripheral vascular intervention, or carotid artery revascularization from up to 852 US hospitals in the Nationwide Readmissions Database were identified. Crude and risk‐standardized red blood cell transfusion rates were determined for each procedure. Pearson correlation coefficients were calculated between respective procedural transfusion rates. Median odds ratios were estimated to reflect between‐hospital variability in red blood cell transfusion rates following the same procedure for a given patient. There was wide variation in red blood cell transfusion rates across different procedures, from 2% following carotid endarterectomy to 29% following surgical aortic valve replacement. For surgical and endovascular modalities, transfusion rates at the same hospital were highly correlated for aortic valve replacement (r=0.67; P<0.001), moderately correlated for coronary revascularization (r=0.56; P<0.001) and peripheral vascular intervention (r=0.51; P<0.001), and weakly correlated for carotid artery revascularization (r=0.19, P<0.001). Median odds ratios were all >2, highest for coronary artery bypass graft surgery and surgical aortic valve replacement, indicating substantial site variation in transfusion rates.

Conclusions

After adjustment for patient‐related factors, wide variation in red blood cell transfusion rates remained across surgical and endovascular procedures employed for the same cardiovascular condition. Transfusion rates following these procedures are highly correlated at individual hospitals and vary widely across hospitals. In aggregate, these findings suggest that local institutional culture significantly influences the decision to transfuse following invasive cardiovascular procedures and highlight the need for randomized data to inform such decisions.

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.

Analysis of serum tranexamic acid in patients undergoing open heart surgery

BACKGROUND

Tranexamic acid is a drug used during open cardiac surgery to prevent blood loss. The blood levels of 10-100 µg/mL are reported to be in the therapeutic range and higher levels are linked to increased incidence of adverse effects. The aim of this study was to optimize and validate an LC-MS/MS method for serum tranexamic acid and measure its levels in patients from the DEPOSITION Pilot trial in order to prove the concept that topical administration will yield lower serum concentration.

METHODS

The method development was carried out in several steps including sample preparation, and optimization of chromatography and tandem mass spectrometry parameters. Method validation including day-to-day precision with 4 QC levels, limit of detection, sample stability, carryover, and concentration-signal linearity was carried out. Ninety patient samples were analyzed using the validated method.

RESULTS

Fast and efficient LC-MS/MS method for analysis of tranexamic acid in serum was developed. The run time was 7 min with the total time of one hour including the sample preparation. The method precision was acceptable (%CV = 10.5-12.6%) with no sample carryover observed. The matrix effect on the analytical sensitivity was negligible and the lower limit of detection was 0.5 µg/mL. The difference in the mean adjusted concentrations between topical (45 patients) and intravenous (45 patients) groups was statistically significant (0.1154 µg/mL/kg vs. 0.2542 µg/mL/kg, p < 0.0001) CONCLUSIONS: Rapid and simple LC-MS/MS method for analysis of tranexamic acid was optimized and validated. The laboratory has played a crucial role in proving the concept that topical administration yields significantly lower systemic levels of tranexamic acid, and thus decreases the risk of adverse outcomes in patients undergoing open cardiac surgery.

Long-term Impact of Perioperative Red Blood Cell Transfusion on Patients Undergoing Cardiac Surgery

BACKGROUND

There is a known association between need for transfusion and short-term outcomes in patients undergoing cardiac surgery. However long-term data are lacking in the contemporary literature.

METHODS

All patients who underwent open cardiac surgery from 2010 to 2018 were included, except those undergoing transplant, with a ventricular-assist device, and requiring circulatory arrest. Primary outcome included short- and long-term mortality. Secondary outcomes included postoperative complications and hospital readmissions.

RESULTS

The total patient population included 14,281 patients with a median follow-up of 4.03 years (range, 2.25-6.1). Outcomes were stratified into patients with (n = 6239) or without (n = 8042) packed red blood cell (PRBC) use. Patients with PRBC transfusions had significantly (P < .001) worse postoperative outcomes compared with those without PRBC use, including higher operative mortality (6.89% vs 0.98%), return to the operating room (17.8% vs 1.61%), pneumonia (7.84% vs 0.98%), stroke (3.22% vs 1.51%), sepsis (2.66% vs 0.20%), renal failure (8.42% vs 1.12%), and dialysis (5.74% vs 0.42%). On multivariate analysis PRBC transfusion was an independent predictor of mortality (hazard ratio [[HR], 2.39; 95% confidence interval [CI], 2.08-2.64; P < .001) and hospital readmission (HR, 1.15; 95% CI, 1.09-1.21; P < .001). Total units of PRBCs were directly associated with mortality (HR, 1.09; 95% CI, 1.08-1.09; P < .001) and hospital readmissions (HR, 1.02; 95% CI, 1.01-1.03; P < .005).

CONCLUSIONS

Patients with perioperative PRBC transfusions have increased operative and long-term mortality and hospital readmissions. Total units of PRBCs transfused were directly associated with mortality and readmissions.

Functional Testing for Tranexamic Acid Duration of Action Using Modified Viscoelastometry

Introduction

Tranexamic acid (TXA) is the standard medication to prevent or treat hyperfibrinolysis. However, prolonged inhibition of lysis (so-called "fibrinolytic shutdown") correlates with increased mortality. A new viscoelastometric test enables bedside quantification of the antifibrinolytic activity of TXA using tissue plasminogen activator (TPA).

Materials and Methods

Twenty-five cardiac surgery patients were included in this prospective observational study. In vivo, the viscoelastometric TPA test was used to determine lysis time (LT) and maximum lysis (ML) over 96 h after TXA bolus. Additionally, plasma concentrations of TXA and plasminogen activator inhibitor 1 (PAI-1) were measured. Moreover, dose effect curves from the blood of healthy volunteers were performed in vitro. Data are presented as median (25-75th percentile).

Results

In vivo TXA plasma concentration correlated with LT (r = 0.55; p < 0.0001) and ML (r = 0.62; p < 0.0001) at all time points. Lysis was inhibited up to 96 h (LT_TPA-test: baseline: 398 s [229-421 s] vs. at 96 h: 886 s [626-2,175 s]; p = 0.0013). After 24 h, some patients (n = 8) had normalized lysis, but others (n = 17) had strong lysis inhibition (ML <30%; p < 0.001). The high- and low-lysis groups differed regarding kidney function (cystatin C: 1.64 [1.42-2.02] vs. 1.28 [1.01-1.52] mg/L; p = 0.002) in a post hoc analysis. Of note, TXA plasma concentration after 24 h was significantly higher in patients with impaired renal function (9.70 [2.89-13.45] vs.1.41 [1.30-2.34] µg/mL; p < 0.0001). In vitro, TXA concentrations of 10 µg/mL effectively inhibited fibrinolysis in all blood samples.

Conclusions

Determination of antifibrinolytic activity using the TPA test is feasible, and individual fibrinolytic capacity, e.g., in critically ill patients, can potentially be measured. This is of interest since TXA-induced lysis inhibition varies depending on kidney function.

Evaluation of Erythropoietin Stimulating Agents (ESA) and Their Effect on Blood Optimization for Cardiac Surgery

BACKGROUND

Cardiovascular surgeries increase the risk of receiving blood transfusions. Erythropoietin stimulating agents (ESAs) have been used to decrease the transfusion rate. The objective of this study was to evaluate the administration of blood products post-cardiothoracic surgery after receiving ESAs.

METHODS

This is a single-center, retrospective cohort study.

RESULTS

Between May 2017 to May 2018, 52 adult patients underwent cardiac surgery and received ESAs pre-operatively and/or post-operatively. A total of 35 patients were included in the study and 21 (60%) patients did not require a blood transfusion while 14 (40%) patients required a blood transfusion (p = 0.597). The change in hemoglobin (Hgb = 0.773 g/dL, 1.7 g/dL; p = 0.002) and hematocrit (Hct = 2.31%, 4.3%; p = 0.04) was significantly different in patients who received ESAs alone versus ESAs with blood transfusion. Adverse drug reactions showed no significant difference between groups.

CONCLUSIONS

In patients undergoing cardiac surgery, ESAs did not significantly reduce the need for blood transfusion. Future and larger studies are necessary to evaluate the effect of ESAs on blood transfusion.

Cardiopulmonary bypass management and acute kidney injury in 118 Jehovah's Witness patients: a retrospective propensity-matched multicentre cohort from 30,942 patients

INTRODUCTION

Patients refusing blood products in cardiac surgery present challenges for cardiopulmonary bypass. Accurate detail of the modifiable factors of cardiopulmonary bypass relating to acute kidney injury is previously unreported in this patient population.

METHODS

A total of 118 adult Jehovah's Witness patients refusing transfusion were propensity matched to 118 adult patients accepting transfusion from the 30,942 patients in the Australian and New Zealand Collaborative Perfusion Registry. The primary endpoint was acute kidney injury. Intraoperative and bypass management characteristics were also compared between early (2007-2012) and late (2013-2018) cohorts along with the acceptance or refusal of transfusion.

RESULTS

In patients accepting transfusion, 49% received a blood product. In patients refusing transfusion, acute kidney injury was lower (8% vs. 22%; p = 0.003) cell salvage use was higher (70% vs. 22%; p < 0.001), as was use of haemofiltration (8% vs. 4%; p = 0.03) and tranexamic acid in the early period (87% vs. 62%, p = 0.004) but not late (100% vs. 97%; p = 0.15). There was no difference in modifiable cardiopulmonary bypass factors (mean arterial pressure, minimum oxygen delivery (DO2i), retrograde autologous prime, circuit prime volume) between the two groups; however, prime volume decreased and DO2i increased over time for both. Patients refusing transfusion had lower postoperative blood loss (p = 0.02) and shorter postoperative length of stay (p < 0.001) with no difference in morbidity (p = 0.46) or mortality (p = 0.68).

CONCLUSION

Refusal of transfusion in patients undergoing cardiopulmonary bypass was associated with reduced acute kidney injury, hospital stay and postoperative blood loss, while not impacting mortality.

Systematic Review and Meta-Analysis of Diagnostic Test Accuracy Studies Evaluating Point-of-Care Tests of Coagulopathy in Cardiac Surgery

Treatment guidelines recommend the routine use of point-of-care diagnostic tests for coagulopathy in the management of cardiac surgery patients at risk of severe bleeding despite uncertainty as to their diagnostic accuracy. We performed a systematic review and meta-analysis of studies that evaluated the diagnostic accuracy of viscoelastometry, platelet function tests, and modified thromboelastography (TEG) tests, for coagulopathy in cardiac surgery patients. The reference standard included resternotomy for bleeding, transfusion of non-red cell components, or massive transfusion. We searched MEDLINE, EMBASE, CINAHL, and Clinical Trials.gov, from inception to June 2019. Study quality was assessed using QUADAS-2. Bivariate models were used to estimate summary sensitivity and specificity with (95% confidence intervals). All 29 studies (7440 participants) included in the data synthesis evaluated the tests as predictors of bleeding. No study evaluated their role in the management of bleeding. None was at low risk of bias. Four were judged as low concern regarding applicability. Pooled estimates of diagnostic accuracy were; Viscoelastic tests, 12 studies, sensitivity 0.61 (0.44, 0.76), specificity 0.83 (0.70, 0.91) with significant heterogeneity. Platelet function tests, 12 studies, sensitivity 0.63 (0.53, 0.72), specificity 0.75 (0.64, 0.84) with significant heterogeneity. TEG modification tests, 3 studies, sensitivity 0.80 (0.67, 0.89), specificity 0.76 (0.69, 0.82) with no evidence of heterogeneity. Studies reporting the highest values for sensitivity and specificity had important methodological limitations. In conclusion, we did not demonstrate predictive accuracy for commonly used point-of-care devices for coagulopathic bleeding in cardiac surgery. However, the certainty of the evidence was low.

Performance comparison of platelet function analyzers in cardiology patients: VerifyNow and Anysis-200 aspirin assays

BACKGROUND: Analysis of responsiveness to antiplatelet therapy is crucial in the management of patients with cardiovascular diseases. OBJECTIVE: This study aimed to evaluate a new platelet function analysis system (Anysis-200) and to compare it with VerifyNow (Accumetrics, San Diego, CA, USA) in cardiology patients. METHODS: Overall, 125 citrated blood samples were collected from 85 cardiology patients referred for platelet function testing. In Anysis-200, platelet function was measured as blood migration distance (MD) until clogging of flow passage, which is comparable to aspirin resistance units obtained using VerifyNow. The two devices were simultaneously used and compared. RESULTS: The MDs before and after taking aspirin were 175±51 and 247±27 mm, respectively (p < 0.0001). Compared with VerifyNow (reference), the sensitivity and specificity of Anysis-200 was 91.5% and 75.5%, respectively (area under the curve, 0.829). Further, the true positive rate in patients newly taking aspirin was 85% for VerifyNow and 92.5% for Anysis-200, respectively. The Cohen’s kappa coefficient between the two devices was 0.682, indicating a relatively high agreement. CONCLUSIONS: Anysis-200, a novel system for assessing platelet aggregation, has accuracy and precision equivalent to that of, and significant agreement with, VerifyNow. Anysis-200 may be useful in screening patients with abnormal platelet reactivity and aspirin nonresponsiveness.

The effect of transfusion of blood products on ventricular assist device support outcomes

AIMS

Perioperative blood transfusions are common among patients undergoing left ventricular assist device (LVAD) implantation. The association between blood product transfusion at the time of LVAD implantation and mortality has not been described.

METHODS AND RESULTS

This was a retrospective cohort study of all patients who underwent continuous flow LVAD implantation at a single, large, tertiary care, academic centre, from 2008 to 2014. We assessed used of packed red blood cells (pRBCs), platelets, and fresh frozen plasma (FFP). Outcomes of interest included all-cause mortality and acute right ventricular (RV) failure. Standard regression techniques were used to examine the association between blood product exposure and outcomes of interest. A total of 170 patients were included in this study (mean age: 56.5 ± 15.5 years, 79.4% men). Over a median follow-up period of 11.2 months, for every unit of pRBC transfused, the hazard for mortality increased by 4% [hazard ratio (HR) 1.04; 95% CI 1.02-1.07] and odds for acute RV failure increased by 10% (odds ratio 1.10; 95% CI 1.05-1.16). This association persisted for other blood products including platelets (HR for mortality per unit 1.20; 95% CI 1.08-1.32) and FFP (HR for mortality per unit 1.08; 95% CI 1.04-1.12). The most significant predictor of perioperative blood product exposure was a lower pre-implant haemoglobin.

CONCLUSIONS

Perioperative blood transfusions among patients undergoing LVAD implantation were associated with a higher risk for all-cause mortality and acute RV failure. Of all blood products, FFP use was associated with worst outcomes. Future studies are needed to evaluate whether pre-implant interventions, such as intravenous iron supplementation, will improve the outcomes of LVAD candidates by decreasing need for transfusions.

Primary isolated CABG restrictive blood transfusion protocol reduces transfusions and length of stay

BACKGROUND

Cardiac surgery accounts for 10-15% of blood transfusions in the US, despite benefits and calls of limiting its use. We sought to evaluate the impact of a restrictive transfusion protocol on blood use and clinical outcomes in patients undergoing isolated primary coronary artery bypass grafting (CABG).

METHODS

Blood conservation measures, instituted in 2012, include preoperative optimization, intraoperative anesthesia, and pump fluid restriction with retrograde autologous priming and vacuum-assisted drainage, use of aminocaproic acid and cell saver, intra- and postoperative permissive anemia, and administration of iron and low-dose vasopressors if needed. Medical records of patients who underwent isolated primary CABG from 2009 to 2012 (group A; n = 375) and 2013 to 2016 (group B; n = 322) were compared.

RESULTS

CABG with grafting to three or four coronary arteries was performed in 262 (70%) and 222 (69%) patients and bilateral internal thoracic artery grafting in 202 (54%) and 196 (61%) patients in groups A and B, respectively. Mean preoperative and intraoperative hematocrit was 40.3% and 40.7%, 28.9% and 29.4% in groups A and B, respectively. Total blood transfusion was 24% and 6.5%, intraoperative transfusion 11% and 1.2%, and postoperative transfusion 20% and 5.6% (P < .0001 for all) in groups A and B, respectively. Median postoperative length of stay was 5.0 days in group A and 4.5 days in group B (P = .02), with no significant differences in mortality or morbidity.

CONCLUSIONS

A restrictive transfusion protocol reduced blood transfusions and postoperative length of stay without adversely affecting outcomes following isolated primary CABG.

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.

Retrospective Analysis of Thromboelastography-Directed Transfusion in Isolated CABG: Impact on Blood Product Use, Cost, and Outcomes

Cardiac surgeries account for approximately 20% of blood use in the United States. Allogeneic transfusion has been associated with increased risk of morbidity and mortality, further justifying the need to reduce blood use. This study aimed at determining whether a point-of-care coagulation test, thromboelastography (TEG), impacted blood product administration and outcomes. Patients undergoing isolated coronary artery bypass grafting (CABG) were retrospectively reviewed before the use of TEG (2008-2009) (n = 640) and after implementation (2011-2012) (n = 458). Blood product use was compared between time frames. Logistic regression and generalized linear models were created to estimate the impact on outcomes including the reoperation rate, mortality, and cost. The mean use of each blood product was significantly reduced in the perioperative period. Overall blood product use was decreased by over 40%. Mediastinal re-exploration of bleeding was significantly reduced with TEG (4.8 vs. 1.5%). Six-month mortality was not impacted in this cohort nor was the readmission rate or hospital length of stay. However, blood cost and patient charges were significantly lower after TEG was introduced. The use of TEG to guide the administration of blood products during isolated CABG significantly affected the amounts and types of products given intra- and perioperatively. This resulted in less chest tube drainage, fewer returns to the operating room, and more accurate diagnosis of coagulopathic status. Cost savings to the patient and institution were appreciated as a consequence of these improved clinical outcomes.

An In Vitro Pilot Study Comparing the Novel HemoClear Gravity-Driven Microfiltration Cell Salvage System with the Conventional Centrifugal XTRA™ Autotransfusion Device

Background

In 2013, the World Health Organization reported a shortage of 17 million red blood cell units, a number that remains growing. Acts to relieve this shortage have primarily focused on allogeneic blood collection. Nevertheless, autologous transfusion can partially alleviate the current pressure and dependence on blood banking systems. To achieve this, current gold standard autotransfusion devices should be complemented with widely available, cost-efficient, and time-efficient devices. The novel HemoClear cell salvage device (HemoClear BV, Zwolle, Netherlands), a gravity-driven microfilter, potentially is widely employable. We evaluated its performance in the cardiac postoperative setting compared to the centrifugal XTRA™ autotransfusion device.

Methods

In a split-unit study (n = 18), shed blood collected 18 hours after cardiothoracic surgery was divided into two equal volumes. One-half was processed by the XTRA™ device and the other with the HemoClear blood separation system. In this paired set-up, equal washing volumes were used for both methods. Washing effectivity and cellular recovery were determined by measuring of complete blood count, free hemoglobin, complement C3, complement C4, and D-dimer in both concentrate as filtrate. Also, processing times and volumes were evaluated.

Results

The HemoClear and XTRA™ devices showed equal effectiveness in concentrating erythrocytes and leucocytes. Both methods reduced complement C3, complement C4, and D-dimer by ≥90%. The centrifugal device reduced solutes more significantly by up to 99%. Free hemoglobin load was reduced to 12.9% and 15.5% by the XTRA™ and HemoClear, respectively.

Conclusion

The HemoClear device effectively produced washed concentrated red blood cells comparably to the conventional centrifugal XTRA™ autotransfusion device. Although the centrifugal XTRA™ device achieved a significantly higher reduction in contaminants, the HemoClear device achieved acceptable blood quality and seems promising in settings where gold standard cell savers are unaffordable or unpractical.

Blood Loss Kinetics During the First 12 Hours After On-Pump Cardiac Surgical Procedures

BACKGROUND

Anemia and coagulation management and a restrictive transfusion strategy are key points of blood management in patients undergoing cardiac surgical procedures. However, little consideration has been given to the kinetics of postoperative bleeding. This prospective observational study investigated bleeding kinetics from chest tubes to assess whether it was possible to predict, within the early postoperative hours, major bleeding at 12 postoperative hours.

METHODS

Adult cardiac surgical patients who were admitted consecutively to the postoperative intensive care unit in a tertiary academic hospital from January to June 2016 were included. Blood volume was collected from the chest drains, and major bleeding was defined as bleeding exceeding the 90th percentile of the volume distribution at 12 postoperative hours. Receiver operating characteristics curve analysis was performed with hourly bleeding thresholds to determine the best predictor of major bleeding.

RESULTS

In 292 patients, bleeding at 12 postoperative hours ranged from 60 to 2190 mL (median, 350 mL), and 30 patients had major bleeding, with a threshold of 675 mL. Bleeding volume declined logarithmically, 54% [IQR, 45% to 63%] within the first 4 hours. Patients with major bleeding had a higher bleeding volume every hour (P < .004). A good predictive value was observed within the first 2 hours (2.73 mL/kg; receiver operating characteristics area under the curve, 0.87 ± 0.04 [IQR, 0.79 to 0.94]; P< .001).

CONCLUSIONS

The hourly rate of chest tube blood loss seems to be relevant to predict, within the first postoperative hours after cardiac surgical procedures, major bleeding at 12 postoperative hours. Early detection of blood loss may help to improve a patient's blood conservation strategy because it may prompt preemptive treatments.

Vacuum-assisted venous drainage in adult cardiac surgery: a propensity-matched study

OBJECTIVES

Conventional cardiopulmonary bypass with gravity drainage leads inevitably to haemodilution. Vacuum-assisted venous drainage (VAVD) utilizes negative pressure in the venous reservoir, allowing active drainage with a shortened venous line to reduce the priming volume. The goal of this study was to analyse the efficacy and safety of VAVD.

METHODS

Data on 19 687 patients (18 681 with gravity drainage and 1006 with VAVD) who underwent cardiac operations between 1 January 2015 and 31 January 2018 were retrospectively collected from a single centre. Propensity matching identified 1002 matched patient pairs with VAVD and gravity drainage for comparison of blood product transfusion rate, major morbidities and in-hospital mortality rates.

RESULTS

The blood transfusion rate of the VAVD group was lower than that of the gravity drainage group (28.1% vs 35% for red blood cells, 13% vs 18% for fresh frozen plasma and 0.1% vs 1.8% for platelets; P = 0.0009, 0.0020 and <0.0001, respectively). The mean difference (95% confidence interval) between the groups for red blood cells, fresh frozen plasma and platelets was -6.9% (-11.0% to -2.8%), -5.0% (-8.1% to -1.8%) and -1.7% (-2.5% to -0.9%), respectively. No difference was observed regarding the major morbidities of cerebrovascular accidents, acute kidney injury, hepatic failure and perioperative myocardial infarction and the in-hospital deaths between the 2 groups.

CONCLUSIONS

VAVD was associated with a reduction in blood product transfusions, and an increase in the risk of major morbidities and in-hospital deaths of the VAVD group was not observed.

A 0.6-protamine/heparin ratio in cardiac surgery is associated with decreased transfusion of blood products

OBJECTIVES

In cardiac surgery, adequate heparinization is necessary to prevent thrombus formation in the cardiopulmonary bypass (CPB). To counteract the heparin effect after weaning from CPB, protamine is administered. The optimal protamine/heparin ratio is still unknown.

METHODS

In this before-after study, we evaluated the effect of a 0.6/1-protamine/heparin ratio implementation as of May 2017 versus a 0.8/1-protamine/heparin ratio on the 12-h postoperative blood loss and the amount of blood and blood component transfusions (fresh frozen plasma, packed red blood cells, fibrinogen concentrate, platelet concentrate and prothrombin complex concentrate) after cardiac surgery. A total of 2051 patients who underwent cardiac surgery requiring CPB between May 2016 and May 2018 were included.

RESULTS

In the 0.6/1-protamine/heparin ratio group, only 28.8% of the patients received blood component transfusion, compared to 37.9% of the patients in the 0.8/1-ratio group (P < 0.001). The median 12-h postoperative blood loss was 230 ml (interquartile range 140-320) in the 0.6/1-ratio group versus 260 ml (interquartile range 155-365) in the 0.8/1-ratio group (P < 0.001).

CONCLUSIONS

A 0.6/1-protamine/heparin ratio after weaning from CPB is associated with a significantly reduced 12-h postoperative blood loss and blood components transfusion.

Adequacy of hemostatic resuscitation improves therapeutic efficacy of recombinant activated factor VII and reduces reexploration rate for bleeding in postoperative cardiac surgery patients with refractory hemorrhage

Background:

Excessive bleeding and surgical reexploration are common complications that increase the risk of multi-organ failure and prolonged hospitalization after cardiac surgery. Off-label use of recombinant activated factor VII (rFVIIa) is a recommended treatment for refractory bleeding.

Objective:

The objective of the study is to determine if the adequacy of hemostatic resuscitation enhances the efficacy of rFVIIa.

Methods:

This retrospective, observational, cohort study included patients who received rFVIIa for refractory postoperative bleeding after cardiac surgery. Patients were divided into two groups based on the presence or absence of adequate coagulation resuscitation before rFVIIa administration, defined as international ratio (INR) ≤1.5, platelet count ≥100 K/mL, and fibrinogen ≥200 mg/dL. The failure of rFVIIa treatment was defined as surgical reexploration within 24 h, thoracostomy drainage >400 mL/h within 6 h or transfusion of additional blood products or another rFVIIa dose within 6 h after initial rFVIIa dose.

Results:

Of the 3833 patients, screened who underwent cardiothoracic surgery procedures, 58 patients received rFVIIa for refractory postoperative bleeding. Successful hemostasis with rFVIIa was more likely in patients who were adequately resuscitated compared with those who were not (20 [71.4%] vs. 10 [33.3%], respectively; P = 0.0046). Multiple logistic regression analysis indicated that patients who were adequately resuscitated before rFVIIa were less likely to fail treatment (odds ratio, 0.16; 95% confidence interval [0.04–0.62]; P = 0.007).

Conclusions:

The therapeutic efficacy of rFVIIa is dependent on the adequacy of hemostatic resuscitation; restoration of normal serum fibrinogen, INR, and platelet counts >100 K/mL may provide an adequate substrate for rFVIIa to be effective in managing refractory postoperative cardiac surgical bleeding.

Evaluation of Transfusion Practices in Noncardiac Surgeries at High Risk for Red Blood Cell Transfusion: A Retrospective Cohort Study

Perioperative bleeding is a major indication for red blood cell (RBC) transfusion, yet transfusion data in many major noncardiac surgeries are lacking and do not reflect recent blood conservation efforts. We aim to describe transfusion practices in noncardiac surgeries at high risk for RBC transfusion. We completed a retrospective cohort study to evaluate adult patients undergoing major noncardiac surgery at 5 Canadian hospitals between January 2014 and December 2016. We used Canadian Classification of Health Interventions procedure codes within the Discharge Abstract Database, which we linked to transfusion and laboratory databases. We studied all patients undergoing a major noncardiac surgery at ≥5% risk of perioperative RBC transfusion. For each surgery, we characterized the percentage of patients exposed to an RBC transfusion, the mean/median number of RBC units transfused, and platelet and plasma exposure. We identified 85 noncardiac surgeries with an RBC transfusion rate ≥5%, representing 25,607 patient admissions. The baseline RBC transfusion rate was 16%, ranging from 5% to 49% among individual surgeries. Of those transfused, the median (Q1, Q3) number of RBCs transfused was 2 U (1, 3 U); 39% received 1 U RBC, 36% received 2 U RBC, and 8% were transfused ≥5 U RBC. Platelet and plasma transfusions were overall low. In the era of blood conservation, we described transfusion practices in major noncardiac surgeries at high risk for RBC transfusion, which has implications for patient consent, preoperative surgical planning, and blood bank inventory management.

Extravascular Lung Water and Effect on Oxygenation Assessed by Lung Ultrasound in Adult Cardiac Surgery

Introduction

The extravascular lung water content is determined by the use of lung ultrasound (LUS) which is represented as B-lines. The aim of this study was to investigate whether the LUS measurement of extravascular lung water was correlated to changes in oxygenation.

Methods

This prospective cohort study was comprised of 73 patients with an average age of 56 (range: 18 to 87 years) who underwent elective cardiac surgery using cardiopulmonary bypass. The LUS score was performed preoperatively, time zero (T0), at one hour (T1), and at 24 hours (T2) post-surgery. Additionally, arterial oxygen partial pressure and fraction of inspired oxygen (PaO₂/FiO₂) ratio were measured at each time and the time-to-extubation.

Results

A negative correlation was found between the LUS score and PaO₂/FiO₂ at T1 (p < 0.004). Extubation time and changes in the lung ultrasound score at T0 - T2 were positively correlated (p < 0.03). Plus, there was a positive correlation between fluid balance and lung ultrasound score at T2 (p < 0.03).

Conclusion

We found three significant correlations that support the use of LUS in cardiac surgery: 1) the more B-lines, the lower the oxygenation; 2) the more B-lines, the longer the period of ventilation; 3) the more B-lines, the more positive the fluid balance. LUS is a non-invasive bedside investigation that can be used to judge extravascular lung water, providing useful information in the management of patient oxygenation, fluid balance, and extubation.

Building a patient blood management program in a large-volume tertiary hospital setting: Problems and solutions

Successful implementation of a patient blood management program necessitates the collaboration of a strong organization and a multidisciplinary approach. We organized a meeting with broad participation in our center to establish a consensus for implementation of a specific patient blood management program. International and domestic experiences were shared, the importance of coordination and execution of different pillars in patient blood management were discussed, and the problems about the blood transfusion system were also investigated with the proposal for solutions. The data obtained from this meeting are presented to be a guide for similar large-volume tertiary hospitals for integration of a patient blood management protocol.

A Better Predictor of Acute Kidney Injury After Cardiac Surgery: The Largest Area Under the Curve Below the Oxygen Delivery Threshold During Cardiopulmonary Bypass

Background

The aim of this study was to compare the predictive accuracy of acute kidney injury (AKI) after cardiac surgery using cardiopulmonary bypass for the largest area under the curve (AUC) below the oxygen delivery (DO₂) threshold and the cumulative AUC below the DO₂ threshold.

Methods and Results

From March 2017 to October 2019, 202 patients who had undergone cardiac surgery with cardiopulmonary bypass were enrolled. The perfusion parameters were recorded every 20 seconds, and the DO₂ (10×pump flow index [L/min per m²]×[hemoglobin (g/dL)×1.36×arterial oxygen saturation (%)+partial pressure of arterial oxygen (mm Hg)×0.003]) threshold of 300 mL/min per m² was considered to define sufficient DO₂. The nadir DO₂, the cumulative AUC below the DO2300, and the largest AUC below the DO2300 were used to predict the incidence of AKI. Postoperative AKI was observed in 12.4% of patients (25/202). By multivariable analysis, the largest AUC below the DO2300 ≥880 (odds ratio [OR], 4.9; 95% CI, 1.2–21.5 [P=0.022]), preoperative hemoglobin concentration ≤11.6 g/dL (OR, 7.6; 95% CI, 2.0–32.3 [P=0.004]), and red blood cell transfusions during cardiopulmonary bypass ≥2 U (OR, 3.3; 95% CI, 1.0–11.1 [P=0.041]) were detected as independent risk factors for AKI. Receiver operating curve analysis revealed that the largest AUC below the DO2300 was more accurate to predict postoperative AKI compared with the nadir DO₂ and the cumulative AUC below the DO2300 (differences between areas, 0.0691 [P=0.006] and 0.0395 [P=0.001]).

Conclusions

These data suggest that a high AUC below the DO2300 is an important independent risk factor for AKI after cardiopulmonary bypass, which could be considered for risk prediction models of AKI.

Point-of-Care Platelet Function Monitoring: Implications for Patients With Platelet Inhibitors in Cardiac Surgery

Although most physicians are comfortable managing the limited anticoagulant effect of aspirin, the recent administration of potent P2Y₁₂ receptor inhibitors in patients undergoing cardiac surgery remains a dilemma. Guidelines recommend discontinuation of potent P2Y₁₂ inhibitors 5- to- 7 days before surgery to reduce the risk of postoperative hemorrhage. Such a strategy might not be feasible before urgent surgery, due to ongoing myocardial ischemia or in patients at high risk for thromboembolic events. Recently, different point-of-care devices to assess functional platelet quality have become available for clinical use. The aim of this narrative review was to evaluate the implications and potential benefits of platelet function monitoring in guiding perioperative management and therapeutic options in patients treated with antiplatelets, including aspirin or P2Y₁₂ receptor inhibitors, undergoing cardiac surgery. No objective superiority of one point-of-care device over another was found in a large meta-analysis. Their accuracy and reliability are generally limited in the perioperative period. In particular, preoperative platelet function testing has been used to assess platelet contribution to bleeding after cardiac surgery. However, predictive values for postoperative hemorrhage and transfusion requirements are low, and there is a significant variability between and within these tests. Further, platelet function monitoring has been used to optimize the preoperative waiting period after cessation of dual antiplatelet therapy before urgent cardiac surgery. Furthermore, studies assessing their value in therapeutic decisions in bleeding patients after cardiac surgery are scarce. A general and liberal use of perioperative platelet function testing is not yet recommended.

Patient blood management in elective bypass cardiac surgery: A 2-step single-centre interventional trial to analyse the impact of an educational programme and erythropoiesis stimulation on red blood cell transfusion

Anaemia and iron deficiency are frequent in patients scheduled for cardiac surgery. Perioperative patient blood management (PBM) is widely recommended in current practice guidelines. The aim of this protocol is to analyse the effect of a global perioperative PBM programme on the red blood cell (RBC) transfusion ratio, morbidities and rehabilitation score in elective cardiac surgery.

This study is a prospective, single-centre trial with a 2-step protocol, A and B, as follows: A: non-drug intervention: the caregiver is given a blood management educational programme; B: drug intervention: systematic correction of perioperative iron, vitamin deficiencies, and anaemia. This study was designed to enrol 900 patients (500 in group A and 400 in group B) in a rolling period starting at anaesthesia consultation and ending 3 months after surgery. The primary objective was a 20% reduction in RBC transfusion after implementation of PBM programmes (protocol A + B) when compared to our previous transfusion ratio in the first half of 2018 (30.4% vs 38%). The secondary objectives were to evaluate the impact for each step of the study on the RBC transfusion rate, morbidity and the quality of postoperative rehabilitation.

The strength of this study is its evaluation of the effect of a global PBM programme on RBC transfusion in cardiac surgery through a 2-step protocol. We aim to assess for the first time the impact of non-drug and drug interventions on RBC transfusion, comorbidities and delayed rehabilitation parameters.

Trials registrations

ClinicalTrials.gov, NCT04040023: registered 29 July 2019.

Randomized Pilot Trial of Acute Normovolemic Hemodilution in Pediatric Cardiac Surgery Patients

BACKGROUND

Due to the substantial improvement in survival among pediatric patients undergoing congenital heart surgery, reducing early and long-term morbidity is becoming the major focus of care. Blood transfusion is associated with worse postoperative outcomes after cardiac surgery. Acute normovolemic hemodilution (ANH) is a blood conservation strategy that aims to reduce allogenic blood transfusion during cardiac surgery. However, there are scant data regarding its efficacy for pediatric cardiac surgery patients.

METHODS

We designed a single-center, controlled, randomized, pilot trial in patients between 6 and 36 months old undergoing pediatric heart surgery. Patients were equally assigned to undergo ANH prior to initiation of cardiopulmonary bypass or to be managed per usual care. The primary end point was the amount of blood product transfused perioperatively. Secondary end points were markers of morbidity: postoperative bleeding, hematocrit, inotropic agents use, intensive care unit, and hospital stay. The analysis was by intention-to-treat. Estimates of differences between groups are presented with 95% CIs.

RESULTS

Twelve pediatric heart surgery patients were randomized to each group, ANH and usual care. Baseline characteristics were similar between groups. Acute normovolemic hemodilution implementation did not result in a reduction in the administration of blood product transfused (difference between ANH and usual care among patients transfused = -1.4 mL [-29.4 to 26.6], P = .92). Secondary end points were not different between groups.

CONCLUSIONS

In this small trial of pediatric cardiac surgery patients, ANH as a strategy to reduce blood component therapy was safe; however, the study failed to show a reduction in perioperative transfusion or other postoperative outcomes.

Therapeutic potential of fibrinogen γ-chain peptide-coated, ADP-encapsulated liposomes as a haemostatic adjuvant for post-cardiopulmonary bypass coagulopathy

Fibrinogen γ-chain peptide-coated, adenosine 5'-diphosphate (ADP)-encapsulated liposomes (H12-ADP-liposomes) are a potent haemostatic adjuvant to promote platelet thrombi. These liposomes are lipid particles coated with specific binding sites for platelet GPIIb/IIIa and encapsulating ADP. They work at bleeding sites, facilitating haemostasis by promoting aggregation of activated platelets and releasing ADP to strongly activate platelets. In this study, we investigated the therapeutic potential of H12-ADP-liposomes on post-cardiopulmonary bypass (CPB) coagulopathy in a preclinical setting. We created a post-CPB coagulopathy model using male New Zealand White rabbits (body weight, 3 kg). One hour after CPB, subject rabbits were intravenously administered H12-ADP-liposomes with platelet-rich plasma (PRP) collected from donor rabbits (H12-ADP-liposome/PRP group, n = 8) or PRP alone (PRP group, n = 8). Ear bleeding time was greatly reduced for the H12-ADP-liposome/PRP group (263 ± 111 s) compared with the PRP group (441 ± 108 s, p < 0.001). Electron microscopy showed platelet thrombus containing liposomes at the bleeding site in the H12-ADP-liposome/PRP group. However, such liposome-involved platelet thrombi were not observed in the end organs after H12-ADP-liposome administration. These findings suggest that H12-ADP-liposomes could help effectively and safely consolidate platelet haemostasis in post-CPB coagulopathy and may have potential for reducing bleeding complications after cardiovascular surgery with CPB.

Association of Adenosine Diphosphate-Induced Platelet Maximum Amplitude With Postoperative Bleeding and Blood Transfusions in Patients Undergoing Coronary Artery Bypass Grafting

OBJECTIVES

To investigate the association of adenosine diphosphate (ADP)-induced platelet maximum amplitude (MA_ADP) with postoperative bleeding and blood product transfusions in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB).

DESIGN

This single-center observational study recruited 200 patients who underwent elective, first-time, isolated CABG with CPB. A rapid thromboelastography with platelet mapping test was conducted for all patients before the surgery. Patients were categorized by the preoperative MA_ADP into ≤50 mm (MA_ADP ≤50 group [n = 87]) and MA_ADP >50 mm (MA_ADP >50 group [n = 113]). The primary outcome was postoperative bleeding at 6 and 24 hours as measured by chest tube drainage volume. The perioperative blood product transfusions, postoperative complications, postoperative time course, and in-hospital mortality also were evaluated.

SETTING

University hospital.

PARTICIPANTS

Adult patients scheduled to undergo isolated primary CABG with CPB.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The study included 200 patients who underwent CABG with CPB. MA_ADP was >50 mm in 113 (56.5%) patients (MA_ADP >50 group). Compared with the MA_ADP >50 group, the postoperative chest tube drainage volume at 6 and 24 hours was significantly greater in the patients with MA_ADP ≤50 mm (476.90 ± 156.36 mL v 403.36 ± 133.24 mL; p < 0.001 and 935.86 ± 318.43 mL v 667.21 ± 222.75 mL; p < 0.001, respectively). The consumption of blood products in patients with MA_ADP ≤50 mm was significantly more than those with MA_ADP >50 mm. The durations of intensive care unit stay and length of postoperative hospital stay were markedly longer in the MA_ADP ≤50 group than in the MA_ADP >50 group (p = 0.001 and p = 0.005; respectively). There were no significant differences in adverse outcomes between the 2 groups except for the postoperative atrial fibrillation, which occurred more in the MA_ADP ≤50 group than in the MA_ADP >50 group (8.05% v 1.77%; p = 0.043). MA_ADP (area under the receiver operating characteristic curve of 0.767; p < 0.001) was demonstrated to have significant ability to predict bleeding tendency, with a sensitivity of 76.2% and a specificity of 69.0%.

CONCLUSIONS

Preoperative MA_ADP may play a potential role in the prediction of postoperative bleeding and allogeneic blood transfusions and guide clinicians in perioperative management of patients undergoing CABG with CPB.

A review of the management of patients with advanced heart failure in the intensive care unit

Despite progress in the medical and device therapy for heart failure (HF), the prognosis for those with advanced HF remains poor. Acute heart failure (AcHF) is the rapid development of, or worsening of symptoms and signs of HF typically leading to hospitalization. Whilst many HF decompensations are managed at a ward-based level, a proportion of patients require higher acuity care in the intensive care unit (ICU). Admission to ICU is associated with a higher risk of in-hospital mortality, and in those who fail to respond to standard supportive and medical therapy, a proportion maybe suitable for mechanical circulatory support (MCS). The optimal pre-operative management of advanced HF patients awaiting durable MCS or cardiac transplantation (CTx) is vital in improving both short and longer-term outcomes. This review will summarize the clinical assessment, hemodynamic profiling and management of the patient with AcHF in the ICU. The general principles of pre-surgical optimization encompassing individual systems (the kidneys, the liver, blood and glycemic control) will be discussed. Other factors impacting upon post-operative outcomes including nutrition and sarcopenia and pre-surgical skin decolonization have been included. Issues specific to durable MCS including the assessment of the right ventricle and strategies for optimization will also be discussed.

A comprehensive review of topical hemostatic agents: The good, the bad, and the novel

Uncontrolled exsanguination remains the leading cause of death for trauma patients, many of whom die in the pre-hospital setting. Without expedient intervention, trauma-associated hemorrhage induces a host of systemic responses and acute coagulopathy of trauma. For this reason, health care providers and prehospital personal face the challenge of swift and effective hemorrhage control. The utilization of adjuncts to facilitate hemostasis was first recorded in 1886. Commercially available products haves since expanded to include topical hemostats, surgical sealants, and adhesives. The ideal product balances efficacy, with safety practicality and cost-effectiveness. This review of hemostasis provides a guide for successful implementation and simultaneously highlights future opportunities.

Implementation of Perioperative Point-of-Care Platelet Function Analyses Reduces Transfusion Requirements in Cardiac Surgery: A Retrospective Cohort Study

Background Platelet dysfunction is a common cause of bleeding, perioperative blood transfusion, and surgical re-exploration in cardiac surgical patients. We evaluated the effect of incorporating a platelet function analyzer utilizing impedance aggregometry (Multiplate, Roche, Munich, Germany) into our local transfusion algorithm on the rate of platelet transfusion and postoperative blood loss in patients undergoing coronary artery bypass grafting (CABG) surgery.

Methods Data were collected on patients undergoing CABG surgery from January 2015 to April 2017. Patients who underwent surgery before and after introduction of this algorithm were classified into prealgorithm and postalgorithm groups, respectively. The primary outcome was the rate of platelet transfusion before and after implementation of the Multiplate-based transfusion algorithm. Secondary outcomes included transfusion rate of packed red blood cells, postoperative blood loss at 12 and 24 hours, length of stay in the intensive care unit, and the hospital and mortality.

Results A total of 726 patients were included in this analysis with 360 and 366 patients in the pre- and postalgorithm groups, respectively. Transfusion rates of platelets (p = 0.01) and packed red blood cells (p = 0.0004) were significantly lower following introduction of the algorithm in patients (n = 257) who had insufficient time to withhold antiplatelet agents. Receiver operating characteristic curves defined optimal cutoff points of arachidonic acid and adenosine diphosphate assays on the Multiplate to predict future platelet transfusion were 23AU and 43AU, respectively.

Conclusions The introduction of a Multiplate-based platelet transfusion algorithm showed a statistically significant reduction in the administration of platelets to patients undergoing urgent CABG surgery.