oa Southern African Journal of Anaesthesia and Analgesia - What to do if no blood is available but the patient is bleeding? : SASA refresher text
Background: The dilemma of what to do if blood is unavailable (or in very short supply) when a patient is bleeding heavily has confronted all clinicians who work in the pre-hospital setting, operating room, intensive care unit or emergency department. This article reviews methods that are currently available and under investigation for bleeding control and resuscitation, including artificial oxygen carriers (AOCs), tourniquets, elevation / gravity, pro-coagulant technologies, haemostatic agents and minimisation of further blood loss by non-operative and minimally invasive surgical interventions.
Methods: The MEDLINE literature database, textbooks and the authors' 56 combined years of experience in anaesthesia, critical care and bloodless medicine associated with the Shock Trauma Center, Baltimore, Maryland, the Englewood Hospital and Medical Center and other hospitals with major blood use were resorted to in evaluating the management strategies described.
Results: A multitude of strategies and options are available. Infusions of AOCs will enhance oxygen carriage and can also be used for volume expansion. Haemoglobin-based oxygen carriers (HBOCs) are a major group of AOCs. HBOC therapy should include monitoring daily plasma haemoglobin (Hb) and haematocrit levels. HBOCs have limited half-life and decreasing plasma Hb, in the context of decreasing total Hb, indicates the need for re-dosing with HBOC. Total Hb, not haematocrit, is used for the assessment of anaemia, because haemodilution by the cell-free Hb solutions can cause haematocrit to be proportionally unrelated to total Hb. HBOCs can make patients appear jaundiced due to metabolism of free Hb. Interferences with laboratory and oximetry monitoring technology should also be considered. HBOCs, like erythropoietin, can act as haematinics and provide added benefits by stimulating erythropoiesis. There are still challenges that need to be resolved regarding the safety and efficacy of these products.
The application of external pressure (e.g. using tourniquets to occlude bleeding from arterial and venous sites and inflatable splints or compression bandages as a temporising means of haemorrhage control for major pelvic fractures) can minimise bleeding. Intra-abdominal packing is an excellent means of salvage when haemorrhage is profuse (e.g. from a major liver laceration) and blood is unavailable.
Intra-operatively, minimally invasive techniques and reduction of blood pressure can reduce surgical blood loss. Cell salvage technology and acute normovolaemic haemodilution will enable some vital surgeries to be completed with fewer transfusions or completely without blood. The use of pro-coagulant technologies, such as fibrin bandages, ChitoFlex dressing, and zeolitebased products (e.g. QuikClot®), can stop arterial and venous bleeding in a few minutes. Haemostatic agents such as recombinant Factor VIIa (rFVIIa) can reduce intra-abdominal bleeding (e.g. liver lacerations). The use of percutaneous screw fixation to stabilise orthopaedic fractures enables the reduction of bleeding that would normally be uncontrolled. Trauma patients have impaired erythropoiesis and a hypoferric state secondary to a complex network of bleeding and inflammatory mediators appearing within 12 hours of injury and lasting more than nine days. Erythropoietin therapy in this population may improve survival. If bleeding occurs intra-operatively, high FIO2, maintaining sedation, neuromuscular paralysis and intubation with mechanical ventilation will minimise oxygen consumption. The maintenance of normovolaemia with crystalloids and colloids and the initiation of blood conservation techniques described above are recommended.
Conclusions: External pressure, abdominal packing or insufflation, haemostatic technologies (bandages, rFVIIa), early orthopaedic fracture reduction with external fixation, interventional radiological embolisation, and minimally invasive percutaneous surgery are effective management strategies for managing bleeding without blood. AOCs function as both oxygen-carrying and volume-expanding tools to bridge the loss of oxygen delivery of blood during the first 10 days after injury until intrinsic reticulocytosis regenerates native red cell production. Used in combination with other resuscitation measures, these techniques and strategies can significantly reduce transfusion requirement and prove to be life saving in cases of severe bleeding where no transfusion is available.
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