British journal of anaesthesia
-
Editorial Comment
Consciousness and the outside world: is there anyone listening?
Sedated patients have graded levels of consciousness and perceptual connection with the outside world. Disconnection is associated with widespread changes in the electroencephalogram, whereas full unconsciousness is linked with decreased activity specifically in the deep midline regions of the brain. These findings can be interpreted within the predictive coding model of consciousness as differences in model generation vs discrepancy detection. Anaesthetists should be cognisant that apparently unresponsive patients might still have some ongoing partially disconnected consciousness activity.
-
In postgraduate specialist training, workplace assessments are expected to provide the information required for decisions on trainee progression. Research suggests that meeting this expectation can be difficult in practice, which has led to the development of informal processes, or 'shadow systems' of assessment. Rather than rejecting these informal approaches to workplace assessment, we propose borrowing from sociology the concept of 'desire paths' to legitimise and strengthen these well-trodden approaches. We asked what information about trainees is currently used or desired by those charged with making decisions on trainee progression, and how is it obtained? ⋯ From these themes, we propose a set of design principles for future workplace assessment. Understanding the reasons desire paths exist can inform future assessment redesign, and may address the current disjunct between the formal workplace assessment system and what happens in practice.
-
Editorial Comment
Realising the potential of functional imaging to reveal brain changes after anaesthesia and surgery.
We highlight the ability of functional brain imaging to detect changes in human brain function, even when changes are not seen in cognitive testing. These imaging changes are plausible as they correlate with known activity changes in carriers of APOE4, a genetic variant associated with increased risk for Alzheimer's disease. However, to realise the potential of functional imaging for perioperative neurocognitive disorders, collaborations similar to the Alzheimer's Disease Neuroimaging Initiative (ADNI) with open data sharing will be required. For the practicing anaesthesiologist, we believe that postoperative cognitive issues are important topics to discuss during the informed consent process.
-
General anaesthetics have marked effects on synaptic transmission, but their neuronal and circuit-level effects remain unclear. The volatile anaesthetic isoflurane differentially inhibits synaptic vesicle exocytosis in specific neuronal subtypes, but whether other common anaesthetics also have neurone-subtype-specific actions is unknown. ⋯ Anaesthetic-agent-selective effects on presynaptic Ca2+ entry have functional implications for hippocampal circuit function during i.v. or volatile anaesthetic-mediated anaesthesia. Hippocampal interneurones have distinct subtype-specific sensitivities to volatile anaesthetic actions on presynaptic Ca2+, which are similar between isoflurane and sevoflurane.