A novel streamlined trauma response team training improves imaging efficiency for pediatric blunt abdominal trauma patients

Background/purpose The morbidity and mortality of children with traumatic injuries are directly related to the time to definitive management of their injuries. Imaging studies are used in the trauma evaluation to determine the injury type and severity. The goal of this project is to determine if a formal streamlined trauma response improves efficiency in pediatric blunt trauma by evaluating time to acquisition of imaging studies and definitive management. Methods This study is a chart review of patients < 18 years who presented to a pediatric trauma center following blunt trauma requiring trauma team activation. 413 records were reviewed to determine if training changed the efficiency of CT acquisition and 652 were evaluated for FAST efficiency. The metrics used for comparison were time from ED arrival to CT image, FAST, and disposition. Results Time from arrival to CT acquisition decreased from 37 (SD 23) to 28 (SD27) min (p < 0.05) after implementation. The proportion of FAST scans increased from 315 (63.5%) to 337 (80.8%) and the time to FAST decreased from 18 (SD15) to 8 (SD10) min (p < 0.05). The time to operating room (OR) decreased after implementation. Conclusion The implementation of a streamlined trauma team approach is associated with both decreased time to CT, FAST, OR, and an increased proportion of FAST scans in the pediatric trauma evaluation. This could result in the rapid identification of injuries, faster disposition from the ED, and potentially improve outcomes in bluntly injured children

Generalizations of the Strong Arnold Property and the minimum number of distinct eigenvalues of a graph

For a given graph G and an associated class of real symmetric matrices whose off-diagonal entries are governed by the adjacencies in G, the collection of all possible spectra for such matrices is considered. Building on the pioneering work of Colin de Verdiere in connection with the Strong Arnold Property, two extensions are devised that target a better understanding of all possible spectra and their associated multiplicities. These new properties are referred to as the Strong Spectral Property and the Strong Multiplicity Property. Finally, these ideas are applied to the minimum number of distinct eigenvalues associated with G, denoted by q(G). The graphs for which q(G) is at least the number of vertices of G less one are characterized.Comment: 26 pages; corrected statement of Theorem 3.5 (a

On the maximum rank of totally nonnegative matrices

[EN] Let A is an element of R-nxn be a totally nonnegative matrix with principal rank p, that is, every minor of A is nonnegative and p is the size of the largest invertible principal submatrix of A. We introduce the sequence of the first p-indices of A as the first initial row and column indices of a p x p invertible principal submatrix of A with rank p. Then, we study the linear dependence relations between the rows and columns indexed by the sequence of the first p-indices of A and the remaining of its rows and columns. These relations, together with the irreducibility property of some submatrices of A, allow us to present an algorithm that calculates the maximum rank of A as a function of the distribution of the first p-indices. Finally, we present a method to construct n x n totally nonnegative matrices with given rank r, principal rank p and a specific sequence of the first p-indices. (C) 2018 Elsevier Inc. All rights reserved.This research was supported by the Spanish DGI grants MTM2013-43678-P, MTM2017-85669-P and MTM2017-90682-REDT.Cantó Colomina, R.; Urbano Salvador, AM. (2018). On the maximum rank of totally nonnegative matrices. Linear Algebra and its Applications. 551:125-146. https://doi.org/10.1016/j.laa.2018.03.045S12514655