Knowledge
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A collection of landmark papers relevant to anaesthesia and anesthesiology.
Generally, these papers are practice changing and hold current, ongoing significance beyond their historical importance.
This is a dynamic and changing document that will be updated, pruned and added to as appropriate. Many of these papers have free full-text provided by the publisher because of their significance.
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The association of anesthesia in the sitting beach-chair position with intra-operative stroke, continues to be controversial. Although some studies have identified this as a risk, it is still a rare complication, albeit devastating.
Expert opinion suggests intra-arterial blood pressure monitoring is best practice, but most importantly with consideration for actual cerebral perfusion pressure given the sitting position.
Some research suggests regional anaesthesia, possibly combined with spontaneous ventilation GA (rather than relaxation GA with IPPV) offers unique benefits that better maintain cerebral oxygenation, although the exact difference is unclear.
Similarly, the benefit and role of non-invasive cerebral perfusion monitoring has not been conclusively shown, although it appears logical that it may offer benefit in these patients.
Case studies of patients suffering cerebral ischaemia under beach-chair, do point to combinations of poor intra-operative blood pressure management and possibly pre-existing mild cardiovascular disease (eg. hypertension) as contributing to some degree.
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An extensive collection of research debunking a range of myths and misconceptions regarding the way we use neuromuscular blocking drugs.
- Myth 1: Modern relaxants are so reliable and predictable that monitoring is unnecessary.
- Myth 2: Post-op residual paralysis is neither common or important.
- Myth 3: Post-op residual paralysis is easy to identify.
- Myth 4: Sugammadex makes residual paralysis a non-issue. (it might, but only if it is routinely available and used!)
- Myth 5: Using propofol and remifentanil we can avoid relaxants for intubation all together.
- Myth 6: Neuromuscular blockade has no effect on BIS.
And bonus myth: deep relaxation is necessary for improving surgical access during laparoscopy.
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...and 1 more note
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The potential for dexamethasone and other glucocorticoids to prolong peripheral nerve blocks was first noted almost 20 years ago.
While the effect has been observed with several different blocks (upper & lower extremity, and even TAP blocks), the clinical significance varies and several questions still remain:
Is the effect exclusive to perineural dexamethasone? Several studies have observed similar effects for both IV and perineural dexamethasone (though less profound than other papers).
Is the effect safe? This is perhaps the most concerning, as there are suggestions that the effect may represent an enhancement of the well-known neurotoxicity of local anaesthetic agents.
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First described in 1909, and then used for treatment of various types of headache and facial pain, the sphenopalatine ganglion block may offer a novel, simple and less-invasive treatment for post-dural puncture headache.
Very little has been published, primarily case studies, case series and retrospective audits. This limited data does however suggest that the technique may be as effective as the traditional epidural blood patch, though with significantly fewer risks.
Larger studies are however needed to properly define the block's role in treating PDPH.
Publications describe a trans-nasal approach, either sitting or supine. First topicalising with co-phenylcaine spray, then placing 2%-4% viscous lignocaine-soaked cotton-tipped applicators for 10 minutes, and finally repeated for a further 20 minutes. Success appears to range from 30-70%.
The mechanism of action may result from parasympathetic blockade at the SPG, resulting in reversal of the cerebral vasodilation thought to be associated with post dural puncture headache.
Several videos showing how simple SPG techniques:
- Roger Browning demonstrating one method for performing a topical SPG block.
- SPG Block for chronic migraine.
- SPG demonstration in the ED setting.
- SPG demonstration for family member to perform later at home.