Red blood cell transfusion following burn

Summary

A severe burn will significantly alter haematologic parameters, and manifest as anaemia, which is commonly found in patients with greater than 10% total body surface area (TBSA) involvement. Maintaining haemoglobin and haematocrit levels with blood transfusion has been the gold standard for the treatment of anaemia for many years.

While there is no consensus on when to transfuse, an increasing number of authors have expressed that less blood products should be transfused.

Current transfusion protocols use a specific level of haemoglobin or haematocrit, which dictates when to transfuse packed red blood cells (PRBCs). This level is known as the trigger. There is no one ‘common trigger’ as values range from 6 g dl⁻¹ to 8 g dl⁻¹ of haemoglobin.

The aim of this study was to analyse the current status of red blood cell (RBC) transfusions in the treatment of burn patients, and address new information regarding burn and blood transfusion management.

Analysis of existing transfusion literature confirms that individual burn centres transfuse at a lower trigger than in previous years.

The quest for a universal transfusion trigger should be abandoned. All RBC transfusions should be tailored to the patient's blood volume status, acuity of blood loss and ongoing perfusion requirements.

We also focus on the prevention of unnecessary transfusion as well as techniques to minimise blood loss, optimise red cell production and determine when transfusion is appropriate.

Introduction

A severe burn will significantly alter haematologic parameters. This manifests as anaemia, which is commonly found in patients with greater than 10% total body surface area (TBSA) involvement [1], [2], [3]. The aetiology of anaemia in severe burns is multifactorial (Table 1). This is important because blood transfusions have potential complications and collateral effects [4], [5], [6]. Despite the potential complications, blood transfusion remains common, with approximately 12 million units of packed red blood cells (PRBCs) transfused each year in the United States [7].

This practice can have an immunomodulatory effect, by decreasing cell-mediated immunity, increasing a proinflammatory state, augmenting the risk of infection, increasing the risk of acute respiratory distress syndrome (ARDS) and ultimately causing multi-system organ failure (MOF) [8], [9], [10].

Historically, blood is transfused when the haemoglobin (Hb) level falls below 10 g dl⁻¹ or the haematocrit (Htc) is less than 30%. Maintaining haemoglobin and haematocrit levels with blood transfusion has been the gold standard for treatment of anaemia for many years [11], [12], [13], [14], [15], [16], [17]. Multicentre trials have shown that a restricted blood transfusion protocol is associated with a lower in-hospital mortality rate, cardiac complication rate and organ dysfunction compared with a liberal transfusion group [8], [11], [13], [14]. Similar results were shown in a cohort of burn patients and in paediatric burn patients [18], [19]. Over the past few years, several studies have shown that a restrictive red blood cell (RBC) transfusion policy reduces complications.

While a consensus on when to transfuse has been elusive even until today, an increasing number of authors are agreeing that less blood products should be transfused.

Current transfusion protocols use a specific level of haemoglobin or haematocrit, which dictates when to transfuse PRBCs. This level is known as the trigger. There is no one ‘common trigger’ as values range from a 6 g dl⁻¹ to 8 g dl⁻¹ of haemoglobin.

The aim of this article is to analyse the current status of RBC transfusions in the treatment of burn patients and address new information regarding burn and blood transfusion management. We also focus on the prevention of unnecessary transfusion as well as techniques to minimise blood loss, optimise red cell production and determine when transfusion is appropriate.