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Why were Anaesthetists so early on COVID?

On a Monday morning in March, anaesthetist Dr Rob Hackett stood outside his children's inner Sydney school as a solitary protestor, asking parents to keep their children home if they could.

In the heady early days of the coronavirus pandemic, alarm was raised by a disparate mix of professionals: virologists and epidemiologists, journalists and technologists, and a range of frontline and critical care medical specialists exposed to the first COVID patients.

But as concern spread from the earliest hit countries to those threatened by their own surge, one specialty group was over-represented in public calls for early action: anaesthesia.

In Australia, medical anaesthetists from all states and territories spoke-up, not for health authorities and legislators, but for their communities. For a specialty most comfortable when not spoken of, suddenly anaesthetists were appearing in national newspapers, on radio, television, and even (very small) picket lines.

In Victoria, Dr Pieter Peach was a prominent early voice pushing for cancellation of Melbourne's Grand Prix. The Australian Society of Anaesthetist's fearless president Dr Suzi Nou guided the society's careful campaigns to prepare for the pandemic, pause elective surgery and then cautiously restart. In NSW, Dr Tanya Selak's advocacy was celebrated on Telstra's #saythanks billboard, while Rob picketed outside his children's school.

Like a warning telegram from 1940s London, the message scrawled on Rob's chest captured the zeitgeist of our specialty at the time:

"Lives depend on it. Government too slow to act."

Read on for why…

The Paradox of Avoidance

The cries of 'over-reaction' are as predictable as they are simplistic. Epidemiologists and pubic health experts knew they were coming, because avoiding a disaster brings little thanks.

As Australia emerges unevenly from its soft lockdown, anxious and still responding to COVID flares, it is the envy of much of the world. Alongside success achieved in places as varied as New Zealand, Vietnam, Taiwan, South Korea, Iceland and even austerity-inflicted Greece – the contrast with those that have suffered disastrous outcomes is obvious.

And yet the naysayers still question the painful necessity of the lockdowns, even as study after study demonstrates how the measures have avoided or delayed hundreds of millions of infections.

The United Kingdom, uniquely and even justifiably proud of its National Health System, first chose instead to ignore expert advice and offer up its venerated NHS as a funeral-pyre sacrifice to COVID and the gods of conservatism. Today more than 43,000 British are dead. (You know what would help NHS healthcare workers more than clapping? Earlier border closure and adequate access to PPE!)

Sweden pursued a Claytons lockdown founded on an ideological mix of misplaced intellectual-exceptionalism and responsibility-abdicating libertarianism (my eyes are rolling...). It has not gone well.

Despite making up less than 40% of the Nordic population, Sweden now accounts for five out of of six Nordic COVID deaths. Sweden has twice the population of neighbouring Norway but twenty-times the COVID mortality.

And then there is the Land of the Free, the United States. The wealthiest country on the planet, now the epicentre of the pandemic with well over 2 million infected and 120,000 deaths. A disaster due to a failure to act either early or decisively, a dash of magical thinking and an embarrassing absence of leadership.

It is disappointing that the main contribution the United States is currently making to the global COVID response is to serve as a warning to other nations.

The common theme among these failures is the inability to develop a rational response guided by expert advice. A virus does not care for your wishful thinking. A virus does not care for your political posturing, your dog-whistling or your belief in national uniqueness. A virus is the honey-badger of microbiology.

Which leads us back to the braying calls of 'over-reaction'. Whether former politicians, conservative economists, or performance artists playing opinion writers, they are all making the same mistake: misattributing causality and misunderstanding the purpose of modelling.

Read more on the paradox of avoidance...

Flattening the curve of pandemic research

The wave of COVID research continues, much of it low-quality and hurriedly published. This is apparently the norm for academic publishing during a pandemic: fast, furious and haphazard.

However, two very significant reviews appeared in The Lancet this week that impact and inform anaesthetists and other critical care specialists.

Post-operative mortality, COVID & surgery

Early pandemic data suggested that COVID-19 patients having even minor elective surgery suffered worse post-operative outcomes, particularly high post-operative mortality. The COVIDSurg Collaborative has confirmed this after a multicenter trial across 24 countries.

Across the entire 1,128 patient cohort, 30-day mortality was a jaw-dropping 24%. Yes, 1 in 4 died within 30 days of surgery.

Pulmonary complications (pneumonia, ARDS or unexpected post-op ventilation) were very common (51%) and were associated with an even higher mortality (38%; and 83% of all deaths). Mortality was unsurprisingly associated with older age ≥ 70 years, male sex, ASA ≥ 3, emergency surgery, major surgery, and malignancy.

But even among low-risk groups, post-operative mortality was shockingly high: 30-49 year olds (6%), women (18%), ASA 1-2 patients (12%), and even those without comorbidities (7%). Being asymptomatic at admission did not have a significant protective effect (22% vs 27% mortality).

Elective surgery still carried a 19% mortality rate, and even for minor surgery mortality was 16%! Anaesthesia modality (local, regional or GA) did not have a significant impact.

Click through to read the summary or full-text, though the obvious take-away is that non-essential surgery should be avoided as much as is possible in those with confirmed or suspected COVID.

This will have huge implications for recommencement of elective surgery in many pandemic-hit countries. (Cook & Harrop-Griffiths explore this very topic in an NHS-context in their recent editorial.)

Read on for physical distancing, face-mask and HCQ research...

Old, new and current trends in obstetric anaesthesia

Some interesting research on common and not-so-common obstetric anaesthesia topics: both new trends and continuing trends, as well as a cautionary medicolegal reminder.

Supraglottic airways for GA Caesarean?

Metodiev & Mushambi's editorial looks at the attitude shift among obstetric anaesthesiologists to more favourably consider the LMA or SGA for Caesarean section under GA.

They review the evidence for aspiration risk, particularly noting what we learned from NAP4 (2011) but contrast this with many studies showing safety of SGAs for GA CS (over 8,000 patients in total, with Halaseah 2010 investigating 3,000 alone!). Interesting, but before we get too excited keep in mind that the populations studied are likely very different from parturients you may typically look after.

They conclude:

"...there is insufficient evidence to recommend universal or selective replacement of tracheal tubes with SGA devices during general anaesthesia for Caesarean delivery. Aspiration remains the main concern." – Metodiev & Mushambi (2020)

Cautionary reminders of neuraxial injury

McCombe & Bogod reviewed 21 years of obstetric anaesthetic medicolegal claims, noting common themes around consent, types of nerve injury, and recognition and management failures.

Not only is neurological injury the second most common reason for obstetric anaesthetic claims (behind inadequately managed pain during Caesarean section), it carries the highest average claim cost.

The review is full of many useful observations, but Reynold's 2000 advice regarding interspace level choice for spinal access is by far the most important: always access the intrathecal space at the lowest possible level, and "...the L2/3 interspace should not be an option."

McCombe & Bogod spend some time exploring the variability of cord termination level, individual variability of the intercristal line, and the inaccuracy of anaesthetist interspace level estimation. Well worth reading the whole review.

Read on for CS vasopressor choices & heavy bupivacaine alternatives...

All Things Endotracheal

There have been some interesting papers recently exploring all-things endotracheal, relevant to anaesthesiologists, intensivists and emergency physicians alike.

Some challenge long-accepted dogma (ETT size), others confirm natural trends (cuffed paediatric tubes), or delve into ventilation physiology long forgotten by some of us (the ventral shift...).

Here's a brief stroll through five articles that may challenge your practice.

Choose smaller...

First, Karmali & Rose challenge the dogma surrounding endotracheal tube sizing in adult anaesthesia. They explore both the functional consequences of ETT size, good and bad, as well as the implications for airway trauma.

They describe how a modern ETT ≥ 6.0mm ID will accomodate most intraluminal devices, and in fact smaller sizes might even facilitate some airway procedures. Similarly, inspiratory and expiratory flow dynamics of smaller ETTs are inconsequential for most fit and healthy patients.

Noting that there is wide individual variation in tracheal dimensions, such that some patients are poorly served by a traditional ETT-size choice, they highlight the correlation between ETT size and airway trauma, hoarseness and sore throat, noting that for many patients a 'large' ETT offers little practical benefit.

"Instead of opting for ‘the largest tube that the larynx will comfortably accommodate’, we perhaps should consider using the smallest tube which permits the safe conduct of anaesthesia."

For routine anaesthesia of ASA 1 & 2 patients, an ETT sized 6.0-7.0 mm is probably the best balance between ventilation needs and airway trauma.

Don't cough

Yang et al.'s high quality meta-analysis explores the use of intravenous lidocaine/lignocaine to reduce a common, but potentially significant post-operative problem: coughing on extubation. Both coughing (reported incidence 15-94%) and post-operative sore throat (21-72%) are common among surgical patients.

This meta-analysis of 16 trials (though only 1,516 total subjects) showed a significant reduction in cough RR 0.64 (0.48-0.86 & NNT=5), and post-operative sore throat RR 0.46 (0.32-0.67), though no difference in laryngospasm, adverse events or time to extubation when using modern volatile agents.

However, they could make no clear recommendation of optimal timing or dose of lidocaine – although past reviews had found suggestion of a dose-effect, settling on 1.5 mg/kg as the best choice (Clivio et al. 2019).

Regardless, a simple intervention with peri-operative IV lidocaine reduces coughing on extubation and reduces post-operative sore throat, without any apparent increase in adverse events.

Read on for more ETT tidbits...

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