British journal of anaesthesia
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Train-of-four (TOF) fade during nerve-mediated muscle contraction is postulated to be attributable to inhibition of prejunctional nicotinic α3β2 acetylcholine receptors (nAChRs), while decrease of twitch tension is attributable to block of postjunctional muscle nAChRs. The validity of these presumptions was tested using specific prejunctional and postjunctional nAChR antagonists, testing the hypothesis that fade is not always a prejunctional phenomenon. ⋯ Occupation of postjunctional nAChRs alone by α-BTX or α-conotoxin GI causes fade. As the prejunctional effects of DHβE on fade became manifest only when co-administered with α-BTX or α-conotoxin GI, specific inhibition of prejunctional nAChR alone is not necessary and sufficient to cause fade. Fade observed during repetitive nerve stimulation can be because of block of either postjunctional nAChRs alone, or block of prejunctional and postjunctional nAChRs together.
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Anaesthetic drugs act at sites within the brain that undergo profound changes during typical ageing. We postulated that anaesthesia-induced brain dynamics observed in the EEG change with age. ⋯ These profound age-related changes in the EEG are consistent with known neurobiological and neuroanatomical changes that occur during typical ageing. Commercial EEG-based depth-of-anaesthesia indices do not account for age and are therefore likely to be inaccurate in elderly patients. In contrast, monitoring the unprocessed EEG and its spectrogram can account for age and individual patient characteristics.
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The isolated forearm technique (IFT) enables an otherwise paralysed patient to communicate awareness to the anaesthetist. We present a debate that focuses on how best to interpret IFT responses. On one side, Pandit argues that there is a range of response types from none through to movement initiated by the patient to alert the researcher. ⋯ In rebuttal, Russell and Wang argue that IFT response types are not so discrete, and that the IFT technique precludes higher levels of response. They argue that overinterpretation of IFT responses might in fact result in a greater risk of accidental awareness; a binary interpretation of the IFT response is the safest option. All authors agree that the IFT has a role in clinical practice and the study of anaesthetic mechanisms.
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Clinical Trial
Prediction of fluid responsiveness using a non-invasive cardiac output monitor in children undergoing cardiac surgery.
This study evaluated the ability of a non-invasive cardiac output monitoring device (NICOM) to predict fluid responsiveness in paediatric patients undergoing cardiac surgery. ⋯ ClinicalTrials.gov NCT01996956.