Overview
Definition:
Autotransfusion using a cell saver is a technique where a patient's own shed blood is collected during surgery, processed to remove non-erythrocyte components like free hemoglobin, lipids, and anticoagulants, and then reinfused back into the patient
This aims to reduce the need for allogeneic blood transfusions
The cell saver works by aspirating shed blood, washing it with saline, centrifuging it to separate plasma and contaminants, and collecting the concentrated red blood cells for reinfusion
It is distinct from intraoperative blood salvage in that it specifically involves processing collected blood
Clinical significance lies in its potential to conserve allogeneic blood resources, reduce transfusion-related risks, and manage blood loss in specific surgical scenarios.
Epidemiology:
The incidence of using cell saver technology varies widely depending on the surgical specialty, hospital protocols, and surgeon preference
It is most commonly employed in cardiac, orthopedic, major vascular, and oncologic surgeries where significant blood loss is anticipated
While specific epidemiological data for cell saver usage is scarce, the demand for blood products in India, as in many parts of the world, remains high, making autotransfusion an important consideration.
Clinical Significance:
Autotransfusion using a cell saver is crucial for preserving patient autonomy, reducing exposure to immunomodulatory effects of allogeneic blood, minimizing risks of transfusion-transmitted infections, and mitigating alloimmunization
It is particularly valuable in Jehovah's Witness patients or those with rare blood types who cannot receive allogeneic transfusions
Furthermore, it can be cost-effective by reducing the overall blood bank expenditure
Understanding the indications ensures appropriate application, maximizing benefits while avoiding potential contraindications.
Indications
Anticipated Major Hemorrhage:
High likelihood of significant intraoperative blood loss exceeding 1000-1500 mL, such as in complex cardiac procedures (CABG, valve replacement), major orthopedic surgeries (total hip/knee arthroplasty, spinal fusion), extensive oncological resections (pelvic exenteration, liver resections), and aortic surgery.
Patient Refusal Of Allogeneic Blood:
Crucial for patients who refuse allogeneic blood transfusions for religious (e.g., Jehovah's Witnesses) or personal reasons, where autotransfusion becomes the primary method of managing anticipated blood loss.
Rare Blood Types Or Alloimmunization:
Patients with rare blood types that are difficult to match or those who are alloimmunized against common red blood cell antigens, increasing the risk of transfusion reactions with allogeneic blood.
Chronic Anemia And Need For Transfusion Avoidance:
In selected cases of chronic anemia where the patient's own red blood cells, even if fewer in number, are preferred over allogeneic blood, especially if transfusion is to be delayed or avoided.
Situations With Limited Blood Bank Resources:
In remote areas or during mass casualty events where the availability of allogeneic blood may be compromised, making autotransfusion a vital resource.
Contraindications
Gross Bacterial Contamination:
When the surgical field is overtly contaminated with bacteria, pus, or fecal matter, as the cell saver cannot effectively remove bacteria from the reinfused blood, leading to sepsis.
Neoplastic Cells In Field:
In surgeries involving certain malignancies where tumor cells may be shed into the surgical field
While some protocols allow cell salvage in specific oncologic procedures (e.g., lung resections for certain tumors), caution is advised due to the theoretical risk of metastasis
Always adhere to institutional guidelines.
Presence Of Irrigation Fluids Or Antiseptics:
If the surgical field is extensively irrigated with solutions containing antiseptics (like povidone-iodine) or cytotoxic agents, these can be concentrated during processing and become toxic upon reinfusion
Use of hypotonic solutions for irrigation should also be avoided.
Prolonged Exposure To Hypothermia:
When blood is shed and exposed to prolonged extreme hypothermia, red blood cells may undergo significant damage, making them less viable for reinfusion.
Certain Coagulopathies:
While not an absolute contraindication, severe coagulopathies that are difficult to correct may complicate the management of shed blood and increase the risk of reinfusing poorly processed or clotted blood
Careful assessment and management are required.
Embolism Risk:
In procedures where air or particulate emboli are a significant risk, although modern cell saver systems have safeguards to prevent this.
Procedure Overview And Processing
Blood Collection:
Shed blood from the surgical field is aspirated using a sterile, heparinized suction device (often with pre-packaged circuit)
The anticoagulant used (e.g., citrate or heparin) is critical and depends on the specific cell saver device and institutional protocol
Heparin is commonly used for its ease of management during the procedure
The collected blood is then transferred to the cell saver reservoir.
Washing And Centrifugation:
The collected blood is washed with a sterile isotonic saline solution
The cell saver centrifuges the blood at high speed, separating red blood cells from plasma, free hemoglobin, excess anticoagulant, platelets, and white blood cells
The washing process removes these unwanted components, reducing the risk of fluid overload and transfusion reactions.
Red Blood Cell Concentration:
The processed red blood cells are then collected into a sterile bag, forming a concentrated erythrocyte solution
The hematocrit of the reinfused blood typically ranges from 50-70%
The volume of reinfused cells depends on the amount of blood salvaged and the patient's needs.
Reinfusion:
The concentrated red blood cells are reinfused back into the patient through a standard blood filter, similar to an allogeneic blood transfusion
It is crucial to monitor the patient closely during reinfusion for any signs of adverse reactions
The reinfused product is essentially a red blood cell concentrate with a high hematocrit and a reduced volume of plasma.
Preoperative Considerations And Monitoring
Patient Assessment:
Thorough preoperative assessment of patient's hematological status, comorbidities, and anticipated blood loss is essential
Discussing the procedure and potential benefits/risks with the patient is important, especially if it is their first time undergoing autotransfusion.
Anesthesia Team Coordination:
Close collaboration between the surgical and anesthesia teams is vital
The anesthesia team is responsible for monitoring hemodynamic status, managing anticoagulation (if used), and administering the reinfused blood
Communication regarding the initiation and cessation of cell saver operation is critical.
Cell Saver Readiness:
Ensuring the cell saver unit is functioning correctly and all necessary disposables are available and sterile before the start of surgery
The technician or qualified personnel should be present to operate the machine efficiently.
Monitoring During Procedure:
Continuous monitoring of the patient's vital signs, urine output, and central venous pressure is essential
Hemodynamic instability may necessitate immediate cessation of cell saver operation and consideration of allogeneic transfusion
Serial hemoglobin and hematocrit levels help guide the need for reinfusion.
Key Points
Exam Focus:
Cell saver is indicated for anticipated major blood loss (>1000-1500 mL), patients refusing allogeneic blood, rare blood types, and alloimmunization
Contraindications include gross contamination, certain neoplastic shedding, and significant presence of antiseptics.
Clinical Pearls:
Always confirm the type of anticoagulant used and its concentration
Communicate clearly with the cell saver operator and anesthesia team
Monitor patient's coagulation status closely post-reinfusion
Consider the theoretical risk of tumor cell spread in oncologic cases and follow institutional guidelines.
Common Mistakes:
Failure to identify absolute contraindications like gross contamination, leading to septic complications
Over-reliance on cell saver in mild bleeding scenarios where it may not be cost-effective
Inadequate patient selection leading to unnecessary use of the technology.