British journal of anaesthesia
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The metabolic response to stress is part of the adaptive response to survive critical illness. Several mechanisms are well preserved during evolution, including the stimulation of the sympathetic nervous system, the release of pituitary hormones, a peripheral resistance to the effects of these and other anabolic factors, triggered to increase the provision of energy substrates to the vital tissues. The pathways of energy production are altered and alternative substrates are used as a result of the loss of control of energy substrate utilization by their availability. ⋯ The loss of muscle proteins and function is a major long-term consequence of stress metabolism. Specific therapeutic interventions, including hormone supplementation, enhanced protein intake, and early mobilization, are investigated. This review aims to summarize the pathophysiological mechanisms, the clinical consequences, and therapeutic implications of the metabolic response to stress.
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Enormous interest has emerged in the perioperative use of high concentrations of inspired oxygen in an attempt to increase tissue oxygenation and thereby improve postoperative outcome. An extensive debate has arisen regarding the risk/benefit ratio of oxygen therapy, with some researchers advocating the benefits of perioperative hyperoxia, particularly with regard to surgical site infection, whereas others emphasize its detrimental consequences on multiple organs, particularly the lungs and the brain. As one aspect of this debate, there is increased awareness of effects of reactive oxygen metabolites, a feature that contributes to the complexity of achieving consensus regarding optimum oxygen concentration in the perioperative period. ⋯ The present narrative review provides a comprehensive overview of the physiological mechanisms and clinical outcomes across the age range from neonates to the elderly. Risks greatly outweigh the benefits of hyperoxia both in the very young, where growth and development are the hallmarks, and in the elderly, where ageing increases sensitivity to oxidative stress. Conversely, in middle age, benefits of short-term administration of perioperative oxygen therapy exceed potential adverse change effects, and thus, oxygen supplementation can be considered an important therapy to improve anaesthesia management.
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The concept of rapid delivery of multiple blood products to the bedside of a massively haemorrhaging patient seems to be a logical approach to the management of the massively bleeding patient. However, controversy exists in the use of fixed blood component ratios. Assessing the extent of the coagulopathy through point-of-care testing might provide patients with product administration as needed, and avoid excessive transfusion and its associated complications.
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Comparative Study
Percutaneous transtracheal ventilation in an obstructed airway model in post-apnoeic sheep.
Temporizing oxygenation by percutaneous transtracheal ventilation (PTV) is a recommended emergency technique in 'can't intubate, can't oxygenate' (CICO) situations. Barotrauma risk increases if expiration is obstructed. The Ventrain(®) is a new PTV device that assists expiration. Our aim was to compare key physiological outcomes after PTV with the Ventrain and the Manujet(®) in a large animal obstructed airway model. ⋯ The Ventrain provided stable oxygenation and effective ventilation at low airway pressures during emergency PTV in critically obstructed airways. The Manujet provided effective temporizing oxygenation in this situation with hypoventilation necessary to minimize barotrauma risk. The nature and extent of airway obstruction may not be known in a CICO emergency but an understanding of device differences may help inform optimal ventilation device and method selection.
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Irreversible electroporation (IRE) is a novel tumour ablation technique involving repetitive application of electrical energy around a tumour. The use of pulsed electrical gradients carries a risk of cardiac arrhythmias, severe muscle contractions, and seizures. We aimed to identify IRE-related risks and the appropriate precautions for anaesthetic management. ⋯ Side-effects during IRE on tumours in the liver, pancreas, kidney, and lesser pelvis seem mild and manageable when current recommendations for anaesthesia management, including deep muscle relaxation and ECG synchronized pulsing, are followed. Electrical pulses do not seem to cause reactive cerebral activity and evidence for pre-existing atrial fibrillation as an absolute contra-indication for IRE is questionable.