Blood salvage with a continuous autotransfusion system compared with a haemofiltration system

Comparison of Washing Efficiency and Recovery of Blood Cells Between Centrifugation, Coarse Filtration and Microfiltration Techniques to Prepare Autologous Blood for Transfusion

Purpose

Cell salvage is the process by which blood lost in surgery is collected and washed or filtered to produce autologous blood for re-transfusion to the patient. Cell salvage aims to reduce the need for donor blood. Centrifugal cell salvage washing technique is a preferred medical treatment in order to retain lost red blood cells (RBCs) without contaminants. Although this technology very efficiently collects and washes shed blood, it is costly and often impractical or unavailable, especially in middle- or low-income countries. This study assessed two innovative filter devices as an alternative to centrifugal cell salvage technology: a coarse collection filter device (Hemafuse) and a microfiltration device (HemoClear). In contrast to centrifugal technology, both filter devices do not require electricity, nor costly equipment and extensive training. We compared the effectiveness of these filtration technologies to remove plasma constituents and recover and concentrate the cellular components with centrifugal technology (autoLog^® device).

Methods

Whole blood was processed with each technology according to the device manufacturer’s instructions. Before and after processing, the blood products were analyzed for supernatant solutes and cellular composition.

Results

The centrifugal technology confirmed its efficacy to remove potentially harmful solutes and capture red blood cells. The microfiltration technology (HemoClear) reached comparable levels of removal of solutes, with a potential advantage over centrifugal technology in the ability to also recover platelets. The coarse filtration technology (Hemafuse) had no washing capacity but, like the microfiltration technology, has the advantage of recovering platelets.

Conclusion

Innovative filtration devices represent an alternative to centrifugal technology in the preparation of autologous blood for reinfusion. The HemoClear technology for the first time enables the recovery of washed platelets and red blood cells. Clinical trials will have to be performed to investigate the clinical value of this new autologous blood product.

The effect of a viscoelastic-guided bleeding algorithm implementation on blood products use in adult liver transplant patients. A propensity score-matched before-after study

BACKGROUND

Perioperative blood products transfusion is correlated with increased morbidity and mortality in liver transplantation (LTx). The objectives of our study are to assess the effect of a standardized viscoelastic test (VET)-guided bleeding management algorithm implementation on intraoperative bleeding, allogenic blood products and factor concentrates requirements and on early postoperative complications in LTx.

METHODS

Retrospective before-after study comparing two matched cohorts of patients undergoing LTx before (control cohort) and after (intervention cohort) the implementation of a VET-based bleeding algorithm in a single center academic hospital.

RESULTS

After propensity score matching, we included 94 patients in each cohort. Patients in intervention cohort received significantly less blood products, fresh frozen plasma (FFP), and cryoprecipitate (p < 0.001 for each), while the amount of fibrinogen concentrate used was significantly higher (p < 0.001). Postoperatively, intervention cohort patients had significantly lower postoperative hemoglobin and fibrinogen levels and longer prothrombin time compared to control cohort. There were no significant differences in red blood cells transfusions, intraoperative bleeding, early postoperative complications, and short term survival.

CONCLUSIONS

The implementation of a VET-guided bleeding algorithm decreases allogenic blood products requirements, mainly FFP use and allows a more restrictive management of coagulopathy in patients with chronic liver disease undergoing LTx.

A comparison of haemostatic biomarkers during low-risk patients undergoing cardiopulmonary bypass using either conventional centrifugal cell salvage or the HemoSep device

BACKGROUND

Cardiac surgery using cardiopulmonary bypass (CPB) is associated with a coagulopathy due to haemodilution, thrombocytopenia and platelet dysfunction and the activation of coagulation and fibrinolysis, despite the use of large doses of unfractionated heparin. Conventional red cell salvage may exacerbate post-operative bleeding as plasma containing haemostatic factors is discarded. We hypothesized that a novel cell salvage device (HemoSep) may attenuate haemostatic changes associated with red cell salvage. We studied haemostatic markers following autologous transfusion from conventional cell salvage or the HemoSep device.

METHODS

This randomised, controlled trial compared haemostatic markers in patients undergoing coronary artery bypass grafting or aortic valve replacement who received autologous blood returned from cell salvage (control) or HemoSep (study). Blood samples were taken pre-operatively, end of CPB, post-transfusion of salvaged blood and 3 hours post-operatively and analysed for full blood count (FBC), prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, D-dimer and endogenous thrombin potential (ETP).

RESULTS

Fifty-four patients were recruited (n=28 control, n=26 study). Processed blood volume for transfusion was significantly (p<0.001) higher in the HemoSep group. In the HemoSep group, the PT was shorter (18.7±0.3 vs 19.9±0.3 sec; p<0.05) post-operatively and the aPTT was longer (48.6±3.8 vs 37.3±1.0 sec; p<0.01) following autologous transfusion. In the control group, D-dimer and ETP levels were higher (1903±424 vs.1088±151; p<0.05 and 739±46 vs. 394±60; p<0.001, respectively) following autologous transfusion.

CONCLUSIONS

Although centrifuged cell salvage is known to adequately haemoconcentrate and remove unwanted substrates and bacteriological contamination, the process can exacerbate coagulopathy. The HemoSep device demonstrated some increase in haemostatic markers when used in low-risk cardiac surgery patients.

Dialyzer-based cell salvage system: a superior alternative to conventional cell salvage in off-pump coronary artery bypass grafting

Objectives

Our goal was to test the hypothesis that the use of a dialyzer-based cell salvage system during off-pump coronary artery bypass grafting (OPCABG) reduces requirements for homologous blood transfusions (HBT) and improves postoperative haemtochemical parameters.

Methods

Data were prospectively collected for 222 patients who had OPCABG using 3 different cell salvage techniques: (1) dialyzer-based cell salvage (DBCS) ( n  = 75), (2) conventional cell salvage (CCS) ( n  = 73) and (3) without cell salvage (WCS) ( n  = 74). Salvaged blood was transfused at the end of the operation. The primary outcome of the study was the amount of homologous blood transfused. Secondary outcomes were changes in haemtochemical parameters, postoperative bleeding, need for non-invasive ventilation (NIV), postoperative complications, renal dysfunction, clotting derangement, duration of intensive care unit (ICU) and hospital stay and mortality rates.

Results

There were no deaths. In patients with >1000 ml blood loss, there was a significant reduction in HBT in the DBCS group (300 ± 161 ml) compared with the WCS group (550 ± 85 ml) ( P  <   0.0001). Postoperative changes in haemtochemical parameters were significantly fewer in the DBCS group compared with the other 2 groups. The incidence of NIV ( P  =   0.002), renal dysfunction ( P  =   0.009) and postoperative complications ( P  =   0.003) was least in the DBCS group and highest in the WCS group. Mean ICU stays were comparable ( P  =   0.208); however, the mean hospital stay was significantly shorter in the DBCS group (6.08 ± 3.12 days) compared with the WCS group (7.54 ± 4.46 days) ( P  =   0.022). There was no significant increase in coagulopathy in any group as suggested by comparable chest tube drainage ( P  =   0.285) and comparable prothrombin time.

Conclusions

The use of the DBCS system in OPCABG resulted in a significant reduction in HBT, improvement in postoperative levels of haemoglobin, platelets and albumin and reduction in complications without increased risk of coagulopathy.

Pretransfusion Comparison of Dialyser-Based Hemoconcentrator With Cell Saver System for Perioperative Cell Salvage

OBJECTIVE

Cell Saver system is the method of choice for red blood cell salvage from the surgical field; however, cost is a limiting factor. We at our institute have devised a cost-effective version of dialyser-based autotransfusion system. We performed pretransfusion comparison of our autotransfusion system with conventional cell saver system.

METHODS

A prospective randomized observational study was performed in 104 consecutive patients with coronary artery disease undergoing by off-pump coronary artery bypass grafting. Patients were divided into two groups. In the dialyser group (53 patients), blood from surgical field was salvaged by our dialyser-based system. In the cell saver group (51 patients), blood was salvaged by cell saver. In both groups, 20-mL sample from the salvaged blood was analyzed for hemoglobin, platelets, protein, albumin, free hemoglobin, osmotic fragility, and peripheral blood smear examination.

RESULTS

Total hemoglobin salvaged was comparable in both groups (85% vs 76%). On peripheral smear, red blood cells were swollen, but morphology was preserved. Moreover, normal osmotic fragility suggested absence of any lethal damage to red blood cells in either group. Dialyser-based system was more efficient in salvaging platelets (42.9% vs 6%), proteins (79.2% vs 0%), and albumin (65% vs 0%). Total free hemoglobin was three times more in dialyser group but was well below recommended limits.

CONCLUSIONS

Dialyser-based system is economical, is equally efficacious in salvaging red blood cells, is more effective in salvaging platelets and proteins, and does not contain significant amount of free hemoglobin. Therefore, this salvaged blood can be safely transfused.

Cardiac surgery-associated acute kidney injury

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common and serious postoperative complication of cardiac surgery requiring cardiopulmonary bypass (CPB), and it is the second most common cause of AKI in the intensive care unit. Although the complication has been associated with the use of CPB, the etiology is likely multifactorial and related to intraoperative and early postoperative management including pharmacologic therapy. To date, very little evidence from randomized trials supporting specific interventions to protect from or prevent AKI in broad cardiac surgery populations has been found. The definition of AKI employed by investigators influences not only the incidence of CSA-AKI, but also the identification of risk variables. The advent of novel biomarkers of kidney injury has the potential to facilitate the subclinical diagnosis of CSA-AKI, the assessment of its severity and prognosis, and the early institution of interventions to prevent or reduce kidney damage. Further studies are needed to determine how to optimize cardiac surgical procedures, CPB parameters, and intraoperative and early postoperative blood pressure and renal blood flow to reduce the risk of CSA-AKI. No pharmacologic strategy has demonstrated clear efficacy in the prevention of CSA-AKI; however, some agents, such as the natriuretic peptide nesiritide and the dopamine agonist fenoldopam, have shown promising results in renoprotection. It remains unclear whether CSA-AKI patients can benefit from the early institution of such pharmacologic agents or the early initiation of renal replacement therapy.

Blood-saving techniques

Major surgery is associated with intraoperative and postoperative bleeding, generally treated with homologous blood transfusions, which carry the risk of infection, allergic reactions, or incompatibility as well as a number of organizational and economic problems. Transfusion strategies and steps to minimize perioperative bleeding are needed. Another resource is drugs; human recombinant erythropoietin, aprotinin, and some analogues of lysine have been used to reduce the rate of allogenic transfusions in the perioperative period. The safest method is autologous blood transfusions through predeposits and hemodilution; however, it can only be used for elective surgery. Autologous transfusion techniques include blood collection, both intraoperatively, as described by Orr, and postoperatively, as introduced by Borghi in 1984, which enables the continuous monitoring of postoperative bleeding. Blood collection can also be performed during emergency surgery, reducing the rate and costs of homologous transfusions.