Blood conservation overview

Blood transfusion is a life-saving strategy however, it may also be associated with increased risks of morbidity and mortality. A number of strategies exist that may eliminate the need for transfusion for example, identification and correction of anaemia, use of haemostatic agents, decrease blood sampling and blood salvage techniques.

For the surgical patient, blood conservation begins at the time of the patient’s surgical booking and continues through the operation and into the recovery process.(1)

The National Blood Authority Patient Blood Management Guidelines: Modules 2, 3, 4, 5 and 6 which focus on Perioperative, Medical, Critical Care, Obstetrics and Maternity and Neonatal and Paediatric patients respectively, provide recommendations and practice points on blood conservation strategies.

If a patient requires therapy for anaemia, thrombocytopenia or coagulopathy, transfusion should not be a default decision. Instead, the decision on whether to transfuse should be carefully considered, taking into account the full range of available therapies, and balancing the evidence for efficacy and improved outcome against the potential risks.

Identification and treatment of reversible causes of anaemia, particularly iron deficiency in patients with chronic heart failure, is vital. The routine use of erythrocyte stimulating agents (ESAs) is not recommended in some patient groups, but may be cautiously used in others. Where a red cell transfusion is indicated, a single unit should be followed by clinical assessment to determine the need for further transfusion.

Assessing the patient for anaemia and bleeding risk, optimising haemoglobin level and maximising coagulation function are key blood conservation techniques. Refer to Anaemia and haemostasis management for further information.

Before and after an operation, restricting phlebotomy to essential tests only and taking smaller samples (microsampling) can limit the amount of non-surgical blood loss.

Following the release of the National Blood Authority (NBA) Patient Blood Management (PBM) Guidelines: Module 2 Perioperative, and a review of current evidence and international practice(2,3), the Australian Red Cross Blood Service has reviewed our preoperative autologous blood collection policy.

The Blood Service autologous blood collection policy changes from 1 July 2014. This follows a consultation process and is endorsed by the National Blood Authority.

The Blood Service will continue to provide autologous blood collection for exceptional circumstances, being a patient with a rare blood group or multiple red cell antibodies, whose transfusion requirements cannot be met with allogeneic blood.

Preoperative autologous blood collection:

  • reduces the risk of allogeneic red cell transfusion but increases the risk of receiving any red cell transfusion (allogeneic and autologous)
  • increases the risk of preoperative anaemia which is associated with worse outcomes (than those who were not anaemic preoperatively)(4,5)
  • results in excessive wastage, with a significant percentage of autologous units discarded(7)
  • results in generally higher costs on balance than the value of reported benefits of the actual autologous collection(4,6)
  • carries some of the same risks of allogeneic blood, eg, bacterial contamination; clerical and human errors, including incorrect transfusion; and, febrile reactions(6)

The Patient Blood Management Guidelines: Module 2 supports the following intraoperative strategies for blood conservation:

  • prevention of hypothermia (Grade A)
  • appropriate patient positioning
  • deliberate induced hypotension in specific surgeries (Grade C)
  • acute normovolaemic haemodilution (Grade C)
  • cell salvage (Grade C)
  • haemostasis analysis (Grade C)
  • use of medications such as tranexamic acid (Grade A, B)
  • meticulous operative technique
  • topical haemostatic agents

In select clinical settings, postoperative cell salvage is recommended as a blood conservation strategy (Grade C). This technique involves the collection of a patient’s postoperative blood loss into a wound drain. It is then returned to the patient via a filter, either washed or unwashed depending on the equipment used.(8,9)

Close patient observation and monitoring to identify episodes of uncontrolled bleeding and readiness to return to theatre to control bleeding is important in blood conservation.

 
References
  1. Shander A, Waters JH, Gottschall JL. Perioperative Blood Management: A Physician’s Handbook. 2nd edn. AABB, 2009.
  2. Boulton FE, James V. Guidelines for policies on alternatives to allogeneic blood transfusion. 1 Predeposit autologous blood donation and transfusion. Transfus Med 2007;17:354–365.
  3. Walsh TS, Prowse C. BCSH guidelines for policies on alternatives to allogeneic blood transfusion. 1 Predeposit autologous blood donation and transfusion. Transfus Med 2007;17:353.
  4. Kulier A, Levin J, Moser R, Rumpold-Seitlinger G, Tudor IC, Snyder-Ramos SA et al. Impact of preoperative anemia on outcome in patients undergoing coronary artery bypass graft surgery. Circulation 2007;116:471–479.
  5. Keating EM, Meding JB, Faris PM, Ritter MA. Predictors of transfusion risk in elective knee surgery. Clin Orthop Relat Res 1998;357:50–59.
  6. Yazer MH, Waters JH. How do I implement a hospital-based patient blood management program. Transfusion 2012;52:1640–1645.
  7. Brecher ME, Goodnough LT. The rise and fall of preoperative autologous blood donation. Transfusion 2001;41:1459–1462.
  8. UK Blood Transfusion & Tissue Transplantation Services. Better Blood Transfusion Toolkit, Appropriate Use of Blood, Post-operative cell salvage. [Cited 2011 Dec 13]. Available from: http://www.transfusionguidelines.org.
  9. UK Blood Transfusion & Tissue Transplantation Services. Handbook of Transfusion. [Cited 2011 Dec 13]. Available from: http://www.transfusionguidelines.org.