PREOPERATIVE Establish baseline laboratory studies CBC hemoglobin & hematocrit platelets prothrombin time (PT) determines clotting time for the extrinsic coagulation cascade factors I, II, V, VII, and X normal 12-13 seconds reported with international normalized ratio (INR) normal 0.8-1.2 not correlated with increased transfusion rates partial thromboplastin time (PTT) assesses clotting time of the intrinsic clotting cascade factors XII, XI, IX, VIII, X, V, and II normal 25-39 seconds not correlated with increased transfusion rates fibrinogen also known as factor I normal 200-400 mg/dL below normal ranges have been associated with increased transfusion rates Preoperative blood loss estimation allows for cost-effective treatment with cell salvage systems, allogenic blood transfusions, and antifibrinolytic agents factors associated with increased blood loss: increased body mass index lower body weight mostly associated with increased transfusion requirements lower starting blood volume factor for pediatric spinal deformity advanced age bleeding diathesis number of spinal levels undergoing surgery approximately 200 cc per lumbar level use of instrumentation revision spine surgery iliac crest bone graft harvest interbody fusions trauma or tumor surgery Cobb angle >50° longer expected surgical time neuromuscular scoliosis >6 levels fused for deformity surgery Ponte osteotomies vertebral column resection can lead to 65% of total blood volume loss recommend obtaining a preoperative hemoglobin level of 5 g/dL greater than the treating surgeon's transfusion trigger Hemoglobin optimization goal is to reduce allogenic blood transfusion intraoperatively and postoperatively vitamin supplementation iron major building block of hemoglobin and functions to bind oxygen in the porphyrin ring structure supplementation provides material for hemoglobin synthesis some studies have demonstrated a significant decrease in postoperative transfusions in patients with anemia-reducing vitamins increased side effects constipation heartburn abdominal pain folate and vitamin B12 supplementation essential vitamins for DNA synthesis necessary for erythropoiesis anemia-associated vitamin supplementation iron 256 mg/day, vitamin C 1 g/day, and folate 5 mg/day for 30-45 days preoperatively has been associated with decreased transfusion rates should only be used in patients with a specific deficiency erythropoietin (EPO) recombinant protein of a natural glycoprotein produced by renal pericapillary cells signals bone marrow cells to stimulate RBC production outcomes studies have demonstrated greater efficacy than the use of preoperative autologous blood donation and reinfusion systems indications recommended for high-risk patients preoperative Hb <13 g/dL low body weight (<50 kg) surgeries when considerable blood loss is expected administration three dosing regimens have been proposed: 600 IU/kg for 4 doses: preoperative days 21, 14, 7, and 0 300 IU/kg for 15 doses: preoperative day 10 to postoperative day 4 150 IU/kg for 9 doses: preoperative day 5 to postoperative day 3 high cost associated with use treatment cost equivalent to 4 units of allogenic blood transfusion preoperative autologous blood donation administration preoperative procurement of 1 to 2 units of autologous blood performed at least 3 weeks before the planned surgery to allow for recovery of Hb levels outcomes current literature does not seem to support efficacy and cost effectiveness in the management of postoperative anemia concerns that there is a high incidence of unused units compulsion to transfuse patient indications may be of benefit in patients with normal Hb (>14 g/dL) undergoing procedures with high expected blood loss may be performed in any patient with Hb >11 g/dL and body weight >50 kg administered with sufficient time prior to procedure preoperative embolization indications standard treatment for oncology cases with highly vascular tumors renal cell carcinoma technique performed within 24 hours of the procedure Discontinue anticoagulation medications goal is to decrease risk of intraoperative bleeding without causing adverse events NSAIDs inhibit COX-1 and COX-2 non-aspirin platelet inhibitors (clopidogrel) commonly prescribed after cardiac stenting elective spine surgery should be postponed after such procedures 6 weeks for bare metal stents 6 to 12 months for drug-eluting stents if urgent/emergent surgery, may consider continuing medication if discontinued, need to discuss risks and benefits Plavix can be resumed 12 to 24 hours after surgery if there is no concern for epidural hematoma long-term anticoagulants risks of discontinuing risk of thromboembolic event with discontinuation prior to procedure warfarin discontinue 5 days prior to procedure goal INR <1.4 resuming immediately after a procedure can lead to subtherapeutic INR for 8 to 10 days may consider a bridging agent in these patients low-molecular-weight heparin or unfractionated heparin therapeutic dosing should be postponed for a minimum of 48 to 72 hours after spine surgery to prevent epidural hematoma supplements should be discontinued 14 days prior to surgery to minimize intraoperative blood loss decrease platelet aggregation garlic ginkgo ginseng fish oil flax seed oil saw palmetto inhibit clotting chamomile alter coagulation vitamin E vitamin K green tea (contains vitamin K) Anticoagulation Medications Drug <i>Plasma Half-Life (Hours)</i> Effect on Bleeding <i>Minimum Cessation Prior to Surgery (Days)</i> Diclofenac 1-2 Inhibits COX (reversibly) 1 Ibuprofen 2 Inhibits COX (reversibly) 1 Indomethacin 4-10 Inhibits COX (reversibly) 3 Ketorolac 5-7 Inhibits COX (reversibly) 3 Etodolac 6-7 Inhibits COX (reversibly) 3 Sulindac 8-16 Inhibits COX (reversibly) 3 Naproxen 12-17 Inhibits COX (reversibly) 3 Piroxicam 50 Inhibits COX (reversibly) 7 Celecoxib 11 Inhibits COX-2 (reversibly) 1 Aspirin 6 Inhibits COX (irreversibly) 7 Clopidogrel 1 Irreversibly inhibits platelet ADP receptors 7 Prasugrel 2-15 Irreversibly inhibits platelet ADP receptors 7 Ticagrelor 7-9 Reversibly inhibits platelet ADP receptors 5 Ticlopidine 20-50 Irreversibly inhibits platelet ADP receptors 14 Warfarin 20-60 Inhibits vitamin K-dependent clotting factor synthesis 5 Enoxaparin (LMWH) 3-5 Binds antithrombin and irreversibly blocks thrombin 1 Unfractionated heparin 0.5-2 Binds antithrombin and irreversibly blocks thrombin 4-5 hours Dabigatran 7-14 Reversibly blocks thrombin 3 Rivaroxaban 5-13 Reversibly blocks factor Xa 3 Apixaban 9-14 Reversibly blocks factor Xa 3 Edoxaban 10-14 Reversibly blocks factor Xa 3 Intraoperative Management Hypotensive anesthesia administration of vasodilating agents to a goal systolic blood pressure of 50-80 mm Hg or MAP of 60 mm Hg well validated in pediatric scoliosis surgery has been shown to decrease intraoperative blood loss by 55% without sequelae reduces blood extravasation through the surgical wound does not affect bone bleeding (mostly venous bleeding) complications: concern for possible cord transfusion neuromonitoring changes address by increasing blood pressure, ensuring no halogenated gases, determine last time when gentamicin was given, and increase patient temperature ischemic optic neuropathy Maintenance of normothermia ideal to keep body temperature >36°C decrease in body temperature >1°C can increase blood loss by 16% and increase transfusion rates by 22% hypothermia decreases platelet function and coagulation enzyme activity increase OR temperature if needed minimize exposed skin surface area until draping Patient positioning reverse Trendelenburg positioning decrease central venous pressure Jackson frames that allow abdomen to hang freely decrease intra-abdominal pressure and pressure on inferior vena cava prevent congestion in Batson venous plexus Tranexamic acid (TXA) lysine derivative that competitively blocks plasmin binding sites on fibrin results in a decrease in fibrinolysis and stabilized clot formation 6 to 10 times more potent than epsilon aminocaproic acid multiple studies have demonstrated a significant reduction in operative blood loss and transfusion rates with perioperative administration no increased risk of DVT and PE does not alter PT and PTT times multiple dosing regimens and routes of administration utilized IV, oral, and topical all appear equally efficacious contraindications: history of CVA allergy severe CAD side effects: seizures binds to glycine and GABA channels leading to a reduced seizure threshold Desmopressin vasopressin analog increases factor VIII and von Willebrand factor limited data in spine surgery useful for treating patients with von Willebrand disease Surgical techniques local anesthetic with epinephrine can prevent dermal bleeding over long cases 1:500,000 epinephrine subperiosteal elevation preserves vasculature of paraspinal muscles electrocautery monopolar soft tissue and periosteal elevation ensure no violation of ligamentum in the interlaminar space could go intradural bipolar ideal for hemostasis near neural structures epidural space coagulate bleeding epidural veins saline-irrigated radiofrequency bipolar hemostatic sealers contracts vascular collagen at temperatures <100°C unipolar cautery reaches temperatures >300°C studies have shown substantial blood loss reduction in pediatric deformity surgery increased surgical cost of $493 per case wound packing surgical areas that are not being addressed should be packed decreases low-pressure bleeding saline-soaked sponges or patties can be combined with thrombin or epinephrine for greater hemostasis control Aminocaproic acid lysine derivative that competitively inhibits plasmin results in decreased fibrinolysis studies have demonstrated decreased blood loss with aminocaproic acid in arthroplasty lower cost than TXA does not decrease seizure threshold Topical hemostatic agents collagen agents stimulate the intrinsic pathway of coagulation cascade to promote hemostasis microfibrillar collagen dry, fine, white powder must be applied with dry surgical instruments to a dry field fibrin sealant consists of two separate mixtures one contains fibrin and factor XIII one contains thrombin and calcium combining the mixtures creates a fibrin seal where it is sprayed platelet-rich plasma centrifugation of the patient's blood to isolate plasma with high contents of platelets, growth factors, and clotting factors proposed benefit of improved hemostasis, wound healing, and recovery platelet-poor plasma isolated from centrifugation process combined with thrombin and calcium to provide an autologous fibrin sealant Gelfoam sponges manufactured from animal-skin gelatin and processed into sponge-form isolated use exerts mostly mechanical hemostasis against low-pressure bleeders can be soaked with thrombin, which can act as scaffold for the coagulation cascade excess Gelfoam should be removed as it may interfere with bone healing topical hemostatic agents do not appear to be cost-effective in total joint arthroplasty cases beneficial in spine surgery to promote hemostasis without inflicting harm to adjacent neural structures topical TXA typically administered near the end of the procedure to control postoperative bleeding decreases fibrinolysis and stabilizes clot formation )may be an alternative route of administration in patients with higher risk of complications (history of MI, CAD, or CVA) gelatin-thrombin matrix commonly used in spine surgery to control epidural bleeding brand names include Floseal and Surgiflo consists of porcine or bovine gelatine matrix combined with human derived thrombin acts of the end stage of the coagulation cascade → fibrin formation Reinfusion systems (Cell Saver) recycles intraoperative blood loss for later transfusion can be transfused intraoperatively during longer procedure suctioned blood is filtered, washed, and transfused within 6 to 8 hours of the procedure serves as an alternative to allogenic blood transfusion theoretical benefits of minimizing wound complications and hematoma formation need to avoid suctioning antibiotic irrigation, povidone-iodine solution, and irrigation >42°C into the circuit indications: religious beliefs that preclude allogenic blood transfusion large number of autoantibodies that makes allogenic blood stock incompatible contraindications: surgeries for malignancy and infection not recommended for routine use in lumbar spine surgery not cost effective unless blood loss ≥500 cc complications: coagulopathy altered composition of the transfused blood containing elevated fibrin split products and inflammatory cytokines (TNF-⍺ and interleukins) especially problematic in unwashed systems can lead to increased wound drainage recommended to transfuse 1 unit of FFP for every 1,000 cc of volume of returned transient hemoglobinuria pulmonary complications due to reperfusion of debris contamination cost Postoperative Management Allogenic blood transfusion preoperative hemoglobin is the strongest risk factor for postoperative blood transfusion <13 g/dL more likely to require other risk factors female gender increased age larger patient size longer procedures lateral releases in total knee arthroplasty 1 unit increases Hb by 1 g/dL no absolute criteria for transfusion transfusion should be considered for anyone with Hb <6 g/dL transfusion should be considered for postoperative patients with Hb 7-8 g/dL routine transfusion should be avoided for Hb >8 g/dL no increased mortality has been seen with this criteria, even in patients with cardiac history initiate transfusion if patient is symptomatic orthostatic hypotension tachycardia unresponsive to fluids transfusion for Hb levels between 6-8 g/dL should be based on patient factors expectation of continued blood loss intravascular volume status cardiovascular reserve response to anemia complications increased risk of nosocomial infections immunomodulatory effects increased SSI increased UTIs viral transmission hepatitis B - 1:205,000 units donated hepatitis C - 1:1.8 million units donated human immunodeficiency virus - 1:1.9 million units donated transfusion-related acute lung injury (TRALI) immunologically mediated damage to the lungs can result in adult respiratory distress syndrome acute hemolytic reaction rare but potentially lethal complication results from blood-type mismatch Allogenic platelet transfusion blood product most likely to be contaminated stored at room temperature infections in 10 cases per million units transfused gram-positive organisms most common thrombocytopenia platelet count below 5,000/mm^3 give platelets to avoid spontaneous bleeding platelet count below 50,000/mm^3 give platelets before surgery platelet count above 100,000/mm^3 no need to transfuse Postoperative iron supplementation daily oral iron replacement for mild acute blood loss anemia Drains theoretically prevents surgical site hematomas potential site for infection or neural compression concern for increased post-operative blood negates the tamponade effect by decreasing intra-wound pressure Special Considerations Jehovah's Witness (JW) hold beliefs that blood transfusions are forbidden by the bible some patients may still consent to a blood transfusion some patients may consider the use of Cell Saver as an alternative to allogenic blood transfusion use of colloids and coagulation factors are not forbidden and a matter of personal choice bovine-derived hemostatic agents are generally approved by JW products derived from human plasma are a personal decision of JW should engage in a preoperative discussion about the use of these agents