Anaesthesia
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Review Meta Analysis
Prevention of hypotension after spinal anaesthesia for caesarean section: a systematic review and network meta-analysis of randomised controlled trials.
Why is this review important?
Although the importance of managing spinal anaesthesia-associated hypotension during caesarean section is well appreciated, there continues to be some debate over relative efficacy of interventions, whether vasopressors or fluid-loading.
Fitzgerald at al.'s review and network meta-analysis quantitatively compares a complete range of interventions across 109 studies.
What did they show?
Vasopressors were more effective at preventing intra-operative hypotension than fluid infusion techniques alone. Although there was no statistically significant difference in the incidence of hypotension among metaraminol, phenylephrine or noradrenaline/norepinephrine, metaraminol appeared the most effective (OR 0.04-0.26) and ephedrine the least (0.09-0.85). [vs Norepinephrine (OR 0.06-0.28), Phenylephrine (OR 0.11-0.29)]
Similarly, nausea and vomiting incidence was lower with vasopressors than other interventions. Phenylephrine more commonly caused bradycardia than other pressors, and ephedrine more commonly tachycardia. There was no significant difference in reactive hypertension.
The bottom-line...
The most effective way of preventing and managing maternal intraoperative hypotension is, as international guidelines already assert, alpha-agonist vasopressors. Using more complex protocols, such as phenylephrine or norepinephrine infusions, does not appear to offer benefit over metaraminol. Fluid infusions are at best a secondary intervention.
summary -
Regional anaesthesia has undergone several exciting advances in the past few decades. Ultrasound-guided techniques of peripheral nerve blockade have become the gold standard thanks to the associated improvements in efficacy, ease of performance and safety. This has increased the accessibility and utilisation of regional anaesthesia in the anaesthesia community at large and is timely given the mounting evidence for its potential benefits on various patient-centred outcomes, including major morbidity, cancer recurrence and persistent postoperative pain. ⋯ There is ongoing research into optimising continuous catheter techniques and their management, intravenous and perineural pharmacological adjuncts, and sustained-release local anaesthetic molecules. Finally, there is a growing appreciation for the critical role that regional anaesthesia can play in an overall multimodal anaesthetic strategy. This is especially pertinent given the current focus on eliminating unnecessary peri-operative opioid administration.
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Randomized Controlled Trial
Quadratus lumborum block for analgesia after caesarean section: a randomised controlled trial.
Quadratus lumborum block has been shown to provide satisfactory analgesia after caesarean section performed under neuraxial anaesthesia. However, its efficacy has not been demonstrated in patients who have received intrathecal morphine. The aim of this study was to assess the efficacy of quadratus lumborum block as part of a multimodal analgesic regimen including intrathecal morphine. ⋯ There was a reduction in median (IQR [range]) visual analogue scale pain scores at 6 h with quadratus lumborum block compared with sham block both at rest (6 (0-14 [0-98]) mm vs. 14 (3-23 [0-64]) mm (p = 0.019); and on movement: 23 (10-51 [0-99]) mm vs. 44 (27-61 [2-94]) mm; (p = 0.014)). There was no difference in pain scores at any other time-point up to 48 h. When used in conjunction with intrathecal morphine and spinal anaesthesia, bilateral quadratus lumborum block does not reduce 24-h morphine consumption after caesarean section.
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Editorial Comment
Restoration of function: the holy grail of peri-operative care.