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Also see Carbon Footprint from Anaesthetic gas use [pdf] from the UK’s Sustainable Development Unit.
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The pressure to practice truly patient-focused, evidence-based medicine weighs on every anaesthetist and anaesthesiologist. Yet as the volume of evidence has grown, so has the expectation to always provide the highest quality care.
There is a trap of unknown knowns: evidence known in the greater medical-knowledge body but that we are naively ignorant of.
Bastardising William Gibson (1993), we risk that the evidence:
“…is already here – it's just not very evenly distributed.”
The greatest challenge for evidence-based anaesthesia continues to be the translation of research findings into actual practice change. The key to this is the intersection between quality, personal relevance, general significance, and credibility. But how can we achieve this?
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There has been some observational evidence that a greater depth of anesthesia, as measured by BIS, may be associated with an increase in post-operative mortality. In particular the association of the "triple low state" (low BIS, low volatile-ET, low MAP) with post-operative mortality is worrying.
Completion of the Balanced Anaesthesia Study Group’s large RCT looking at this issue however brings us as close to a final word as we may expect. Short et al. (2019) showed no difference in 1-year mortality for older patients undergoing major surgery, whether they received a deep (BIS target 35) or light (BIS target 50) general anaesthetic.
It is likely that earlier observational studies were showing the consequences of intraoperative hypotension resulting from anaesthetic depth, rather than anaesthetic depth itself.
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