Blood Management Strategies in Scoliosis Surgery: Minimizing Blood Loss and Transfusion Requirements.

Transcription

1 Blood Management Strategies in Scoliosis Surgery: Minimizing Blood Loss and Transfusion Requirements. Matthew A. Halanski, MD Pediatric Orthopaedic Surgery Helen DeVos Children s Hospital

2 Outline Understand why scoliosis surgery is associated with high blood loss. Review the literature to understand the multi-modal treatments used to minimize blood loss during scoliosis surgery. Review our treatment protocol at HDVCH and present our 2 year retrospective data.

3 We Cut Therefore They Bleed. Blood loss during surgery is a combination of Anatomy, Physiology, and Biochemistry.

4 The question is Why SO much during Scoliosis Surgery? >50% blood volume losses. Highly Vascular Arterial-High Pressure Venous-Baston s Plexus Common Problem Vessels Anterior surgery Segmental vessels Posterior -Sacral foraminal bleeding Posterior - Vessels just lateral to facet joints

5 Scoliosis Surgery- Why all the Blood loss? Spinal Deformity Requires Complex Surgery Osseous Bleeding Large incisions Large surface area Time Blood Loss.

6 Things to Remember #1 Not all Scoliosis is the Same Adolescent Idiopathic Scoliosis Neuromuscular Scoliosis

7 Things to Remember #2 Not all Scoliosis Surgery is the Same.

8 Things to Remember #3 Don t Lose Sight of the FOREST When Looking at the TREES!!! We all See the Forest Differently!

9 If we lose sight of the Forest

10 What s the problem with Blood Transfusion? Taken from Spinal Deformities a Comprehensive text.

11 Less Known problems with Increased Blood Loss and Transfusions. Difficulty with Surgery. Difficult to operate where you can t see! Neuro-monitoring Large fluid shifts, changes in BP can cause changes in spinal cord monitoring. Post-operative Pulmonary Complications Increased Post-Operative Infection Rates Triulzi et al. (Spine) Relative Risk of Infection 5.9* Murphy et al. (THA) Relative Risk of Infection 10

12 Known Patient Risk Factors for Increased Blood Loss and Transfusion Patient weight <30 kg Patient diagnosis (Estimated Blood Loss) Neuromuscular ( mL) >Idiopathic ( mL) Duchenne Muscular Dystrophy ( mL) >SMA/SB>Cerebral Palsy ( mL).

13 Known Surgical Risk Factors for Increased Blood Loss Increasing number of levels = Increase blood loss Best predictor Guay et al Average estimate 200cc/level Murray et al Anterior and Posterior Spinal fusions>posterior spinal Fusions ( mL)>Anterior Spinal fusions ( mL)**. PSF (65-150mL/level) ASF (65-135mL/level) ICBG increased blood loss (1828 ml vs 1120mL). Length of procedure More Time = More Blood loss PSF (Pouliquen JC. Chirurgie : ) 2 hours- EBL 500mL 3 hours- EBL 1500mL 4 hours- EBL 2400mL

14 How can we minimize blood loss and Ultimately use of blood products? Medical (BAS/ND/H) Anesthesia Surgical Pre-Op Intra- Operative Post-Op

15 Pre-operative Evaluation:BAS** Bleeding Disorders and Filling up the Tank Comprehensive Pre-operative Evaluation Family Hx/Bleeding History. Anemia (hematinics and Epo if needed) Coagulopathy (factor replacement) Thrombophilia (avoid Antifibrinolytics) Contraceptives for Menorrhagia Routine and special labs based on apparent risk from history. CBC w/o diff Retic count PT PTT Fibrinogen CMP Type & Screen Von Willebrand Antigen Von Willebrand Ristocetin Cofactor FactVIII (8) Act Von Willebrand Multimer Referral to Hematologist/Neuro-Developmental Pediatrician as needed

16 Pre-operative Treatment** Comprehensive Pre-operative Treatment Procrit (Orthobiotech, Bridgewater NJ) Epoetin alpha, Fe++ Colomina et al. Alone may increase Hct enough for procedures with expected blood loss <30% total volume. Vitale et al Procrit in NM patients higher starting and discharge Hct, but no difference in transfusion rate. (levels fused and time) Decrease in allogenic blood transfusion up to 15% in orthopaedic procedures.

17 Autologous Pre-Operative Blood Donation Multiple blood donations for upcoming surgery Hematocrit maintained >33% >50 kg donate normal unit (450+/- 50 ml) <50 kg donation proportionally smaller Maximum 1/3 days however standard is 1 week to 10 days. Shelf life~35 days Last donation 5-7 days prior to allow normalization of plasma protein.

18 Autologous Pre-Operative Blood Donation Benefits Often meets any transfusion requirements. Murray et al 90% PSF patients requirement met. Thomson et al. 71% patients only received autologous blood while 64% of the blood given to those that required homologous transfusion was auto transfusion. Primarily indicated for procedures involving 30-50% patients blood volume. Risks Pediatric patients won t participate- Murray et al 70% patients for PSF donated. Adverse reaction rate similar to that for homologous transfusions, 1.5-5% % autologous blood not transfused-discarded. Risks of bacterial contamination and identification errors.

19 Day of Surgery

20 Preventing Blood Loss: Patient Positioning Un-Kinking the Hose!!**

21 Anesthesia: Saving the Blood Normovolemic Hemodilution Removal of blood day of surgery after anesthesia. From estimated blood volume and preoperative Hct; volume to be remove calculated roughly 20% blood volume. Average 644 ml (Copely et al 1999) Desired Hct of 30% Replaced with crystalloid (Lactated Ringers) Ratio of replacement 3:1 (3 LR:1 blood). Thus when patient bleeds they bleed dilute blood. Held at room temperature- until end of procedure. Given back in reverse RBC plus clotting factors Saved To be Given After Patient s Circulating Blood to Bleed

22 Anesthesia: Controlled Hypotension Turning Down the Faucet** Hypotensive Anethesia Controlled Hypotension Systolic BP mmhg MAP mmhg or 30% decrease in baseline MAP End organ perfusion is maintained via the autoregulatory function in the end organ arteriolar beds. Spinal cord autoregulates (between mean pressures of mmHg, Fahmy et al ) to maintain perfusion. Risk Posterior Ischemic Optic Neuropathy (PION) increased intra-ocular pressure (prone positioning), hypotension, anemia, prolonged prone surgery >6 hours. Benefits- Significant Blood Loss Reduction Patel et al. PSF with hypotensive anesthsia -EBL decreased by 40% and transfusion requirements by 45%. Also decreased operative times by 10% (Fentanyl and Enflurane). Malcom-Smith and McMaster 70% reduction in blood loss

23 Minimizing Blood Loss: Anti-Fibrinolytics** Increased fibrinolysis can cause increased bleeding Inhibit fibrinolysis by preventing plamisminogen plasmin. Anti-fibrinolytics prevent this. Pharmacologic- Anti-Fibrinolytics- All Off label use in Orthopaedic Procedures PSF. Aprotinin Tranexamic Acid (TXA, Cyklokapron, Pfizer, NY, NY) Epsilon amino-caproic acid (Amicar) (Xanodyne Pharmaceuticals, Newport KY)

24 Minimizing Blood Loss: Anti-Fibrinolytics Aprotinin Protease inhibitor isolated from bovine lung (1930). Two effects on coagulation: Inhibits enzymatic formations of plasma kallikrein. This in turn inhibits conversion on plamsinogen plasmin. Protects vwf receptors on platelets which preserves platelet adhesion. Scoliosis (High Risk) 15,000 KIU/kg LD/20 minutes 7,500 KIU/kg/hr during procedure Majority of benefit demonstrated in cardiac patients to decrease blood loss and transfusion requirements. Similar in Orthopaedic literature Kohshhal et al 2003 Scoliosis (N=43) decreased EBL, transfusion rate but no significant. Urban et al. Adult spine surgery (N=60 total) Compared with Placebo, Amicar, and Aprotinin showed a lower blood loss and transfusion requirement in Aprotinin <Amicar <Control.

25 Minimizing Blood Loss: Anti-Fibrinolytics Aprotinin Problems Anaphylactoid reactions increase with repeated exposures: No exposure incidence 0.1% Exposure within last 6 months 5% Exposure >6 months 1% Contra-indicated in those exposed within 12 months. (BART Study) Blood Conservation Using Antifibrinolytics in a Randomized Trial increased 30 day mortality with Aprotinin lead to worldwide suspension of use in Conflicting data on Renal Failure and MI. Increased risk of renal dysfunction in those with DM. Shown Safe in pediatric patients (cardiac surgery) Backer et al 2007 (N=1230 without, N=1251 with) no difference in mortality, kidney failure, dialysis, neurologic complications.

26 Minimizing Blood Loss: Anti-Fibrinolytics** TXA 7-10X as potent as Amicar. Loading dose 10mg/kg Infusion 1mg/kg/hr Amicar Loading dose mg/kg Infusion 10-15mg/kg/hr Both are Lysine analogs- Excreted in urine Saturate the Lysine binding sites of plasminogen to prevent binding to fibrin. Lysine Transexamic Acid Amicar

27 Minimizing Blood Loss: Anti-Fibrinolytics**

28 Prospective Comparisons Anti-Fibrinolytics** Transexamic Acid (TXA) Neilipovitz, AIS (N=40) 1253+/-884mL vs 1784+/-733 (cell saver plus transfusion) significant. Sethna, PSF (N=44) EBL decreased 41% vs placebo. (1230+/-535 vs /-1188) Shapiro, DMD (N=56) EBL decreased 42% (1944+/-789 vs 3382+/-1795) Homologous transfusion decreased 41% Cell Saver Autologous transfusion decreased 42% 100 mg/kg LD then 10 mg/kg/hr Amicar 4 separate studies Florentino-Pineda 2001, 2004 Thompson 2005, 2007 (N=36) Total Peri-operative blood loss decreased was significant 1391+/- 212 vs 1716+/- 284 ml) EBL not significant (893+/-166 ml vs 952+/-303 ml) Post-operative drainage significant. (498+/-179 ml vs 764+/-284 ml) Decreased Autologous units transfused 1.1+/-1U vs 2.1+/-1.3. Increasing fibrinogen levels throughout post operative period 100 mg/kg LD then 10 mg/kg/hr

29 Meta-Analysis Anti-Fibrinolytics** Cochrane Collaboration Tzortopoulou studies looking at the effect of anti-fibrinolytics on perioperative blood loss in patients <18 years old undergoing scoliosis surgery. Included Aprotinin, TXA, Amicar. 6 studies, 127 controls, 127 given anti-fibrinolytics. Anti-fibrinolytic use decreased amount of blood loss by 427 ml. Risk of transfusion was similar in placebo or treatment groups. Amount of blood transfused was less in the treatment group then control group by 327 ml. All three drugs appeared similarly effective. Gill et al JBJS Spine patients (adult) similar findings.

30 Minimizing Blood Loss: Other Agents DDAVP- Desamino-8-d-arginine-Vasopressin Diabetes insipidus Interacts with factor VIII and vwf by increasing their release from endothelial storgae sites. VIII works with IX to activate X vwf stabilizes VIII transports throughout circulation Mediates platelet adhesion to subendothelium Recommended dose ug/kg IV administration minutes before the case prevents hypotension. Increases baseline levels 3-5X s. Intra-nasal and subcutaneous administration also works Mixed Results in the literature no difference in randomized double blinded trials. Theroux et al 1997 EBL and Transfusion rates the same DDAVP/Control Factor VIIIC and VWF increased*

31 Minimizing Blood Loss: Other Agents Recombinant factor VIIa Used in hemophiliacs patients with factor VIII inhibitors. Recent use in non-hemophiliac patients who have failed to clot and has controlled otherwise life threatening hemmorage Dosed g/kg repeating doses at 2-6 hour intervals. Sachs et al 2007 decreased adjusted blood loss and adjusted transfusion levels No ill effects (one ischemic stroke and death!) Premarin (Wyeth-Ayerst Laboratories, Philidelphia,PA) Conjugated estrogen- action unknown they induce polymerization of acid mucopolysaccharides in the walls of capillaries and change them into a gel state-thus the vessel becomes less permeable. Alter factor V levels Alter vessel wall platelet interactions McCall and Bilderback mg/kg IV post-operatively 37% decrease in post-operative drainage over 48 hours in pediatric scoliosis patients no side effects.

32 Day of Surgery

33 Help Stop The Bleeding: Preventing Hypothermia** Mild hypothermia, defined as temperatures less than 36 C,may cause: Coagulopathy due to decreased platelet function Decreased resistance to surgical Infection May affect spinal cord monitoring (SSPE latencies) Maintain at 37 C forced-air warming devices fluid warmers increased ambient temperature in the operating room.

34 Minimizing Blood Loss: Surgical Technique Exposure. Epinepherine injection or electrocautery Sub-periosteal dissection Electrocautery vs blunt cobb exposure Meticulous hemostasis Visualize bleeding Adequate lighting +/-headlamps Magnification if needed (Loupes 3.2X magnification) Hemostasis saves time in allowing better visualization and allows surgery to proceed easier and faster. Two Surgeon Team

35 Minimizing Blood Loss: Cautery Mono-polar Bovie high temperature irreversibly shrinks collagen in vessles completely occluding vessel lumen. High surrounding thermal injury to tissue. Bi-polar current is between tips of forceps More localized Less collateral damage Aquamantys (TissueLink Medical, Dover NH) Bipolar radiofrequency Continuous saline to prevent charring Decreases burning Case reports only

36 Minimizing Blood Loss: Topical Hemostasis Surgical Techniques- topical hemostasis used. Bone Wax= Dutch boy but inhibits bone healing Gel Foam Floseal Surgiflo

37 Minimizing Blood Loss: Topical Hemostasis From Thoms et al JAAOS 2009.

38 Minimizing Blood Loss: Instrumentation Type and Amount Hooks Pedicle Screws

39 Minimizing Blood Loss: Surgical Technique Cutting the Bone Save to the End of the Procedure Osteotomies Facetectomies Bone Graft Decortication Osteotomy

40 Salvaging Lost Blood** Surgical Technique-Blood Salvage Systems Blood rich Coagulation poor may precipitate DIC some give post-operatively only. Recycles blood lost on the field-relatively safe at volumes <3000mL Flynn et al - 50% decrease in homologous blood requirements mean of 1.5 Units salvaged. (spine and orthopaedic) Lennon et al % decrease in the amount of homologous blood used. Copley et al question routine use only 5% spared transfusion from its use. Simpson 1994 found only 12% patients benefited from the salvage (total joints). Expensive and Must lose enough to have enough to get back. Cell Saver (Haemonetics, Braintree MA) Minimum EBL ~500mL Orthopat (Haemonetics, Braintree MA) Smaller Volume blood losses intra-operative Post-Operative Blood Captured and Re-infused. Flynn et al 1991* average 1U blood per patient salvaged.

41 Turning off the Faucet: Post-Operative Care Blood Avoidance Management. Continuation of Anti-fibrinolytics, Hematinics Lab Values Standard Protocol No transfusion<7 others individual basis Surgeon To drain or not to drain. Anesthesia Eyes OK No missing teeth Pain Control

42 Cost Analysis Bone Graft $2600 Implants $10-40,000 Surgeon/Anesthesia fees $10,000 s Spinal Cord Monitoring $3000 $2100 Autologous Donations 3X$700 NormoVolemic Hemodilution $300-$2300+ Pre-operative BAS Evaluation Hematinics /Procrit Referral Hypotensive Anesthesia Decrease Allogenic Transfusion Priceless?? $ Anti-Fibrinolytics TXA- $300 Amicar-$3 Aprotinin-$1200 $$ Surgical Technique Two Surgeon Approach Topical Hemostasis From Thoms et al JAAOS 2009 $800 Blood Salvage BAS Transfusion Practices Post op Hemantics

43 HDVCH Standard Approach Hypotensive Anesthesia Anti-Fibrinolytics TXA Amicar Aprotinin NormoVolemic Hemodilution Surgical Technique Two Surgeon Approach Autologous Donations Pre-operative BAS Evaluation Hematinics Procrit Referral Decrease Allogenic Transfusion Blood Sallvage BAS Transfusion Practices Post op Hematinics

44 HDVCH 2 Year Experience September September 2009* Number of surgeries 110 Neuromuscular 28 Idiopathic 60 Others (Congenital & Secondary) 22 Pre-operative Screening 104 (94%) Pre-operative Hematinics 37 (34%) Pre-operative Epo 13 (12%) Contceptives 2x for Menorrhagia + Antifibrinolytics 1 for month prior to surgery. No Antifibrinolytics developed venous thrombosis *(last 6 months not yet analyzed)

45 Type of Scoliosis and Demographics Idiopathic n=60 Neuromuscular n=28 Sex (F) % 45 (75%) 14 (50%).02* Weight Age (months) P Value (Mann Whitney) Comorbidities 18 (30%) 27 (96%).001* Cobb Angle No of segments fused No of osteotomies P.001 # of Segments Idiopathic # of Osteotomies Neuromuscular * Chi Square test

46 Type of Scoliosis and Outcome Idiopathic Neuromuscular P Total Blood Loss ml/kg * P.002 P.001 Hb drop gm/dl * % Transfused ** * Mann Whitney ** Fishers Exact test

47 Cobb Angle, Blood Loss and Transfusions Blood Loss ml/kg % Transfused n=6 n=20 n=25 n=18 n=15 n=10 Cobb Angle *P.04 KW * P.088 Fishers No difference between I & NM within same Cobb Angle group

48 Anti-Fibrinolytics Effect Amicar (67) Tranexamic (17) Non (12) P Value Initial Hb KW Post-Op Hb a b 0.12 KW Total blood loss /kg KW Hypotension in PACU 31 (46%) 5 (39%) * Transfused 11 (16%) 1 (6%) 1 (8.3%) - Pre Op Fibrinogen Highest Post Op Fibrinogen * Fishers Exact test Remember Not all Scoliosis the SAME!!!

49 Markers of Transfused Scoliosis Patients P.006 P.001 Non Transfused Transfused P.003 P Weight * Idiopathic % ** # Levels Fused * Total Blood loss/kg * * Mann Whitney test **Fisher Exact test

50 Predictors of Transfusion Requirement * Logistic regression of individual variables: more P.001 higher higher P.009 higher P.007 Logistic regression of all variables: Older age OR.973 ( ) P Higher blood loss OR ( ) P.001

51 Incidence of Von Willebrand Disease 12 out of 110 (10.9% ) diagnosed with Von Willebrand disease 4 of 24 (14.3%) Neuromuscular 6 of 60 (10%) Idiopathic 2 of 22 (9.1%) In other scoliosis types Overall P Fisher Exact test Out of groups AIS & NM Von Willebrand patients (n=10) 5 had (+) personal or family history of bleeding 4 received Humate-P intra-operatively One patient out of 10 required a transfusion (10%) (AIS). One patient (in AIS group) had Von Willebrand activity level of < 30, received Humate-P & was not transfused.

52 Von Willebrand in Scoliosis Patients VW Activity AIS NM (+) History Received Humate P Total blood loss a Transfused < 50% ± % ± 56 0 > 70% Mean 53 ± ± 8 Activity b a. P.188 (Kruskall Wallis) b P.171 (Mann Whitney) Only one patient below 30% There was a trend toward higher blood loss with lower Von Willebrand activity levels in this pre-operatively identified group.

53 Summary Blood management in Scoliosis Surgery requires a Multi- Disciplinary Multi-modal Approach. Here at HDVCH we have found our data to compare well with that in the literature: Posterior spinal fusion is associated with significant blood loss & risks of needing transfusions particularly in neuromuscular scoliosis. High blood losses were associated with higher Cobb Angles Transfusion needs were associated with Neuromuscular curves, smaller weight, larger number of segments fused and higher blood losses. Unexpected high incidence of mild Von Willebrand disease was noticed (more in neuromuscular scoliosis) and tended to be associated with higher blood loss. Currently vwf studies and TXA vs Amicar