Regional Anesthesia

Aspirin for Thromboembolism Prophylaxis

“Aspirin alone may be an appropriate alternative to other pharmacologic prophylaxis in preventing VTE for patients undergoing total knee arthroplasty.”

So says this JAMA study but with the limitations of retrospective analysis and the subtleties of non-inferiority design. Nonetheless it adds to the debate and evidence on the use of aspirin alone as a potential strategy (which would also simplify neuraxial anesthesia concerns with anticoagulation).

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Anticoagulants and antiplateles in hip fracture surgery

Delay in hip fracture surgery can increase mortality (link ).

A Scottish Consensus statement on the management of patients on anticoagulants (and antiplatelet agents) presenting for hip fracture surgery incorporates current knowledge and views on when to proceed and how to expedite anticoagulant reversal with Vitamin K and/or Prothrombin Complex Concentrate, as well as antiplatelet agent considerations. Caution may also be needed with neuraxial techniques in such patients.

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Inter-professional Labor Epidural Attitudes

This survey finds differences between nurses, anesthesiologists and obstetricians. Timing of an epidural was influenced by patient desire for an epidural, primigravid patients without membrane rupture, oxytocin infusion initiated, labor epidural in a previous pregnancy, and a difficult airway.

“Different provider groups vary in comfort when managing labor epidural analgesia.

Willingness to advocate for epidural placement may depend on the cervical dilation.

Providers consider patient-specific factors when determining suitability”.

The authors posit that opportunity exists for inter-professional education and collaboration.

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Dural Sac Extent in Neonatal Caudal Block

An anatomic study in neonates sought to determine how close the dural sac was to the apex of the sacral hiatus, as this may lead to unintended spinal injection. Average distance in males was 10.9mm and 9.6mm in females; it increased with greater neonate length. Range was 4.9 -26.3mm.

“Anesthesiologists should be aware of the short distance between the sacral hiatus and the dural sac when performing caudal blocks, the shortest distance was 4.94 mm. Armed with this knowledge, caudal techniques should be modified to improve the safety and reduce the risk of complications, such as dural puncture.”

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Catheter-Over-Needle in Regional Anesthesia

A comparison was made between peripheral nerve blockade using catheter-through-needle and catheter-over-needle systems. There was no difference in analgesia or local anesthetic leakage, and the overall low rate of leakage was noteworthy. The catheter-over-needle system may have advantages in terms of speed of use and rate of inadvertent catheter dislodgement, but was associated with lower needle visibility on ultrasound.

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Transversus Abdominis Plane Block in Children

“In children, quality of postoperative pain control provided by transversus abdominis plane (TAP) block using levobupivacaine 0.4 mg·kg−1 administered as either 0.2% or 0.4% did not differ and was associated with a very low risk of local anesthetic systemic toxicity”. The study involved inguinal day surgery and about 70% did not require any postoperative opioids. However the study only compared the two concentrations, there being no comparison with a control group not given the TAP block.

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Peripheral nerve blockade in diabetic neuropathy

This study found that after ultrasound‐guided popliteal sciatic nerve block, patients with diabetic peripheral neuropathy had a reduced time to onset of sensory blockade, with increased time to first opioid request when compared with patients without neuropathy. 30 ml 1:1 mixture of lidocaine 1% and bupivacaine 0.5% was used

Concern has existed that patients with peripheral neuropathy have increased sensitivity as well as nerve injury risk from local anesthetics. The “double crush” hypothesis of already ischemic/hypoxia nerves suffering more injury from needles or local anesthesia has been a concern although not totally proven; this study was not powered to make such a conclusion. However, it may guide dose selection for peripheral nerve blocks in this population.

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Local vs. general anaesthesia for carotid endarterectomy

A new review may not ultimately settle the debate on general vs. local anesthesia for carotid endarterectomy. Only in analysis of observational studies showed reduced risk of stroke, TIA, MI and mortality. Randomized trial analysis did not show these benefits. LA decreased shunt insertion which may in itself increased embolic stroke.

All in all they conclude “Although randomised studies have not confirmed any advantage for local anaesthesia, this may be due to a lack of pooled statistical power in these trials”. Nonetheless as the gold standard, further randomized studies may be needed to settle the debate to account for confounding and other variables.

Spinal Hip Fracture Surgery and Sedation

A randomized study suggests limiting sedation, at least in those with low comorbidity scores, during hip fracture repair under spinal anesthesia to reduce delirium.  They conclude: “In the primary analysis, limiting the level of sedation provided no significant benefit in reducing incident delirium. However, in a prespecified subgroup analysis, lighter sedation levels benefitted reducing postoperative delirium for persons with a Charlson comorbidity index of 0“.

Whereas benzodiazepines are increasingly out of favour, this study used Propofol for sedation. The current winner for sedation is Dexmedetomidine and needs further study, as does the relationship of comorbidity to delirium, a serious issue linked to outcome and mortality.

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