Monitoring diesel particulate matter and calculating diesel particulate densities using Grimm model 1.109 real-time aerosol monitors in underground mines.

Currently, there is no Mine Safety and Health Administration (MSHA)-approved sampling method that provides real-time results for ambient concentrations of diesel particulates. This study investigated whether a commercially available aerosol spectrometer, the Grimm Portable Aerosol Spectrometer Model 1.109, could be used during underground mine operations to provide accurate real-time diesel particulate data relative to MSHA-approved cassette-based sampling methods. A subset was to estimate size-specific diesel particle densities to potentially improve the diesel particulate concentration estimates using the aerosol monitor. Concurrent sampling was conducted during underground metal mine operations using six duplicate diesel particulate cassettes, according to the MSHA-approved method, and two identical Grimm Model 1.109 instruments. Linear regression was used to develop adjustment factors relating the Grimm results to the average of the cassette results. Statistical models using the Grimm data produced predicted diesel particulate concentrations that highly correlated with the time-weighted average cassette results (R(2) = 0.86, 0.88). Size-specific diesel particulate densities were not constant over the range of particle diameters observed. The variance of the calculated diesel particulate densities by particle diameter size supports the current understanding that diesel emissions are a mixture of particulate aerosols and a complex host of gases and vapors not limited to elemental and organic carbon. Finally, diesel particulate concentrations measured by the Grimm Model 1.109 can be adjusted to provide sufficiently accurate real-time air monitoring data for an underground mining environment.

Preventable transfers in pediatric trauma: A 10-year experience at a level I pediatric trauma center.

BACKGROUND: Injured children are often treated at one facility then transferred to another that specializes in pediatric trauma care. The purpose of this study was to identify and characterize potentially preventable transfers (PT) to a freestanding level-I pediatric trauma center. METHODS: Children with traumatic injuries transferred between 2003 and 2013 were retrospectively analyzed. A PT was defined as a child who was discharged within 36hours of arrival without surgical intervention or advanced imaging studies. RESULTS: During this period, 6380 children were transferred, with head injury being the most common injury. 61% had CT imaging performed before transfer. The mean age was 6.9years, mean injury severity score (ISS) 10.4, and median transfer distance 37miles. 27% of these transfers were classified as PT. Air transport was used in 15% at mean charge of $18,574. 29% were discharged from the emergency department. When compared, PTs were younger (6.0 vs. 7.2years, p<0.001), with lower median ISS (5 vs. 9, p<0.001), shorter median LOS (15 vs. 43.6hours, p<0.001), and less PICU admissions (6% vs. 34%, p<0.001). CONCLUSION: A significant number of pediatric trauma transfers can be classified as preventable. Reducing preventable transfers could offer opportunities for improving value in a trauma care system.