(Anesth Analg. 2019 Jan 8. doi: 10.1213/ANE.0000000000003975) Numerous studies have evaluated the risks and benefits of intrathecal fentanyl when added to bupivacaine during cesarean delivery. While potential advantages of intrathecal fentanyl over intrathecal morphine include faster onset and less cephalad spread, some have feared an increased risk of respiratory depression, a “ceiling effect” at doses >0.25 μg/kg, and increased postoperative intravenous opioid requirement. In order to clarify the benefits, harms, and optimal dosing of this opioid for cesarean delivery, these authors systematically reviewed evidence regarding the efficacy and safety of fentanyl when used as an additive to intrathecal bupivacaine with and without morphine.

The goal of the present systematic review is to determine the efficacy of the quadratus lumborum block (QLB) in providing postoperative analgesia for abdominal wall and hip surgeries when compared with placebo or other analgesic techniques. Methods Electronic databases (Medline, Embase, Cochrane Central, and Scopus) were searched for keywords and controlled vocabulary terms related to QLB from their inception to November 2019. The included studies compared ultrasound-guided singleinjection QLB to placebo and other analgesic techniques in adult patients. Results Forty-two randomized-controlled trials provided the data for this systematic review. Eight studies were assessed as high risk of bias in at least one domain. The included studies had significant heterogeneity with regard to the type of surgery, comparator groups, and outcomes measured; therefore, a limited quantitative analysis was undertaken for the comparison of QLB vs no block or placebo in patients undergoing Cesarean delivery only. For Cesarean delivery, the QLB reduced the opioid use by

Background: Multi-injection targeted intracluster injection ultrasound-guided supraclavicular brachial plexus block has been advocated to provide a faster onset of anaesthesia compared with a double injection technique. By placing the needle within clusters of hypoechoic structures, corresponding to neural tissue, this technique may increase needle trauma and the incidence of nerve injury. This study assessed the rate of sub-perineural needle placement with a single intracluster brachial plexus injection in the supraclavicular fossa of human cadavers. Methods: A single ultrasound-guided intracluster brachial plexus injection was performed bilaterally at the supraclavicular fossa on 21 lightly embalmed clinical grade cadavers. Using an in-plane technique, an echogenic needle was positioned to target the middle or lower trunk 'cluster', where 0.2 ml black India ink was injected. An effort was taken to avoid the hypoechoic structures with the needle tip. Tissue samples were assessed histologically by two experienced reviewers. Results: All 42 injections were sonographically assessed to be within the 'main cluster'. Ink was extra-epineural in 13/41 (32%), sub-epineural but outside perineurium in 18/41 (44%), and sub-perineural in 10/41 sections (24%; 95% confidence interval, 13e41%). The histology from one injection was uninterpretable. Of the 10 sub-perineural deposits, the ink was intrafascicular in nine sections. Conclusions: We observed a high rate of sub-perineural injection with a single intracluster injection. Thus the targeted intracluster injection supraclavicular block cannot be recommended until further evidence is available regarding the safety of this technique.

Both hyperbaric bupivacaine and isobaric bupivacaine provided effective anesthesia with no difference in the failure rate or adverse effects. The hyperbaric formulation allows for a relatively rapid motor block onset, with shorter duration of motor and sensory block. The isobaric formulation has a slower onset and provides a longer duration of both sensory and motor block. Nevertheless, the small sample size and high heterogeneity involving these outcomes suggest that all the results should be treated with caution.

BACKGROUND: Fentanyl and morphine are the 2 most commonly added opioids to bupivacaine for spinal anesthesia during cesarean delivery. Numerous clinical trials have assessed efficacy and safety of different doses of fentanyl added to intrathecal bupivacaine for spinal anesthesia, yet its benefit, harm, and optimal dose remain unclear. This study aimed to systematically review the evidence of the efficacy of fentanyl when added to intrathecal bupivacaine alone and when added to bupivacaine with morphine for spinal anesthesia during cesarean delivery. METHODS: Key electronic databases (PubMed, Embase, and Cochrane Library) were searched for randomized controlled trials in the cesarean delivery population. The primary outcome was the failure rate of spinal anesthesia, as assessed by the need for either conversion to general anesthesia or intraoperative analgesic supplementation. Two reviewers independently extracted the data using a standardized electronic form. Results are expressed as relative risks or mean differences with 95% CIs. RESULTS: Seventeen randomized controlled clinical trials (most judged as low or unclear risk of bias) with 1064 participants provided data for the meta-analysis. Fentanyl added to intrathecal bupivacaine alone reduced the need for intraoperative supplemental analgesia (relative risk, 0.18; 95% CI, 0.11–0.27; number needed to treat, 4) and the incidence of nausea/vomiting (relative risk, 0.41; 95% CI, 0.24–0.70; number needed to treat, 6.5), with longer time to first postoperative analgesia request (mean difference, 91 minutes; 95% CI, 69–113). No difference was observed regarding the need for conversion to general anesthesia (relative risk, 0.67; 95% CI, 0.12–3.57), the incidence of hypotension, the onset of sensory block, or the duration of motor block. However, the addition of intrathecal fentanyl was associated with higher incidence of intraoperative pruritus (relative risk, 5.89; 95% CI, 2.07–16.79; number needed to harm, 13.5). The inclusion of fentanyl to intrathecal bupivacaine–morphine compared to intrathecal bupivacaine–morphine alone conferred a similar benefit, with a significantly reduced need for intraoperative supplemental analgesia (relative risk, 0.16; 95% CI, 0.03–0.95; number needed to treat, 9). Analysis using a funnel plot indicated a possibility of publication bias in included studies. CONCLUSIONS: Current evidence suggests a benefit of using fentanyl as both an additive to intrathecal bupivacaine alone and to intrathecal bupivacaine combined with morphine for cesarean delivery under spinal anesthesia. The possibility of publication bias, small sample size, and high risk of bias in some of the included studies warrant treating the results with caution.

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