British journal of anaesthesia
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Over the past decade, the mechanisms underlying placebo effects have begun to be identified. At the same time, the placebo response appears to have increased in pharmacological trials and marked placebo effects are found in neurostimulation and surgical trials, thereby posing the question whether non-pharmacological interventions should be placebo-controlled to a greater extent. In this narrative review we discuss how the knowledge of placebo mechanisms may help to improve placebo control in pharmacological and non-pharmacological trials. ⋯ Finally, we discuss how systematic investigations into placebo mechanisms across various pain conditions and types of treatment are needed in order to 'personalise' the placebo control to the specific pathophysiology and interventions, which may ultimately lead to identification of more effective treatment for pain patients. In conclusion this review shows that it is important to understand how patients' perception and expectations influence the efficacy of active and placebo treatments in order to improve the test of new treatments. Importantly, this applies not only to assessment of drug efficacy but also to non-pharmacological trials on surgeries and stimulation procedures.
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Clinical indicators are powerful tools to quantify the safety and quality of patient care. Their validity is often unclear and definitions extremely heterogeneous. As part of the International Standardised Endpoints in Perioperative Medicine (StEP) initiative, this study aimed to derive a set of standardised and valid clinical outcome indicators for use in perioperative clinical trials. ⋯ PROSPERO 2016 CRD42016042102 (http://www.crd.york.ac.uk/PROSPERO/display_record.php? ID=CRD42016042102).
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Preoperative anaemia is associated with elevated risks of postoperative complications. This association may be explained by confounding related to poor cardiopulmonary fitness. We conducted a pre-specified substudy of the Measurement of Exercise Tolerance before Surgery (METS) study to examine the associations of preoperative haemoglobin concentration with preoperative cardiopulmonary exercise testing performance (peak oxygen consumption, anaerobic threshold) and postoperative complications. ⋯ Haemoglobin concentration explains a small proportion of variation in exercise capacity. Both anaemia and poor functional capacity are associated with postoperative complications and may therefore be modifiable targets for preoperative optimisation.
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Comparative Study
Measurement of relative lung perfusion with electrical impedance and positron emission tomography: an experimental comparative study.
Electrical impedance tomography (EIT) with indicator dilution may be clinically useful to measure relative lung perfusion, but there is limited information on the performance of this technique. ⋯ The agreement between EIT and PET for measuring and tracking changes of relative lung perfusion was satisfactory for clinical purposes. Indicator-based EIT may prove useful for measuring pulmonary perfusion at bedside.
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Naloxone, an opioid receptor antagonist, is used as a pharmacological tool to detect tonic endogenous activation of opioid receptors in experimental pain models. We describe a pharmacokinetic model linking naloxone pharmacokinetics to its main metabolite after high-dose naloxone infusion. ⋯ NCT01992146.