Efficacité analgésique d'une anesthésie avec opioïdes versus sans opioïdes : une revue systématique de la littérature avec méta-analyses [Analgesic impact of intra-operative opioids versus opioid free anesthesia: a systematic review and meta-analysis] Les opioïdes sont administrés durant l'intervention afin de contrôler la réponse sympathique à un stimulus chirurgical, mais aussi pour soulager la douleur postopératoire. Récemment, l'utilisation des opioïdes durant la chirurgie a été remise en question en raison de l'absence probable de bénéfice dans la phase postopératoire immédiat, mais aussi en raison des effets secondaires, tels que les nausées et vomissements postopératoires. Le but de cette méta-analyse est d'investiguer si l'utilisation d'opioïde intraopératoire comparée à une stratégie sans opioïde permet de diminuer les douleurs postopératoires sans augmenter le taux de nausées et vomissements postopératoires. Nous avons inclus des essais cliniques randomisés et contrôlés effectués chez des patients adultes pour tout type de chirurgie qui ont étudié l'efficacité analgésique postopératoire d'une administration intraopératoire d'opioïde avec soit l'administration d'un placebo, soit l'absence d'administration. L'analyse des 23 études identifiées avec plus de 1300 patients inclus a démontré que les scores de douleurs au repos (échelle de 0 à 10, 0 étant aucune douleur et 10 la pire douleur imaginable) à 2h postopératoire étaient équivalents dans les deux groupes, avec une différence moyenne (IC 95%) de 0,2 point (-0,2 à 0,5), p=0,38. Les taux de nausées et vomissements postopératoires étaient de 24% dans le groupe avec opioïde et 19% dans le groupe sans ce qui représente un risque relatif (IC 95%) de 0,77 (0,61 à 0,97), p=0,03. En conclusion, l'utilisation d'opioïde intraopératoire ne diminue pas les douleurs postopératoires, mais est associée à une augmentation des nausées et vomissements postopératoire.

SummaryIntravenous magnesium has been reported to improve postoperative pain; however, the evidence is inconsistent. The objective of this quantitative systematic review is to evaluate whether or not the peri-operative administration of intravenous magnesium can reduce postoperative pain. Twenty-five trials comparing magnesium with placebo were identified. Independent of the mode of administration (bolus or continuous infusion), peri-operative magnesium reduced cumulative intravenous morphine consumption by 24.4% (mean difference: 7.6 mg, 95% CI )9.5 to )5.8 mg; p < 0.00001) at 24 h postoperatively. Numeric pain scores at rest and on movement at 24 h postoperatively were reduced by 4.2 (95% CI )6.3 to )2.1; p < 0.0001) and 9.2 (95% CI )16.1 to )2.3; p = 0.009) out of 100, respectively. We conclude that peri-operative intravenous magnesium reduces opioid consumption, and to a lesser extent, pain scores, in the first 24 h postoperatively, without any reported serious adverse effects. Magnesium has been reported to produce important analgesic effects including the suppression of neuropathic pain [1], potentiation of morphine analgesia, and attenuation of morphine tolerance [2]. Although the exact mechanism is not yet fully understood, the analgesic properties of magnesium are believed to stem from regulation of calcium influx into the cell [3] and antagonism of N-methyl-D-aspartate (NMDA) receptors in the central nervous system [1,4]. Since the completion of the first positive randomised controlled trial investigating magnesium as an analgesic adjuvant in 1996 [5], several additional trials have been published, with conflicting results [6][7][8]. Two narrative review articles [9,10] recently concluded that peri-operative magnesium does not confer any important analgesic benefit, but these conclusions were drawn from a small number of trials [9] and subject to inaccuracies in data reporting [10]. The administration of intravenous magnesium in the peri-operative setting is not without risk and should be based on evidence, as it may prolong neuromuscular blockade after administration of neuromuscular blocking drugs [11,12], increase sedation [13] and contribute to serious cardiac morbidity [14]. Consequently, the aim of this review is to define quantitatively the effect of peri-operative intravenous magnesium on acute postoperative pain.

Choosing Wisely (CW) campaigns globally have focused attention on the need to reduce low-value care, which can represent up to 30% of the costs of healthcare. Despite early enthusiasm for the CW initiative, few large-scale changes in rates of low-value care have been reported since the launch of these campaigns. Recent commentaries suggest that the focus of the campaign should be on implementation of evidence-based strategies to effectively reduce low-value care. This paper describes the Choosing Wisely De-Implementation Framework (CWDIF), a novel framework that builds on previous work in the field of implementation science and proposes a comprehensive approach to systematically reduce low-value care in both hospital and community settings and advance the science of de-implementation.The CWDIF consists of five phases: Phase 0, identification of potential areas of low-value healthcare; Phase 1, identification of local priorities for implementation of CW recommendations; Phase 2, identification of barriers to implementing CW recommendations and potential interventions to overcome these; Phase 3, rigorous evaluations of CW implementation programmes; Phase 4, spread of effective CW implementation programmes. We provide a worked example of applying the CWDIF to develop and evaluate an implementation programme to reduce unnecessary preoperative testing in healthy patients undergoing low-risk surgeries and to further develop the evidence base to reduce low-value care.