Perfusion Index: Physical Principles, Physiological Meanings and Clinical Implications in Anaesthesia and Critical Care

Short title: Clinical Usefulness of Perfusion IndexInternational audiencePhotoplethysmography (PPG) has been extensively used for pulse oximetry monitoring in anaesthesia, perioperative and intensive care. However, some components of PPG signal have been employed for other purposes, such as non-invasive haemodynamic monitoring. Perfusion index (PI) is derived from PPG signal and represents the ratio of pulsatile on non-pulsatile light absorbance or reflectance of the PPG signal. PI determinants are complex and interlinked, involving and reflecting the interaction between peripheral and central haemodynamic characteristics, such as vascular tone and stroke volume. Recently, several studies have shed light on the interesting performances of this variable, especially assessing regional or neuraxial block success, and haemodynamic monitoring in anaesthesia, perioperative and intensive care. Nevertheless, no review has yet been published concerning the interest of PI in these fields. In this narrative review will be exposed first the physiological and pathophysiological determinants of PI, and then the mean to measure this value as well as its potential limitations. In the second part, the existing data concerning usefulness of PI in different clinical settings such as operating theatres, intensive care units and emergency departments will be presented and discussed. Finally, the perspectives concerning the use of PI and mentioned aspects that should be explored regarding this tool will be underlined

Does Culture Shape Our Understanding of Others’ Thoughts and Emotions? An Investigation Across 12 Countries

Q2Q2Measures of social cognition have now become central in neuropsychology, being essential for early and differential diagnoses, follow-up, and rehabilitation in a wide range of conditions. With the scientific world becoming increasingly interconnected, international neuropsychological and medical collaborations are burgeoning to tackle the global challenges that are mental health conditions. These initiatives commonly merge data across a diversity of populations and countries, while ignoring their specificity. Objective: In this context, we aimed to estimate the influence of participants’ nationality on social cognition evaluation. This issue is of particular importance as most cognitive tasks are developed in highly specific contexts, not representative of that encountered by the world’s population. Method: Through a large international study across 18 sites, neuropsychologists assessed core aspects of social cognition in 587 participants from 12 countries using traditional and widely used tasks. Results: Age, gender, and education were found to impact measures of mentalizing and emotion recognition. After controlling for these factors, differences between countries accounted for more than 20% of the variance on both measures. Importantly, it was possible to isolate participants’ nationality from potential translation issues, which classically constitute a major limitation. Conclusions: Overall, these findings highlight the need for important methodological shifts to better represent social cognition in both fundamental research and clinical practice, especially within emerging international networks and consortia.https://orcid.org/0000-0001-9422-3579https://orcid.org/0000-0001-6529-7077Revista Internacional - IndexadaA2N

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Arrêt ou poursuite des antihypertenseurs en peropératoire ? Le point de vue de l’anesthésiste-réanimateur

International audienceAnaesthesia of hypertensive is a common and risky situation due to the occurrence of cardiovascular complications. A cardiovascular evaluation needs to be performed before surgery. Treatments with beta-blockers have to be continued per operatively but the introduction of a new treatment has not been demonstrated to be beneficial. European guidelines but not American ones recommend stopping preoperative administration of CEI and ARA-2 except in case of cardiac failure. Calcium channels inhibitors don’t need to be interrupted. Diuretics are commonly stopped the day of surgery and their effect on electrolytic balance need to be checked before anaesthesia. There is no strong evidence supporting the introduction of clonidine before surgery

Perfusion Index: Physical Principles, Physiological Meanings and Clinical Implications in Anaesthesia and Critical Care

Short title: Clinical Usefulness of Perfusion IndexInternational audiencePhotoplethysmography (PPG) has been extensively used for pulse oximetry monitoring in anaesthesia, perioperative and intensive care. However, some components of PPG signal have been employed for other purposes, such as non-invasive haemodynamic monitoring. Perfusion index (PI) is derived from PPG signal and represents the ratio of pulsatile on non-pulsatile light absorbance or reflectance of the PPG signal. PI determinants are complex and interlinked, involving and reflecting the interaction between peripheral and central haemodynamic characteristics, such as vascular tone and stroke volume. Recently, several studies have shed light on the interesting performances of this variable, especially assessing regional or neuraxial block success, and haemodynamic monitoring in anaesthesia, perioperative and intensive care. Nevertheless, no review has yet been published concerning the interest of PI in these fields. In this narrative review will be exposed first the physiological and pathophysiological determinants of PI, and then the mean to measure this value as well as its potential limitations. In the second part, the existing data concerning usefulness of PI in different clinical settings such as operating theatres, intensive care units and emergency departments will be presented and discussed. Finally, the perspectives concerning the use of PI and mentioned aspects that should be explored regarding this tool will be underlined

Interplay between a Foldamer Helix and a Macrocycle in a Foldarotaxane Architecture

The design and synthesis of a novel rotaxane/foldaxane hybrid architecture is reported. The winding of an aromatic oligoamide helix host around a dumbbell-shaped thread-like guest, or axle, already surrounded by a macrocycle was evidenced by NMR spectroscopy and X-ray crystallography. The process proved to depend on the position of the macrocycle along the axle and the associated steric hindrance. The macrocycle thus behaves as a switchable shield that modulates the affinity of the helix for the axle. Reciprocally, the foldamer helix acts as a supramolecular auxiliary that compartmentalizes the axle. In some cases, the macrocycle is forced to move along the axle to allow the foldamer to reach its best recognition site.Des FoldaRotaxanes pour la Synthèse généralisée de Molécules Entrelacées Improbable

Inside Cover: Interplay between a Foldamer Helix and a Macrocycle in a Foldarotaxane Architecture (Angew. Chem. Int. Ed. 15/2021)

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[3]Foldarotaxane-mediated synthesis of an improbable [2]rotaxane

International audienceThe wrapping of a helix around the axle of a [2]rotaxane induced compartmentalization by sequestrating the macrocycle around a part of the axle for which it has no affinity. It gave this way the opportunity to yield an improbable [2]rotaxane

Activation of the renin-angiotensin-aldosterone system is associated with Acute Kidney Injury in COVID-19.

The pathophysiology of acute kidney injury (AKI) in COVID-19 patients is still poorly understood. SARS-CoV-2 has been suggested to modulate the renin-angiotensin-aldosterone system (RAAS). In this series of COVID-19 critically ill patients, we report evidence of activation of the RAAS in COVID-19 patients with AKI