澳纽专科考题2005年A

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2005A15: Discuss the advantages and disadvantages of intra-operative blood salvage


Definition:



A technique that is used to return washed or unwashed autologous blood to the
patient ·

• Commonly in cardiac, vascular, orthopedic surgery, & liver transplants
  ·
• Considered where significant blood loss is anticipated ·
• Blood is collected by a suction technique which anticoagulates the blood
  immediately with heparin or Na citrate or both, as it is retrieved. These red
  cells then are washed and packed by centrifugation. The effluent that contains
  heparin and cellular and tissue debris is removed as part of the washing and
  centrifugation process, and the packed red cells then can be reinfused into the
  patient either intraoperatively or postoperatively. ·
• Washing and haemoconcentration creates a product with an average haematocrit
  of 50% that carries normal erythrocyte survival, with minimal coagulation
  factors or platelets. ·
• The necessity of washing collected blood before autotransfusion has
  been questioned in the literature.

Advantages ·

• Intraoperative blood salvage can allow as much as 60 per cent of the
  red blood cells that are lost during the operative procedure to be recovered for
  subsequent autotransfusion.
• · More cost effective as the amount of blood collected increases.
  ·
• Cost effective: once initial machinery bought disposable kit has
  similar cost to 1 unit of leucocyte depleted cells and can process limitless
  units of packed cells ·
• Especially useful in high-volume blood loss situations (AA repair,
  major orthopedic, cardiac)
• · Reduced the risk of allogeneic blood exposure by up to 40% and reduced the
  mean transfusion requirement per patient ·
• If the blood is not transfused intraoperatively, it can be stored for
  up to 24 hours at 1°C to 6°C, and it should be handled like any other autologous
  unit ·
• In orthopaedics many studies show it is safe and efficacious: advantageous
  in major orthopaedic surgery because most contaminants including
  methylmethacrylate monomer, antibiotic from the irrigation fluid, free
  hemoglobin, fat, and bacteria are removed from the suctioned fluid from the
  operative site.
• · There are no published adverse reactions to washed autologous red
  cells in patients undergoing THR. ·
• 2,3 diphosphoglycerate is preserved, thereby enhanced the ability of red
  blood cells to deliver O2 to tissues ·
• May be beneficial for patients who are unwilling to accept allogeneic
  transfusions for religious reasons, such as Jehovah's Witnesses ·
• It is possible to process a unit of salvaged erythrocytes in less than
  5 minutes when the patient is bleeding rapidly ·
• When bleeding is slower, blood can be held in the collection reservoir until
  there is enough to process ·
• Can be of particular benefit to patients who are unable to donate before
  surgery ·
• Salvaged blood does not need to be tested for compatibility or disease
  markers if it never leaves the OR. ·
• There are different types of instruments available for IBS, ranging
  from simple canister collection systems to table-top cell salvage instruments
  and "high-speed" cell salvage instruments. Some of the instruments also can be
  programmed to allow sequestration of platelet-rich plasma if desired ·
• Cells are equal or superior to bank blood in red cell survival, pH, 2,3 DPG
  levels, potassium levels ·
• Eliminates risks of homologous blood (clerical errors and infection)

Disadvantages: ·

• There is controversy surrounding the merits of washed versus unwashed
  salvaged blood. It appears that unwashed blood can be transfused in small
  amounts (2 L or less) with minimal adverse effects. Washing blood removes much
  of the debris, anticoagulants, and free hemoglobin from the red cell product.
  Red cell survival is comparable with that of allogeneic erythrocytes ·
• To be effective, a minimum of 400 ml of drainage is required. ·
• May only be cost effective when expected blood loss is 1000ml or
  greater. ·
• Significant loss of clotting factors and platelets from salvaged blood can
  be anticipated.
• · Particulate debris may be concentrated during processing warranting
  microaggregate filters before or during reinfusion to the patient. ·
  Cost-effectiveness of returning washed autologous blood to patients has been
  questioned because the technique requires an expensive device and technical
  expertise to operate it. Ideally, unwashed autologous blood should be filtered
  and transfused within four hours after collection to avoid potential febrile
  reactions. ·
• Blood collected perioperatively cannot be transfused to other patients
  ·
• Possibility of air embolism. However, many of the newer cell salvage
  instruments contain an in-line "bubble detector," which will stop the pump once
  air is detected in the reinfusion line. Another way to prevent air embolism is
  to avoid direct connection between the reinfusion bag and the patient. air
  embolism is almost unheard of with current devices ·
• Haemolysis can occur if operative suction pressures are high (> 100mmHg)
  or centrifugation rates excessive. ·
• Coagulopathy ranging from mild to severe DIC is a complex multifactorial
  problem that rarely occurs after autologous transfusion, especially if cell
  washing is performed. Exposure to foreign surfaces, haemodilution of coagulation
  factors, hypothermia, heparinisation, and other factors may be contributory.
  ·
• Instruments need dedicated trained operators.
• · Relative contraindications: obvious blood contamination (although this
  reportedly has been successful in some desperate trauma cases), sickle cell
  disease, and cancer surgery, based on concerns of dissemination ·
• Pregnancy is a contraindication because of the concern that final post
  transfused RBC may be contaminated with amniotic fluid elements that can cause
  amniotic fluid embolism syndrome. Despite a lack of proven safety in obstetrics,
  there are numerous anecdotal reports of its use in massive obstetric haemorrhage
  during caesarean section, with no adverse sequelae.
• · Can precipitate sickling in pts with sickle cell disease ·
• Cost: centrifuge/cell washing device is costly.
• Free haemoglobin can be nephrotoxic in pts with impaired renal fxn
  (recommend suction < 150 torr) ·

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