The Spine Journal 12 (2012) 463–465

Commentary

Commentary: True blood—changes in blood management in pediatricdeformity surgery

Meghan N. Imrie, MD*Department of Orthopaedics, Lucile Packard Children’s Hospital at Stanford University, 300 Pasteur Dr, Edwards Building R105, Stanford, CA 94305, USA

Received 20 June 2012; accepted 21 June 2012

COMMENTARY ON: Long TR, Stans AA, Sh

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Author disclosure

* Corresponding a

Children’s Hospital at

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http://dx.doi.org/10.10

aughnessyWJ, et al. Changes in red blood cell trans-fusion practice during the past quarter century: a retrospective analysis of pediatric patients undergo-ing elective scoliosis surgery using the Mayo database. Spine J 2012;12:455–62 (in this issue).

Since the first successful animal-to-animal blood trans-fusion by the physician Richard Lower in 1665 and the firstsuccessful human blood transfusion for postpartum hemor-rhage by James Blundell in 1818 [1], the role of red bloodcell (RBC) transfusion has been continually evolving. Thismonth’s study by Long et al. [2] reviews changes in trans-fusion practice in pediatric patients undergoing electivescoliosis surgery at the Mayo clinic over a 25-year epoch.

In the early to mid-1900s, numerous advances made theuse of RBC transfusion increasingly safe, including the de-velopment of blood typing and crossmatching, better pro-cessing, preservation, and storage of blood, and thefounding and organization of blood collection programsthrough the Red Cross. The overall safety and availabilityof allogeneic blood allowed for significant advances in med-icine and surgery. However, starting with the discovery ofhuman immunodeficiency virus (HIV) and AIDS in themid-1980s, the absolute safety of allogeneic transfusionstarted to be called in to question, and there has been a generaltrend towardminimizing or avoiding transfusion over the last20 years [3]. The main risks/complications of blood transfu-sion fall into either infectious or noninfectious categories.Since the Red Cross began testing blood for HIV antibodiesin 1985 [1], the use of stringent banking protocols has re-sulted in extremely low rates of infection; however, the trans-mission of a viral, bacterial, protozoan, or fungal infectionremains a possibility. There have been isolated reports

ticle: 10.1016/j.spinee.2012.03.032.

status: Not applicable.

s: MNI: Nothing to disclose.

uthor. Department of Orthopaedics, Lucile Packard

Stanford University, 300 Pasteur Dr, Edwards Build-

A 94305, USA. Tel.: (650) 723-5243.

nimrie@stanford.edu (M.N. Imrie)

nt matter � 2012 Elsevier Inc. All rights reserved.

16/j.spinee.2012.06.013

of transfusion-related parasitic infections, a variant ofCreutzfeldt-Jakob disease, and 23 of the 4,000 known casesof West Nile viral encephalopathy during the 2002 US epi-demic were thought to be related to transfusion [3]. However,cytomegalovirus is thought to pose the greatest infectiousthreat as 40% of blood donors have been infected with cyto-megalovirus at some point, and although this is well toleratedin immunocompetent patients, it can be devastating in theimmunocompromised and neonatal populations [3]. Finally,the risk of death from bacterial transmission is reported tobe one in eight million units of packed RBCs transfused—

extremely low, almost zero, but not quite. The present studycompares groups from two time periods, which were chosento represent their transfusion practices both immediately be-fore the AIDS era and immediately after widespread aware-ness of transfusion-relatedHIV transmission—a reflection ofhow the possibility of infection transmission through alloge-neic blood products may influence transfusion practices.

Although less sensational than infection transmission, thenoninfectious complications of transfusion have also influ-enced utilization of allogeneic blood andmaymore routinelyaffect transfusion thresholds. These include febrile nonhe-molytic transfusion reaction, acute hemolytic transfusion re-actions to ABO incompatibility, volume overload, metabolicabnormalities like transient hypocalcemia, and coagulationdefects, especially if clotting factors are not replaced in con-junction with massive RBC transfusions [3]. Additionally,blood transfusions can lead to immunosuppression and an in-creased risk of nosocomial infection and multiple organ dys-function in critically ill patients [3]. Finally, we are learningmore about transfusion-related acute lung injury, the acutelung injury temporally related to blood product transfusionwhose incidence is estimated at one in every 5,000 transfu-sions [3]. Finally, although not a complication, the relative

464 M.N. Imrie / The Spine Journal 12 (2012) 463–465

scarcity of blood products is important to keep in mind—

allogeneic blood is a limited resource and should be usedonly when absolutely necessary.

Therefore, because of increasing understanding of theabove potential downsides, more recent efforts, especiallyin spine surgery, have focused on minimizing allogeneicblood transfusions in elective pediatric deformity surgery.The predictive factors for needing a blood transfusion in thispatient population are fairly unmodifiable and include degreeof spine curvature, the presence of neurogenic scoliosis, needfor lumbosacral fusion, coexisting pulmonary disease, neu-raxial tumor surgery, and increased number of spinal levelsfused [4,5]. Some risk factors are modifiable, such as in-creased number of preoperatively donated autologous RBCunits (increases risk) and preoperative erythropoietin use(decreases risk) [4,5]. Because most risk factors for bloodtransfusion in pediatric spinal deformity surgery are patientspecific and cannot be avoided, efforts to minimize alloge-neic transfusion have instead focused on increased interestin autologous blood donation, a better understanding ofhow low a hemoglobin (Hb) concentration patients can toler-atewithout an increase inmorbidity ormortality, and specificperioperative ‘‘blood sparing’’ techniques.

Because of the potential of pathogen transmission andother transfusion complications, there has been increasedinterest in autologous blood donation, especially in electivespine surgery, over the years. Although autologous donationis more time consuming and costly compared with alloge-neic donations, it is thought to be safer from the standpointof infection transmission and transfusion reactions [6].Unfortunately, it has also been implicated as a risk factorfor perioperative allogeneic RBC transfusion during spinesurgery [4]. Its routine use in otherwise healthy patientsis therefore not universally advocated.

Exactly when is a blood transfusion necessary? The‘‘absolute’’ threshold for RBC transfusion is a controversialmoving target, especially in the pediatric population, andthe trend has been toward a lower absolute Hb transfusiontrigger over the years. In the adult population, formany years,anesthesiologists and intensivists often transfused to keep theHb at or above 10 to 13 g/dL, based mainly on clinical expe-rience [3]. More recently, the American Society of Anesthe-siologists recommends transfusing if the Hb is less than6 g/dL, although they do not advocate a single transfusiontrigger but rather assessment of the patient’s comorbid condi-tions and current state [7]. The American Association ofBlood Banks advises using a Hb threshold of 7 to 8 g/dL instable hospitalized patients [8]. Most recommendations forthe pediatric population are based either on expert opinionor derived from adult studies, but as in the adult population,the trend has been toward tolerating lower Hb concentrations.

Finally, concurrent with this lower Hb concentrationthreshold trend, practitioners have been learning moreabout how to minimize blood loss in pediatric scoliosis pa-tients to improve outcomes and hopefully avoid the poten-tial complications associated with RBC transfusion. These

‘‘blood sparing’’ techniques include perioperative interven-tions—such as preoperative erythropoietin use and patientpositioning to avoid increased intra-abdominal pressure—

as well as intraoperative measures like controlled hypo-tensive anesthesia, acute normovolemic hemodilution,intraoperative cell salvage systems, intraoperative use ofantifibrinolytics such as tranexamic acid and epsilon-aminocaprioc acid, and application of fibrin sealant to de-corticated bone. All are thought to minimize blood lossand, therefore, the need for transfusion [6,9,10].

The article in thismonth’s The Spine Journal byLong et al.reflects many of these changes in transfusion practice in pedi-atric patients undergoing elective spine surgery at the authors’institution over a 25-year epoch. The authors looked at twogroups of patients, those treated before the initiation of HIVscreening known as the early practice group (1975–1985)and those treated after the initiation of screening known asthe recent practice group (1990–2000); their purpose was toascertain changes in transfusion practice during this timeand determine whether these changes had any impact on thefrequency of perioperative morbidity and mortality in pediat-ric patients undergoing major spine surgery. The authorsfound many differences between these groups, and not justin allogeneic blooduse, that reflect overall changes in scoliosispractice over the years. The recent practice groupwas slightlyyounger, was more likely to have neuromuscular, rather thanidiopathic, scoliosis, and was more likely to receive Cotrel-Dubousset instrumentation rather thanHarrington rods. In ad-dition, theywere, on average, sicker (higherAmericanSocietyofAnesthesiologists’ classification,more frequent central ner-vous system and respiratory diseases) and more crooked(higher Cobb angles). It is, therefore, not surprising that therecent practice group had longer anesthesia times, more com-bined anterior/posterior procedures, and lower Hb concentra-tions at all time points. Despite this, the authors found a 58%reduction in the number of patients receiving an allogeneicRBC transfusion.At the same time, they found an eightfold in-crease in utilization of autologous blood transfusions anda 4.5-fold increase in utilization of intraoperative cell salvagein the recent practice group. This likely explains that, overall,the recent practice group received 5.864.4 total RBC units(allogeneic, autologous, and cell salvage) versus only4.562.8 units in the early practice group, and a slightly higherpercentage of patients in the recent practice group receivedany transfusion at all (95%vs. 99%). Therewere no significantdifferences in morbidity or mortality between groups. Thestrengths of this study are that the authors compare largegroups of patients in a (presumed) consistent single environ-ment. The fact that this study occured at a single institutionis also a limitation in that its results may not accurately reflectthe broader practice principles of the time.

In summary, the present study nicely compares the RBCtransfusion practices between two groups at different timesfrom one institution. However the ‘‘recent’’ group was op-erated on between 10 and 20 years ago, and it will be inter-esting to see how things have evolved ever since then; how

465M.N. Imrie / The Spine Journal 12 (2012) 463–465

changes such as the trend toward use of more pediclescrews, away from anterior approaches, the increased pop-ularity of posterior-based osteotomies (Pontes, pedicle sub-traction, and vertebral column resection), and the increaseduse of ‘‘blood sparing’’ techniques like transexamic acidmay affect blood loss, Hb management, and transfusionpractices in the last 10 years. Hopefully, Long et al. or otherauthors will take a repeat look in another few years.

References

[1] American Red Cross. History of blood transfusion. 2012. Available at:

http://www.redcrossblood.org/learn-about-blood/history-blood-transfusion.

[2] Long TR, Stans AA, Shaughnessy WJ, et al. Changes in red blood

cell transfusion practice during the past quarter century: a retrospec-

tive analysis of pediatric patients undergoing elective scoliosis sur-

gery using the Mayo database. Spine J 2012;12:455–62.

[3] Istaphanous GK, Wheeler DS, Lisco SJ, Shander A. Red blood cell

transfusion in critically ill children: a narrative review. Pediatr Crit

Care Med 2011;12:174–83.

[4] Nutall GA, Horlocker TT, Santrach PJ, et al. Predictors of blood

transfusions in spinal instrumentation and fusion surgery. Spine

2000;25:596–601.

[5] Vitale MG, Levy DE, Park MC, et al. Quantifying risk of transfusion

in children undergoing spine surgery. Spine J 2002;2:166–72.

[6] Webb KM, Helm GA. Complications and risks of blood products,

hemostatic agents, dural substitutes, and sealants. In: Vaccaro AR,

Regan J, Crawford A, et al, eds. Complications of pediatric and adult

spinal surgery. New York, NY: Marcel Dekker, 2004.

[7] Practice guidelines for blood component therapy: a report by the

American Society of Anesthesiologists Task Force on Blood Compo-

nent Therapy. Anesthesiology 1996;84:732–47.

[8] Kuehn BM. Guideline tightens transfusion criteria. JAMA 2012;307:

1788–9.

[9] Dhawale AA, Shah SA, Sponseller PD, et al. Are antifibrinolytics

helpful in decreasing blood loss and transfusions during spinal fusion

surgery in children with cerebral palsy scoliosis? Spine 2012;37:

E549–55.

[10] Bowen RE, Gardner S, Scaduto AA, et al. Efficacy of intraoperative

cell salvage systems in pediatric idiopathic scoliosis patients under-

going posterior spinal fusion with segmental spinal instrumentation.

Spine 2010;35:246–51.