Article Notes
- Female patients treated in EDs with a higher percentage or a higher number of female physicians were more likely to survive. Although true of both care from a female or male physician, the beneficial survival effect of a greater female physician presence, was more marked when treated by a male doctor.
- Female patients treated by male physicians were also more likely to survive when the male physician had previously seen more female patients (0.02% increased survival for each female patient seen in the last quarter!).
- Intraoperative EEG accurately monitors anaesthetic depth.
- Using EEG to guide intraoperative depth may reduce both anaesthetic use and postoperative delirium.
- Reducing drug exposure and depth of anaesthesia probably has significant patient and societal benefits.
- All anaesthetists and anesthesiologists should be familiar with interpreting the raw EEG in the context of anaesthesia.
- While postoperative delirium is common in the over 65y age group (15-20%) and is associated with adverse outcomes, it is less clear that avoiding excessive depth reliably reduces postoperative delirium (some studies say yes, others...)
- Additionally, because post-op delirium is often used as (or at least inadvertently becomes) a surrogate marker for a range of adverse post-op events, then it follows that EEG monitoring should also be associated with reducing these events. This has not yet been shown.
- Analgesia post-caesarean section (CS) is of global importance, as both the most frequently performed surgical procedure, and one that is commonly associated with significant pain, impacting maternal experience.
- Fascial blocks, such as the transversus abdominis plane (TAP) and quadratus lumborum block (QLB), have been advocated for use in reducing post-CS pain. This network meta-analysis confirms the equivalent benefit of either block in improving post-operative pain in the absence of using intrathecal morphine.
- Although the QLB is advocated for its potential to reduce both somatic and visceral pain, unlike the TAP block, comparing studies investigating either block did not reveal any significant benefit of TAP over QLB.
- No analgesic benefit was found for either when intrathecal morphine is used (although TAP block may be associated with lower incidence of nausea, vomiting & sedation, in the presence of IT morphine).
- As is common to many meta-analyses, these conclusions are somewhat undermined by the moderate-to-low levels of evidence in the included studies.
Very interesting study covering 20 years of Floridian ED patient admissions for myocardial infarct, looking specifically at the influence of gender-discordance between patient and doctor.
The headline finding was that female heart-attack patients experienced lower survival when treated by a male physician than when by a female physician. Baseline mortality across all patients was 11.9%, with a 1.5% absolute survival decrease when compared to male patients treated by female physicians.
Although on the surface this absolute effect size could be misinterpreted as small, it represents a 12% relative risk difference – quite meaningful when we are considering mortality from the leading cause of death in the U.S.
Could the researchers suggest a reason?
The authors identified two interesting points:
"These results suggest a reason why gender inequality in heart attack mortality persists: Most physicians are male, and male physicians appear to have trouble treating female patients." – Greenwood, 2018
Daniel Jolley
Infratentorial craniotomies require a longer duration of surgery and higher exposure to anesthetic drugs and analgesics, and consequently are associated with higher rates of PONV. The article describes a 3 drug regimen adding scopolamine to the usual combination of dexamethasone and ondansetron.
Matthew Smith
A compelling argument that the EEG and it's derivative monitors should be 'standard of care' during anaesthesia, contrasting this with the ECG, arguably a less useful, actionable or meaningful monitor, yet has been widely considered a routine monitor for three decades.
The authors' main thesis is that:
However...
Daniel Jolley
Take-away message
Daniel Jolley
This large study 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."
Daniel Jolley
Unfortunate wording in the conclusion here, implying causation where in fact there is no evidence of such. Delivery mode does not have a significant effect – it is rather significantly associated with PPD.
The mode of delivery has a significant effect on the occurrence of mild postpartum depression.
It's unfortunate that the authors and editors were not more careful with their wording in a very emotionally-charged and controversial area.
Daniel Jolley
This airway study is a neat little randomised-but-not-blinded study of the effect of head rotation on the oropharyngeal leak pressure of both the i-gel and LMA Supreme 2nd generation supraglottic airways.
The researchers investigated the leak pressure (OPLP) of the i-gel and LMA Supreme in paralysed patients with the head: 1. neutral, 2. rotated 30°, and 3. rotated 60°. They found that rotation of the head through 30° and 60° progressively increased OPLP by a clinically-significantly amount (0° vs 60° 5.5 cmH2O (3.3-7.8) & 6.5 cmH2O (5.1-8.0) respectively).
Before you get too excited...
The result however may not be reliably applicable to all populations, notably the study subjects were overwhelmingly small (x̄ ~160cm & 60kg) Japanese women (71%), receiving a TIVA muscle-relaxant anaesthetic (propofol, remifentanil, rocuronium). How well this improvement-with-rotation holds up among, for example, spontaneously ventilating large Caucasian males, is unclear.
Bottom-line
When using an i-gel or LMA Supreme 2nd generation supraglottic airway, careful head rotation to 60° may increased oropharyngeal leak pressure and so assist with ventilation troubleshooting. However head and neck rotation of anaesthetised, paralysed patients should be performed gently and cautiously – you are after all, not a chiropractor!
Daniel Jolley
This interesting prospective simulation & equipment study is 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.
Daniel Jolley
This reassuring study published in Nature by researchers from Wash U Med investigated persisting COVID immunity following the Pfizer mRNA vaccination (BNT162b2). Turner et al. looked at the presence of not only circulating antibody-secreting B cells, but also germinal centre B cells found in the axillary lymph nodes of 14 study volunteers.
While the persistence of mRNA-vaccine induced immunity to SARS-CoV-2 has already been demonstrated to last at least 6 months, and likely 12 months, we just do not yet have the data to know if or when vaccine boosters will be required beyond that.
Turner's study is particularly exciting because they found spike-protein binding B cells in the germinal centre of draining lymph nodes in all 14 post-immunisation participants for the full 15 weeks of the study. The germinal centre response was so vigorous and persistent that the researchers believe this could represent COVID-protection lasting for years.
"Ellebedy said the immune response observed in his team’s study appears so robust and persistent that he thinks that it could last for years. The researcher based his assessment on the fact that germinal centre reactions that persist for several months or longer usually indicate an extremely vigorous immune response that culminates in the production of large numbers of long-lasting immune cells, called memory B cells. Some memory B cells can survive for years or even decades..." – Dr Francis Collins, NIH Directors Blog
This study builds on the same team's earlier work (Turner 2021 May) looking at bone marrow plasma cells in those who have recovered from mild COVID infection, also showing a long-lived immune response.
COVID persistent immunity takeaway:
Although COVID-19 and developed vaccines have been circulating for only 12-18 months, these immune-response studies give some hope that the miracle of mRNA vaccines may not only be in their efficacy, but also in the longevity of protection.
Daniel Jolley