Distinct electrophysiological signatures of task-unrelated and dynamic thoughts.

Humans spend much of their lives engaging with their internal train of thoughts. Traditionally, research focused on whether or not these thoughts are related to ongoing tasks, and has identified reliable and distinct behavioral and neural correlates of task-unrelated and task-related thought. A recent theoretical framework highlighted a different aspect of thinking-how it dynamically moves between topics. However, the neural correlates of such thought dynamics are unknown. The current study aimed to determine the electrophysiological signatures of these dynamics by recording electroencephalogram (EEG) while participants performed an attention task and periodically answered thought-sampling questions about whether their thoughts were 1) task-unrelated, 2) freely moving, 3) deliberately constrained, and 4) automatically constrained. We examined three EEG measures across different time windows as a function of each thought type: stimulus-evoked P3 event-related potentials and non-stimulus-evoked alpha power and variability. Parietal P3 was larger for task-related relative to task-unrelated thoughts, whereas frontal P3 was increased for deliberately constrained compared with unconstrained thoughts. Frontal electrodes showed enhanced alpha power for freely moving thoughts relative to non-freely moving thoughts. Alpha-power variability was increased for task-unrelated, freely moving, and unconstrained thoughts. Our findings indicate distinct electrophysiological patterns associated with task-unrelated and dynamic thoughts, suggesting these neural measures capture the heterogeneity of our ongoing thoughts.

Proning in Non-Intubated (PINI) in Times of COVID-19: Case Series and a Review.

It has been well known for decades that prone positioning (PP) improves oxygenation. However, it has gained widespread acceptance only in the last few years since studies have shown significant survival benefit. Many centers have established prone ventilation in their treatment algorithm for mechanically ventilated patients with severe acute respiratory distress syndrome (ARDS). Physiologically, PP should also benefit awake, non-intubated patients with acute hypoxemic respiratory failure. However, proning in non-intubated (PINI) patients did not gain any momentum until a few months ago when the Coronavirus disease 2019 (COVID-19) pandemic surged. A large number of sick patients overwhelmed the health care system, and many centers faced a dearth of ventilators. In addition, outcomes of patients placed on mechanical ventilation because of COVID-19 infection have been highly variable and often dismal. Hence, increased focus has shifted to using various strategies to prevent intubation, such as PINI. There is accumulating evidence that PINI is a low-risk intervention that can be performed even outside intensive care unit with minimal assistance and may prevent intubation in certain patients with ARDS. It can also be performed safely at smaller centers and, therefore, may reduce the patient transfer to larger institutions that are overwhelmed in the current crisis. We present a case series of 2 patients with acute hypoxemic respiratory failure who experienced significant improvements in oxygenation with PP. In addition, the physiology of PP is described, and concerns such as proning in obese and patient's anxiety are addressed; an educational pamphlet that may be useful for both patients and health care providers is provided.

Systematic comparison between a wireless EEG system with dry electrodes and a wired EEG system with wet electrodes.

Recent advances in dry electrodes technology have facilitated the recording of EEG in situations not previously possible, thanks to the relatively swift electrode preparation and avoidance of applying gel to subject's hair. However, to become a true alternative, these systems should be compared to state-of-the-art wet EEG systems commonly used in clinical or research applications. In our study, we conducted a systematic comparison of electrodes application speed, subject comfort, and most critically electrophysiological signal quality between the conventional and wired Biosemi EEG system using wet active electrodes and the compact and wireless F1 EEG system consisting of dry passive electrodes. All subjects (n = 27) participated in two recording sessions on separate days, one with the wet EEG system and one with the dry EEG system, in which the session order was counterbalanced across subjects. In each session, we recorded their EEG during separate rest periods with eyes open and closed followed by two versions of a serial visual presentation target detection task. Each task component allows for a neural measure reflecting different characteristics of the data, including spectral power in canonical low frequency bands, event-related potential components (specifically, the P3b), and single trial classification based on machine learning. The performance across the two systems was similar in most measures, including the P3b amplitude and topography, as well as low frequency (theta, alpha, and beta) spectral power at rest. Both EEG systems performed well above chance in the classification analysis, with a marginal advantage of the wet system over the dry. Critically, all aforementioned electrophysiological metrics showed significant positive correlations (r = 0.54-0.89) between the two EEG systems. This multitude of measures provides a comprehensive comparison that captures different aspects of EEG data, including temporal precision, frequency domain as well as multivariate patterns of activity. Taken together, our results indicate that the dry EEG system used in this experiment can effectively record electrophysiological measures commonly used across the research and clinical contexts with comparable quality to the conventional wet EEG system.

Choice of Intravenous Crystalloid Fluid and Mortality in Critically Ill Adult Patients.

OBJECTIVES: Intravenous balanced crystalloid fluid therapy may improve mortality and other outcomes in critically ill adult patients, but data are conflicting. We conducted a meta-analysis and literature review to evaluate the impact of intravenous balanced crystalloid, as compared with normal saline, fluid therapy on outcomes in critically ill adult patients. METHODS: We searched PubMed, Scopus, MEDLINE, and the Cochrane Register of Clinical Trials for relevant studies. Randomized controlled trials comparing the effects of balanced intravenous crystalloids with normal saline on intensive care unit (ICU) or hospital mortality were included. Pooled risk ratios (RRs) were calculated using a fixed effects model. Heterogeneity was calculated using the I2 statistic. The risk of bias was assessed using the Cochrane tool. RESULTS: Seven randomized controlled trials with 20,171 patients (10,179 participants received balanced crystalloids and 9992 participants received normal saline) were included. For hospital mortality, the pooled RR (95% confidence interval [CI]) was 0.92 (0.85-1.00). For ICU mortality, the pooled RR (95% CI) was 0.91 (0.82-1.00). For major adverse kidney events at 30 days, pooled RR (95% CI) was 0.95 (0.88-1.01). For stage ≥2 acute kidney injury, the pooled RR (95% CI) was 0.94 (0.86-1.02). For receipt of new renal replacement therapy, the pooled RR (95% CI) was 0.91 (0.77-1.07). None of these findings reached statistical significance. CONCLUSIONS: Intravenous balanced crystalloid use, compared with normal saline, does not result in a statistically significant reduction in hospital or ICU mortality, major adverse kidney events at 30 days, stage ≥2 acute kidney injury, or receipt of new renal replacement therapy in critically ill adult patients.

A Narrative Review of Existing Options for COVID-19-Specific Treatments.

The new coronavirus disease 2019 (COVID-19) was declared a global pandemic in early 2020. The ongoing COVID-19 pandemic has affected morbidity and mortality tremendously. Even though multiple drugs are being used throughout the world since the advent of COVID-19, only limited treatment options are available for COVID-19. Therefore, drugs targeting various pathologic aspects of the disease are being explored. Multiple studies have been published to demonstrate their clinical efficacy until now. Based on the current evidence to date, we summarized the mechanism, roles, and side effects of all existing treatment options to target this potentially fatal virus.

Dietary fiber and serum 16α-hydroxyestrone, an estrogen metabolite associated with lower systolic blood pressure.

OBJECTIVE: We recently identified an inverse relation between systolic blood pressure (SBP) and serum 16α-hydroxyestrone, a metabolite of 17ß-estradiol, in postmenopausal women. Formation of 16α-hydroxyestrone is catalyzed primarily by CYP1A2, a cytochrome P450 enzyme. The objective of this study was to evaluate the relations between known modifiers of CYP1A2 activity and serum 16α-hydroxyestrone in postmenopausal women. We hypothesized that fruits, vegetables, and grains, which contain more soluble fiber (a known inducer of CYP1A2) as a proportion of total fiber, would be more positively associated with serum 16α-hydroxyestrone than legumes, which contain less soluble fiber as a proportion of total fiber. METHODS: Serum from a population-based sample of 42 postmenopausal women 55 to 69 y of age living in Cook County, Illinois, was assayed for 16α-hydroxyestrone using mass spectrometry. Ordinal logistic regression was used to evaluate the cross-sectional relation between dietary fiber and serum 16α-hydroxyestrone after adjusting for multiple covariates. RESULTS: Compared with dietary fiber from legumes, dietary fiber from fruits and vegetables was associated with a greater log odds (B=0.201, P=0.036) of having higher serum concentrations of 16α-hydroxyestrone. The log odds of having higher serum concentrations of 16α-hydroxyestrone was also lower in African-American women (B=-2.300, P=0.030) compared with white women. CONCLUSION: These results are consistent with previous studies demonstrating a negative relation between SBP and dietary fruits and vegetables and a positive relation between African-American race and SBP. Further research is needed regarding dietary factors that may influence the serum concentration of 16α-hydroxyestrone.