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Posts tagged Anesthesiology.

Does a GA CS increase PPD risk? Plus LMA studies & COVID vaccine optimism

GA caesarean section & post-partum depression

This large study (Guglielminotti 2020) of 428,204 New York caesarean section records (2006-2013), including 34,356 general anaesthetics (8%), investigated the association between mode of anaesthesia and post-partum depression (PPD). Other studies have shown an association between caesarean section (emergency > elective) and PPD. (Sun 2021, Xu 2017, and others), though this is the first to look specifically at general anaesthesia as a PPD risk factor.

Guglielminotti and Li found that general anaesthesia increased the odds of severe PPD by 54% (aOR 1.54, 1.21-1.95), and suicidal ideation by a massive 91% (aOR 1.91, 1.12-3.25), though not a significant increase in anxiety or PTSD.

The researchers discuss many potential causative factors, particularly known associations between GA CS & poor pain control, and subsequent pain & PPD – while also acknowledging the obvious potential for confounders. Of note patients receiving GA were older, more often non-Caucasian, had more co-morbidities, neonatal complexity, and lower socio-economic levels – also all independently associated with PPD risk.

In order to quantify the potential confounding contribution of emergency vs elective status, the researchers employed the novel E value:

To assess the impact of emergent cesarean delivery on our results, we calculated the E value associated with the aOR for the risk of PPD and suicidality. This relatively new metric takes into consideration 2 associations: (1) that between the confounder (emergent cesarean delivery) and the outcome (PPD); and (2) the association between the confounder (emergent cesarean delivery) and the exposure (general anesthesia).

An E value of 1.7 for the unmeasured confounder emergent cesarean delivery indicates that to explain away the association between general anesthesia and depression, either: (1) emergent cesarean delivery increases the risk of depression by at least 70%; or (2) emergent cesarean delivery is at least 70% more prevalent among general anesthesia than among neuraxial anesthesia. Either association is clinically plausible.

Keep it in perspective...

We already know that general anaesthesia for CS is suboptimal: it compromises both maternal experience and safety, but it should (hopefully) only ever be a chosen mode of anaesthesia when there is a true contraindication to regional anaesthesia – even at the modestly-high 8% GA rate among this New York cohort.

Looking at it from the other end, bear in mind that the modestly-faster time-to-incision for GA over regional is also of questionable neonatal benefit.

The take-home:

Just another reason to avoid GA CS when possible – but you already knew that, right?

"...general anesthesia is a potentially modifiable risk factor for PPD. This finding provides further supporting evidence favoring neuraxial over general anesthesia in cesarean delivery whenever possible."

Supraglottic airway training and manikins

Interesting prospective simulation & equipment study by way of the University of Freiburg. Schmutz et al. investigated how effective five different second generation supraglottic airway devices (SADs) performed in two common airway manikins: the TruCorp AirSim® and the crowd favourite, Laerdal's Resusci Anne® Airway Trainer™.

While ventilation was achieved in all SAD-manikin combinations, the Resusci Anne® Airway Trainer™ was associated with better and more consistent performance for SAD position, participant subjective assessment and ease of gastric tube insertion for most of the SADs. The TruCorp AirSim® did however achieve better leak pressures across most of the SADs (LMA® Supreme™, Ambu® AuraGain™, i-gel®, KOO™-SGA & LTS-D™).

But then, what are the implications for airway simulation training? The researchers correctly note that:

The most important quality of a manikin is the ability to simulate the real-world conditions and thus to give the trainee an authentic feedback.

The bottom line for SAD manikins?

While considering how manikin choice and SAD availability match with your aims for simulation training, the bigger picture is that the primary goal of any manikin-SAD coupling is real-life fidelity – and for that reason, participant subjective assessment is king. And so in this study at least, the Resusci Anne® Airway Trainer™ wins.

Read on for head rotation with LMAs & COVID vaccine persistence...

PONV, Perioperative Bleeding Aids & Surgery Timing After COVID

A big PONV meta-analysis

Interesting Cochrane meta-analysis looking at PONV prophylaxis from German (Weibel et al. 2021) that included almost 100,000 study participants across 585 trials. Interesting not so much because it confirms much of what we already new (or assumed, based on our common PONV prophylaxis drug choices), but because it reassures us that side-effects from commonly used PONV drugs are low to non-existent.

PONV Takeaway:

Granisetron is probably the best single-agent or in combination with other agents because of it's efficacy (better than ondansetron), low-cost, long duration, and absent side-effects.

A cognitive aid to better manage perioperative bleeding

Although the benefits of cognitive aids to many areas of anaesthesia are well established, our resistance to using decision support tools persists. Whether due to misplaced perceptions of losing autonomy or Dunning Kruger-adjacent inflated belief in our ability to perform under pressure, is unclear.

In Anaesthesia, Kataife et al. (2021) describe a cognitive aid for better managing perioperative haemorrhage, the Haemostasis Traffic Light algorithm. Using a simulation-based RCT across two centres (University Hospital Zurich & The Italian Hospital of Buenos Aires, N=84), they showed that using the HTL improved case solutions (OR 7.23, 3.82-13.68), quickened therapeutic decisions, (HR 1.97, 1.18-3.29), improved therapeutic confidence, (OR 4.31, 1.67-11.11) and reduced workload perception.

The aim of the HTL is to improve both situational awareness and decision making, by integrating clinical judgement and point-of-care testing (ROTEM) within an accessible, structured algorithm.

Haemostasis Traffic Light takeaway:

Kataife's study again shows the benefit of cognitive aids, particularly in critical, time-sensitive situations. The anaesthesia and critical care community's historical resistance to decision-support tools requires challenge.

Read on for timing of surgery after COVID infection...

A & A Case Reports now indexed by metajournal

Anesthesia and Analgesia's companion journal Anesthesia and Analgesia Case Reports is now indexed by metajournal, after being requested by our users.

A & A Case Reports has only been around since October 2013, after spinning off from the prestigious Anesthesia & Analgesia. It is now a standalone publication "...devoted exclusively to publishing cases that are educational and unusual."

A & A Case Reports now indexed by metajournal

You can jump in a browse the latest from A & A Case Reports among our indexed journals.

UPDATE:

Anesthesia & Analgesia has now evolved A & A Case Reports into A & A Practice – naturally, also indexed by metajournal!

The Cardiology Referral: Avoid hypoxia, avoid hypotension?

Recently I needed to refer a patient preoperatively to a cardiologist for review. This is not an uncommon situation – one which happens thousands of times every week throughout the world. And yet it is a referral that anesthesiologists and anesthetists often do very poorly.

Avoid hypoxia, avoid hypotension?

We sometimes roll our eyes at recommendations made by physician colleagues: either providing unhelpful physiological parameters that we normally aim to maintain anyway (“avoid hypoxia?”), or stepping outside their expertise and boxing the anesthetist in by suggesting specific anesthetic techniques (“okay for a spinal”).

It is easy to be annoyed at both the lack of value this adds to our perioperative planning, as well as to the nonchalant ignorance of intraoperative medicine that it betrays. At the end of the day though, it’s our fault.

As Dr Andrew Silvers, a Melbourne cardiac and neuro-anesthetist recently opined, if your cardiologist replies with “avoid hypoxia and avoid hypotension” then YOU the anesthetist or anesthesiologist are at fault for not asking your cardiology colleague specific questions that will materially effect your perioperative planning.

Read more...

Sugammadex and rocuronium anaphylaxis

I have been intrigued since the first case reports appeared describing the use of sugammadex in rocuronium anaphylaxis. It sounds beautiful and elegant. A drug that magically mops up the offending molecule, removing it from circulation; quickly reversing the cardiovascular collapse as rapidly as it reverses muscle relaxation.

The little we know

  1. There have been case reports from 5 countries showing dramatic improvement of rocuronium-confirmed anaphylaxis after administration of sugammadex.
  2. One case study showed a dose-dependent effect of sugammadex on modifying anaphylaxis.
  3. There are not yet any published cases of rocuronium anaphylaxis where sugammadex was administered without clinical improvement (though beware).
  4. Sugammadex although incompletely encapsulating rocuronium, does prevent the rocuronium epitope from binding IgE.
  5. Cutaneous and in vitro models of hypersensitivity have shown no or limited ability of sugammadex to modify type 1 hypersensitivty after triggering.
  6. Our understanding of the pathophysiology of anaphylaxis is over-simplified and incomplete.

Unfortunately the truth is not quite as clear. Case reports showing impressive recovery of rocuronium anaphylaxis minutes after giving sugammadex are tempered by in vitro and in vivoimmunological studies suggesting an inability of sugammadex to modify a type 1 hypersensitivity reaction. The reality is likely somewhere in between, highlighting our limited understanding of anaphylaxis and our tendency to rush to over-simplified models of disease processes.

The story so far...

Jones and Turkstra first raised the possibility of using sugammadex to treat rocuronium anaphylaxis in 2010.1 One year later Nolan McDonnell and team published the first case report of a remarkable use of sugammadex to manage rocuronium anaphylaxis.2 McDonnell described a 33 year old having an elective diagnostic laparoscopy suffering anaphylaxis to rocuronium. After 19 min of conventional resuscitation, involving CPR, 3500 mL of intravenous fluids and 4 mg of epinephrine/adrenaline - 500 mg of sugammadex was given with remarkable effect:

"A dose of 500 mg (6.5 mg kg21) was given while chest compressions were in progress. The last dose of epinephrine had been given 4 min previously. Approximately 45 s after administration and while chest compressions were in progress, the patient suddenly opened her eyes and reached for her tracheal tube.

Read more...


  1. Jones PM, Turkstra TP. Mitigation of rocuronium-induced anaphylaxis by sugammadex: the great unknown. Anaesthesia. 2010 Jan;65(1):89-90; author reply 90. 

  2. McDonnell NJ, Pavy TJ, Green LK, Platt PR. Sugammadex in the management of rocuronium-induced anaphylaxis. Br J Anaesth. 2011 Feb;106(2):199-201. 

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