gasexchange

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 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...

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...

Ah, videolaryngoscopes – wonderful toys increasingly common in operating rooms, intensive care units and emergency departments throughout the world.

After the first video laryngoscope was conceived by New York emergency physician Jon Berall in 1998, commercial success quickly followed with the 2001 Glidescope (designed by a vascular surgeon nonetheless!). Our love of the videolaryngoscope has grown ever since.

Like many anaesthetists and anesthesiologists I've used several different videolaryngoscopes over the past few years. The character that sets apart the videoscopes I like to use from those I do not is how well they enhance airway techniques I use every day rather than requiring a new technique specific to their device.

Overwhelmingly this comes down to how similar the laryngoscope is to a standard Macintosh blade rather than inventing a whole new shape. While there may be theoretical (or even real!) benefits to increasing the angle of the blade or adding extra conduits, when I have a difficult airway I want to augment the tools and techniques I use every day rather than change to something completely different. (When I want to change to something completely different I'll pick up a fibreoptic bronchoscope or something sharp!)

Read more...

I recently learned of something in educational theory that lead me to a small epiphany: threshold concepts.

Critical care specialties are full of threshold concepts.

What is a threshold concept?

The idea of a threshold concept in learning was first introduced by Meyer and Land¹, focusing on economics education. They described this as concepts that "...once understood, transform perception of a given subject."

A threshold concept provides a gateway to a greater, more in-depth understanding of an area – but is often difficult to master. Meyer and Land described a threshold concept as having:

"...the notion of transformation (in which students change the way they perceive and practice aspects of their discipline), irreversibility (once learnt rarely forgotten or 'unlearnt'), integrative (whereby connections are made to concepts or knowledge of previously unknown or concealed areas), bounded (in that they help define the boundaries of a subject area) and potentially troublesome." K. Connan (2014)

Read more...