Unwashed blood: is widespread use justified? A review of currentknowledgetatm_1162 1..6

MANUEL MUÑOZ*, MD, PhD & ROBERT SLAPPENDEL†, MD, PhD

*GIEMSA, Transfusion Medicine,Facultad de Medicina, Universidad deMálaga, Málaga, Spain;†Amphia Hospital, Breda,The Netherlands

Correspondence to:Prof. M. Muñoz, GIEMSA, TransfusionMedicine, Facultad de Medicina,Universidad de Málaga, 29071 Málaga,SpainE-mail: mmunoz@uma.es

Publication dataReceived: 12 January 2012Accepted: 28 January 2012

Keywords• Costs• Efficacy• Postoperative cell salvage• Safety• Unwashed blood

SUMMARY

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) areassociated with a considerable amount of total blood loss. This results ina significant postoperative decline in hemoglobin levels, and thereby theuse of allogeneic blood transfusion (ABT), which is not a risk-freetherapy. Postoperative shed blood (PSB) salvage and retransfusion, afterwashing or filtering, was introduced as a unique blood saving concept todecrease perioperative blood loss, to maintain higher postoperativehemoglobin levels and to decrease the use of ABT. PSB reinfusion mustbe restricted to elective procedures with an anticipated postoperativeblood loss between 750 mL and 1500 mL, allowing for the recovery of atleast the equivalent of one unit of packed red cells, and used inconjunction with a defined ABT protocol. The results of a number ofclinical and laboratory studies strongly suggest that reinfusion ofunwashed PSB can reduce the requirements for ABT, and that most of thepotential adverse effects of unwashed PSB are no more than theoretical.Therefore, reinfusion of unwashed PSB after THA and TKA is easy-to-use,safe, economic and clinically beneficial, as it may reduce ABT-associatedrisks. The superiority of washed PSB over unwashed PSB in theseprocedures has not been demonstrated. All these make widespread use ofunwashed PSB available for all patients and justified.

INTRODUCT ION

Worldwide, 960,000 total hip and 1,300,000 total kneeprostheses are implanted each year.1,2 Total hiparthroplasty (THA) and total knee arthroplasty (TKA) areassociated with a considerable amount of total bloodloss of 1500 mL on average, from a preoperative bloodvolume of approximately 5000 mL. This results in apostoperative decline in hemoglobin levels of 3.0 to4.0 g/dL from preoperative hemoglobin levels of14.0 g/dL on average,3 and thereby the use of allogeneicblood transfusion (ABT). The knowledge of ABT has also

increased during the last two decades. The transfusion-related risks of ABT encompass infections due tocontaminated blood, incompatibility reactions andeffects on the immune system, such as an increased riskof postoperative infection, delay of wound healing andprolonged hospital stay.4–8

The main reason for using postoperative drains isdiminishing hematoma and compression of vitalstructures. Further, the presence of postoperativehematoma is also related with increased postoperativepain and impaired wound heeling after surgery. Botheffects result in impaired rehabilitation and prolonged

Transfusion Alternatives in Transfusion Medicine TATM

© 2012 The AuthorsTransfusion Alternatives in Transfusion Medicine © 2012 Medical Education Global Solutionsdoi: 10.1111/j.1778-428X.2012.01162.x

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hospital stay. Despite the lack of double-blinded studies,the use of drains after surgery is established andwidespread for decades, but only empirically based.

Using the postoperative shed blood (PSB) forretransfusion was introduced as a unique blood savingconcept to decrease perioperative blood loss, tomaintain higher postoperative hemoglobin levels and todecrease the use of ABT. In this procedure, either bloodfrom a postoperative drain is collected and thenreturned with microaggregate filtering alone or theblood is washed, concentrated, and then returned. Intheory, washed blood may be safer than unwashedblood. This review article is focused on unwashed bloodwith the underlying question: ‘Is widespread use ofunwashed blood justified?’

CL IN ICAL SETT ING OF APPL ICAT ION

The most common practice is to return PSB with simplemicroaggregate filtering within a period of 6 hours aftermajor orthopedic surgery. There is no widespread use inother type of surgeries. However, PSB reinfusion mustbe restricted to elective procedures with an anticipatedpostoperative blood loss between 750 mL and 1500 mL,allowing for the recovery of at least the equivalent ofone unit of packed red cells (e.g. TKA, THA,instrumented spine surgery), and used in conjunctionwith a defined ABT protocol.

In 2005, approximately 320,000 postoperativecollection devices were sold, including products such asthe AutoVac (Boehringer Laboratories Inc., Phoenixville,PA, USA), Orthofuser (Sorin Group Italia, Mirandola,Italy), Hemovac (Zimmer Inc., Dover, OH, USA),Suretrans (Davol Inc., Crauston, RI, USA), Bellovac ABT(AstraTech, Mölndal, Sweden), Constavac CBCII (StrykerCorp., Kalamazoo, MI, USA) and Donor (Van StratenMedical, Nieuwegein, the Netherlands).9 Two surveys inDutch hospitals, in 2002 and 2007, showed an increasein the use of reinfusion shed blood from 10% to nearly60% after major orthopedic surgery. Over the last 10years the number of devices sold in Europe hasincreased progressively, and at least one of them,Bellovac ABT, has surpassed the figure of 1,000,000units (data provided by AstraTech).

THE DEVICE

As mentioned above, there are a lot of devices availablewhich are easy-to-use after surgery. There are low

requirements for personnel training, and for unwashedshed blood there are no sophisticated machinesnecessary in clinical practice. It runs without anyelectricity. This means it can be used quickly and safe inthe operating theatre, the recovery and intensive careward, but also the orthopedic ward. The more transfersbetween wards the more personnel have to be trained.The technique of unwashed cell saving can be installedwhen there is a need and no surgical schedule isdependent or will be delayed. There is also apsychological effect on the patient; he or she actuallysees how own blood is returned to his or her body.Although these are all soft issues which are difficult tostudy, it facilitated the widespread use withoutavoidable incidents in clinical practice.

COSTS

The purchase costs of these devices differ per supplier,per country and the amount delivered. Roughly, we cansay that a reinfusion drainage system is more expensivethan regular drains, but cheaper than the disposable kitsfor cell saver machines and there are no maintenancecosts as compared to washing cell saving machines.Device costs are between €80 and €120 in Spain, and€35–95 in the Netherlands.

The difference in costs between reinfusion drainagesystems and allogeneic blood is more difficult to assess.At first, the purchase price of allogeneic red blood fromthe blood bank differs enormously between countries(Figure 1). The direct and indirect overhead costs ofallogeneic blood are even more complex. For instance,an estimation performed in Sweden comes up to €702for one unit of allogeneic red blood cells.10 In Spain, astudy in orthopedic surgery showed a cost of €321 foreach transfused red cell unit in the base case scenario.11

Similar results found in a more recent study in fourhospitals, overhead costs of allogeneic blood rangedfrom $611 to $1183.12 All extra costs due to risks of ABT(disturbed wound heeling, extra hospital stay) are notincluded in these studies. With an increase of twohospital days after total hip surgery8,13 due to ABT, theprice goes up easily to €1500 or more.

EFF ICACY

There are a number of trials in orthopedic surgeryconcerning reinfusion drainage system. In Table 1, we

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© 2012 The AuthorsTransfusion Alternatives in Transfusion Medicine © 2012 Medical Education Global Solutions • ••, ••–••

try to summarize the results of recent randomizedcontrolled trials regarding the efficacy of PSB reinfusionfor avoiding ABT in the major orthopedic types ofsurgery: elective THA, elective TKA and elective revisionTHA.14–20 Overall, only two randomized controlled trialsfailed to show a positive difference between controlgroup and reinfusion group.17,20

Observational studies are harder to evaluate. Theresults of eight observational studies (2068 patients;� 100 patients per study; 1999–2004) indicate thatpostoperative cell salvage (PCS) with filtered bloodsignificantly reduced the risk of receiving ABT (RR:

0.34; 95% CI: 0.29–0.38), although there was not atransfusion protocol in many of them: a circumstancethat might have influenced the transfusion practice.21

Nevertheless, there is some controversy regarding theefficacy and safety of reinfusion of filtered PSB incomparison to washed PSB. Thomas et al.22 performed arandomized controlled trial of 231 patients undergoingTKA, in which postoperatively drained blood waseither processed and returned using the Cell Saver 5®(Haemonetics Corp., Braintree, MA, USA) or discarded,and a hemoglobin concentration < 9 g/dL was thetransfusion trigger. Only 7% of patients with PCS

price of 1 bag allogenic red cell blood (in euro's)

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Figure 1. Acquisitions cost of onepacked red cell unit in differentcountries worldwide.

Table 1. Effect of reinfusion filtered postoperative salvaged blood on allogeneic blood transfusion (ABT) requirements in majororthopedic surgery

ReferenceNumber ofpatients

Amount of patientsreceiving ABT in thecontrol group

Amount of patientsreceiving ABT in thereinfusion group Difference

Elective total hip arthroplastyMoonen et al.14 83 20.8% 11.4% 9.4%Smith et al.15 158 25.6% 7.9% 17.7%

Elective total knee arthroplastyAmin et al.16 178 15.1% 13.0% 1.9%Moonen et al.14 77 15.6% 2.2% 13.4%Abuzakuk et al.17 104 23.1% 25% -1.9%Zacharopoulos et al.18 60 33.3% 16.7% 16.6%Cheng et al.19 60 38.2% 15.4% 22.8%

Elective revision total hip arthroplastySlappendel et al.20 179 15.9% 9.9% 6%

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received ABT, in comparison with 28% of patients fromthe control group (P < 0.01). However, filtered PSB ismost commonly used after TKA, and in a recentobservational study of 581 patients, in which thetransfusion threshold was also a hemoglobin < 9 g/dL,reinfusion of filtered PSB resulted in a similar reductionof ABT rate with respect to a control group (8.4% vs.30.6%, respectively; P < 0.01),23 suggesting again thatreinfusion of washed or filtered PSB is equallyefficacious. In addition, a prospective randomized studyshowed that for TKA surgery, PCS with filtered blood isas efficacious in reducing ABT as the preoperativedonation of one autologous blood unit.24

COST-EFF ICACY

Cost-efficacy is depending on the number of reinfusedpatients and avoidance of ABT. In this way cost-efficacycan be calculated for every patient in every hospital.Having a reinfusion drainage system for €70, and anallogeneic blood price of €702, there is a cost-efficacywhen the transfusion ratio is going down from 0.70 to0.60 (or 70% to 60%). Taking in account also thetransfusion-related costs, there is already a cost–benefitratio when the transfusion ratio is going down from0.70 to 0.65. Having in mind the transfusion variabilityin elective total hip surgery (range transfusion ratesfrom 14% to 84%),25 there cannot be an overalloutcome regarding cost-efficacy. In this regard, afterstratification of patients by preoperative hemoglobinconcentration, a controlled observational studyincluding 953 TKA patients suggested that those with ahemoglobin concentration between 12 g/dL and 14 g/dLwould benefit most from PSB as a unique blood-conservation technique. This would not be necessary inpatients with hemoglobin greater than 14 g/dL andshould be associated with other blood-saving techniques(e.g. iron, rHuEPO) in patients with a hemoglobinconcentration less than 12 g/dL.26 These results seem toindicate that a careful selection of patients may greatlyincreased the cost-efficacy of the procedure.

SAFETY

PSB has a very variable red blood cell content and maybe contaminated with tissue and chemical debris (fatparticles, free hemoglobin, activated coagulationfactors, fibrin degradation products, activated white

blood cells or inflammatory mediators),27 and someauthors have questioned the quality and safety of thistransfusion product, suggesting that it should be washedprior to be returned to the patient,28,29 even though fewserious side effects have been witnessed after itsreinfusion (e.g. acute cardiorespiratory dysfunction,respiratory distress and upper airway edema).30,31 Besidesthese reported complications, there are numerousclinical studies that seem to support the notion thatreinfusion of unwashed PSB is safe. In an evaluation of1819 patients receiving unwashed PSB after electivelower limb arthroplasty in 38 Dutch hospitals, thefrequency of serious adverse events (0.1%; one patienthad a brief asystole during reinfusion which respondedquickly to medication; and the other, with a history ofdeep vein thrombosis, had pulmonary embolism) andminor adverse events (3.5%, mostly fever or shivering)was similar to that in other smaller clinical studies.32

Nine (0.5%) patients were retransfused with volumesabove 1500 mL, without adverse events. Based on thelow incidence of side effects in this large cohort oforthopedic patients, postoperative PSB after electivearthroplasty is considered to be clinically safe.

In addition, there are a number of laboratory studieson the potential adverse effects of unwashed PSBreinfusion after orthopedic procedures, including renaltoxicity by free hemoglobin, risks of fat embolism,disturbances of hemostasis, and alterations of theinflammatory mediators and immune responses. Theresults of these studies strongly suggest that most ofthese potential adverse effects of PSB are no morethan theoretical (see Muñoz et al.33 for an updatereview). Moreover, unwashed filtered PSB is notimmunologically neutral. Data from previous reportsseem to indicate a positive effect of unwashed PSB oncellular immunity, namely significant increases in theproduction of reactive oxygen species by theneutrophils34 and in natural killer cell precursorfrequency35 in patients who received unwashed PSB. Onthe other hand, co-incubation of postoperative venousblood with unwashed PSB in the presence of endotoxinresulted in a significant depression of tumor necrosisfactor alpha (TNFa) synthesis, without significanteffects on interleukin (IL)-10 synthesis, thus suggestingthat unwashed PSB contains an anti-inflammatoryagent (IL-6).36 May be these findings attribute to theclinical experience of low infection rates afterorthopedic surgery?

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Nevertheless, it seems reasonable to set an upper limiton the volume of unwashed PSB to be reinfused(although the most accepted figure of approximately1000 mL is arbitrary).37 In the search for an alternativesolution to this problem, a validated, simple, low-costprocedure has been developed, for improving andstandardizing the quality of unwashed PSB; thisprocedure exploits a colloid solution in a closed system38

and the ability of colloids to counteract the negativelycharged repulsive forces of red cells, leading to red cellaggregation, rouleaux formation and acceleratedsedimentation, and the consequent upward plasmaflow.39–41 In these experiments, unwashed PSB samples(Hb 10.9 g/dL) were drawn from the reinfusion bag andmixed with a hydroxyethyl starch or gelatin solution(15–30%, colloid volume/total volume). PSB red bloodcells were allowed to settle by gravity for 30 minutes;the supernatant was evacuated and the red blood cellconcentrate analyzed. After colloid treatment, 90% ofred cells were recovered, and the hemoglobin content ofthe PSB was similar to that of leukodepleted packed redcells. In addition, the procedure reduced the amount ofleukocytes (60%), platelets (48%), total protein (76%),cytokines (70–77%) and plasma-free hemoglobin (53%)in the PSB, without major differences between colloids.Therefore, processing PSB with commercially available

colloid solutions might be a feasible, low-costalternative for improving and standardizing the qualityof unwashed PSB prior to returning it to the patient,thus increasing the patient’s safety and allowing theinclusion of this transfusion product in a qualitymanagement program. However, more clinical researchis needed to ascertain the impact of this procedure onpatients’ outcome and whether this method applies tointraoperatively salvaged blood.

CONCLUS ION

Reinfusion of unwashed PSB after orthopedicprocedures is easy-to-use, safe, economic and clinicallybeneficial, as it can reduce the requirements for ABT andthe associated risks of allogeneic blood. The superiorityof washed PSB over unwashed PSB in these procedureshas not been demonstrated. All these make widespreaduse of unwashed PSB available for all patients andjustified. However, although this technique may beeffective on its own in many procedures, the aim ofperforming major surgical procedures without the use ofABT and without placing the patient at risk of anemia-related complications may be better accomplished bycombining several blood-conservation strategies into adefined algorithm.42

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