Search

Abstract Light carries intrinsic spin angular momentum (SAM) when the electric or magnetic field vector rotates over time. A familiar vector equation calculates the direction of light’s SAM density using the right-hand rule with reference to the electric and magnetic polarisation ellipses. Using Maxwell’s equations, this vector equation can be decomposed into a sum of two distinct terms, akin to the well-known Poynting vector decomposition into orbital and spin currents. We present the first general study of this spin decomposition, showing that the two terms, which we call canonical and Poynting spin, are chiral analogies to the canonical and spin momenta of light in its interaction with matter. Like canonical momentum, canonical spin is directly measurable. Both canonical and Poynting spin incorporate spatial variation of the electric and magnetic fields and are influenced by optical vortices. The decomposition allows us to show that a linearly polarised vortex beam, which has no total SAM, can nevertheless exert longitudinal chiral pressure due to equal and opposite canonical and Poynting spins.

Introduction: Obstetric hemorrhage remains a largely preventable cause of maternal mortality globally. The contribution of uterine atony to hemorrhage‐related maternal mortality has decreased in France, while the contribution of other causes of obstetric hemorrhage such as surgical injury during cesarean has been reported to increase. However, little evidence exists regarding the risk factors and care processes of women who died from this cause of hemorrhage. Therefore, we aimed to describe the clinical profile, underlying mechanisms, and preventability factors among women who died from obstetric hemorrhage by surgical injury during cesarean section. Material and Methods: Nationwide analysis of all hemorrhage‐related maternal deaths by surgical injury during cesarean in France identified by the nationwide permanent enhanced maternal mortality surveillance system (ENCMM) between 2007 and 2018. We described the characteristics of the women, delivery hospitals, circumstances of hemorrhage, features of obstetric and resuscitation/transfusion care, and main preventability factors. Results: Between 2007 and 2018, hemorrhage‐related maternal mortality in France decreased from 1.6/100 000 live births (95% CI 1.1–2.2) (39/2 472 650) in 2007–2009 to 0.8/100 000 live births (95% CI 0.5–1.3) (19/2 311 783) in 2016–2018. Hemorrhage‐related maternal mortality ratio due to surgical injury during cesarean increased from 0.08 (95% CI 0.01–0.3) (2/2 472 650) to 0.2 (95% CI 0.07–0.5) (5/2 311 783) per 100 000 live births. Among the 18 women who died from surgical injury during cesarean over the 12‐year study period, we report a high prevalence of obesity (67%, 12/18), previous cesarean (72%, 13/18), and second‐stage cesareans (56%, 10/18). In 22% (4/18), cesarean section was performed in a hospital providing <1000 births annually, with no blood bank (39%, 7/18) or no adult intensive care (44%, 8/18) on‐site. Overall preventability of deaths was 94% (17/18). Main preventability factors were related to delay in hemorrhage diagnosis (77%, 14/18) due to late recognition of abnormal parameters (33%, 6/18) and late bedside ultrasound (56%, 10/18), and delay in management due to insufficient surgical skills (56%, 10/18). Conclusions: In France, surgical injury during cesarean section is an increasing, largely preventable contributor to hemorrhage‐related maternal mortality, as other causes of fatal hemorrhage have become less frequent. The profile of these women showed a high prevalence of obesity, previous cesarean, second‐stage cesarean, and delivery in hospitals with limited medical and surgical resources, which suggests explanatory mechanisms for the fatal outcome and opportunities for prevention. [ABSTRACT FROM AUTHOR]

Objective: To determine the prevalence of maternal sudden death (MSD) and to compare the characteristics of death between women with explained and unexplained sudden death. Design: A national retrospective study in France. Population Maternal deaths related to an unexpected sudden cardiac arrest were extracted from the French National Confidential Enquiry into Maternal Deaths database for 2007–2012. Methods: Maternal, pregnancy, sudden death characteristics and maternal investigations were compared between women with explained and unexplained cause of death. Results: A total of 83 maternal sudden deaths and 4 949 890 live births occurred over the period studied, thus accounting for 16% of all maternal deaths (n = 510). Death was explained in 51 (61%) women and unexplained in 32 women (39%). Compared with women with unexplained death, women with explained death were more often found to have in‐hospital cardiac arrest (47% versus 12%, P < 0.01), witnessed cardiac arrest (86% versus 62%, P = 0.03) and in‐hospital death (82% versus 47%, P < 0.01). Postmortem investigations such as autopsy and/or CT scan (65% versus 31%, P < 0.01) were also more often carried out in women with explained death. The proportion of deaths for which the preventability factors could not be assessed was 58% among unexplained MSD and 7% among explained MSD. Conclusion: Maternal sudden death is a rare event but accounts for a high proportion of all maternal deaths. This highlights the importance of providing training in diagnostic and management strategy for care providers. Systematic postmortem investigations are required to help understand causes and improve practices. [ABSTRACT FROM AUTHOR]

Introduction: Pre‐viable premature rupture of membranes (pre‐viable PROM) is a rare event occurring in less than 1% of pregnancies. Nevertheless, it can be responsible for severe maternal complications, the risk of which needs to be balanced with the possibility to prolong the pregnancy up to viable gestational age. Maternal sepsis was reported in 1%–5% of women who received conservative management and prophylactic antibiotics, but information on maternal mortality is lacking. Our objective was to identify maternal deaths in women who had pre‐viable PROM, describe the characteristics of the women, explore preventability factors within the care they received, and estimate the lethality of pre‐viable PROM. Material and methods: We identified all maternal deaths associated with pre‐viable PROM from the 2001–2015 French National Confidential Enquiry into Maternal Deaths (NCMM). Data on women's characteristics and the care they received were extracted from the ENCMM database. The lethality was determined after estimating the total number of pregnant women with pre‐viable PROM from the national hospital discharge database. Results: Between 2001 and 2015, we identified seven maternal deaths associated with pre‐viable PROM, representing 0.6% of all maternal deaths over this period (ie, maternal mortality ratio 0.06/100 000 live births). Six maternal deaths were attributed to sepsis after genital infection by Gram‐negative bacilli and one to postpartum hemorrhage due to placenta accreta. Four of these seven cases were considered preventable. The main preventability factors were delayed diagnosis, delayed fetal extraction, and inappropriate antibiotic treatment. The estimated lethality was 4.5/10 000 women with pre‐viable PROM. Conclusions: Maternal death associated with pre‐viable PROM is rare but possible. Most of these deaths seem preventable, with areas for improvement related to earlier diagnosis and better treatment of uterine infections, which can evolve rapidly. [ABSTRACT FROM AUTHOR]

Pregnancy in women with inherited thrombocytopenias is a major matter of concern as both the mothers and the newborns are potentially at risk of bleeding. However, medical management of this condition cannot be based on evidence because of the lack of consistent information in the literature. To advance knowledge on this matter, we performed a multicentric, retrospective study evaluating 339 pregnancies in 181 women with 13 different forms of inherited thrombocytopenia. Neither the degree of thrombocytopenia nor the severity of bleeding tendency worsened during pregnancy and the course of pregnancy did not differ from that of healthy subjects in terms of miscarriages, fetal bleeding and pre-term births. The degree of thrombocytopenia in the babies was similar to that in the mother. Only 7 of 156 affected newborns had delivery-related bleeding, but 2 of them died of cerebral hemorrhage. The frequency of delivery-related maternal bleeding ranged from 6.8% to 14.2% depending on the definition of abnormal blood loss, suggesting that the risk of abnormal blood loss was increased with respect to the general population. However, no mother died or had to undergo hysterectomy to arrest bleeding. The search for parameters predicting delivery-related bleeding in the mother suggested that hemorrhages requiring blood transfusion were more frequent in women with history of severe bleedings before pregnancy and with platelet count at delivery below 50 × 109/L.

Private sector provision of basic services (water, energy, financial services and housing) for people in developing countries is a necessity if we really want to try to curb poverty. However, ‘traditional’ private funding is not spontaneously directed towards these sectors, largely as a result of rejecting the idea that poor population groups should ‘pay’ for essential services; an issue that has often been the subject of opposition campaigns mounted by social stakeholders. Nevertheless, there are many, many examples to show that given the impact of these services on their quality of life, consumers in these countries - and especially those at the ‘bottom of the pyramid’ - are prepared to pay for them as long as they have access to a high-quality service. In these sectors, the nominal cost of the service concerned matters much less than its opportunity cost and the impact it will have on the lives of those who benefit from it. Very often, this service may even be paid for in advance as a way of enabling families to gain greater control over the expenditure they can devote to obtaining it. It is, however, important to distinguish between the supply of essential services and those of consumer goods, and - of course - to avoid abuses. In any event, the possibility of building financially-balanced models is what governs the process of securing sufficient funding from local and international financial institutions. In this area, as in others, the way forward is probably the happy medium: avoiding the excesses of overpricing, but accepting the need to maintain profitable economic models. These should enable investors to receive a level of profit that encourages them to continue and increase their investment, thereby increasing the number of recipients as quickly as possible. Aspiring to build social models that reject the ambition to achieve a reasonable profit and rule out any distribution of dividends to shareholders is to condemn the poorest populations to long-term dependency on charity or hypothetical budget surpluses, and seriously restrict their access to essential services.

La couverture, via le secteur privé, des besoins en services de base (eau, énergie, services financiers, logement,..) des populations des pays en développement est une nécessité si l’on veut essayer de faire reculer la pauvreté. Toutefois les financements privés « classiques » ne s’orientent pas spontanément vers ces secteurs notamment en raison du refus de faire « payer » un service essentiel à des populations pauvres, sujet qui a fait souvent l’objet de campagnes de rejets de la part d’acteurs de la société civile. De très nombreux exemples montrent pourtant que, compte tenu de l’impact de ces services sur leur qualité de vie, les consommateurs de ces pays, notamment du « bas de la pyramide » sont disposés à les payer pourvus qu’ils aient accès à un service de qualité. Dans ces secteurs, le coût nominal du service importe beaucoup moins que son coût d’opportunité et l’impact qu’aura ce service sur la vie des bénéficiaires. Bien souvent ce service peut même être payé ex ante ce qui peut permettre aux familles de mieux contrôler les dépenses qu’elles peuvent y consacrer. Il faut toutefois distinguer la fourniture de services essentiels de celles de bien de consommation courante et bien entendu éviter les dérives. En tout état de cause la possibilité de construire des modèles équilibrés financièrement conditionne la mobilisation de financement en quantité suffisante de la part des acteurs financiers locaux et internationaux. Dans ce domaine comme dans d’autres, la voie est donc probablement la voie du juste milieu, en évitant les excès d’une sur-tarification, mais en acceptant de conserver des modèles économiques rentables. Ceux-ci doivent permettre aux investisseurs d’avoir des résultats qui les conduisent à accroitre et poursuivre leurs investissements, et d’augmenter le plus rapidement possible le nombre de bénéficiaires. Prétendre construire des modèles sociaux refusant la recherche d’un profit raisonnable et ne permettant aucune distribution de dividendes à leurs actionnaires revient à condamner durablement les plus pauvres à dépendre de la charité ou d’excédents budgétaires hypothétiques et à limiter fortement leur accès à des services pourtant essentiels.

Background: In this prospective study, we describe the electroencephalographic (EEG) profiles in children anesthetized with sevoflurane or propofol. Methods: Seventy‐three subjects (11 years, range 5‐18) were included and randomly assigned to two groups according to the anesthetic agent. Anesthesia was performed by target‐controlled infusion of propofol (group P) or by sevoflurane inhalation (group S). Steady‐state periods were performed at a fixed randomized concentration between 2, 3, 4, 5, and 6 μg.ml−1 of propofol in group P and between 1, 2, 3, 4, and 5% of sevoflurane in group S. Remifentanil was continuously administered throughout the study. Clinical data, Bispectral Index (BIS), and raw EEG were continuously recorded. The relationship between BIS and anesthetic concentrations was studied using nonlinear regression. For all steady‐state periods, EEG traces were reviewed to assess the presence of epileptoid signs, and spectral analysis of raw EEG was performed. Results: Under propofol, BIS decreased monotonically and EEG slowed down as concentrations increased from 2 to 6 μg.ml−1. Under sevoflurane, BIS decreased from 0% to 4% and paradoxically rose from 4% to 5% of expired concentration: this increase in BIS was associated with the occurrence of fast oscillations and epileptoid signs on the EEG trace. Propofol was associated with more delta waves and burst suppression periods compared to sevoflurane. Conclusion: Under deep anesthesia, the BIS and electroencephalographic profiles differ between propofol and sevoflurane. For high concentrations of sevoflurane, an elevated BIS value may be interpreted as a sign of epileptoid patterns or EEG fast oscillations rather than an insufficient depth of hypnosis. [ABSTRACT FROM AUTHOR]

Objective: Develop a core outcome set of international consensus definitions for severe maternal morbidities.Design: Electronic Delphi study.Setting: International.Population: Eight expert panels.Methods: All 13 high-income countries represented in the International Network of Obstetric Surveillance Systems (INOSS) nominated five experts per condition of morbidity, who submitted possible definitions. From these suggestions, a steering committee distilled critical components: eclampsia: 23, amniotic fluid embolism: 15, pregnancy-related hysterectomy: 11, severe primary postpartum haemorrhage: 19, uterine rupture: 20, abnormally invasive placentation: 12, spontaneous haemoperitoneum in pregnancy: 16, and cardiac arrest in pregnancy: 10. These components were assessed by the expert panel using a 5-point Likert scale, following which a framework for an encompassing definition was constructed. Possible definitions were evaluated in rounds until a rate of agreement of more than 70% was reached. Expert commentaries were used in each round to improve definitions.Main Outcome Measures: Definitions with a rate of agreement of more than 70%.Results: The invitation to participate in one or more of eight Delphi processes was accepted by 103 experts from 13 high-income countries. Consensus definitions were developed for all of the conditions.Conclusion: Consensus definitions for eight morbidity conditions were successfully developed using the Delphi process. These should be used in national registrations and international studies, and should be taken up by the Core Outcomes in Women's and Newborn Health initiative.Tweetable Abstract: Consensus definitions for eight morbidity conditions were successfully developed using the Delphi process. [ABSTRACT FROM AUTHOR]

In type III hereditary angioedema (HAE type III), the phenotype is the same as type I and type II disease, but the level and function of C1-esterase inhibitor (C1-INH) is normal. Hereditary angioedema type III has been described as an oestrogen-sensitive form because it can be triggered or aggravated by exposure to high oestrogen levels as seen during pregnancy, especially when associated with Factor XII mutation. This case report describes the evolution and management of repeated angioedema attacks during pregnancy in a woman with HAE, with normal levels and function of C1-INH (type III); and a mis-sense mutation of factor XII. The physiopathology and genetic features, the unpredictability of clinical manifestations and the management during pregnancy and delivery are discussed. [ABSTRACT FROM AUTHOR]

Background In children, only a few studies have compared different modes of propofol infusion during a total intravenous anesthesia ( TIVA) with propofol and remifentanil. The aim of this study was to compare Bispectral Index ( BIS) profiles (percentage of time spent at adequate BIS values) between four modes of propofol infusion: titration of the infusion rate on clinical signs ( TIVA0), titration of the infusion rate on the BIS (TIVABIS), target controlled infusion ( TCI) guided by the BIS either with the Kataria model ( TCI KBIS) or the Schnider model ( TCI SBIS). Methods Sixty-six children (aged from 4 to 14 years) were prospectively randomized into one of the four groups. In the TIVA0 group, the anesthesiologist was blinded to the BIS. In each group, the percentage of time with adequate BIS values (45-55), the bias, and imprecision were calculated. Results The propofol consumption was similar in the four groups. During the maintenance phase, the percentage of time spent in the targeted BIS range was significantly lower in the TIVA0 group compared to the three other groups ( TIVA0: 31% ± 22, TIVABIS: 59% ± 17, TCI KBIS: 53% ± 12, TCI SBIS: 56% ± 17). The bias was not statistically different between the four groups, but the imprecision was larger for the TIVA0 group. Compared to the Kataria model, the Schnider model was associated with shorter time delay to reach the desired BIS, to eyes opening, and to tracheal extubation. Conclusions Propofol administration using manual infusion guided by clinical signs was associated with higher risks of over- or underdosage when compared to BIS-guided administrations. When propofol infusion was guided by the BIS, no major difference was found between TIVA and TCI (either with the Kataria or the Schnider model). This study highlights the need of a pharmacodynamic feedback during propofol anesthesia in children. [ABSTRACT FROM AUTHOR]