Thermodilution vs estimated Fick cardiac output measurement in an elderly cohort of patients: A single-centre experience

AIMS: Patients referred to the cath-lab are an increasingly elderly population. Thermodilution (TD, gold standard) and the estimated Fick method (eFM) are interchangeably used in the clinical routine to measure cardiac output (CO). However, their correlation in an elderly cohort of cardiac patients has not been tested so far. METHODS: A single, clinically-indicated right heart catheterization was performed on each patient with CO estimated by eFM and TD in 155 consecutive patients (75.1±6.8 years, 57.7% male) between April 2015 and August 2017. Whole Body Oxygen Consumption (VO2) was assumed by applying the formulas of LaFarge (LaF), Dehmer (De) and Bergstra (Be). CO was indexed to body surface area (Cardiac Index, CI). RESULTS: CI-TD showed an overall moderate correlation to CI-eFM as assessed by LaF, De or Be (r2 = 0.53, r2 = 0.54, r2 = 0.57, all p < .001, respectively) with large limits of agreement (-0.64 to 1.09, -1.07 to 0.77, -1.38 to 0.53 l/m2/min, respectively). The mean difference of CI between methods was 0.22, -0.15 and -0.42 (all p<0.001 for difference to TD), respectively. A rate of error ≥20% occurred with the equations by LaF, De or Be in 40.6%, 26.5% and 36.1% of patients, respectively. A CI <2.2 l/m2min was present in 42.6% of patients according to TD and in 60.0%, 31.0% and in 16.1% of patients according to eFM by the formulas of LaF, De or Be. CONCLUSION: Although CI-eFM shows an overall reasonable correlation with CI-TD, the predictive value in a single patient is low. CI-eFM cannot replace CI-TD in elderly patients

The Vascular Flora and Community Structure of Little Calumet Headwaters Nature Preserve, Laporte Country, Indiana

Little Calumet Headwaters Nature Preserve is a 108-acre tract of woodland and wetland areas that comprise the headwaters of the Little Calumet River in northwestern Indiana. The preserve, consisting of upland hardwood forests, groundwater seeps, and wetland complex, is an area of high diversity due to its topographical variation. A floristic inventory, plot sampling, and seed bank analysis were used to determine the structure and composition of the plant communities. The flora consists of 298 species (27 exotic) representing 188 genera and 84 families. Dominant vegetation of the forest includes Liriodendron tulipifera, Prunus serotina, Packera aurea and Podophyllum peltatum. Each groundwater seep contains similar plant communities with variant species that depend on water flow and topography. They include species such as Symplocarpus foetidus, Impatiens capensis, and Caltha palustris and lack an extensive woody overstory except for occasional Salix spp. or Cornus spp. The wetland complex contains three distinct areas: an open fen dominated by Leersia oryzoides and Cornus spp.; a marsh dominated by Typha latifolia and Carex lasiocarpa; and a shrub-carr portion dominated by Symplocarpus foetidus, Cornus alternifolia, and Salix nigra. A wetland seed bank study resulted in a total of 46 species representing 33 genera and 22 families. A similarity of 71.7% was determined between the seed bank samples and the above-ground vegetation. The entire preserve has a high floristic quality index (FQI) of 70.1 and average mean coefficient of conservatism of 4.1. The high FQI value is influenced by property size and the number of communities in the preserve

Visuomotor Crowding: The Resolution of Grasping in Cluttered Scenes

Reaching toward a cup of coffee while reading the newspaper becomes exceedingly difficult when other objects are nearby. Although much is known about the precision of visual perception in cluttered scenes, relatively little is understood about acting within these environments – the spatial resolution of visuomotor behavior. When the number and density of objects overwhelm visual processing, crowding results, which serves as a bottleneck for object recognition. Despite crowding, featural information of the ensemble persists, thereby supporting texture perception. While texture is beneficial for visual perception, it is relatively uninformative for guiding the metrics of grasping. Therefore, it would be adaptive if the visual and visuomotor systems utilized the clutter differently. Using an orientation task, we measured the effect of crowding on vision and visually guided grasping and found that the density of clutter similarly limited discrimination performance. However, while vision integrates the surround to compute a texture, action discounts this global information. We propose that this dissociation reflects an optimal use of information by each system

Fast Radiometric Compensation for Nonlinear Projectors

Radiometric compensation can be accomplished on nonlinearprojector-camera systems through the use of pixelwise lookup ta-bles. Existing methods are both computationally and memory inten-sive. Such methods are impractical to be implemented for currenthigh-end projector technology. In this paper, a novel computation-ally efficient method for nonlinear radiometric compensation of pro-jectors is proposed. The compensation accuracy of the proposedmethod is assessed with the use of a spectroradiometer. Experi-mental results show both the effectiveness of the method and thereduction in compensation time compared to a recent state-of-the-art method

Constraints for Time-Multiplexed Structured Light with a Hand-held Camera

Multi-frame structured light in projector-camera systems affords high-density and non-contact methods of 3D surface reconstruction. However, they have strict setup constraints which can become expensive and time-consuming. Here, we investigate the conditions under which a projective homography can be used to compensate for small perturbations in pose caused by a hand-held camera. We synthesize data using a pinhole camera model and use it to determine the average 2D reprojection error per point correspondence. This error map is grouped into regions with specified upper-bounds to classify which regions produce sufficiently minimal error to be considered feasible for a structured-light projector-camera system with a hand-held camera. Empirical results demonstrate that a sub-pixel reprojection accuracy is achievable with a feasible geometric constraint