Bleeding in Cardiac Surgery: Its Prevention and Treatment—an Evidence-Based Review

A dimensional analysis of experienced intensive care unit nurses' clinical decision-making for bleeding after cardiac surgery

BACKGROUND

Bleeding following cardiac surgery is common and serious, yet a gap persists in understanding how experienced intensive care nurses identify and respond to such complications.

AIM

To describe the clinical decision-making of experienced intensive care unit nurses in addressing bleeding after cardiac surgery.

STUDY DESIGN

This qualitative study adopted the Recognition-Primed Decision Model as its theoretical framework. Thirty-nine experienced nurses from four adult intensive care units participated in semi-structured interviews based on the critical decision method. The interviews explored their clinical judgements and decisions in bleeding situations, and data were analysed through dimensional analysis, an alternative to grounded theory.

RESULTS

Participants maintained consistent vigilance towards post-cardiac surgery bleeding, recognizing it through a haemorrhagic dimension associated with blood loss and chest drainage and a hypovolemic dimension focusing on the repercussions of reduced blood volume. These dimensions organized their understanding of bleeding types (i.e., normal, medical, surgical, tamponade) and necessary actions. Their decision-making encompassed monitoring bleeding, identifying the cause, stopping the bleeding, stabilizing haemodynamic and supporting the patient and family. Participants also adapted their actions to specific circumstances, including local practices, professional autonomy, interprofessional dynamics and resource availability.

CONCLUSIONS

Nurses' decision-making was shaped by their personal attributes, the patient's condition and contextual circumstances, underscoring their expertise and pivotal role in anticipating actions and adapting to diverse conditions. The concept of actionability emerged as the central dimension explaining their decision-making, defined as the capability to implement actions towards specific goals within the possibilities and constraints of a situation.

RELEVANCE TO CLINICAL PRACTICE

This study underscores the need for continual updates to care protocols to align with current evidence and for quality improvement initiatives to close existing practice gaps. Exploring the concept of actionability further, developing adaptability-focused educational programmes, and understanding decision-making intricacies are crucial for informing nursing education and decision-support systems.

Polyphenol-stabilized coacervates for enzyme-triggered drug delivery

Stability issues in membrane-free coacervates have been addressed with coating strategies, but these approaches often compromise the permeability of the coacervate. Here we report a facile approach to maintain both stability and permeability using tannic acid and then demonstrate the value of this approach in enzyme-triggered drug release. First, we develop size-tunable coacervates via self-assembly of heparin glycosaminoglycan with tyrosine and arginine-based peptides. A thrombin-recognition site within the peptide building block results in heparin release upon thrombin proteolysis. Notably, polyphenols are integrated within the nano-coacervates to improve stability in biofluids. Phenolic crosslinking at the liquid-liquid interface enables nano-coacervates to maintain exceptional structural integrity across various environments. We discover a pivotal polyphenol threshold for preserving enzymatic activity alongside enhanced stability. The disassembly rate of the nano-coacervates increases as a function of thrombin activity, thus preventing a coagulation cascade. This polyphenol-based approach not only improves stability but also opens the way for applications in biomedicine, protease sensing, and bio-responsive drug delivery.

Red Blood Cell Transfusion Guided by Hemoglobin Only or Integrating Perfusion Markers in Patients Undergoing Cardiac Surgery: A Systematic Review and Meta-Analysis With Trial Sequential Analysis

OBJECTIVE

Strategies for red blood cell (RBC) transfusion in patients undergoing cardiac surgery have been traditionally anchored to hemoglobin (Hb) targets. A more physiologic approach would consider markers of organ hypoperfusion.

DESIGN

The authors conducted a systematic review and meta-analysis with trial sequential analysis of randomized controlled trials (RCTs).

SETTING

Cardiac surgery.

PARTICIPANTS

Adult patients.

INTERVENTION

RBC transfusion targeting only Hb levels compared with strategies combining Hb values with markers of organ hypoperfusion.

MEASUREMENTS AND MAIN RESULTS

Primary outcomes were the number of RBC units transfused, the number of patients transfused at least once, and the average number of transfusions. Secondary outcomes were postoperative complications, intensive care (ICU) and hospital lengths of stay, and mortality. Only 2 RCTs were included (n = 257 patients), and both used central venous oxygen saturation (ScvO2) as a marker of organ hypoperfusion (cut-off: <70% or ≤65%). A transfusion protocol combining Hb and ScvO2 reduced the overall number of RBC units transfused (risk ratio [RR]: 1.57 [1.33-1.85]; p < 0.0001, I2 = 0%), and the number of patients transfused at least once (RR: 1.33 [1.16-1.53]; p < 0.0001, I2 = 41%), but not the average number of transfusions (mean difference [MD]: 0.18 [-0.11 to 0.47]; p = 0.24, I2 = 66%), with moderate certainty of evidence. Mortality (RR: 1.29, [0.29-5.77]; p = 0.73, I2 = 0%), ICU length-of-stay (MD: -0.06 [-0.58 to 0.46]; p = 0.81, I2 = 0%), hospital length-of-stay (MD: -0.05 [-1.49 to 1.39];p = 0.95, I2 = 0%), and all postoperative complications were not affected.

CONCLUSIONS

In adult patients undergoing cardiac surgery, a restrictive protocol integrating Hb values with a marker of organ hypoperfusion (ScvO2) reduces the number of RBC units transfused and the number of patients transfused at least once without apparent signals of harm. These findings were preliminary and warrant further multicentric research.

Immobilization of blood coagulant factor VII on polycaprolactone membrane through polydopamine grafting

Postoperative bleeding following cardiac surgeries is still an issue that deranges the medical resources and cost. The oral and injection administrations of blood coagulation protein, Factor VII (FVII), is effective to stop the bleeding. However, its short half-life has limited the effectiveness of this treatment and frequent FVII intake may distress the patients. Instead, incorporating FVII into synthetic biodegradable polymers such as polycaprolactone (PCL) that is commonly used in drug delivery applications should provide a solution. Therefore, this study aimed to immobilize FVII on PCL membranes through a cross-linkage polydopamine (PDA) grafting as an intermediate layer. These membranes are intended to provide a solution for cardiac bleeding in coagulating blood and sealing the sutured region. The membranes were evaluated in terms of its physio-chemical properties, thermal behavior, FVII release profile and biocompatibility properties. The ATR-FTIR was used to analyze the chemical functionalities of the membranes. Further validation was done with XPS where the appearances of 0.45 ± 0.06% sulfur composition and C-S peak have confirmed the immobilization of FVII on the PCL membranes. The cross-linked FVIIs were viewed in spherical immobilization on the PCL membranes with a size range between 30 and 210 nm. The surface roughness and hydrophilicity of the membranes were enhanced with a slight shift of melting temperature. The PCL-PDA-FVII0.03 and PCL-PDA-FVII0.05 membranes, with wide area of FVII immobilization released approximately only 22% of FVII into the solution within 60 days period and, it is found that the PCL-PDA-FVIIx membranes projected the Higuchi release model with non-Fickian anomalous transport. While the cytotoxic and hemocompatibility analyses showed advance cell viability, identical coagulation time and low hemolysis ratio on the PCL-PDA-FVIIx membranes. The erythrocytes were viewed in polyhedrocyte coagulated structure under SEM visualization. These results validate the biocompatibility of the membranes and its ability to prolong blood coagulation, thus highlighting its potential application as cardiac bleeding sealant.

Antithrombotic management for Impella® temporary ventricular assist devices: An analysis of an academic health-system experience

The use of acute mechanical circulatory support (MCS) has increased over the last decade. For patients with left-ventricular failure, an Impella^® (Abiomed, Danvers, MA) may be used to improve cardiac output. The purpose of this study is to describe Impella^® anticoagulation patterns and evaluate the safety and effectiveness of our protocol. This is a retrospective review of all adult patients who required at least 24 h of Impella^® support and received a heparin-based purge solution. In total, 109 patients were included in the final analysis. The most common indication for Impella^® device insertion was cardiogenic shock (76%) with the remaining patients receiving a device for a high-risk procedures; typically coronary artery bypass grafting or percutaneous coronary intervention. A total of 9 thrombotic events occurred among 8 (7%) patients and 50 bleeding events occurred among 43 (39%) patients, with the most common classification being BARC 3a (60%). A univariate analysis revealed that patients were more likely to bleed if they were less than 65 years old, had an indication of cardiogenic shock for Impella^®, inserted the device peripherally, were on dual antiplatelet therapy, or had an intra-aortic balloon pump prior to Impella^® insertion, the latter of which was confirmed with a multivariate analysis (OR 2.5 [1.072-5.830]; p = 0.034). For those monitored by anti-Xa, the presence of two or more values greater than 0.40 IU/mL was a risk factor for bleeding (p = 0.037). Our study identifies risk factors for bleeding in patients receiving temporary MCS with an Impella^®.

Effect of changes in cerebral oximeter values during cardiac surgery on the incidence of postoperative neurocognitive deficits (POND): A retrospective study based on propensity score-matched analysis

Objectives

The occurrence of postoperative neurocognitive deficits(POND)after major cardiac surgery is associated with an increase in perioperative mortality and morbidity. Oxidative stress caused by oxygen can affect neuronal damage, which can lead to POND. Whether the intraoperative rSO₂ value reflects oxidative stress and the associated incidence of POND is unknown.

Methods

Among 3482 patients undergoing cardiac surgery, 976 patients were allocated for this retrospective study. Of these, 230 patients (32.5%) were observed to have postoperative neurologic symptoms. After propensity score 1:2 ratio matching, a total of 690 patients were included in the analysis. Recorded data on the occurrence of POND from the postoperative period to predischarge were collected from the electronic records.

Results

The mean baseline rSO₂ value was higher in the POND (–) group than in the POND (+) group. The mean overall minimum rSO₂ value was lower in the POND (+) group (52.2 ± 8.3 vs 48.3 ± 10.5, P < 0.001). The mean overall maximum rSO₂ values were not significantly different between the two groups (72.7 ± 8.3 vs 73.2 ± 9.2, P = 0.526). However, there was a greater increase in the overall maximum rSO₂ values as compared with baseline in the POND (+) group (10.9 ± 8.2 vs 17.9 ± 10.2, P < 0.001). The degree of increase in the maximum rSO2 value was a risk factor affecting the occurrence of POND (adjusted odds ratio, 1.08; 95% confidence interval [CI], 1.04–1.11; P < 0.001). The areas under the receiver-operating characteristic curve for delta values of minimal and maximal compared with baseline values were 0.60 and 0.71, respectively.

Conclusions

Increased cerebral oximeter levels during cardiac surgery may also be a risk factor for POND. This is considered to reflect the possibility of oxidative neuronal damage, and further studies are needed in the future.

A comparison of the in vitro effects of three fibrinogen concentrates on clot strength in blood samples from cardiac surgery patients

BACKGROUND

Fibrinogen concentrate is used clinically to improve hemostasis in bleeding patients. We investigated and compared the efficacy of three commercially available fibrinogen concentrates to improve clot strength in blood samples from cardiac surgery patients.

OBJECTIVES

Postoperative blood samples were collected from 23 cardiac surgery patients. Samples were each divided into four vials, each supplemented with 1.125 mg of fibrinogen of one of three fibrinogen concentrates (RiaSTAP^® , Fibryga^® , FibCLOT^® ), or placebo. The fibrinogen dose corresponded to 2.5 g per 70 kg of body weight. Clot strength after supplementation was assessed in duplicate with rotational thromboelastometry (ROTEM^® ) using FIBTEM maximum clot firmness, EXTEM clot formation time, and maximum clot firmness assays.

RESULTS

In vitro fibrinogen concentrate supplementation of the samples resulted in higher plasma fibrinogen concentrations and improved clot strength with all three concentrates. Supplementation with FibCLOT increased FIBTEM maximum clot firmness (+46% [25th-75th percentile 35-55] compared to placebo) significantly more than did supplementation with Fibryga (+26% [21-35]) and RiaSTAP (+29% [22-47], p < .001). FibCLOT supplementation also shortened EXTEM clot formation time and increased EXTEM maximum clot firmness to a greater extent than did the other concentrates (both p < .001).

CONCLUSIONS

At the selected dose, FibCLOT was more effective than Fibryga and RiaSTAP in restoring clot strength in postoperative blood samples from cardiac surgery patients. These results may have implications for the choice of fibrinogen concentrate and dosing.

Reducing antithrombotic-related bleeding risk in urgent and emergency cardiac surgery

This review focuses on the role of CytoSorb® (CytoSorbents Corporation, Monmouth Junction, New Jersey, USA), a technology for purifying extracorporeal blood. The technology is designed for several indications to prevent bleeding complications during on-pump cardiac surgery, including removal of the antiplatelet agent, ticagrelor, and the oral anticoagulant, rivaroxaban, from the blood. Recent clinical studies are briefly reviewed.

Clinical impact of rotational thromboelastometry in cardiac surgery

Patients undergoing cardiac surgery are at high risk of postoperative bleeding, which is related to worse prognosis and survival. The use of ROTEM®, together with the implementation of a specific treatment algorithm, to reduce the risk of postoperative bleeding. An observational, comparative, cross-case study with historical controls. A total of 1772 consecutive patients admitted to intensive care unit after having undergone cardiac surgery, was divided into 3 groups: Group 1: Coagulation was only monitored by the classical coagulation test (control group). Group 2: Monitorization was done by ROTEM®, according to a protocol designed in our center. Group 3: VerifyNow® was added to ROTEM®, implementing a specific treatment algorithm. We observed a decreased of red blood cell transfusion (Group 1 55.5%, Group 2 52.7%, Group 3 46.6%, P<0.01). Postoperative results include a significant reduction in complications with a marked improvement in overall survival in the ROTEM® - guided groups. Conclusions: Monitoring of hemostasis by POCT'S (ROTEM® and VerifyNow®) in patients undergoing cardiac surgery and cardiac transplantation was associated with a decreased incidence of blood transfusion, postoperative clinical complications, and mortality.

Gelatin and the risk of bleeding after cardiac surgery

BACKGROUND

Gelatins has been used in cardiac surgery because of their ability to preserve intravascular volume better than crystalloids. Unfortunately, gelatin has been associated with impaired coagulation and hemostasis, that may cause increased bleeding. We investigated whether the administration of gelatin increases postoperative bleeding after cardiac surgery.

METHODS

Retrospective, observational single-center cohort study in the intensive care unit of a tertiary teaching hospital. Postoperative bleeding, chest tube drainage volume and consumption of blood products were compared between groups.

RESULTS

Cohort included 3067 consecutive patients who underwent cardiac surgery. First 1698 patients received gelatin (gelatin group), and 1369 patients did not (crystalloid group). The characteristics of the patients in the gelatin and crystalloid groups were comparable. Postoperative chest tube drainage was 18% (95% CI 11%-20%) greater during the first 12 hours (P < .001) and 15% (95% CI 7%-17%) greater during the first 24 hours (P < .001) in the gelatin group compared to the crystalloid group. Severe and massive postoperative bleeding was more common in the gelatin group compared to the crystalloid group (21% vs 16%, P < .001). Patients in the gelatin group received red blood cells (40% vs 20%, P < .001) and platelets (12% vs 8%, P < .001) more frequently than patients in the crystalloid group. However, the number of administered fresh-frozen plasma transfusions did not differ between the groups.

CONCLUSION

Gelatin may increase postoperative bleeding and the need for blood product transfusions after cardiac surgery.

Diagnostic accuracy of viscoelastic point-of-care identification of hypofibrinogenaemia in cardiac surgical patients: A systematic review

Hypofibrinogenaemia during cardiac surgery may increase blood loss and bleeding complications. Viscoelastic point-of-care tests provide more rapid diagnosis than laboratory measurement, allowing earlier treatment. However, their diagnostic test accuracy for hypofibrinogenaemia has never been reviewed systematically. We aimed to systematically review their diagnostic test accuracy for the identification of hypofibrinogenaemia during cardiac surgery. Two reviewers assessed relevant articles from seven electronic databases, extracted data from eligible articles and assessed quality. The primary outcomes were sensitivity, specificity and positive and negative predictive values. A total of 576 articles were screened and 81 full texts were assessed, most of which were clinical agreement or outcome studies. Only 10 diagnostic test accuracy studies were identified and only nine were eligible (ROTEM delta 7; TEG5000 1; TEG6S 1, n = 1820 patients) (ROTEM, TEM International GmbH, Munich, Germany; TEG, Haemonetics, Braintree, MA, USA). None had a low risk of bias. Four ROTEM studies with a fibrinogen threshold less than 1.5–1.6 g/l and FIBTEM threshold A10 less than 7.5–8 mm had point estimates for sensitivity of 0.61–0.88; specificity 0.54–0.94; positive predictive value 0.42–0.70; and negative predictive value 0.74–0.98 (i.e. false positive rate 30%–58%; false negative rate 2%–26%). Two ROTEM studies with higher thresholds for both fibrinogen (<2 g/l) and FIBTEM A10 (<9.5 mm) had similar false positive rates (25%–46%), as did the two TEG studies (15%–48%). This review demonstrates that there have been few diagnostic test accuracy studies of viscoelastic point-of-care identification of hypofibrinogenaemia in cardiac surgical patients. The studies performed so far report false positive rates of up to 58%, but low false negative rates. Further diagnostic test accuracy studies of viscoelastic point-of-care identification of hypofibrinogenaemia are required to guide their better use during cardiac surgery.

Thrombelastometry guided blood-component therapy after cardiac surgery: a randomized study

Background

Significant bleeding is a well known complication after cardiac surgical procedures and is associated with worse outcome. Thrombelastometry (ROTEM®) allows point-of-care testing of the coagulation status but only limited data is available yet. The aim was to evaluate the ROTEM®-guided blood component therapy in a randomized trial.

Methods

In case of significant postoperative bleeding (> 200 ml/h) following elective isolated or combined cardiac surgical procedures (including 14% re-do procedures and 4% requiring circulatory arrest) patients were randomized to either a 4-chamber ROTEM®-guided blood-component transfusion protocol or received treatment guided by an algorithm based on standard coagulation testing (control). One hundred four patients (mean age: 67.2 ± 10.4 years, mean log. EuroSCORE 7.0 ± 8.8%) met the inclusion criteria. Mean CPB-time was 112.1 ± 55.1 min., mean cross-clamp time 72.5 ± 39.9 min.

Results

Baseline demographics were comparable in both groups. Overall there was no significant difference in transfusion requirements regarding red blood cells, platelets, plasma, fibrinogen or pooled factors and the re-thoracotomy rate was comparable (ROTEM®: 29% vs. control: 25%). However, there was a trend towards less 24-h drainage loss visible in the ROTEM®-group (ROTEM®: 1599.1 ± 834.3 ml vs. control: 1867.4 ± 827.4 ml; p = 0.066). In the subgroup of patients with long CPB-times (> 115 min.; n = 55) known to exhibit an increased risk for diffuse coagulopathy ROTEM®-guided treatment resulted in a significantly lower 24-h drainage loss (ROTEM®: 1538.2 ± 806.4 ml vs. control: 2056.8 ± 974.5 ml; p = 0.032) and reduced 5-year mortality (ROTEM®: 0% vs. control: 15%; p = 0.03).

Conclusion

In case of postoperative bleeding following cardiac surgical procedures a treatment algorithm based on “point-of-care” 4-chamber ROTEM® seems to be at least as effective as standard therapy. In patients with long CPB-times ROTEM®-guided treatment may result in less bleeding, a marked reduction in costs and long-term mortality.

Trial registration

German Clinical Trials Register, TRN: DRKS00017367, date of registration: 05.06.2019, ‘retrospectively registered’.

Review of current transfusion therapy and blood banking practices

Transfusion Medicine is a dynamically evolving field. Recent high-quality research has reshaped the paradigms guiding blood transfusion. As increasing evidence supports the benefit of limiting transfusion, guidelines have been developed and disseminated into clinical practice governing optimal transfusion of red cells, platelets, plasma and cryoprecipitate. Concepts ranging from transfusion thresholds to prophylactic use to maximal storage time are addressed in guidelines. Patient blood management programs have developed to implement principles of patient safety through limiting transfusion in clinical practice. Data from National Hemovigilance Surveys showing dramatic declines in blood utilization over the past decade demonstrate the practical uptake of current principles guiding patient safety. In parallel with decreasing use of traditional blood products, the development of new technologies for blood transfusion such as freeze drying and cold storage has accelerated. Approaches to policy decision making to augment blood safety have also changed. Drivers of these changes include a deeper understanding of emerging threats and adverse events based on hemovigilance, and an increasing healthcare system expectation to align blood safety decision making with approaches used in other healthcare disciplines.

Early Outcomes of Low Postoperative Bleeding after Off-Pump Coronary Artery Bypass Grafting

Objective

To investigate whether low bleeding influences the early outcomes after off-pump coronary artery bypass grafting (CABG).

Methods

Retrospective analysis of ischemic heart disease patients who underwent off-pump CABG from January 2013 to December 2017. Patients were divided into low-bleeding group (n=659) and bleeding group (n=270), according to total drainage from chest tube during the first postoperative 12 hours. Clinical material and early outcomes were compared between the groups.

Results

Baseline was similar in the two groups. Operation time was 270±51 min in the low-bleeding group and 235±46 min in the bleeding group (P<0.0001). The low-bleeding group presented smaller drainage during the first 12 h (237±47 ml) and shorter mechanical ventilation time (6.86±3.78 h) than the bleeding group (557±169 ml and 10.66±5.19 h, respectively) (P<0.0001). Hemodynamic status was more stable in the low-bleeding group (P<0.0001) and usage rate of more than two vasoactive agents in this group was lower than in the bleeding group (P<0.0001). Number of distal anastomosis, reoperation for bleeding, suddenly increase in chest tube output, intensive care unit (ICU) stay, hospital stay, and other early outcomes had no statistical significance between the groups (P>0.05).

Conclusion

Postoperative bleeding < 300 ml/12 h in off-pump CABG patients did not require blood product transfusion and reoperation and that would contribute to reduction in mechanical ventilation time and maintaining hemodynamic stability. Bleeding < 800 ml during the first postoperative 12 h did not increase infection rates and ICU length of stay.

The Pathophysiology of Cardiac Surgery-Associated Acute Kidney Injury (CSA-AKI)

Cardiac surgery associated acute kidney injury (CSA-AKI) is a significant clinical problem. Its pathogenesis is complex and multifactorial. It likely involved at least six major injury pathways: exogenous and endogenous toxins, metabolic factors, ischemia and reperfusion, neurohormonal activation, inflammation and oxidative stress. These mechanisms of injury are likely to be active at different times with different intensity and probably act synergistically. Because of such complexity and the small number of randomised controlled investigations in this field only limited recommendations can be made. Nonetheless, it appears important to avoid nephrotoxic drugs and desirable to avoid hyperglycemia in the peri-operative period. The duration of cardiopulmonary bypass should be limited whenever possible. Off-pump surgery, when indicated, may decrease the risk of AKI. Invasive hemodynamic monitoring focussed on attention to maintaining euvolemia, an adequate cardiac output and an adequate arterial blood pressure is desirable. Echocardiography may be useful in minimizing atheroembolic complications. The administration of N-acetylcysteine to protect the kidney from oxidative stress is not recommended. There is marked lack of randomised controlled trials in this field.

[Postoperative excessive blood loss after cardiac surgery can be predicted with International Society on Thrombosis and Hemostasis scoring system]

BACKGROUND AND OBJECTIVE

Prediction of postoperative excessive blood loss is useful for management of Intensive Care Unit after cardiac surgery. The aim of present study was to examine the effectiveness of International Society on Thrombosis and Hemostasis scoring system in patients with cardiac surgery.

METHOD

After obtaining approval from the institutional review board, the medical records of patients undergoing elective cardiac surgery using Cardio-Pulmonary Bypass between March 2010 and February 2014 were retrospectively reviewed. International Society on Thrombosis and Hemostasis score was calculated in intensive care unit and patients were divided with overt disseminated intravascular coagulation group and non-overt disseminated intravascular coagulation group. To evaluate correlation with estimated blood loss, student t-test and correlation analyses were used.

RESULTS

Among 384 patients with cardiac surgery, 70 patients with overt disseminated intravascular coagulation group (n=20) or non-overt disseminated intravascular coagulation group (n=50) were enrolled. Mean disseminated intravascular coagulation scores at intensive care unit admission was 5.35±0.59 (overt disseminated intravascular coagulation group) and 2.66±1.29 (non-overt disseminated intravascular coagulation group) and overt disseminated intravascular coagulation was induced in 29% (20/70). Overt disseminated intravascular coagulation group had much more EBL for 24h (p=0.006) and maintained longer time of intubation time (p=0.005).

CONCLUSION

In spite of limitation of retrospective design, management using International Society on Thrombosis and Hemostasis score in patients after cardiac surgery seems to be helpful for prediction of the post- cardio-pulmonary bypass excessive blood loss and prolonged tracheal intubation duration.

The Role of Platelet Function Analyzer Testing in Cardiac Surgery Transfusion Management

BACKGROUND

Identifying high-risk patients for transfusion after cardiac operations would alter postoperative management. The aim of this study was to investigate closure time (CT) measured by platelet function analyzer (PFA) for prediction of bleeding and transfusions.

METHODS

66 patients were scheduled for coronary artery bypass graft (CABG) surgery and 30 patients for valve repair and replacement (non-CABG). Measurements of PFA-100® CT for collagen and adenosine diphosphate (cADP) and collagen and epinephrine (cEPI) were performed 15 min after protamine administration. Blood loss was measured, and the amount of transfusion products was recorded postoperatively.

RESULTS

The study demonstrated significant differences between CABG patients with cADP-CT ≥ 118 s and those with cADP-CT < 118 s with regard to blood loss for 24 h (p = 0.001) and blood loss for 25-48 h (p = 0.003) as well as fresh frozen plasma (p = 0.015), platelet (p > 0.001) and red blood cell (p = 0.002) units given in 48 postoperative h. There were no differences cardiopulmonary bypass when was applied. In non-CABG patients, there were no differences in blood loss and transfusion requirements with respect to cADP-CT and cEPI-CT.

CONCLUSION

Postoperative platelet dysfunction measured by a prolonged cADP-CT was significant predictor of blood loss and transfusion in CABG patients.

Early postoperative blood pressure and blood loss after cardiac surgery: A retrospective analysis

BACKGROUND

Increased blood loss after cardiac surgery is a risk factor for patient morbidity and mortality. Guidelines for postoperative haemodynamics management recommend normotensive blood pressure to avoid increased chest drain volumes. The aim of this study was to verify the correlation of early postoperative hypertension and blood loss in patients after cardiac surgery during the early postoperative period.

METHODS

Postoperative mean blood pressure values and chest drain volumes of 431 patients were registered by an intensive care monitoring system during first 60minutes after intensive care admission. Correlation between blood pressure and blood loss was calculated by linear regression analysis.

RESULTS

In the entire patient cohort and in various subgroup analyses (body-mass-index, type of surgery, comorbidity, emergency surgery, preoperative anticoagulation therapy) no association between early mean blood pressure >80mmHg and increased blood loss was evident in simple regression analysis. Merely, after aortic surgery a correlation of hypertension and blood loss was found. Multiple regression revealed postoperative INR values >1.5 and thrombocyte counts <100.000/nL to impact blood loss in contrast to postoperative hypertension.

CONCLUSION

Evidence for strict blood pressure management to reduce blood loss after cardiac surgery is scarce. Instead, in face of higher INR and low thrombocytes increasing postoperative blood loss, achieving and maintaining a physiological coagulation is essential.

2015 proceedings of the National Heart, Lung, and Blood Institute's State of the Science in Transfusion Medicine symposium

On March 25 and 26, 2015, the National Heart, Lung, and Blood Institute sponsored a meeting on the State of the Science in Transfusion Medicine on the National Institutes of Health (NIH) campus in Bethesda, Maryland, which was attended by a diverse group of 330 registrants. The meeting's goal was to identify important research questions that could be answered in the next 5 to 10 years and which would have the potential to transform the clinical practice of transfusion medicine. These questions could be addressed by basic, translational, and/or clinical research studies and were focused on four areas: the three "classical" transfusion products (i.e., red blood cells, platelets, and plasma) and blood donor issues. Before the meeting, four working groups, one for each area, prepared five major questions for discussion along with a list of five to 10 additional questions for consideration. At the meeting itself, all of these questions, and others, were discussed in keynote lectures, small-group breakout sessions, and large-group sessions with open discourse involving all meeting attendees. In addition to the final lists of questions, provided herein, the meeting attendees identified multiple overarching, cross-cutting themes that addressed issues common to all four areas; the latter are also provided. It is anticipated that addressing these scientific priorities, with careful attention to the overarching themes, will inform funding priorities developed by the NIH and provide a solid research platform for transforming the future practice of transfusion medicine.

Platelet transfusion: a clinical practice guideline from the AABB

BACKGROUND

The AABB (formerly, the American Association of Blood Banks) developed this guideline on appropriate use of platelet transfusion in adult patients.

METHODS

These guidelines are based on a systematic review of randomized, clinical trials and observational studies (1900 to September 2014) that reported clinical outcomes on patients receiving prophylactic or therapeutic platelet transfusions. An expert panel reviewed the data and developed recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework.

RECOMMENDATION 1

The AABB recommends that platelets should be transfused prophylactically to reduce the risk for spontaneous bleeding in hospitalized adult patients with therapy-induced hypoproliferative thrombocytopenia. The AABB recommends transfusing hospitalized adult patients with a platelet count of 10 × 109 cells/L or less to reduce the risk for spontaneous bleeding. The AABB recommends transfusing up to a single apheresis unit or equivalent. Greater doses are not more effective, and lower doses equal to one half of a standard apheresis unit are equally effective. (Grade: strong recommendation; moderate-quality evidence).

RECOMMENDATION 2

The AABB suggests prophylactic platelet transfusion for patients having elective central venous catheter placement with a platelet count less than 20 × 109 cells/L. (Grade: weak recommendation; low-quality evidence).

RECOMMENDATION 3

The AABB suggests prophylactic platelet transfusion for patients having elective diagnostic lumbar puncture with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence).

RECOMMENDATION 4

The AABB suggests prophylactic platelet transfusion for patients having major elective nonneuraxial surgery with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence).

RECOMMENDATION 5

The AABB recommends against routine prophylactic platelet transfusion for patients who are nonthrombocytopenic and have cardiac surgery with cardiopulmonary bypass. The AABB suggests platelet transfusion for patients having bypass who exhibit perioperative bleeding with thrombocytopenia and/or evidence of platelet dysfunction. (Grade: weak recommendation; very-low-quality evidence).

RECOMMENDATION 6

The AABB cannot recommend for or against platelet transfusion for patients receiving antiplatelet therapy who have intracranial hemorrhage (traumatic or spontaneous). (Grade: uncertain recommendation; very-low-quality evidence).

Thromboelastography is a suboptimal test for determination of the underlying cause of bleeding associated with cardiopulmonary bypass and may not predict a hypercoagulable state

OBJECTIVES

Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) are at risk of bleeding. The goal of this investigation was to compare thromboelastography (TEG) with standard coagulation tests (prothrombin time [PT], partial thromboplastin time [PTT], fibrinogen, and D-dimer) in patients with active bleeding.

METHODS

A retrospective study of patients who underwent cardiac surgery with CPB was performed. A second analysis was performed to determine if a shortened TEG R time is associated with thrombosis.

RESULTS

Paired TEG and standard coagulation tests were available from 21 bleeding patients; of the 15 patients with normal TEG values and three with a shortened R time, all had abnormalities of standard coagulation tests. Eighteen of 67 patients who underwent surgery with CPB had an episode of postoperative bleeding. The TEG R time and coagulation index, PT, and PTT collected after CPB were associated with postoperative bleeding in the univariate analysis, but only PT was independently associated with postoperative bleeding in the multivariate analysis. In the second analysis, three of 38 patients with a normal TEG and four of 43 patients with a shortened R time had a thrombotic event during hospitalization (P = 1.00).

CONCLUSIONS

TEG had limited utility in identifying the underlying cause of bleeding and was not predictive of postoperative bleeding associated with cardiac surgery compared with conventional coagulation tests. A shortened TEG R time may not represent a hypercoagulable state.

Therapeutic options to minimize allogeneic blood transfusions and their adverse effects in cardiac surgery: a systematic review

INTRODUCTION

Allogeneic blood is an exhaustible therapeutic resource. New evidence indicates that blood consumption is excessive and that donations have decreased, resulting in reduced blood supplies worldwide. Blood transfusions are associated with increased morbidity and mortality, as well as higher hospital costs. This makes it necessary to seek out new treatment options. Such options exist but are still virtually unknown and are rarely utilized.

OBJECTIVE

To gather and describe in a systematic, objective, and practical way all clinical and surgical strategies as effective therapeutic options to minimize or avoid allogeneic blood transfusions and their adverse effects in surgical cardiac patients.

METHODS

A bibliographic search was conducted using the MeSH term "Blood Transfusion" and the terms "Cardiac Surgery" and "Blood Management." Studies with titles not directly related to this research or that did not contain information related to it in their abstracts as well as older studies reporting on the same strategies were not included.

RESULTS

Treating anemia and thrombocytopenia, suspending anticoagulants and antiplatelet agents, reducing routine phlebotomies, utilizing less traumatic surgical techniques with moderate hypothermia and hypotension, meticulous hemostasis, use of topical and systemic hemostatic agents, acute normovolemic hemodilution, cell salvage, anemia tolerance (supplementary oxygen and normothermia), as well as various other therapeutic options have proved to be effective strategies for reducing allogeneic blood transfusions.

CONCLUSION

There are a number of clinical and surgical strategies that can be used to optimize erythrocyte mass and coagulation status, minimize blood loss, and improve anemia tolerance. In order to decrease the consumption of blood components, diminish morbidity and mortality, and reduce hospital costs, these treatment strategies should be incorporated into medical practice worldwide.

Mortality risk is dose-dependent on the number of packed red blood cell transfused after coronary artery bypass graft

Introduction

Transfusions of one or more packed red blood cells is a widely strategy used in cardiac surgery, even after several evidences of increased morbidity and mortality. The world's blood shortage is also already evident.

Objective

To assess whether the risk of mortality is dose-de>pendent on the number of packed red blood cells transfused after coronary artery bypass graft.

Methods

Between June 2009 and July 2010, were analyzed 3010 patients: transfused and non-transfused. Transfused patients were divided into six groups according to the number of packed red blood cells received: one, two, three, four, five, six or more units, then we assess the mortality risk in each group after a year of coronary artery bypass graft. To calculate the odds ratio was used the multivariate logistic regression model.

Results

The increasing number of allogeneic packed red blood cells transfused results in an increasing risk of mortality, highlighting a dose-dependent relation. The odds ratio values increase with the increased number of packed red blood cells transfused. The death's gross odds ratio was 1.42 (P=0.165), 1.94 (P=0.005), 4.17; 4.22, 8.70, 33.33 (P<0.001) and the adjusted death's odds ratio was 1.22 (P=0.43), 1.52 (P=0.08); 2.85; 2.86; 4.91 and 17.61 (P<0.001), as they received one, two, three, four, five, six or more packed red blood cells, respectively.

Conclusion

The mortality risk is directly proportional to the number of packed red blood cells transfused in coronary artery bypass graft. The greater the amount of allogeneic blood transfused the greater the risk of mortality. The current transfusion practice needs to be reevaluated.

How do we manage cardiopulmonary bypass coagulopathy?

BACKGROUND

Patients who undergo cardiopulmonary bypass (CPB) are at risk for coagulopathy. Suboptimal turnaround time (TAT) of laboratory coagulation testing results in empiric administration of blood products to treat massive bleeding. We describe our initiative in establishing the coagulation-based hemotherapy (CBH) service, a clinical pathology consultation service that uses rapid TAT coagulation testing and provides comprehensive assessment of bleeding in patients undergoing CPB. A transfusion algorithm that treats the underlying cause of coagulopathy was developed.

STUDY DESIGN AND METHODS

The coagulation testing menu includes all aspects of coagulopathy with close proximity of the laboratory to the operating room to allow for rapid test results. The hemotherapy pathologist monitors laboratory results at several stages in surgery and uses a comprehensive algorithm to monitor a patient's hemostasis. The optimal number and type of blood products are selected when the patient is taken off CPB.

RESULTS

The CBH service was consulted for 44 ventricular assist device implants, 30 heart transplants, and 31 other cardiovascular surgeries from May 2012 through November 2013. The TAT for laboratory tests was 15 minutes for complete blood count, antithrombin, and coagulation panel and 30 minutes for VerifyNow and thromboelastography, in comparison to 45 to 60 minutes in normal settings. The transfusion algorithms were used with optimal administration of blood components with preliminary data suggestive of reduced blood product usage and better patient outcomes.

CONCLUSION

We described the successful introduction of a novel pathology consultation service that uses a rapid TAT coagulation testing menu with transfusion algorithms for improved management of CPB patients.

Successful aortic valve replacement surgery in a patient with severe haemophilia a with low titre inhibitor

In spite of the modern day innovations, managing severe Haemophilia patients with inhibitors continues to be a challenge. The management of patients with severe haemophilia with inhibitors who are undergoing major surgeries like open heart surgery is technically demanding, fraught with peri-operative complications and needs a multidisciplinary approach. We describe a young man with severe haemophilia with low titre inhibitors who underwent a successful open heart surgery and aortic valve replacement, supported only with bolus doses of Factor VIII and tranexamic acid without any complications.

Coagulopathy in the intensive care unit

Coagulopathy is a potential problem for many critically ill patients, placing them at risk for hemorrhage. Critical illness activates both hemostasis and the inflammatory-immune system, leading to both physiological and potentially pathophysiological responses. Following complex surgery or trauma, patients are at high risk for development of problems such as thrombocytopenia and postoperative bleeding, challenging nurses to recognize and manage these problems. The clinical manifestations of coagulopathy may be obvious or occult, and correlation with the coagulation panel results is a complex process. Transfusion of blood and components has long been an important part of patient management, but is known to put patients at risk for transfusion-related complications. Current clinical practice guidelines provide blood conservation strategies and criteria to guide decisions on transfusion therapy.

[Haemorrhage and morbidity associated with the use of tranexamic acid in cardiac surgery: a retrospective, multicentre cohort study]

INTRODUCTION

Postoperative bleeding is common complication, affecting up to 20% of patients, after cardiac bypass surgery. Fibrinolysis is one of the causes of this excessive bleeding, and for this reason the use of tranexamic acid is recommended. The problem with using this is that there are numerous guidelines and differences in the dose to be administered. Our aim was to evaluate whether there were any differences in postoperative bleeding and morbidity after cardiac surgery with the administering of different tranexamic acid doses in three university hospitals.

MATERIAL AND METHODS

A retrospective, multicentre cohort study was conducted. A total of 146 patients who were subjected to elective cardiac bypass surgery according to the anaesthetic-surgical protocol of each hospital were included in the study. The clinical histories were reviewed, and they were divided into two groups according to the tranexamic acid dose: Group A (high doses), initial dose of 20mg/kg and continuous infusion of 4 mg/kg/hour until closure of the sternotomy. A further 100mg was added to prime the bypass machine. Group B (low doses), initial dose of 10mg/kg followed by a continuous infusion of 2mg/kg/hour until closure of the sternotomy. A further 50mg was added to prime the bypass machine. Variables, such as age, sex, weight, height, type of surgical procedure (valvular, coronary or mixed), haematocrit, INR, and preoperative platelet count, time and temperature of the bypass machine, and haematocrit on sternum closure, were recorded. Among the post-operative variables collected were: debit due to drainage at 6, 12 and 24 hours after surgery, number and type of blood products transfused in the first 24 hours, need for further surgery due to haemorrhage, CVA, TIA, or a new acute myocardial infarction, convulsions, and mortality.

RESULTS

The incidence of increased bleeding (patients in the 90 percentile) was higher in Group B at all the study evaluation times (P<.05). The incidence of further surgery due to bleeding, and the need for transfusion of ≥ 3 units of packed red cells was lower in Group A (5.56%) than in Group B (13.89%). There were no significant differences in the requirements for blood products transfusions between the groups. As regards associated morbidity, there was one isolated case of convulsion and a perioperative AMI in another case in Group A, and three cases of perioperative AMI in Group B.

CONCLUSIONS

Elevated doses of tranexamic acid in cardiac bypass surgery appear to significantly reduce bleeding in the first hours after surgery compared to low doses. However, this decrease did not lead to a reduction in the needs for blood products.

Prothrombin complex concentrate (Beriplex P/N) in severe bleeding: experience in a large tertiary hospital

Introduction

Major blood loss can often be life-threatening and is most commonly encountered in the settings of surgery and trauma. Patients receiving anticoagulant therapy are also at increased risk of bleeding. We investigated the use of a prothrombin complex concentrate (PCC; Beriplex P/N, CSL Behring, Marburg, Germany) to treat severe bleeding in a variety of settings: cardiac surgery, warfarin therapy and other surgery.

Methods

Thirty consecutive patients who had received PCC were identified from blood transfusion records. For cardiac surgery and warfarin reversal, PCC was administered in accordance with hospital protocols. PCC was administered to cardiac and other surgical patients responding poorly to recognized blood products, whereas it was administered first-line to patients with life-threatening bleeds and requiring warfarin reversal, in accordance with British Committee for Standards in Haematology guidelines. We conducted a retrospective analysis of patient records in order to ascertain PCC dose, use of other blood products and response to PCC (clotting screen results before and after PCC administration, haemostasis achievement, and survival).

Results

Six patients (20%) were excluded because of inadequate documentation (n = 5) or acquired haemophilia (n = 1). Therefore, 24 patients were included in the analysis: coronary artery bypass graft (n = 5), mitral/aortic valve replacement (n = 2), other surgery (n = 9) and warfarin reversal (n = 8). Most patients (83.3%) received no more than 1500 IU of Beriplex P/N 500. Considerable reduction in administration of other blood products was seen during the 24 hours after PCC administration. Partial or complete haemostasis was achieved in 14 out of 18 cases (77.8%). In total, 12 out of 24 patients (50%) died during the study; two-thirds of the deaths were considered unrelated to bleeding. No thrombotic complications or adverse drug reactions were observed.

Conclusion

This study emphasizes the value of PCC in reversing the effects of oral anticoagulant therapy in bleeding patients. It also demonstrates the potential value of PCC in controlling bleeding in patients undergoing cardiac and other surgical procedures. The use of PCC in bleeding patients without hereditary or anticoagulation-related coagulopathy is novel, and further investigation is warranted. In the future, it may be possible to use PCC as a substitute for fresh frozen plasma in this setting; adequate documentation is crucial for all blood products.

Determinants of complications with recombinant factor VIIa for refractory blood loss in cardiac surgery

PURPOSE

Recombinant factor VIIa (rFVIIa) is being used for refractory, excessive blood loss (EBL) after cardiac surgery, but its safety for this indication is not known.

METHODS

The unadjusted and risk-adjusted adverse event (AE) rates were compared between 114 consecutive cardiac surgical patients who received rFVIIa for refractory EBL and 541 concurrent patients who developed EBL but did not receive rFVIIa. Similarly, timing of rFVIIa therapy was assessed by dichotomizing rFVIIa patients based on median number of red blood cell (RBC) units received before therapy. The measured AE was a composite of death, stroke, renal failure, myocardial infarction, and major vein thrombosis. For risk adjustment, logistic regression models for this outcome were constructed using known predictors of AEs.

RESULTS

The median RBC units transfused before rFVIIa therapy was eight. The AE rates in the untreated, early (< or = 8 U), and late (> 8 U) treated patients were 24% (129/541), 30% (20/66), and 60% (29/48). The risk-adjustment model included total RBC units, pump time, weaning difficulty, gender, weight, and age. The unadjusted and adjusted AE odds ratios (OR) in the treated vs untreated groups were 2.41 [confidence interval (CI) 1.58-3.67; P < 0.0001] and 1.04 (CI 0.60-1.81; P = 0.9). In the rFVIIa group, the adjusted AE OR was lower in the early treated group (OR 0.41; CI 0.18-0.92; P = 0.03).

CONCLUSION

In cardiac surgical patients with refractory hemorrhage, rFVIIa therapy is not associated with increased risk of AEs, and early treatment may be associated with better outcomes.

The effects of a treatment protocol for cardiac surgical patients with excessive blood loss on clinical outcomes

BACKGROUND AND OBJECTIVES

Excessive blood loss (EBL) is a common complication of cardiac surgery that is associated with adverse events. The objective of this before/after study was to determine whether the implementation of a protocol for management of cardiac surgical patients with EBL was associated with improved clinical outcomes.

MATERIALS AND METHODS

In November 2002, a protocol for prompt identification and aggressive management of cardiac surgical patients with EBL was implemented at our institution. The independent relationship between protocol implementation and adverse outcomes was measured by comparing the outcomes of patients who received > or = 4 RBC (red blood cell) units within 1 day of surgery and were operated on before protocol implementation (2000-02) with those operated on after protocol implementation (2003-05), using multivariable logistic regression analysis to control for the effects of confounders. The primary outcome was a composite of adverse events that included death, renal failure, stroke, and sepsis. Bootstrapping was used to confirm the validity of the results.

RESULTS

Of the 11,314 patients who underwent surgery during the study period, 1875 (16.6%) received > or = 4 RBC units within 1 day of surgery, with 958 and 917 in the pre- and postprotocol periods, respectively. The composite adverse outcome occurred in 164 (17.1%) patients in the preprotocol period and 115 (12.5%) patients in the postprotocol period (P = 0.005). Protocol implementation was independently associated with reduced odds of the composite adverse outcome (odds ratio 0.67; 95% confidence interval 0.50, 0.91; P = 0.01). This estimate was stable in bootstrap sampling.

CONCLUSION

Implementation of a protocol to manage EBL in cardiac surgery was independently associated with improved outcomes.

Prediction of massive blood transfusion in cardiac surgery

PURPOSE

In cardiac surgery with cardiopulmonary bypass (CPB), excessive blood loss requiring the transfusion of multiple red blood cell (RBC) units is a common complication that is associated with significant morbidity and mortality. The objective of this study was to develop a prediction rule for massive blood transfusion (MBT) that could be used to optimize the management of, and research on, at-risk patients.

METHODS

Data were collected prospectively over the period from 2000 to 2005, on patients who underwent surgery with CPB at one hospital. Patients who received > or = five units of RBC within one day of surgery were classified as MBT. Logistic regression was used to appropriately select and weigh perioperative variables in the prediction rule, which was developed on the initial 60% of the sample and validated on the remaining 40%.

RESULTS

Of the 10,667 patients included, 925 (8.7%) had MBT. The clinical prediction rule included 12 variables (listed in order of predictive value: CPB duration, preoperative hemoglobin concentration, body surface area, nadir CPB hematocrit, previous sternotomy, preoperative shock, preoperative platelet count, urgency of surgery, age, surgeon, deep hypothermic circulatory arrest, and type of procedure) and was highly discriminative (c-index = 0.88). In the validation set, those classified as low-, moderate-, and high-risk by a simple risk score derived from the prediction rule had a 5%, 27%, and 58% chance of MBT, respectively.

CONCLUSION

A clinical prediction rule was developed that accurately identified patients at low-risk or high-risk for MBT. Studies are needed to determine the external generalizability and clinical utility of the prediction rule.