Hypothermia in the Combat Trauma Population.

BACKGROUND: The MARCH (Massive hemorrhage, Airway, Respirations, Circulation, and Hypothermia/Head injuries) algorithm taught to military medics includes interventions to prevent hypothermia. As possible sequelae from major trauma, hypothermia is associated with coagulopathy and lower survival. This paper sought to define hypothermia within our combat trauma population using an outcomes-based method, and determine clinical variables associated with hypothermia. METHODS: This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry focused on casualties who received prehospital care. A receiver operating curve was constructed and Youden's index was used to define hypothermia within the predetermined population based on mortality risk. A multivariable regression model was used to identify associations. RESULTS: There were 23,243 encounters that met the inclusion criteria for this study with patients having received prehospital care and documentation of at least one emergency department temperature. An optimal threshold of 36.2° C was found to predict mortality; 3,159 casualties had temperatures below this threshold (14%). Survival to discharge was lower among casualties with hypothermia (91% versus 98%). Hypothermic casualties were less likely to undergo blanket application (38% versus 40%). However, they had higher proportions with Hypothermia Prevention and Management Kit application (11% versus 7%) and radiant warming (2% versus 1%). On multivariable regression modeling, none of the hypothermia interventions were associated with a decreased likelihood of hypothermia. Non-hypothermia interventions associated with hypothermia included prehospital intubation (OR 1.57, 95% CI 1.45-1.69) and blood product administration. CONCLUSIONS: Hypothermia, including a single recorded low temperature in the patient care record, was associated with worse outcomes in this combat trauma population. Prehospital intubation was most strongly associated with developing hypothermia. Prehospital warming interventions were not associated with a reduction in hypothermia risk. Our dataset suggests that current methods for prehospital warming are inadequate.

A Conceptual Framework for Non-Military Investigators to Understand the Joint Roles of Medical Care in the Setting of Future Large Scale Combat Operations.

As the wars in Iraq and Afghanistan end, the US military has begun to transition to the multi-domain operations concept with preparation for large scale combat operations against a near-peer adversary. In large scale combat operations, the deployed trauma system will likely see challenges not experienced during the Global War on Terrorism. The development of science and technology will be critical to close existing capability gaps and optimize casualty survival. This review comprises a framework of deployed trauma care to provide nonmilitary investigators a general understanding of our deployed trauma care system. Trauma care begins at the Role 1 which encompasses all care from the point of injury and the battalion aid station, through transport to the Role 2 or forward staged mobile surgical team such as a Forward Resuscitative Surgical Detachment. Role 1 point of injury care approximates the care delivered by Emergency Medical Services (EMS) personnel. The Battalion Aid Station approximates the care available at a freestanding emergency center with significant differences in training level of the providers, number of beds, and diagnostic capabilities. Role 2 medical care is part of an area support medical company with surgical capabilities. The Role 2 represents the first role of care which provides damage control surgery. This capability approximates a small community hospital with the primary difference being limited patient holding capacity and reduced diagnostic equipment. The Role 3 field hospital is the largest military treatment facility in the deployed setting. The Role 3 approximates a civilian level 2 trauma center with smaller holding capabilities and diagnostic abilities limited to that of a computed tomography (CT) scanner and less.

An analysis of early volume resuscitation and the association with prolonged mechanical ventilation.

BACKGROUND: Previous studies have found that intravenous fluid administration within the first 24 h may be associated with prolonged mechanical ventilation (PMV). We examined the association between initial 24 h fluids and PMV in combat casualties. METHODS: This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry (DODTR). We included casualties with at least 24 h on the ventilator and no significant traumatic brain injury. The definition of PMV and associations were constructed using univariable and multivariable logistic regression models. RESULTS: We identified 1508 casualties available for analysis for this study - 1275 in the non-PMV cohort (<9 days on ventilator vs. 233 in the PMV cohort (≥9 days on ventilator). Explosives comprised the most common mechanism of injury for both groups (72% vs. 75%) followed by firearms (21% vs. 16%). The composite injury severity score (ISS) was lower in the non-PMV cohort (18 vs. 30, p < .001). There were lower volumes of all resuscitation fluid within the first 24 h in the non-PMV cohort. When adjusting for composite ISS and mechanism of injury in a multivariable logistic regression model with PMV as the outcome, crystalloid volume (unit odds ratio [UOR] 1.07) and colloid volume (UOR 1.03) were both associated with PMV. CONCLUSIONS: We found that volume of resuscitation fluids were substantially higher in the PMV cohort. Our findings suggest the need for caution with the routine use of crystalloid and colloid in the first 24 h of resuscitation.

An Analysis of Patient Movements during Sustained Combat Operations in the US Central Command: Implications for Remote Support Capabilities.

BACKGROUND: The US Central Command (CENTCOM) area of responsibility (AOR) spans 20 nations in the Middle East, Central, and South Asia. Evacuations outside this AOR include all injury types and severities; however, it remains unclear what proportion of evacuations were due to disease and non-battle injuries (DNBI). Understanding these patterns may be useful for defining future medical support requirements for multi domain operations (MDO). We sought to analyze encounters obtained from the Transportation Command Regulating and Command and Control Evacuation System (TRAC2ES) data for medical evacuations within CENTCOM. METHODS: We obtained all encounters within TRAC2ES from February 2009 to November 2018. We analyzed data using entered demographic data and keyword categorization of free text information provided by the medical officer requesting patient movement. RESULTS: There were 50,036 patient movement requests entered into TRAC2ES originating from the CENTCOM AOR for both military and civilian personnel. After removal of ineligible entries (for example, military working dogs), the number of eligible subjects was 49,259, 13 percent combat (n equals 6,389) and 87 percent were noncombat (n equals 42,870). The primary age group requiring evacuation was 18 through 29 (59 percent) and were mostly male (87 percent). Most went by routine status (80 percent), followed by priority (16 percent). Most of the transfers originated from Afghanistan (58 percent) and Iraq (22 percent), with Germany serving as the primary destination (79 percent). Results showed the total number of patient evacuations increased from 2009 to 2010 and then decreased from 2011 to 2017. The most frequent body region associated with the transfer was the extremities for both combat (54 percent) and noncombat (32 percent). CONCLUSIONS: Out of theater disease and non combat injury evacuation rates were nearly 7 times higher than for combat related injuries. Our results highlight the need for additional research and development resources of DNBI related medical care. As we move into future MDO with limited evacuation capabilities, we will need support solutions to cover the full gamut of DNBI.

Digitized hand-wrist radiographs: comparison of subjective and software-derived image quality at various compression ratios.

INTRODUCTION: The objectives of this study were to compare the effect of JPEG 2000 compression of hand-wrist radiographs on observer image quality qualitative assessment and to compare with a software-derived quantitative image quality index. METHODS: Fifteen hand-wrist radiographs were digitized and saved as TIFF and JPEG 2000 images at 4 levels of compression (20:1, 40:1, 60:1, and 80:1). The images, including rereads, were viewed by 13 orthodontic residents who determined the image quality rating on a scale of 1 to 5. A quantitative analysis was also performed by using a readily available software based on the human visual system (Image Quality Measure Computer Program, version 6.2, Mitre, Bedford, Mass). ANOVA was used to determine the optimal compression level (P < or =.05). RESULTS: When we compared subjective indexes, JPEG compression greater than 60:1 significantly reduced image quality. When we used quantitative indexes, the JPEG 2000 images had lower quality at all compression ratios compared with the original TIFF images. There was excellent correlation (R2 >0.92) between qualitative and quantitative indexes. CONCLUSIONS: Image Quality Measure indexes are more sensitive than subjective image quality assessments in quantifying image degradation with compression. There is potential for this software-based quantitative method in determining the optimal compression ratio for any image without the use of subjective raters.