British journal of anaesthesia
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Recommendations for resuscitation of patients in early haemorrhagic shock, with active ongoing bleeding, have evolved in recent years. This review covers current theories of the pathophysiology of shock and recommended treatments, including damage control surgery, deliberate hypotensive management, administration of antifibrinolytics, early support of the coagulation system, and the possible role of deep anaesthesia. Future directions for resuscitation research are discussed.
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Comparative Study
Relationship between approximate entropy and visual inspection of irregularity in the EEG signal, a comparison with spectral entropy.
Several measures have been developed to quantify the change in EEG from wakefulness to deep anaesthesia. Measures of signal complexity or entropy have been popular and even applied in commercial monitors. These measures quantify different features of the signal, however, and may therefore behave in an incomparable way when calculated for standardized EEG patterns. ⋯ Spectral entropy and approximate entropy of EEG are two totally different measures. They change similarly in deepening anaesthesia due to an increase in slow activity. In some cases, however, they may change in opposite directions when the EEG signal properties change during anaesthesia. Failure to understand the behaviour of these measures can lead to misinterpretation of the monitor readings or study results if no reference to the raw EEG signal is taken.
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Transpulmonary ultrasound dilution (TPUD) is a promising method for cardiac output (CO) measurement in severely ill neonates. The incidence of lung injury in this population is high, which might influence CO measurement using TPUD because of altered lung perfusion. We evaluated the influence of lung injury on the accuracy and precision of CO measurement using TPUD in an animal model. ⋯ The accuracy and precision of CO measurement using TPUD is not influenced in the presence of heterogeneous lung injury in an animal model.
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Intraoperative hypotension is associated with increased risk of perioperative complications. The N-methyl-d-aspartate (NMDA) receptor (NMDA-R) antagonist xenon (Xe) induces general anaesthesia without impairment of cardiac output and vascular resistance. Mechanisms involved in cardiovascular stability have not been identified. ⋯ In vivo, Xe anaesthesia does not alter sympathetic activity and baroreflex gain, despite increased mean arterial pressure. In vitro, Xe decreases the uptake of NE in neuronal cells by the inhibition of NET. This inhibition might be related to NMDA-R antagonism and explain increased NE concentrations at the synaptic cleft and in plasma, contributing to cardiovascular stability during Xe anaesthesia.