Dexmedetomidine may reduce post-operative delirium and at one month post-operative cognitive decline in elderly patients, associated with changes in brain-derived neurotrophic factor.
Children who are exposed to multiple general anaesthetics before age three demonstrate deficits on neurosphycological testing, although not children with a single exposure.
Although there is reasonable confidence that a single general anaesthetic before three years of age has no consequences for intelligence development, there is an association between multiple exposures and learning and behavioural difficulties, possibly including ADHD. Animal studies have demonstrated ADHD-like changes in juvenile rats exposed to general anaesthetics.
There is a plausible physiological explanation for how general anaesthesia may induce ADHD, involving disruption of the prefrontal cortex and basal ganglia via dopaminergic, glutaminergic and neutrophic factor mechanisms.
Nonetheless, evidence to date linking general anaesthetic exposure in young children and ADHD development is far from conclusive and – as with many areas of practice – requires further research.
The remifentanil PCA for labour analgesia controversy continues...
Those advocating its first-line use point to reassuring evidence of maternal satisfaction and acceptability, reduced epidural rates, and some suggestion of reduced instrumental delivery rates.
For the negative, the ongoing safety concerns created by routine use of remifentanil PCAs are foremost, particularly given how uneven hospitals can be at implementing best safety practices. Observed rates of significant desaturation range from 25-70%, in addition to potential neonatal effects.
The greatest challenge facing the remiPCA advocates, is that the labour epidural is still the most effective form of labour analgesia, and has only improved over the decades as safety has been both maintained and increased.
Maternal desaturation is common during remifentanil PCA analgesia for labour.
In women receiving a remifentanil PCA for labour analgesia, detectable hypoxia occurs in 25% of women and neonatal CPR potentially related to remifentanil in 1 in 300 babies.
Opioid anti-tussive pholcodine is a potent IgE stimulator, and may increase the risk of perioperative anaphylaxis, and contribute to observed regional variations in rocuronium anaphylaxis.
Pholcodine is an opioid anti-tussive (ie. cough suppressant). It is a common component of over-the-counter cough medications. However it has a special significant to anesthesiologists in relation to anaphylaxis risk, particularly related to neuromuscular agents.
Florvaag et al's 2009 review covers this issue very comprehensively. Earlier 2006 research from Florvaag et al attempting to explain some of the regional variability in anaphylaxis rates showed that exposure to pholcodine causes an 60-105 times increase in IgE levels!
Countries where pholcodine use is common (eg Norway) seem to have experienced higher levels of anaphylaxis to neuromuscular blocking agents than countries where it is not common (eg Sweden). In fact, in Norway rocuronium anaphylaxis was such a problem that its use was restricted to modified rapid sequence inductions. A pholcodine containing cough syrup has been withdrawn from the market in Norway because of this (and levels of sensitisation seem to be dropping although it is still too early to draw conclusions). It will be interesting to see if there are other compounds that have a similar effect on IgE sensitisation and whether other countries will consider withdrawing pholcodine products.
In addition to the two articles from Florvaag that specifically look at Pholcodine and it's effects, there is also an interesting review looking at recent insights into anaphylaxis in the anaesthetic setting from Dewachter and team.
High STOP-Bang score ≥ 3 continues to be a useful predictor of post-operative complications and length of hospital stay.