Evaluation of Repeated Quick Sepsis-Related Organ Failure Assessment Measurements Among Patients With Suspected Infection.

OBJECTIVES: Among patients with suspected infection, a single measurement of the quick Sepsis-related Organ Failure Assessment has good predictive validity for sepsis, yet the increase in validity from repeated measurements is unknown. We sought to determine the incremental predictive validity for sepsis of repeated quick Sepsis-related Organ Failure Assessment measurements over 48 hours compared with the initial measurement. DESIGN: Retrospective cohort study. SETTING: Twelve hospitals in southwestern Pennsylvania in 2012. PATIENTS: All adult medical and surgical encounters in the emergency department, hospital ward, postanesthesia care unit, and ICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among 1.3 million adult encounters, we identified those with a first episode of suspected infection. Using the maximum quick Sepsis-related Organ Failure Assessment score in each 6-hour epoch from onset of suspected infection until 48 hours later, we characterized repeated quick Sepsis-related Organ Failure Assessment with: 1) summary measures (e.g., mean over 48 hr), 2) crude trajectory groups, and 3) group-based trajectory modeling. We measured the predictive validity of repeated quick Sepsis-related Organ Failure Assessment using incremental changes in the area under the receiver operating characteristic curve for in-hospital mortality beyond that of baseline risk (age, sex, race/ethnicity, and comorbidity). Of 37,591 encounters with suspected infection, 1,769 (4.7%) died before discharge. Both the mean quick Sepsis-related Organ Failure Assessment at 48 hours (area under the receiver operating characteristic, 0.86 [95% CI, 0.85-0.86]) and crude trajectory groups (area under the receiver operating characteristic, 0.83 [95% CI, 0.83-0.83]) improved predictive validity compared with initial quick Sepsis-related Organ Failure Assessment (area under the receiver operating characteristic, 0.79 [95% CI, 0.78-0.80]) (p < 0.001 for both). Group-based trajectory modeling found five trajectories (quick Sepsis-related Organ Failure Assessment always low, increasing, decreasing, moderate, and always high) with greater predictive validity than the initial measurement (area under the receiver operating characteristic, 0.85 [95% CI, 0.84-0.85]; p < 0.001). CONCLUSIONS: Repeated measurements of quick Sepsis-related Organ Failure Assessment improve predictive validity for sepsis using in-hospital mortality compared with a single measurement of quick Sepsis-related Organ Failure Assessment at the time a clinician suspects infection.

High-Resolution Laminar Identification in Macaque Primary Visual Cortex Using Neuropixels Probes.

Laminar electrode arrays allow simultaneous recording of activity of many cortical neurons and assignment to correct layers using current source density (CSD) analyses. Electrode arrays with 100-micron contact spacing can estimate borders between layer 4 versus superficial or deep layers, but in macaque primary visual cortex (V1) there are far more layers, such as 4A which is only 50-100 microns thick. Neuropixels electrode arrays have 20-micron spacing, and thus could potentially discern thinner layers and more precisely identify laminar borders. Here we show that CSD signals lack the spatial resolution required to take advantage of high density Neuropixels arrays and describe the development of approaches based on higher resolution electrical signals and analyses, including spike waveforms and spatial spread, unit density, high-frequency action potential (AP) power spectrum, temporal power change, and coherence spectrum, that afford far higher resolution of laminar distinctions, including the ability to precisely detect the borders of even the thinnest layers of V1.

Cone opponent functional domains in primary visual cortex combine signals for color appearance mechanisms.

Studies of color perception have led to mechanistic models of how cone-opponent signals from retinal ganglion cells are integrated to generate color appearance. But it is unknown how this hypothesized integration occurs in the brain. Here we show that cone-opponent signals transmitted from retina to primary visual cortex (V1) are integrated through highly organized circuits within V1 to implement the color opponent interactions required for color appearance. Combining intrinsic signal optical imaging (ISI) and 2-photon calcium imaging (2PCI) at single cell resolution, we demonstrate cone-opponent functional domains (COFDs) that combine L/M cone-opponent and S/L + M cone-opponent signals following the rules predicted from psychophysical studies of color perception. These give rise to an orderly organization of hue preferences of the neurons within the COFDs and the generation of hue "pinwheels". Thus, spatially organized neural circuits mediate an orderly transition from cone-opponency to color appearance that begins in V1.