Regional Anesthesia

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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Pediatric Regional Anesthesia Complications

A somewhat reassuring study on pediatric anesthesia regional anesthesia that included both peripheral nerve and neuraxial blocks finds: “In a prospective multicenter cohort of more than 100,000 blocks in children, there were no cases of permanent neurologic deficit associated with regional anesthesia. The rate of transient neurologic deficit was low at 2.4 per 10,000, and the incidence of local anesthesia toxicity was also low at 0.76 per 10,000”.

There was only one epidural abscess, and one epidural hematoma in a paravertebral block. Transient neurological deficits did not differ between peripheral and neuraxial blocks. Importantly, no additional risk was observed with placing blocks under general anesthesia.

The most common adverse events were benign catheter-related failures (4%).

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Neuraxial Technique and Arthroplasty Outcome

A retrospective study on total hip and knee arthroplasty complications and correlation with neuraxial technique yields some interesting results. Whereas Combined Spinal Epidural (CSE) was the commonest technique, numerous post operative outcomes – cardiac, pulmonary, gastrointestinal, renal/genitourinary, and thromboembolic complications, and prolonged length of stay – were all lower in the Spinal Anesthesia group, suggesting an advantage for this technique. Pure epidural technique outcomes were no different from CSE.

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Neuraxial Morphine / Diamorphine & Cesarean Respiratory Depression

A systematic review of the use of neuraxial Morphine and Diamorphine found that the highest and lowest prevalences of  clinically significant respiratory depression after Cesarean delivery with the use of clinically relevant doses of neuraxial morphine ranged between 1.63 per 10,000 (95% CI, 0.62–8.77) and 1.08 per 10,000 (95% CI, 0.24–7.22), respectively. This study review is reassuring on the safety of neuraxial opioid analgesia at current practice doses (eg. 0.1 – 0.15mg spinal Morphine).

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Epidural Top-Ups in 2nd Stage Labor

The effect of top-ups in the second stage of labor was studied. Most women who received a top-up had a vaginal (spontaneous or assisted) delivery. Compared with women without a top-up, women requiring a top-up had more predictors of difficult labour and higher rates of assisted vaginal delivery and Cesarean delivery.

The need for top-ups may be a marker for difficult labor involving induction, augmentation, prolonged second stage etc.

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Hip Arthroscopy and Fascia Iliaca Block

“Preoperative fascia iliaca blockade in addition to intraarticular local anesthetic injection did not improve pain control after hip arthroscopy but did result in quadriceps weakness, which may contribute to an increased fall risk. Routine use of this block cannot be recommended in this patient population”.

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Note however that this block is highly recommended for elderly hip fracture blog link

 

Dexmedetomidine IV Prolongs ISBPB

The conclusion of this study was: “Intravenous Dexmedetomidine at a dose of 2.0 μg/kg significantly increased the duration of Interscalene Brachial Plexus Block analgesia without prolonging motor blockade and reduced the cumulative opioid consumption at the first 24 hours in patients undergoing arthroscopic shoulder surgery“. There was no greater degree of hypotension, bradycardia or sedation.

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Cesarean Spinal vs. Combined Spinal-Epidural

A literature search and analysis found no difference in spinal vs. combined spinal-epidural (CSE) for Cesarean in terms of sensory height, recede time, hypotension, vasopressor use, nausea and vomiting. A longer block time noted in the combined spinal-epidural group found, as might be expected.

Much uncertainty remains as to how different trial populations were managed e.g. lower intrathecal doses, epidural catheter use, post-op catheter use, and the individual circumstances that might prompt CSE use. Many anesthesiologists would still opt for CSE for anticipated longer surgeries or to use lowers spinal doses and also to have a rescue option rather than GA.  As a routine practice however, there seems no great advantage over spinal for Cesarean. This was not a study of CSE in labor analgesia.

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