Coagulopathy and blood component transfusion in trauma

Trauma is a serious global health problem, accounting for approximately one in 10 deaths worldwide. Uncontrollable bleeding accounts for 39% of trauma-related deaths and is the leading cause of potentially preventable death in patients with major trauma. While bleeding from vascular injury can usually be repaired surgically, coagulopathy-related bleeding is often more difficult to manage and may also mask the site of vascular injury. The causes of coagulopathy in patients with severe trauma are multifactorial, including consumption and dilution of platelets and coagulation factors, as well as dysfunction of platelets and the coagulation system. The interplay between hypothermia, acidosis and progressive coagulopathy, referred to as the ‘lethal triad', often results in exsanguination. Current management of coagulopathy-related bleeding is based on blood component replacement therapy. However, there is a limit on the level of haemostasis that can be restored by replacement therapy. In addition, there is evidence that transfusion of red blood cells immediately after injury increases the incidence of post-injury infection and multiple organ failure. Strategies to prevent significant coagulopathy and to control critical bleeding effectively in the presence of coagulopathy may decrease the requirement for blood transfusion, thereby improving clinical outcome of patients with major traum

Haemoglobin, oxygen carriers and perioperative organ perfusion

Under normal conditions, only 20-30% of the delivered oxygen is metabolised. In normovolaemic anaemia, the organism reacts with increases in cardiac output and oxygen extraction. Once these mechanisms are exceeded, allogeneic blood transfusions may be administered. However, such transfusions are associated with serious adverse effects and alternatives such as artificial oxygen carriers are being sought. The main groups of artificial oxygen carriers are extracellular haemoglobin solutions and perfluorocarbons. Preparations undergoing experimental and clinical assessment include Human Polymerized Haemoglobin (Polyheme), Polymerized Bovine Haemoglobin-based Oxygen Carrier (HBOC-201, Hemopure), Haemoglobin Raffimer (HemoLink), Diaspirin Cross-linked Haemoglobin (HemAssist), Human Recombinant Haemoglobin (rHb), Enzyme Cross-linked Poly-haemoglobin, Maleimide-activated Polyethylene-glycol Modified Haemoglobin (MP4, Hemospan), Zero-linked Haemoglobin (ZL-HbBv) and Recombinant Hybrid of Human-alpha-chains and Bovine-beta-chains and Perflubron (Oxygent). Research into some of these compounds has been discontinued, while others have advanced into clinical phase III trials, but none has achieved market approval for Europe, US or Canada so far

Updates in perioperative coagulation: physiology and management of thromboembolism and haemorrhage

Understanding of blood coagulation has evolved significantly in recent years. Both new coagulation proteins and inhibitors have been found and new interactions among previously known components of the coagulation system have been discovered. This increased knowledge has led to the development of various new diagnostic coagulation tests and promising antithrombotic and haemostatic drugs. Several such agents are currently being introduced into clinical medicine for both the treatment or prophylaxis of thromboembolic disease and for the treatment of bleeding. This review aims to elucidate these new concepts and to outline some consequences for clinical anaesthesia and perioperative medicin

Allogeneic red blood cell transfusions: efficacy, risks, alternatives and indications

Careful assessment of risks and benefits has to precede each decision on allogeneic red blood cell (RBC) transfusion. Currently, a number of key issues in transfusion medicine are highly controversial, most importantly the influence of different transfusion thresholds on clinical outcome. The aim of this article is to review current evidence on blood transfusions, to highlight ‘hot topics' with respect to efficacy, outcome and risks, and to provide the reader with transfusion guidelines. In addition, a brief synopsis of transfusion alternatives will be given. Based on up-to-date information of current evidence, together with clinical knowledge and experience, the physician will be able to make transfusion decisions that bear the lowest risk for the patien

High-frequency jet ventilation for minimizing breathing-related liver motion during percutaneous radiofrequency ablation of multiple hepatic tumours

Movements of the liver caused by spontaneous breathing (during sedation or local anaesthesia) or by ventilation during anaesthesia are a source of concern in CT-guided procedures because of the limited spatial and contrast resolution of unenhanced imaging, artifacts caused by the probes and the relatively low temporal resolution of the fluoroscopy mode. During CT-guided radiofrequency ablation (RFA), it is essential that the lesion can be visualized optimally and that the ablation probe is positioned accurately to avoid non-target injuries. We therefore used high-frequency jet ventilation and general anaesthesia to minimize ventilation-related liver movement and provide optimal conditions for a patient undergoing RFA of hepatic metastases. The technical and anaesthetic considerations are discussed, and a specific limitation of transcutaneous Pco2 measurement during activation of the ablation is reported for the first tim

Perioperative antiplatelet therapy: the case for continuing therapy in patients at risk of myocardial infarction

Recent clinical data show that the risk of coronary thrombosis after antiplatelet drugs withdrawal is much higher than that of surgical bleeding if they are continued. In secondary prevention, aspirin is a lifelong therapy and should never be stopped. Clopidogrel is regarded as mandatory until the coronary stents are fully endothelialized, which takes 3 months for bare metal stents, but up to 1 yr for drug-eluting stents. Therefore, interruption of antiplatelet therapy 10 days before surgery should be revised. After reviewing the data on the use of antiplatelet drugs in cardiology and in surgery, we propose an algorithm for the management of patients, based on the risk of myocardial ischaemia and death compared with that of bleeding, for different types of surgery. Even if large prospective studies with a high degree of evidence are still lacking on different antiplatelet regimens during non-cardiac surgery, we propose that, apart from low coronary risk situations, patients on antiplatelet drugs should continue their treatment throughout surgery, except when bleeding might occur in a closed space. A therapeutic bridge with shorter-acting antiplatelet drugs may be considere