British journal of anaesthesia
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Why is this important?
Hypotension associated with spinal anaesthesia for Caesarean section is common. Increased interested over the past decade has resulted in some consensus recommending phenylephrine infusions, however there are few studies that directly compare this to other vasopressors.
What did Singh and team do?
By analysing 52 high-to-moderate quality RCTs and over 4,000 patients, Singh performed a Bayesian network meta-analysis to indirectly compare various vasopressors.
It's notable that umbilical artery base excess was used as the primary outcome, although other neonatal and maternal outcomes (nausea, vomiting, bradycardia) were secondarily assessed. Nonetheless, this study prioritised the fetal effects of hypotension management.
"We selected umbilical arterial BE as our primary outcome because it is thought to represent the effect of pronounced fetal hypoxaemia, anaerobic metabolism, and accumulation of non-volatile acids, that is the metabolic component of acidaemia."
Ok, what's a Bayesian network meta-analysis anyway?
A network meta-analysis compares trial interventions indirectly, when researchers are interested in a comparison between two factors (eg. use of metaraminol vs phenylephrine) that have not been directly compared by included RCTs (eg. a study comparing metaraminol vs ephedrine, and a study of phenylepherine vs ephedrine). A Bayesian NMA allows simultaneous comparison of multiple-arm trials, considering prior probability along with the likelihood of outcome rank between interventions.
A Bayesian NMA acknowledges the uncertainty of research conclusions and the probabilistic nature of clinical decision making.
Singh concluded...
Norepinephrine (noradrenaline), metaraminol, and mephentermine showed the lowest likelihood of adverse neonatal acid-base effects, and ephedrine the greatest.
"...norepinephrine, metaraminol, and mephentermine had the lowest probability of adversely affecting the fetal acid-base status as assessed by their effect on umbilical arterial base excess (probability rank order: norepinephrine > mephentermine > metaraminol > phenylephrine > ephedrine)."
When combined, there was a 66% probability that norepinephrine & mephentermine are the best agents for supporting umbilical a. BE.
There was a 66% probability that metaraminol is the best treatment for optimising umbilical artery pH, an 85% combined-probability that metaraminol & norepinephrine are best for umbilical a. pCO2, and 85% that they are the two best agents for avoiding maternal nausea and vomiting.
Be smart
Given the very nature of meta-analyses and the challenge of indirect comparison among agents from heterogenous studies, the conclusions are only suggestive of the benefits of phenylephrine alternatives. A large RCT is still needed! (And despite it's popularity in some countries, there are still only a small number of trials of metaraminol.)
Nevertheless, other than for bradycardia, ephedrine was most likely the worst for all outcomes, reinforcing past conclusions that there are better pressor choices.
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Review Meta Analysis
Intravenous lidocaine to prevent postoperative airway complications in adults: a systematic review and meta-analysis.
Intravenous lidocaine/lignocaine reduces post-extubation cough and sore throat.
pearl -
Randomized Controlled Trial Multicenter Study
Hypnosis and communication reduce pain and anxiety in peripheral intravenous cannulation: Effect of Language and Confusion on Pain During Peripheral Intravenous Catheterization (KTHYPE), a multicentre randomised trial.
Clinicians traditionally warn patients of pain before peripheral i.v. cannulation (PIVC). However, using words related to pain or undesirable experiences can result in greater pain and anxiety. The use of positive words can improve pain perception and subjective patient experience. We aimed to compare the effects of three types of communication, including hypnotic communication, on pain, comfort, and anxiety in patients during PIVC. ⋯ NCT02662322.
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Multicenter Study
Association between propofol dose and 1-year mortality in patients with and without a diagnosis of solid cancer.
Preclinical data suggest suppression of cancer proliferation by propofol, and retrospective studies suggest improved survival after cancer surgery with propofol-based anaesthesia. ⋯ Increasing propofol dose is associated with lower 1-yr mortality in patients without, but not in patients with, a diagnosis of solid cancer. We found evidence for competing effects, modifying the association between propofol dose and mortality.
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The Women in Anaesthesia Research Symposium (Prato, Italy; 4 June, 2019), supported by the British Journal of Anaesthesia in collaboration with Monash University, was organised to discuss challenges facing women in anaesthesia clinical practice and research. We provide an overview of institutional or departmental measures that were proposed during the symposium that may empower women in anaesthesia today.