Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Oct 2023
Crystallization of short-acting and intermediate-acting local anesthetics when mixed with adjuvants: a semiquantitative light microscopy analysis.
The addition of adjuvants to short-acting local anesthetics (LA) is common practice in clinical routine to speed up block onset and decrease pain on injection. In a previous study, we observed the development of microscopic crystal precipitations after bupivacaine or ropivacaine were mixed with adjuvants; this follow-up study is intended to clarify whether crystallization (A) also occurs in short-acting or intermediate-acting LA-adjuvant mixtures, (B) changes over time, and (C) is associated with the solutions' pH. ⋯ Lidocaine 2% and mepivacaine 2% plus sodium bicarbonate 8.4%, and mepivacaine 2% plus dexamethasone developed delayed grade 5 crystallization over 1 hour. Prilocaine-based, procaine-based and chloroprocaine-based mixtures showed much less pronounced crystallization, with a maximum of grade 2. Initial pH and grade of crystallization showed weak monotonic relationships at time points t0, t15 and t30 (ρ=-0.17, 0.31 and 0.32, (all p>0.05)) and a moderate relationship time point t60 (ρ=0.57 (p=0.0003)) CONCLUSIONS: Our study revealed high grades of crystallization in lidocaine/mepivacaine-bicarbonate and mepivacaine-dexamethasone mixtures, although these were previously considered safe for local, perineural or neuraxial use. Our findings cast particular doubt on the safety of preparing these formulations for later use.
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Reg Anesth Pain Med · Oct 2023
Evaluating two approaches to the erector spinae plane block: an anatomical study.
Studies show variable spread with thoracic erector spinae plane (ESP) injections. Injection sites vary from lateral end of the transverse process (TP) to 3 cm from the spinous process, with many not describing the precise site of injection. This human cadaveric study examined dye spread of ultrasound-guided thoracic ESP block at two needle locations. ⋯ An ESP injection administered between TPs exhibits more extensive spread than a medial TP injection in a human cadaveric model.
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Reg Anesth Pain Med · Oct 2023
Case ReportsStellate ganglion block catheter for paroxysmal sympathetic hyperactivity: calming the 'neuro-storm'.
Paroxysmal sympathetic hyperactivity (PSH) is an autonomic disorder affecting patients with severe acquired brain injury characterized by intermittent sympathetic discharges with limited therapeutic options. We hypothesized that the PSH pathophysiology could be interrupted via stellate ganglion blockade (SGB). ⋯ SGB is a promising therapy for PSH, overcoming the limitations of systemic medications and may serve to recalibrate aberrant autonomic states.