Anaesthesia
-
It is estimated that up to 1% of the general population has a congenital bleeding disorder. With this level of disease burden, it is more likely than not that any practising surgeon or anaesthetist will, at one time or another, have occasion to manage one such patient. Congenital haemophilia, both A and B, von Willebrand's disease, and inherited qualitative platelet defects, constitute the bulk of these disorders, with the rest distributed between much rarer conditions. ⋯ Of equal importance, at least in developed countries, has been the ease of access to highly purified, safe and effective haemostatic products. The key to successful surgical management of the patient with a bleeding disorder is a multidisciplinary approach involving not only surgeons, anaesthetists and haematologists, but also laboratory scientists, specialist physiotherapists and haemophilia nurses. With careful planning, most surgical and invasive procedures can be carried out safely in persons with haemophilia and other bleeding disorders.
-
Allogeneic red cell transfusion is a commonly used treatment to improve the oxygen carrying capacity of blood during the peri-operative period. Increasing arterial oxygen content by increasing haemoglobin does not necessarily increase tissue oxygen delivery or uptake. Although the evidence-base for red cell transfusion practice is incomplete, randomised studies across a range of clinical settings, including surgery, consistently support the restrictive use of red cells, with no evidence of benefit for maintaining patients at higher haemoglobin thresholds (liberal strategy). ⋯ The degree to which the optimal haemoglobin concentration or transfusion trigger should be modified for patients with additional specific risk factors (e.g. ischaemic heart disease), remains less clear and requires further research. Although most clinical practice guidelines recommend restrictive use of red cells, and many blood transfusion services have seen marked falls in overall usage of red cells, the use of other blood components such as fresh frozen plasma, platelets, and cryoprecipitate has risen. In clinical practice, administration of fresh frozen plasma is usually guided by laboratory tests of coagulation, mainly prothrombin time, international normalised ratio and activated partial thromboplastin time, but the predictive value of these tests to predict bleeding is poor.
-
Recent research in the management of haemorrhage has led to several changes in clinical practice. Evidence is accumulating that point-of-care testing results in fewer transfusions, improved patient outcomes, and reduced hospital costs. ⋯ A change in philosophy is required, from performing testing only when there is an obvious bleeding problem, towards the concept of routinely monitoring high-risk patients throughout the surgical procedure. This informs clinical practice, establishes normal ranges for that population, identifies patients at risk and allows early identification and treatment of evolving coagulopathy.
-
The management of antithrombotic therapy in the peri-operative setting is a common problem, balancing haemorrhagic risk with continued treatment and thrombotic risk when discontinued. High-quality evidence is lacking regarding the optimal approach for patients on oral anticoagulants or antiplatelet agents. ⋯ Aspirin can be continued for most procedures. Dual antiplatelet agents for patients with a recently inserted coronary artery stent should be continued if possible but decisions should be individualised and taken after multidisciplinary discussion.
-
Understanding the complex immunological consequences of red cell transfusion is essential if we are to use this valuable resource wisely and safely. The decision to transfuse red cells should be made after serious considerations of the associated risks and benefits. ⋯ Red cell transfusions should be acknowledged as immunological exposures, with consequences weighed against expected benefits. This article reviews immunological consequences and the emerging evidence that may inform risk-benefit considerations in clinical practice.