Best practice & research. Clinical anaesthesiology
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Acute kidney injury (AKI) is a significant cause of perioperative patient morbidity and mortality. The definition of AKI has recently changed and further research is underway to identify clinically relevant biomarkers to aid in the diagnosis of the syndrome. ⋯ An anesthesiologist's main objective for perioperative renal protection is prevention by maintenance of euvolemia, preservation of adequate renal perfusion, and avoidance of nephrotoxins. This review will address the definition and diagnosis of AKI, identify patients at risk of AKI, and critically appraise management options for perioperative renal protection.
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Best Pract Res Clin Anaesthesiol · Mar 2008
ReviewBeta blockers and alpha2 agonists for cardioprotection.
Perioperative beta blockade or the use of alpha2 agonists remains a contentious and controversial area of perioperative medicine. Although there is no question that the liberal use of beta blockers (or alpha2 agonists) to prevent or reduce overt signs of sympathetic overactivity, particularly at known periods of stress (e.g. induction, incision, emergence, etc) is an important and routine part of the management of high risk patients, there remains considerable controversy in the literature regarding the efficacy of either short or long-term regimens on cardiac morbidity or long-term outcomes, particularly in those patients not previously receiving medication for known coronary artery disease or hypertension. The role of strict heart rate control (and its safety with regards to hypotension and possibly congestive heart failure) versus intermittent fixed dosing of beta blockers is particularly contentious. We consider the latest literature on this topic and identify areas of agreement and contention and present the latest recommendations of the American Heart Association/American College of Cardiology Perioperative Guidelines Group.
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Best Pract Res Clin Anaesthesiol · Mar 2008
ReviewPreconditioning, anesthetics, and perioperative medication.
Activation of endogenous signal transduction pathways, by a variety of stimuli including ischemic and anesthetic pre- and post-conditioning, protects myocardium against ischemia and reperfusion injury. Experimental evidence suggests that adenosine-regulated potassium channels, cyclooxygenase-2, intracellular kinases, endothelial nitric oxide synthase, and membrane bound receptors play critical roles in signal transduction, and that intracellular signaling pathways ultimately converge on mitochondria to produce cardioprotection. Disease states, and perioperative medications such as sulfonylureas and COX-2 antagonists, could have adverse effects on cardioprotection by impairing activation of ion channels and proteins that are important in cell signaling. Insights gained from animal and clinical studies are reviewed and recommendations given for the use of perioperative anesthetics and medications.
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The ability to reduce brain injury before, during or after an ischaemic injury, irrespective of the cause, remains an exciting prospect. In this article, we will discuss some of the current research behind cerebral protection, which will include the use of anaesthetic agents, as well as therapies targeted specifically at the complex cascades following brain injury.
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Best Pract Res Clin Anaesthesiol · Mar 2008
ReviewHaemoglobin, 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. ⋯ 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.