Fig. 2. Patient 2. (A, B) Axial T2 FLAIR showing hyperintense foci (arrows) involving the subcortical white matter of the right occipital lobe and the left cerebellar hemisphere with effacement of the adjacent local sulci compatible with PRES. (C, D) Axial susceptibility weighted imaging (SWI) showing characteristic petechial hemorrhage (arrows) often seen with PRES. Of note, diffusion weighted imaging (DWI) and T1 post-contrast imaging were unremarkable.

Aims: Prior investigation has found that mechanical ventilation with lower tidal volumes (Vt) following out-of-hospital cardiac arrest is associated with better neurologic outcomes. The relationship between Vt and neurologic outcome following in-hospital cardiac arrest (IHCA) has not previously been explored. In the present study, we investigate the association between Vt and neurologic outcome following IHCA. Methods: This was an observational study using a prospectively collected database of IHCA patients at a tertiary care hospital in the United States. The relationship between time-weighted average Vt per predicted body weight (PBW) over the first 6- and 48 h after cardiac arrest and neurologic outcome were assessed using propensity-score adjusted logistic regression. Measurements and main results: Of 185 IHCA patients who received invasive mechanical ventilation within 6 h of return of spontaneous circulation (ROSC), the average Vt over the first 6 h was 7.7 ±2.0 ml/kg and 68 (36.8%) patients received an average Vt >8.0 ml/kg. Of 121 patients who received mechanical ventilation for at least 48 h post-ROSC, the average Vt was 7.6 ±1.5 ml/kg and 46 (38.0%) patients received an average Vt > 8.0 ml/kg. There was no relationship between Vt/PBW over the first 6- or 48 h post-ROSC and neurologic outcome (OR 0.99; 95%CI 0.84–1.16; p = 0.89; OR 1.03; 95%CI 0.78–1.37; p = 0.83 respectively). Conclusions: This study did not identify a relationship between Vt and neurologic outcome following IHCA. This contrasts with results in OHCA, where higher Vt has been associated with worse neurologic outcome. Additional investigation is needed with respect to other potential benefits of low-Vt post IHCA.

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Background:Human stampedes (HS) may result in mass casualty incidents (MCI) that arise due to complex interactions between individuals, collective crowd, and space, which have yet to be described from a physics perspective. HS events were analyzed using basic physics principles to better understand the dynamic kinetic variables that give rise to HS.Methods:A literature review was performed of medical and nonmedical sourced databases, Library of Congress databases, and online sources for the term human stampedes resulting in 25,123 references. Filters were applied to exclude nonhuman events. Retrieved references were reviewed for a predefined list of physics terms. Data collection involved recording frequency of each phrase and physics principle to give the final proportions of each predefined principle used a single-entry method for each of the 105 event reports analyzed. Data analysis was performed using the R statistics packages “tidyverse”, “psych”, “lubridate”, and “Hmisc” with descriptive statistics used to describe the frequency of each observed variable.Results:Of the 105 reports of HS resulting in injury or death reviewed, the following frequency of terms were found: density change in a limited capacity, 45%; XY-axis motion failure, 100%; loss of proxemics, 100%; deceleration with average velocity of zero, 90%; Z-axis displacement pathology (falls), 92%; associated structure with nozzle effect, 93%; and matched fluid dynamic of high pressure stagnation of mass gathering, 100%.Conclusions:Description or reference to principles of physics was seen in differing frequency in 105 reports. These include XY-axis motion failure of deceleration that leads to loss of human to human proxemics, and high stagnation pressure resulting in the Z-axis displacement effect (falls) causing injury and death. Real-time video-analysis monitoring of high capacity events or those with known nozzle effects for loss of proxemics and Z-axis displacement pathology offers the opportunity to prevent mortality from human stampedes.