Minimizing Blood Loss in Orthopedics
“Every blood transfusion is like a miniature organ transplant, with the potential for reactions, errors and infection.”
In modern day orthopedic surgeries, apart from the complications directly related to fractures and implants, a surgeon faces numerous perioperative complications. These range from excessive intraoperative and postoperative blood loss, infection, poor wound healing, electrolyte imbalance to even acute renal shut down and shock. Surgeries in orthopedics being more invasive leads to more blood loss when compared to other surgical specialties.
In primary hip surgery, the blood loss is estimated at 3.2 +/- 1.3 units and 4.07 +/- 1.74 grams of haemoglobin. In revision hip surgery, the blood loss is about 4.0 +/- 2.1 units. In primary knee replacement, the blood loss ranges from 1000-1500mls and can average 3.85 +/- 1.4 grams of haemoglobin and may be higher in cementless knee replacements). Transfusion rates of 2.0 +/- 1.8 units for primary THR and 2.9 +/- 2.3 units for revision THRs have been documented. The rates for knee replacements are not well studied but are estimated at 1 – 2 units for primary surgery and can be up to 3-4 units for revision surgery.
Allogenic Blood transfusion has its own disadvantages and slowly people are becoming conscious about its use. There is enough evidence to show that it increases infection rates following Arthroplasty.
In an attempt to provide optimal patient management balanced with patient safety, it is now common practice for clinicians to define transfusion thresholds of haemoglobin below which level the patient’s haemoglobin should not fall during the perioperative period.
It is known that preoperative anaemia increases the likelihood of allogeneic transfusion and hence an attempt should be made to correct the haemoglobin level prior to a major orthopaedic operation where inevitably, a substantial amount of blood loss is expected or anticipated. Usually, a preoperative lower limit of 100g/L is taken prior to major orthopaedic surgery, in spite of there being little evidence for this arbitrary level.
“Pre operative threshold for trasfusion 10g/dL”
Accurate measurement of intraoperative blood loss is difficult. Rapid intraoperative measurement of haemoglobin levels using near-patient testing may improve safety margins and avoid unnecessary transfusions.
There have been two new technological advancements which can help estimate blood loss and need for trasfusion. The Triton is a cloud based app that can accurately estimate blood loss from mops and suction drains within seconds.
Laboratory Hb values are generally used to determine the need for blood transfusions, but testing is done intermittently and the results are not available immediately. Using the Pulse CO-Oximeter and multiwavelength adhesive sensor, it is now possible to perform continuous noninvasive Hb (SpHb) monitoring.
A small randomized control trial involving elderly patients with fractured necks of femur found no difference in mortality in patients transfused when symptomatic or with a haemoglobin of less than 80g/L compared with the haemoglobin maintained at 10g/L.
“Post operative threshold for transfusion in elderly 8g/dL and young adults 7g/dL”
Blood sparing strategies
Blood sparing strategies should be considered in every patient undergoing major blood loosing surgery in orthopaedics. In addition, special situations where these can be considered and may indeed be the only alternative include Jehovah’s witnesses, those with multiple antibodies and those with serious anxieties about allogeneic blood transfusion.
Strategies include the following:
- Preoperative optimization of patient
- Preoperative autologous blood donation (PABD)
- Acute normovolaemic haemodilution (ANH)
- Surgical technique
- Anaesthetic techniques
- Pharmacological therapies
- Increase RBC production – erythropoietin
- Reduce bleeding – antifibrinolytics, topical haemostatic agents, recombinant factor VII
- Cell salvage
Preoperative optimization of patient
Effective preoperative evaluation and preparation of the patient are essential to limit allogeneic blood product use. Many of the patients presenting for major orthopedic surgery have chronic medical conditions that affect coagulation function. Patient on anticonvulsants must be adminstered a dose of Vit K preoperatively.
Other medications such as nonsteroidal anti-in- flammatory agents (NSAIDs) may also affect platelet function. These agents are frequently taken by patients with chronic orthopedic problems and pain. Acetylsalicylic acid irreversibly inhibits cyclo-oxygenase and platelet function for the life of the platelet; however, NSAIDs produce reversible inhibition of platelet function that is dependent on the plasma concentration and hence the half-life of the NSAID. Discontinuation of most NSAIDs for 2 to 5 days prior to surgery will result in a return of normal platelet function
Specialist anaesthetic techniques such as hypotensive anaesthesia, regional anaesthesia and euthermia may reduce surgical bleeding in arthroplasty surgery. For example, in one study, a difference in mean arterial pressure of 10mmHg significantly reduced mean intraoperative blood loss from 263mls to 179mls on average in patients undergoing primary THR.
” Use Hypotensive anesthesia during major orthopedic surgeries Level of Evidence 1″
“Post operative Knee Positioning in flexion significantly reduces blood loss”
Harmonic Bone Scalpel to reduce bleeding
Preoperative autologous blood donation (PABD)
This entails the patient donating a unit of blood every week for 3-5 weeks preoperatively. In orthopaedic surgery patients it has been used safely in elderly populations with diverse comorbidities . However, it is recommended that patients should be stratified according to the risk of requiring a transfusion and should be considered if the likelihood of transfusion exceeds 50%. Generally two units are stored preoperatively for THR patients.
” Encourage patient for Preoperative autologous blood donation when risk of operative blood loss high “
Acute normovolaemic haemodilution (ANH)
This is the removal of whole blood and the restoration of blood volume with acellular fluid shortly before anticipated significant surgical blood loss.The choice of intraoperative fluid administration may affect coagulation function, thereby impacting on blood loss. During ANH, blood (including red blood cells, coagulation factors, and platelets) is removed and replaced with crystalloids and/or colloids. One might therefore assume that coagulation would be adversely affected by this process of hemodilution. However, as the procedure results in the dilution of anticoagulatory proteins, such as antithrombin III, a hemodilution to a hematocrit of 25% to 30% actually exerts a procoagulant effect.
” Acute normovolemic hemodilution is an effective strategy in patients to reduce blood loss and also reduces DVT risk”
Usual schedule is a dose of 300 IU per kilogram (kg) of body weight per day for 10 days prior to surgery, the day of surgery and four days after surgery. An alternate schedule is 600 IU per kg body weight administered once weekly beginning three weeks before surgery, then a fourth dose on the day of surgery. Iron supplementation should be given along with the hormone.
” Erythropoientin may be used in patients who have preoperative hemoglobin between 10-13g/dL”
Aprotinin is a competitive inhibitor of several serine proteases, specifically trypsin, chymotrypsin and plasmin . Its action on kallikrein leads to the inhibition of the formation of factor XIIa. As a result, both the intrinsic pathway of coagulation and fibrinolysis are inhibited. Its action on plasmin independently slows fibrinolysis.
Large-Dose Aprotinin (4 M kallikrein inactivator unit [KIU] bolus before surgery followed by a continuous infusion of 1 M KIU/h until the end of surgery), Small-Dose Aprotinin (2 M KIU bolus plus 0.5 M KIU/h).
“Aprotinin is a cost effective way of reducing blood loss in major orthopedic surgeries
Level of EVIDENCE 1″
Antifibrinolytic drugs (Tranexamic acid and aminocaproic acid)
These inhibit fibrinolysis by binding to the lysine-binding sites of plasminogen to fibrin. They have been used in TKR patients who have had their operations under tourniquet control. In this situation, local fibrinolytic activity may be enhanced and may cause postoperative bleeding on release of the tourniquet A reduction in blood loss of between 43-54% as well as a significant reduction in the total number of units transfused and the number of patients exposed to allogeneic blood has been demonstrated in a series of randomized control studies where the antifibrinolytic drug was given prior to tourniquet release.
” Tranexemic acid injection 1g iv before torniquet release and intra articular tranexemic acid 2-3g dissolved in 50ml saline are effective way of reducing bleeding postoperatively a repeat dose or oral tranexemic acid further reduces drain output without increasing DVT or PE risk
Level of EVIDENCE 1″
Topical haemostatic agents
Topically active agents that have been used include thrombin, collagen and fibrin glue. Fibrin glue made with highly concentrated human fibrinogen and clotting factors does not depend on platelet or clotting factor levels to be effective. The use of fibrin tissue adhesive has been shown to significantly reduce mean postoperative blood loss from 878-360mls in TKR.
” Fibrin sealant tropical application before wound closure reduces blood loss Level Of EVIDENCE 1″
Cell salvage has been shown to have some benefit in reducing the exposure to allogeneic blood. Seven orthopaedic trials with a total of 427 patients between them reported on data for volume of allogeneic blood transfused. For the patients that were randomized to cell salvage, there was an average saving of 0.82 units of red blood cells per patient. When cell salvage was used in orthopaedic surgery, the risk of exposure to allogeneic transfusion was reduced by 54%.
Increasing evidence has demonstrated the potential adverse effects of using allogeneic blood products. These effects may have significant deleterious effects on patients, which may impact on cost and length of hospitalization and in specific circumstances even on mortality. Many of the major orthopedic surgical procedures result in significant blood loss and the need for allogeneic blood transfusions. Therefore a series of options to limit the need for allogeneic blood product administration during orthopedic surgical procedures have been developed. These include general surgical considerations, autologous transfusion therapy, blood salvage, pharmacologic manipulation of the coagulation cascade, and controlled hypotension. Although many of these techniques are effective alone, the combination of several of these techniques can potentially lead us to the goal of performing major orthopedic surgical procedures without the use of allogeneic blood products.