Trends in Prehospital Blood, Crystalloid, and Colloid Administration in Accordance With Changes in Tactical Combat Casualty Care Guidelines.

INTRODUCTION: Hemorrhage is the leading threat to the survival of battlefield casualties. This study aims to investigate the types of fluids and blood products administered in prehospital trauma encounters to discover the effectiveness of Tactical Combat Casualty Care (TCCC) recommendations. MATERIALS AND METHODS: This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry with a focus on prehospital fluid and blood administration in conjunction with changes in the TCCC guidelines. We collected demographic information on each patient. We categorized receipt of each fluid type and blood product as a binary variable for each casualty and evaluated trends over 2007-2020 both unadjusted and controlling for injury severity and mechanism of injury. RESULTS: Our original dataset comprised 25,897 adult casualties from January 1, 2007 through March 17, 2020. Most (97.3%) of the casualties were male with a median age of 25. Most (95.5%) survived to hospital discharge, and 12.2% of the dataset received fluids of any kind. Medical personnel used crystalloids in 7.4% of encounters, packed red blood cells in 2.0%, and whole blood in 0.5% with very few receiving platelets or freeze-dried plasma. In the adjusted model, we noted significant year-to-year increases in intravenous fluid administration from 2014 to 2015 and 2018 to 2019, with significant decreases noted in 2008-2009, 2010-2012, and 2015-2016. We noted no significant increases in Hextend used, but we did note significant decreases in 2010-2012. For any blood product, we noted significant increases from 2016 to 2017, with decreases noted in 2009-2013, 2015-2016, and 2017-2018. Overall, we noted a general spike in all uses in 2011-2012 that rapidly dropped off 2012-2013. Crystalloids consistently outpaced the use of blood products. We noted a small upward trend in all blood products from 2017 to 2019. CONCLUSIONS: Changes in TCCC guidelines did not immediately translate into changes in prehospital fluid administration practices. Crystalloid fluids continue to dominate as the most commonly administered fluid even after the 2014 TCCC guidelines changed to use of blood products over crystalloids. There should be future studies to investigate the reasons for delay in guideline implementation and efforts to improve adherence.

Obtaining Cross-Sections of Paint Layers in Cultural Artifacts Using Femtosecond Pulsed Lasers.

Recently, ultrafast lasers exhibiting high peak powers and extremely short pulse durations have created a new paradigm in materials processing. The precision and minimal thermal damage provided by ultrafast lasers in the machining of metals and dielectrics also suggests a novel application in obtaining precise cross-sections of fragile, combustible paint layers in artwork and cultural heritage property. Cross-sections of paint and other decorative layers on artwork provide critical information into its history and authenticity. However, the current methodology which uses a scalpel to obtain a cross-section can cause further damage, including crumbling, delamination, and paint compression. Here, we demonstrate the ability to make controlled cross-sections of paint layers with a femtosecond pulsed laser, with minimal damage to the surrounding artwork. The femtosecond laser cutting overcomes challenges such as fragile paint disintegrating under scalpel pressure, or oxidation by the continuous-wave (CW) laser. Variations in laser power and translational speed of the laser while cutting exhibit different benefits for cross-section sampling. The use of femtosecond lasers in studying artwork also presents new possibilities in analyzing, sampling, and cleaning of artwork with minimal destructive effects.