Knowledge
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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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Early in the COVID pandemic, diagnostic testing relied entirely on precise-but-expensive PCR testing. Late in 2020 the Lateral Flow Testing techniques, already widely used for home-pregnancy tests and similar, were developed for SARS-CoV-2 antigens, leading to COVID-19 Rapid Antigen Tests (RATs).
While cheap, scalable and able to give a result in 10-15 minutes, they were initially seen mostly as a supplement to PCR testing, with less accuracy. Although true that RATs have lower sensitivity than SARS-CoV-2 PCR – most licensed-RATs have sensitivity 80-95% – today this is both less important, and possibly even a strength of RATs over PCR.
Early in the pandemic the role of testing has primarily about diagnosis, in those either symptomatic or pre-symptomatic. Viral presence was practically assumed to be synonymous with contagion. Today with over half a billion cumulative COVID cases worldwide and counting, along with access to effective vaccines and antivirals, it is often more useful to know whether an individual is infectious or not at a discrete moment in time.
Growing research over the last 12 months shows that adequately-sensitive RATs are effective at identifying infectious individuals, even if the high-sensitivity of PCR testing identifies viral particles in those who are infected but otherwise non-infectious (either pre-infectious, or post-infectious with ongoing viral shedding).
PCR positive results with cycle thresholds (ie. number of thermal cycles of RNA replication required before fluorescence is detected) above 25-30 have good correlation with being non-infectious (ie. unable to culture virus). Adequately approved & validated RATs (by FDA, TGA, MHRA, etc.) have very high sensitivity at CT less than this 25-30 range, depending on the study and specific manufacturer.
The bottom line...
An adequately-validated RAT, when correctly performed, is likely a sensitive indictor of individual infectiousness at that specific moment in time. The reliability of a negative RAT will be improved if using the same manufacturer and technique as a RAT previously positive test, and more so if there are several subsequent negative RATs.
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The World Health Organisation's Surgical Safety Checklist has been adopted and implemented by many hospitals throughout the world: from large tertiary teaching hospitals in wealthy countries, to small hospitals in low-resource settings.
The benefits to each hospital however are likely not the same. Does the WHO SSC implemented in a hospital that already has a 'Time Out' process bring the same benefit, if any, as to a hospital for which the checklist was completely new? Possibly not.
Several studies across a wide range of health systems have shown conflicting results in terms of reducing morbidity, mortality and length of stay.
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File under correlation-is-not-causation-but...
Sometimes even correlations are too significant and important to just be fobbed off by epidemiological cliché. This collection contains articles repeatedly showing association between doctor characteristics, particularly gender, and patient outcome.
Although most recently shown by Wallis in JAMA Surgery (2021), gender-outcome associations are depressingly not new.
- Female patients treated by male surgeons more commonly experience post-operative complications and death than when treated by female surgeons. (Wallis 2021)
- Care from male surgeons and/or anaesthesiologists is associated with longer lengths of stay after cardiac surgery. (Sun 2021)
- Female heart-attack patients are less likely to survive when treated by a male physician than a female physician. (Greenwood 2018)
- Treatment from female surgeons is associated with a lower 30 day mortality than the same from male surgeons. (Wallis 2017)
- In-patient care from a female physician is associated with lower 30 day mortality and readmission rate among elderly patients. (Tsugawa 2017)
The cause of this gender outcome disparity is unclear, and importantly these studies are hypothesis forming, rather than proving. Nonetheless both Wallis (2021) and Greenwood (2018) hint at causes, namely a lack of experience treating female patients for some male doctors, and consequential lesser understanding of gender-disease differences.
The temptation when attempting to understand this is to descend into medical gender essentialism – ironically, probably a contributor to the actual outcome disparities.
A similar doctor-outcome disparity is seen with age. Among physicians, care from older doctors was associated with worse outcomes (Tsugawa 2017), yet for surgeons older age conferred better outcomes (Tsugawa 2018; Satkunasivam 2020). Causes here are possibly a nexus between experience, up-to-date knowledge and work volume – but also, still unclear.
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