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.
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Review Meta Analysis
Effect of intravenous dexamethasone on postoperative pain after spinal anaesthesia - a systematic review with meta-analysis and trial sequential analysis.
There are data suggesting that intravenous dexamethasone has an effect on postoperative analgesia when given during single-shot spinal anaesthesia. However, the research literature is equivocal. We performed a systematic literature search followed by conventional meta-analysis (random effects model). ⋯ The time to first analgesic request (95%CI) was significantly prolonged by 86.62 (10.62-162.62) min, I2 = 93%, in the dexamethasone group. For other secondary outcomes including number of patients requiring rescue analgesia, or visual analogue scale pain scores, we found no evidence of a significant difference between the treatment arms. We report a high level of evidence that intravenous dexamethasone improves postoperative analgesia after spinal anaesthesia.
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Review Meta Analysis Comparative Study
Intra-operative analgesia with remifentanil vs. dexmedetomidine: a systematic review and meta-analysis with trial sequential analysis.
Intraoperative dexmedetomidine infusions result in less postoperative pain, hypotension, shivering and PONV than remifentanil.
pearl -
Review Meta Analysis
Evidence for compromised data integrity in studies of liberal peri-operative inspired oxygen.
High intraoperative FiO2 does not significantly reduce surgical site infections.
pearl -
Review Meta Analysis
Analgesic impact of intra-operative opioids vs. opioid-free anaesthesia: a systematic review and meta-analysis.
Opioids are administered peri-operatively for postoperative analgesia, and intra-operatively to control the sympathetic response to surgical stimuli, frequently as a surrogate for presumed pain. However, opioid use during surgery is a matter of dispute in contemporary practice and carries the risk of side-effects such as postoperative nausea and vomiting. This meta-analysis investigated whether opioid-inclusive, compared with opioid-free anaesthesia, would reduce postoperative pain, without increasing the rate of postoperative nausea and vomiting. ⋯ Pain scores at rest at two postoperative hours were equivalent in the opioid-inclusive and opioid-free groups with a mean difference (95%CI) of 0.2 (-0.2 to 0.5), I2 = 83%, p = 0.38 and a high quality of evidence. Similarly, there was high-quality evidence that the rate of postoperative nausea and vomiting was reduced in the opioid-free group, with a risk ratio (95%CI) of 0.77 (0.61-0.97), I2 = 16%, p = 0.03 and high-quality evidence for a similar length of stay in the recovery area, the mean difference (95%CI) being 0.6 (-8.2 to 9.3), min, I2 = 60%, p = 0.90. As there is strong evidence that opioid-inclusive anaesthesia does not reduce postoperative pain, but is associated with more postoperative nausea and vomiting, when compared with opioid-free anaesthesia, we suggest that anaesthetists should reconsider their intra-operative opioid choices on a case-by-case basis.