Assessing the reproducibility and predictive value of objective cough measurement for successful withdrawal of invasive ventilatory support in adult patients.

BACKGROUND: Utilizing clinical tests, such as objective cough measurement, can assist in predicting the success of the weaning process in critically ill patients. METHODS: A multicenter observational analytical study was conducted within a prospective cohort of patients recruited to participate in COBRE-US. We assessed the capability of objective cough measurement to predict the success of the spontaneous breathing trial (SBT) and extubation. Intra- and inter-observer reproducibility of the cough test and was evaluated using the intraclass correlation coefficient (ICC) and Cohen's weighted kappa. We used receiver operating characteristic curves (ROC-curve) to evaluate the predictive ability of objective cough measurement. RESULTS: We recruited 367 subjects who were receiving invasive mechanical ventilation. A total of 451 objective cough measurements and 456 SBTs were conducted. A significant association was found between objective cough measurement and successful SBT (OR: 1.68; 95% CI 1.48-1.90; p = 0.001). The predictive capability of the objective cough test for SBT success had a ROC-curve of 0.58 (95% CI: 0.56-0.61). Objective cough measurement to predict successful extubation had a ROC-curve of 0.61 (95% CI: 0.56-0.66). The intraobserver reproducibility exhibited an ICC of 0.94 (95% CI: 0.89-0.96; p < 0.001), while the interobserver reproducibility demonstrated an ICC of 0.72 (95% CI: 0.51-0.85; p < 0.001). The intraobserver agreement, assessed using Cohen's weighted kappa was 0.94 (95% CI: 0.93-0.99; p < 0.001), whereas the interobserver agreement was 0.84 (95% CI: 0.67 - 0.10; p < 0.001). CONCLUSIONS: The objective measurement of cough using the method employed in our study demonstrates nearly perfect intra-observer reproducibility and agreement. However, its ability to predict success or failure in the weaning process is limited.

Utilization of spontaneous breathing trial, objective cough test, and diaphragmatic ultrasound results to predict extubation success: COBRE-US trial.

BACKGROUND: The results of clinical and weaning readiness tests and the spontaneous breathing trial (SBT) are used to predict the success of the weaning process and extubation. METHODS: We evaluated the capacity of the cuff leak test, rate of rapid and shallow breathing, cough intensity, and diaphragmatic contraction velocity (DCV) to predict the success of the SBT and extubation in a prospective, multicenter observational study with consecutive adult patients admitted to four intensive care units. We used receiver operating characteristic (ROC) curves to assess the tests' predictive capacity and built predictive models using logistic regression. RESULTS: We recruited 367 subjects who were receiving invasive mechanical ventilation and on whom 456 SBTs were performed, with a success rate of 76.5%. To predict the success of the SBT, we derived the following equation: (0.56 × Cough) - (0.13 × DCV) + 0.25. When the cutoff point was ≥ 0.83, the sensitivity was 91.5%, the specificity was 22.1%, and the overall accuracy was 76.2%. The area under the ROC curve (AUC-ROC) was 0.63. To predict extubation success, we derived the following equation: (5.7 × SBT) + (0.75 × Cough) - (0.25 × DCV) - 4.5. When the cutoff point was ≥ 1.25, the sensitivity was 96.8%, the specificity was 78.4%, and the overall accuracy was 91.5%. The AUC-ROC of this model was 0.91. CONCLUSION: Objective measurement of cough and diaphragmatic contraction velocity could be used to predict SBT success. The equation for predicting successful extubation, which includes SBT, cough, and diaphragmatic contraction velocity values, showed excellent discriminative capacity.

Ultrasound measurement of optic nerve sheath diameter in a healthy adult Colombian population.

BACKGROUND: Measurement of the optic nerve sheath diameter (ONSD) provides a rapid, safe, and easy method for detecting increased intracranial pressure (ICP). However, the normal mean and upper limit values may vary according to sex, age, ethnicity, and ultrasound technique. AIM: We aimed to obtain the mean ONSD in a healthy Colombian adult population and to correlate it with demographic and anthropometric measures. METHODS: In a prospective study using a 10-13 MHz linear ultrasound probe, eye transverse diameter (ETD) and ONSD in the transverse (ONSD-TP) and sagittal planes (ONSD-SP) were measured in healthy adult volunteers in Bogota, Colombia. RESULTS: A total of 100 healthy subjects were included, with a mean age of 26,7 ± 8,3 years and 62 women. The mean ETD, ONSD-TP and ONSD-SP was 23.11 mm (95% confidence interval (CI): 22.90 mm-23.32 mm), 3.96 mm (95% CI: 3.85 mm-4.07 mm) and 4.0 mm (95% CI: 3.90 mm-4.11 mm), respectively. The ONSD in both planes ranged from 2.35 mm to 5.20 mm. There was a significant correlation between ONSD-SP and ONSD-TP (p < 0.0001) but no correlation between the ocular measures and demographic or anthropometric variables (p > 0.05). The intraclass correlation between the eyes was statistically significant. CONCLUSION: Our study shows that ultrasound-measured ONSD in healthy adults in Colombia is similar to that found worldwide. An ONSD of 5.5 mm may be considered the upper limit for healthy adults in Colombia. ONSD can be measured in either plane; there is a good correlation between the two eyes; and ONSD is not modified by demographic or anthropometric characteristics.

Mortalidad y desenlaces clínicos en pacientes críticamente enfermos con infecciones por bacterias productoras de carbapenemasas en un hospital de alta complejidad en Bogotá, Colombia / Mortality and clinical outcomes in critically ill patients with carbapenemase-producing bacteria in a tertiary-care hospital in Bogotá, Colombia

Resumen Introducción: Los microorganismos capaces de producir carbapenemasas vienen incrementándose a nivel mundial y se han convertido en un problema de salud pública global. En Colombia actualmente la resistencia a carbapenémicos en las unidades de cuidado intensivo está aumentando y se desconoce su impacto en desenlaces clínicos. Objetivos: Determinar las características demográficas, clínicas, y los desenlaces de los pacientes adultos en estado crítico con infección por microorganismos productores de carbapenemasas en una unidad de cuidado intensivo polivalente de una institución de alta complejidad. Métodos: Estudio observacional, descriptivo y retrospectivo, incluyendo pacientes con infección por bacterias resistentes a carbapenémicos, ingresados a la unidad de cuidado intensivo entre el 1 de Enero de 2014 y el 1 de Enero de 2018. Se excluyeron los pacientes colonizados. Se evaluaron complicaciones clínicas, estancia en UCI y hospitalaria, así como la mortalidad en UCI y hospitalaria. Resultados: Se incluyó 58 pacientes. La mortalidad global fue de 67,2%, de los cuales 55,17% murió durante su estancia en la unidad de cuidado intensivo y 12.06% en hospitalización. La mediana de estancia en la unidad de cuidado intensivo fue de 18 días (RIQ 4-28). La causa más frecuente de mortalidad fue choque séptico en 51% y las complicaciones más comunes fueron lesión renal aguda y delirium en un 55,2% y 43,1%, respectivamente. La mediana de estancia en la UCI fue de 18 días (RIQ 4-28). Conclusiones: Las infecciones por bacterias resistentes a carbapenémicos en pacientes críticamente enfermos se relacionan con altas tasas de mortalidad, complicaciones y estancia prolongada en UCI

Abstract Introduction: Microorganisms able to produce carbapenemases are spreading worldwide and have become a concerning global public-health problem. In Colombia, the Gram-negative resistance to carbapenems at intensive care units is currently increasing and its impact on clinical outcomes is not well known. Objectives: To determine the demographic, clinical characteristics and outcomes of critically ill adult patients with infection by carbapenemase producing bacteria in a polyvalent intensive care unit of a highly complex institution. Methods: Single-center retrospective, descriptive observational study including critically ill adult patients infected by carbapenemase-producing bacteria and transferred to a polyvalent intensive care unit from January 1th 2014 to January 1th 2018. Known colonized patients were excluded. Clinical complications, ICU and in-hospital days of stay were evaluated, as ICU and in-hospital mortality. Results: A total of 58 patients were included. Overall mortality was 67.2%, of which 55.17% died during their stay in the intensive care unit and 12.06% in hospitalization. The median stay in the intensive care unit was 18 days (IQR 4-28). The most frequent cause of death was septic shock in 51% and the most common complications were acute renal injury and delirium in 55.2% and 43.1%, respectively. The median stay in the ICU was 18 days (RIQ 4-28). Conclusions: Infections caused by carbapenem-resistant bacteria in critically ill patients are associated with high mortality rates, complications and long stay in ICU.

Feature Surfaces in Symmetric Tensor Fields Based on Eigenvalue Manifold.

Three-dimensional symmetric tensor fields have a wide range of applications in solid and fluid mechanics. Recent advances in the (topological) analysis of 3D symmetric tensor fields focus on degenerate tensors which form curves. In this paper, we introduce a number of feature surfaces, such as neutral surfaces and traceless surfaces, into tensor field analysis, based on the notion of eigenvalue manifold. Neutral surfaces are the boundary between linear tensors and planar tensors, and the traceless surfaces are the boundary between tensors of positive traces and those of negative traces. Degenerate curves, neutral surfaces, and traceless surfaces together form a partition of the eigenvalue manifold, which provides a more complete tensor field analysis than degenerate curves alone. We also extract and visualize the isosurfaces of tensor modes, tensor isotropy, and tensor magnitude, which we have found useful for domain applications in fluid and solid mechanics. Extracting neutral and traceless surfaces using the Marching Tetrahedra method can cause the loss of geometric and topological details, which can lead to false physical interpretation. To robustly extract neutral surfaces and traceless surfaces, we develop a polynomial description of them which enables us to borrow techniques from algebraic surface extraction, a topic well-researched by the computer-aided design (CAD) community as well as the algebraic geometry community. In addition, we adapt the surface extraction technique, called A-patches, to improve the speed of finding degenerate curves. Finally, we apply our analysis to data from solid and fluid mechanics as well as scalar field analysis.

Hexagonal global parameterization of arbitrary surfaces.

We introduce hexagonal global parameterization, a new type of surface parameterization in which parameter lines respect sixfold rotational symmetries (6-RoSy). Such parameterizations enable the tiling of surfaces with nearly regular hexagonal or triangular patterns, and can be used for triangular remeshing. Our framework to construct a hexagonal parameterization, referred to as HEXCOVER, extends the QUADCOVER algorithm and formulates necessary conditions for hexagonal parameterization. We also provide an algorithm to automatically generate a 6-RoSy field that respects directional and singularity features in the surface. We demonstrate the usefulness of our geometry-aware global parameterization with applications such as surface tiling with nearly regular textures and geometry patterns, as well as triangular and hexagonal remeshing.

Interactive Visualization of Rotational Symmetry Fields on Surfaces.

Rotational symmetries (RoSys) have found uses in several computer graphics applications, such as global surface parameterization, geometry remeshing, texture and geometry synthesis, and nonphotorealistic visualization of surfaces. The visualization of N-way rotational symmetry (N-RoSy) fields is a challenging problem due to the ambiguities in the N directions represented by an N-way symmetry. We provide an algorithm that allows faithful and interactive representation of N-RoSy fields in the plane and on surfaces, by adapting the well-known line integral convolution (LIC) technique from vector and second-order tensor fields. Our algorithm captures N directions associated with each point in a given field by decomposing the field into multiple different vector fields, generating LIC images of these fields, and then blending the results. To address the loss of contrast caused by the blending of images, we observe that the pixel values in LIC images closely approximate normally distributed random variables. This allows us to use concepts from probability theory to correct the loss of contrast without the need to perform any image analysis at each frame.

Metric-driven RoSy field design and remeshing.

Designing rotational symmetry fields on surfaces is an important task for a wide range of graphics applications. This work introduces a rigorous and practical approach for automatic N-RoSy field design on arbitrary surfaces with user-defined field topologies. The user has full control of the number, positions, and indexes of the singularities (as long as they are compatible with necessary global constraints), the turning numbers of the loops, and is able to edit the field interactively. We formulate N-RoSy field construction as designing a Riemannian metric such that the holonomy along any loop is compatible with the local symmetry of N-RoSy fields. We prove the compatibility condition using discrete parallel transport. The complexity of N-RoSy field design is caused by curvatures. In our work, we propose to simplify the Riemannian metric to make it flat almost everywhere. This approach greatly simplifies the process and improves the flexibility such that it can design N-RoSy fields with single singularity and mixed-RoSy fields. This approach can also be generalized to construct regular remeshing on surfaces. To demonstrate the effectiveness of our approach, we apply our design system to pen-and-ink sketching and geometry remeshing. Furthermore, based on our remeshing results with high global symmetry, we generate Celtic knots on surfaces directly.