Paradoxical lucidity in dementia is a clinically significant but understudied phenomenon. A provisional definition was proposed by the 2018 National Institute on Aging expert workshop and published in Alzheimer's and Dementia. However, several conceptual features of this definition remain vague, creating barriers to robust clinical research. Here, we critically analyze the provisional definition and present a refined definition that can be applied in clinical research. The refined definition is based on an analytic process our research group recently undertook to operationalize paradoxical lucidity for our own study protocol. Our goal is to facilitate debate and potentially harmonize interpretations of paradoxical lucidity among research groups.

Background Mechanical ventilation worsens acute respiratory distress syndrome, but this secondary “ventilator-associated” injury is variable and difficult to predict. The authors aimed to visualize the propagation of such ventilator-induced injury, in the presence (and absence) of a primary underlying lung injury, and to determine the predictors of propagation. Methods Anesthetized rats (n = 20) received acid aspiration (hydrochloric acid) followed by ventilation with moderate tidal volume (VT). In animals surviving ventilation for at least 2 h, propagation of injury was quantified by using serial computed tomography. Baseline lung status was assessed by oxygenation, lung weight, and lung strain (VT/expiratory lung volume). Separate groups of rats without hydrochloric acid aspiration were ventilated with large (n = 10) or moderate (n = 6) VT. Results In 15 rats surviving longer than 2 h, computed tomography opacities spread outward from the initial site of injury. Propagation was associated with higher baseline strain (propagation vs. no propagation [mean ± SD]: 1.52 ± 0.13 vs. 1.16 ± 0.20, P < 0.01) but similar oxygenation and lung weight. Propagation did not occur where baseline strain was less than 1.29. In healthy animals, large VT caused injury that was propagated inward from the lung periphery; in the absence of preexisting injury, propagation did not occur where strain was less than 2.0. Conclusions Compared with healthy lungs, underlying injury causes propagation to occur at a lower strain threshold and it originates at the site of injury; this suggests that tissue around the primary lesion is more sensitive. Understanding how injury is propagated may ultimately facilitate a more individualized monitoring or management.

BackgroundUncertain prediction of outcome in acute respiratory distress syndrome (ARDS) impedes individual patient management and clinical trial design.ObjectivesTo develop a radiological metric of injurious inflation derived from matched inspiratory and expiratory CT scans, calibrate it in a model of experimental lung injury, and test it in patients with ARDS.Methods73 anaesthetised rats (acid aspiration model) were ventilated (protective or non-protective) for up to 4 hours to generate a spectrum of lung injury. CT was performed (inspiratory and expiratory) at baseline each hour, paired inspiratory and expiratory images were superimposed and voxels tracked in sequential scans. In nine patients with ARDS, paired inspiratory and expiratory CT scans from the first intensive care unit week were analysed.ResultsIn experimental studies, regions of lung with unstable inflation (ie, partial or reversible airspace filling reflecting local strain) were the areas in which subsequent progression of injury was greatest in terms of progressive infiltrates (R=0.77) and impaired compliance (R=0.67, p<0.01). In patients with ARDS, a threshold fraction of tissue with unstable inflation was apparent: >28% in all patients who died and ≤28% in all who survived, whereas segregation of survivors versus non-survivors was not possible based on oxygenation or lung mechanics.ConclusionsA single set of superimposed inspiratory–expiratory CT scans may predict progression of lung injury and outcome in ARDS; if these preliminary results are validated, this could facilitate clinical trial recruitment and individualised care.

Until recently, molecular imaging using magnetic resonance (MR) has been limited by the modality’s low sensitivity, especially with non-proton nuclei. The advent of hyperpolarized (HP) MR overcomes this limitation by substantially enhancing the signal of certain biologically important probes through a process known as external nuclear polarization, enabling real-time assessment of tissue function and metabolism. The metabolic information obtained by HP MR imaging holds significant promise in the clinic, where it could play a critical role in disease diagnosis and therapeutic monitoring. This review will provide a comprehensive overview of the developments made in the field of hyperpolarized MR, including advancements in polarization techniques and delivery, probe development, pulse sequence optimization, characterization of healthy and diseased tissues, and the steps made towards clinical translation.

q RSNA, 2016 Purpose:To assess the feasibility and optimize the accuracy of the multibreath wash-in hyperpolarized helium 3 ( 3 He) approach to ventilation measurement by using magnetic resonance (MR) imaging as well as to examine the physiologic differences that this approach reveals among nonsmokers, asymptomatic smokers, and patients with chronic obstructive pulmonary disease (COPD). Materials and Methods:All experiments were approved by the local institutional review board and compliant with HIPAA. Informed consent was obtained from all subjects. To measure fractional ventilation, the authors administered a series of identical normoxic hyperpolarized gas breaths to the subject; after each inspiration, an image was acquired during a short breath hold. Signal intensity buildup was fit to a recursive model that regionally solves for fractional ventilation. This measurement was successfully performed in nine subjects: three healthy nonsmokers (one man, two women; mean age, 45 years 6 4), three asymptomatic smokers (three men; mean age, 51 years 6 5), and three patients with COPD (three men; mean age, 59 years 6 5). Repeated measures analysis of variance was performed, followed by post hoc tests with Bonferroni correction, to assess the differences among the three cohorts. Results: Whole-lung fractional ventilation as measured with hyperpolarized 3He in all subjects (mean, 0.24 6 0.06) showed a strong correlation with global fractional ventilation as measured with a gas delivery device (R 2 = 0.96, P , .001). Significant differences between the means of whole-lung fractional ventilation (F 2,10 = 7.144, P = .012) and fractional ventilation heterogeneity (F 2,10 = 7.639, P = .010) were detected among cohorts. In patients with COPD, the protocol revealed regions wherein fractional ventilation varied substantially over multiple breaths. Conclusion:Multibreath wash-in hyperpolarized 3He MR imaging of fractional ventilation is feasible in human subjects and demonstrates very good global (whole-lung) precision. Fractional ventilation measurement with this physiologically realistic approach reveals significant differences between patients with COPD and healthy subjects. To minimize error, several sources of potential bias must be corrected when calculating fractional ventilation.q RSNA, 2016

Equation E4in Appendix E1 (online) should have appeared as follows:

This review on shared decision-making comes at a time when international healthcare policy, domestic law and patient expectation demand a bringing-together of the patient's values and preferences with the physician's expertise to determine the best bespoke care package for the individual. Despite robust guidance in terms of consent, the anaesthetic community have lagged behind in terms of embracing the patient-focused rather than doctor-focused aspects of shared decision-making. For many, confusion has arisen due to a conflation of informed consent, risk assessment, decision aids and shared decision-making. Although they may well be linked, they are discrete entities. The obstacles to delivering shared decisionmaking are many. Lack of time is the most widely cited barrier from the perspective of physicians across specialties, with little time available to the anaesthetist at the day-of-surgery pre-operative visit. A more natural place to start the process may be the pre-operative assessment clinic, especially for the 'high-risk' patient. Yet shared decision-making is for all, even the 'low-risk' patient. Another barrier is the flow and the focus of the typical anaesthetic consultation; the truncated format presents the danger of a cursory, 'timeefficient' and mechanical process as the anaesthetist assesses risk and determines the safest anaesthetic. As patients have already decided to proceed with therapy or investigation and may be more concerned about the surgery than the anaesthesia, it is often assumed they will accept whatever anaesthetic is offered and defer to the clinician's expertisewithout discussion. Furthermore, shared decision-making does not stop at time of anaesthesia for the peri-operative physician. It continues until discharge and requires the anaesthetist to engage in shared decision-making for prescribing and deprescribing peri-operative medicines.

Background: Debriefing after an actual critical event is an established good practice in medicine, but a gap exists between principle and implementation. The authors' objective was to understand barriers to debriefing, characterize quantifiable patterns and qualitative themes, and learn potential solutions through a mixed-methods study of actual critical events experienced by anesthesia personnel.Methods: At a large academic medical center, anesthesiology residents and a small number of attending anesthesiologists were audited and/or interviewed for the occurrence and patterns of debriefing after critical events during their recent shift, including operating room crises and disruptive behavior. Patterns of the events, including event locations and event types, were quantified. A comparison was done of the proportion of cases debriefed based on whether the event contained a critical communication breakdown. Qualitative analysis, using an abductive approach, was performed on the interviews to add insight to quantitative findings.Results: During a 1-yr period, 89 critical events were identified. The overall debriefing rate was 49% (44 of 89). Nearly half of events occurred outside the operating room. Events included crisis events (e.g., cardiac arrest, difficult airway requiring an urgent surgical airway), disruptive behavior, and critical communication breakdowns. Events containing critical communication breakdowns were strongly associated with not being debriefed (64.4% [29 of 45] not debriefed in events with a communication breakdown vs. 36.4% [16 of 44] not debriefed in cases without a communication breakdown; P = 0.008). Interview responses qualitatively demonstrated that lapses in communication were associated with enduring confusion that could inhibit or shape the content of discussions between involved providers.conclusions: Despite the value of proximal debriefing to reducing provider burnout and improving wellness and learning, failure to debrief after critical events can be common among anesthesia trainees and perhaps anesthesia teams. Modifiable interpersonal factors, such as communication breakdowns, were associated with the failure to debrief. (ANESTHESIOLOGY 2019; 130:1039-48) EditoR'S PERSPEctiVE What We Already Know about This Topic• Debriefing after an actual critical event is an established good practice in medicine, but a gap exists between principle and implementation. What This Article Tells us That Is New• Failure to debrief after critical events is common among anesthesia trainees and likely anesthesia teams. Communication breakdowns are associated with a high rate of the failure to debrief. . Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology's articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.anEStHESioLoGY REFLEctionS FRoM tHE Wood LiBRaRY-MuSEuM