Laboratory characteristics and clinical utility of post-operative cell salvage: washed or unwashed blood transfusion?

Cell Salvage in Oncological Surgery, Peripartum Haemorrhage and Trauma

Oncological surgery, obstetric haemorrhage and severe trauma are the most challenging conditions for establishing clinical recommendations for the use of cell salvage. When the likelihood of allogeneic transfusion is high, the intraoperative use of this blood-saving technique would be justified, but specific patient selection criteria are needed. The main concerns in the case of oncological surgery are the reinfusion of tumour cells, thereby increasing the risk of metastasis. This threat could be minimized, which may help to rationalize its indication. In severe peripartum haemorrhage, cell salvage has not proven cost-effective, damage control techniques have been developed, and, given the risk of fetomaternal alloimmunization and amniotic fluid embolism, it is increasingly out of use. In trauma, bleeding may originate from multiple sites, coagulopathy may develop, and it should be evaluated whether re-transfusion of autologous blood collected from uncontaminated organ cavities would be feasible. General safety measures include washing recovered blood and its passage through leukocyte depletion filters. To date, no well-defined indications for cell salvage have been established for these pathologies, but with accurate case selection and selective implementation, it could become safe and effective. Randomized clinical trials are urgently needed.

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.

Perioperative blood management strategies for patients undergoing total knee replacement: Where do we stand now?

Total knee replacement (TKR) is one of the most common surgeries over the last decade. Patients undergoing TKR are at high risk for postoperative anemia and furthermore for allogeneic blood transfusions (ABT). Complications associated with ABT including chills, rigor, fever, dyspnea, light-headedness should be early recognized in order to lead to a better prognosis. Therefore, perioperative blood management program should be adopted with main aim to reduce the risk of blood transfusion while maximizing hemoglobin simultaneously. Many blood conservation strategies have been attempted including preoperative autologous blood donation, acute normovolemic haemodilution, autologous blood transfusion, intraoperative cell saver, drain clamping, pneumatic tourniquet application, and the use of tranexamic acid. For practical and clinical reasons we will try to classify these strategies in three main stages/pillars: Pre-operative optimization, intra-operative and post-operative protocols. The aim of this work is review the strategies currently in use and reports our experience regarding the perioperative blood management strategies in TKR.

Postoperative autotransfusion drain after total hip arthroplasty: a meta-analysis of randomized controlled trials

The use of a postoperative autotransfusion drain (PATD) to reduce allogenic blood transfusions in total hip arthroplasty (THA) remains controversial. Therefore, we conducted a meta-analysis to evaluate the efficacy and safety of this technique. Randomized controlled trials (RCTs) were identified from PubMed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL). Thirteen RCTs (1,424 participants) were included in our meta-analysis. The results showed that PATD reduced the rate of allogenic transfusions (RR = 0.56; 95% CI [0.40, 0.77]) and total blood loss (MD = -196.04; 95% CI [-311.01, -81.07]). Haemoglobin (Hb) levels were higher in the PATD group on postoperative day 1 (MD = 0.28; 95% CI [0.06, 0.49]), but no significant differences on postoperative days 2 or 3 (MD = 0.29; 95% CI [-0.02, 0.60]; MD = 0.26; 95% CI [-0.04, 0.56]; respectively). There were no differences in length of hospital stay (MD = -0.18; 95% CI [-0.61, 0.25]), febrile reaction (RR = 1.26; 95% CI [0.95, 1.67]), infection (RR = 0.95; 95% CI [0.54, 1.65]), wound problems (RR = 1.07; 95% CI [0.87, 1.33]), or serious adverse events (RR = 0.59; 95% CI [0.10, 3.58]). Our findings suggest that PATD is effective in reducing the rate of allogenic transfusion. However, the included studies are inadequately powered to conclusively determine the safety of this technique.

Post-traumatic immunosuppression is reversed by anti-coagulated salvaged blood transfusion: deductions from studying immune status after knee arthroplasty

Major trauma increases vulnerability to systemic infections due to poorly defined immunosuppressive mechanisms. It confers no evolutionary advantage. Our objective was to develop better biomarkers of post-traumatic immunosuppression (PTI) and to extend our observation that PTI was reversed by anti-coagulated salvaged blood transfusion, in the knowledge that others have shown that non-anti-coagulated (fibrinolysed) salvaged blood was immunosuppressive. A prospective non-randomized cohort study of patients undergoing primary total knee arthroplasty included 25 who received salvaged blood transfusions collected post-operatively into acid-citrate-dextrose anti-coagulant (ASBT cohort), and 18 non-transfused patients (NSBT cohort). Biomarkers of sterile trauma included haematological values, damage-associated molecular patterns (DAMPs), cytokines and chemokines. Salvaged blood was analysed within 1 and 6 h after commencing collection. Biomarkers were expressed as fold-changes over preoperative values. Certain biomarkers of sterile trauma were common to all 43 patients, including supranormal levels of: interleukin (IL)-6, IL-1-receptor-antagonist, IL-8, heat shock protein-70 and calgranulin-S100-A8/9. Other proinflammatory biomarkers which were subnormal in NSBT became supranormal in ASBT patients, including IL-1β, IL-2, IL-17A, interferon (IFN)-γ, tumour necrosis factor (TNF)-α and annexin-A2. Furthermore, ASBT exhibited subnormal levels of anti-inflammatory biomarkers: IL-4, IL-5, IL-10 and IL-13. Salvaged blood analyses revealed sustained high levels of IL-9, IL-10 and certain DAMPs, including calgranulin-S100-A8/9, alpha-defensin and heat shock proteins 27, 60 and 70. Active synthesis during salvaged blood collection yielded increasingly elevated levels of annexin-A2, IL-1β, Il-1-receptor-antagonist, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IFN-γ, TNF-α, transforming growth factor (TGF)-β1, monocyte chemotactic protein-1 and macrophage inflammatory protein-1α. Elevated levels of high-mobility group-box protein-1 decreased. In conclusion, we demonstrated that anti-coagulated salvaged blood reversed PTI, and was attributed to immune stimulants generated during salvaged blood collection.

The effect of salvaged blood on coagulation function as measured by thromboelastography

BACKGROUND

There is concern that salvaged blood has the potential to activate the coagulation system, which might place patients at risk of thrombotic complications. The aim of this study was to determine whether transfusion of salvaged blood after total knee arthroplasty (TKA) would lead to procoagulopathic changes as measured by thromboelastography (TEG) and furthermore if washing would reduce this risk.

STUDY DESIGN AND METHODS

Twenty-two patients undergoing TKA were enrolled. Control samples were venous blood samples taken before surgery. Test samples were created by mixing the control samples with postoperatively salvaged blood, either washed or unwashed. TEG profiles were measured, noting the time to initiate clotting (R), the time of clot formation (K), the angle of clot formation (α-angle), and the maximum amplitude (clot strength [MA]).

RESULTS

The changes in the coagulation profile from control samples to test samples were consistent for both the washed and the unwashed groups: R time decreased, MA decreased, and K and α-angle remained the same. However, the changes were more pronounced in the unwashed group than the washed group, with a 61% decrease in R time compared with 14%, and a 26% decrease in MA compared with 6%.

CONCLUSION

The addition of salvaged blood to the patient's preoperative blood resulted in decreased MA as well as decreased R time. This suggests that the reinfusion of postoperatively salvaged washed or unwashed blood after TKA favors a change toward a more hypocoagulable state, and washing appears to reduce this effect.

The cost of post-operative shed blood salvage after total knee arthroplasty: an analysis of 1,093 consecutive procedures

BACKGROUND

Requirements for allogeneic red cell transfusion after total knee arthroplasty are still high (20-50%), and salvage and reinfusion of unwashed, filtered post-operative shed blood is an established method for reducing transfusion requirements following this operation. We performed a cost analysis to ascertain whether this alternative is likely to be cost-effective.

MATERIALS AND METHODS

Data from 1,093 consecutive primary total knee arthroplasties, managed with (reinfusion group, n=763) or without reinfusion of unwashed salvaged blood (control group, n=330), were retrospectively reviewed. The costs of low-vacuum drains, shed blood collection canisters (Bellovac ABT, Wellspect HealthCare and ConstaVac CBC II, Stryker), shed blood reinfusion, acquisition and transfusion of allogeneic red cell concentrate, haemoglobin measurements, and prolonged length of hospital stay were used for the blood management cost analysis.

RESULTS

Patients in the reinfusion group received 152±64 mL of red blood cells from postoperatively salvaged blood, without clinically relevant incidents, and showed a lower allogeneic transfusion rate (24.5% vs. 8.5%, for the control and reinfusion groups, respectively; p =0.001). There were no differences in post-operative infection rates. Patients receiving allogeneic transfusions stayed in hospital longer (+1.9 days [95% CI: 1.2 to 2.6]). As reinfusion of unwashed salvaged blood reduced the allogeneic transfusion rate, both reinfusion systems may provide net savings in different cost scenarios (€ 4.6 to € 106/patient for Bellovac ABT, and € -51.9 to € 49.9/patient for ConstaVac CBCII).

DISCUSSION

Return of unwashed salvaged blood after total knee arthroplasty seems to save costs in patients with pre-operative haemoglobin between 12 and 15 g/dL. It is not cost-saving in patients with a pre-operative haemoglobin >15 g/dL, whereas in those with a pre-operative haemoglobin <12 g/dL, although cost-saving, its efficacy could be increased by associating some other blood-saving method.

Washing and filtering of cell-salvaged blood - does it make autotransfusion safer?

Autologous transfusion was first performed in the late 1800s, but it was not until the 1970s that devices were developed that enabled widespread adoption of the practice. Unwashed salvaged blood contains thrombogenic products, cell breakdown products and plasma proteins, and gross chemical, cellular and physical contaminants. Washing and filtering of salvaged blood is routinely performed to remove or reduce these elements. In this paper we review the clinical data supporting the need for washing and filtering of salvaged blood.

A cost study of postoperative cell salvage in the setting of elective primary hip and knee arthroplasty

BACKGROUND

The increasing costs, limited supply, and clinical risks associated with allogeneic blood transfusion have prompted investigation into autologous blood management strategies, such as postoperative red blood cell (RBC) salvage. This study provides a cost comparison of transfusing washed postoperatively salvaged RBCs using an orthopedic perioperative autotransfusion device (OrthoPat, Haemonetics Corporation) versus unwashed shed blood and banked allogeneic blood.

STUDY DESIGN AND METHODS

Cell salvage data were retrospectively reviewed for a sample of 392 patients who underwent primary hip or knee arthroplasty. Mean unit costs were calculated for washed salvaged RBCs, equivalent units of unwashed shed blood, and therapeutically equivalent volumes of allogeneic RBCs.

RESULTS

No initial capital investment was required for the establishment of the postoperative cell salvage program. For patients undergoing total knee arthroplasty (TKA), the mean unit costs for washed postoperatively salvaged cells, unwashed shed blood, and allogeneic banked blood were $758.80, $474.95, and $765.49, respectively. In patients undergoing total hip arthroplasty (THA), the mean unit costs for washed postoperatively salvaged cells, unwashed shed blood, and allogeneic banked blood were $1827.41, $1167.41, and $2609.44, respectively.

CONCLUSION

This analysis suggests that transfusing washed postoperatively salvaged cells using the OrthoPat device is more costly than using unwashed shed blood in both THA and TKA. When compared to allogeneic transfusion, washed postoperatively salvaged cells carry a comparable cost in TKA, but potentially represent a significant savings in patients undergoing THA. Sensitivity analysis suggests that in the case of TKA, however, cost comparability exists within a narrow range of units collected and infused.