Thoracic Trauma: a Combat and Military Perspective

Emergency Operable Traumatic Pulmonary Injury at a Level 1 Trauma Center: A Retrospective Descriptive Study

INTRODUCTION

Despite the use of body armor, emergency operable pulmonary trauma (EOPT) remains a major cause of battlefield morbidity and mortality. While EOPT during military conflicts has some features that distinguish it from EOPT in civilian settings, the 2 occurrences demonstrate overall parallel findings related to presentation, management, and outcome. The goals of the present study were to provide a descriptive analysis of the nature of EOPT and its management at a level 1 trauma center and to determine the associations between EOPT patient demographics and/or patient management and outcome in order to better understand battlefield EOPT.

MATERIALS AND METHODS

This is a retrospective, descriptive analysis of EOPT at a level 1 trauma center during a recent 9-year period (2012-2020). The Oregon Health & Science University Trauma Registry was searched, and 106 patients met inclusion criteria for the study. Patients with primary cardiac trauma were excluded. Individual electronic medical records were reviewed to obtain descriptive data, and associations were evaluated for statistical significance.

RESULTS

In-hospital mortality in this cohort was 17.0%. The most common pulmonary injury associated with EOPT was unilateral diaphragmatic laceration (62.3%), and the most common single operation performed for EOPT was a laparotomy (71.7%) often involving diaphragmatic repair. In the remaining instances of EOPT, a thoracotomy (11.3%), a thoracotomy and a laparotomy (10.4%), or another surgery (6.6%) occurred. The primary indication for EOPT surgery was uncontrolled hemorrhage, and one-third of patients received massive transfusion. One-lung ventilation (OLV) was infrequently employed (8.5%). When OLV was used, it was equally likely to involve a single-lumen endotracheal tube (SLETT) with mainstem bronchus insertion, a SLETT with a bronchial blocker, or a double-lumen endotracheal tube. Time from EOPT to operating room arrival was inversely related to in-hospital mortality. Also, both initial in-hospital endotracheal intubation and low injury severity score were strongly associated with survival in the population studied.

CONCLUSIONS

The most common indication for EOPT surgery was uncontrolled hemorrhage. The most frequent operation performed for this EOPT cohort was a laparotomy for diaphragmatic repair. A total of 91.5% of EOPT surgery was performed without OLV, an unexpected finding. When OLV occurred, it was equally likely to involve an SLETT with mainstem bronchus insertion, an SLETT with bronchial blocker, or a double-lumen endotracheal tube. The most common indication for OLV was surgical exposure. More extensive injury (expressed as an injury severity score), preadmission endotracheal intubation, and a shorter time from EOPT to operating room arrival were associated with increased odds ratios for mortality. A better understanding of the nature of EOPT at a civilian level 1 trauma center can serve to identify conditions that are associated with more favorable outcomes for EOPT under battlefield conditions and thereby assist in both management decisions and to help prognosticate and triage severely injured patients in that setting.

Assessing the evolution of pre-hospital combat casualty care: A comparative study of two conflicts a decade apart

BACKGROUND

Combat casualty care has advanced significantly with the implementation of evidence-based protocols designed to lower combat-related mortality. Over the last decade, two major urban conflicts in southern Israel have challenged the evolving military trauma system. This study aimed to assess differences in prehospital care and compare the outcomes of aeromedically evacuated casualties from the 2014 and 2023 conflicts.

METHODS

This retrospective registry-based cohort study utilized records from the Military Airborne Combat Evacuation Unit (MACEU) and the Israeli National Trauma Registry. Eligible patients evacuated by MACEU between 07.17.14 and 08.16.14 and between 10.27.23 and 03.17.24 were compared. Ground-evacuated casualties were excluded. Demographics, prehospital interventions, and clinical outcomes were compared.

RESULTS

During the 2014 conflict, 251 patients were evacuated alive, compared to 940 in 2023. Both conflicts involved mostly young males injured by explosions, with comparable injury distributions across body regions. The time from injury to hospital arrival decreased from 65 min (IQR 47-94) in 2014 to 60 min (IQR 47-180) in 2023 (d = 0.5, p < 0.001). The proportion of severely injured patients (ISS ≥ 16) increased from 18.3 % to 25.2 % (OR 1.5 [95 % CI 1.06-2.14], p = 0.03), and critically injured patients (ISS ≥ 25) from 7.6 % to 12.8 % (OR 1.79 [95 % CI 1.08-2.96], p = 0.03). Prehospital advanced airway interventions and tube thoracostomies decreased from 11.6 % to 6.0 % (OR 0.48 [95 % CI 0.30-0.76], p < 0.001) and from 7.0 % to 2.1 % (OR 0.28 [95 % CI 0.15-0.54], p < 0.001), respectively. Prehospital blood transfusions use increased from 6.6 % to 16.4 % (OR 2.78 [95 % CI 1.64-4.76], p < 0.001). In-hospital mortality rates remained stable (2.7 % vs. 2.5 %, OR 1.12 [95 % CI 0.44-2.81], p = 0.99). Although not statistically significant, lower mortality rates were recorded among the severely (13.0 % vs. 8.4 %, OR 0.61 [95 % CI 0.23-1.61, p = 0.48) and critically injured (26.3 % vs. 15.8 %, OR 0.53 [95 % CI 0.17-1.64], p = 0.32).

CONCLUSION

Over the past decade, there has been a decline in prehospital airway interventions and thoracostomies, coupled with an increase in early blood transfusions. Despite greater injury severity, mortality rates have remained stable. Although not statistically significant, lower mortality rates were recorded among the severely and critically injured. These findings support the "less is more" approach in modern prehospital combat casualty care.

Continued Development and Testing of a Novel Steerable Chest Tube, Extendable Infusion Cannula, and Portable Suction-Infusion Pump for Use in Austere and Transport Environments to Prevent Retained Hemothorax

With blunt and penetrating trauma to the chest, warfighters frequently suffer from hemothorax. Optimal management requires the placement of a chest tube to evacuate the blood. Malposition of the tube may be a causative factor of inadequate drainage (retained hemothorax). As a potential solution, we developed a previously reported steerable chest tube allowing accurate placement into a desired location to enhance effectiveness. To provide assisted aspiration, we developed a portable, battery-operated suction device capable of simultaneous or sequential infusion. This report details the ongoing progress of this project. Updated steerable tube and pump prototypes were designed and produced. The tubes were tested for feasibility in two pigs and one cadaver by fluoroscopically comparing tip positions after insertion by a number of providers. Measured drainage volumes comparing standard vs. steerable tubes after pleural infusion of 1,000 mL of saline in two pigs were compared. Testing of the pump focused on the accuracy of suction and volume functions. The steerable tube prototype consists of sequentially bonded segments of differing flexibility and an ergonomic tensioning handle. The portable suction pump accurately provides up to 80 cmH2O of suction, an infusion capability of up to 10 mL/min, and a 950 mL removable reservoir canister. After minimal training, providers easily and repeatedly placed the tip of the steerable tube in the lateral diaphragmatic sulcus in animals and cadavers. Arc was limited to the distal segment. Compared to a standard tube, the steerable tube placed along the diaphragm improved pleural fluid drainage volumes by 17%, although this did not reach statistical significance in six trials. These new prototypes represent substantial improvements and were performed according to expectations. We believe that this steerable chest tube and portable suction-infusion pump can be effectively used for warfighters with chest injuries in austere environments.

Erector spinae plane block for affective and safe analgesia in a patient with severe penetrating chest trauma caused by an explosion in the battlefield

The ongoing conflict in Ukraine continues to generate many complex traumatic injuries and provides unique challenges to anaesthesiologists who provide medical care at various levels of medical evacuation. We report the successful use of an ultrasound-guided continuous erector spinae plane (ESP) block in a patient with severe posterolateral chest trauma. The acute perioperative outcome of the patient was improved with the ESP block, the main benefits being excellent analgesia and minimal postoperative morphine requirements without influencing the risk of bleeding and coagulopathy. We conclude that continuous ESP block can be utilized to provide excellent analgesia following massive thoracic trauma. It's ease of placement under ultrasound guidance and low risk of complications makes this technique particularly useful in war medicine.

Ex vivo hemostatic and immuno-inflammatory profiles of freeze-dried plasma

BACKGROUND

Hemorrhage is a leading cause of preventable death in civilian and military trauma. Freeze-dried plasma is promising for hemostatic resuscitation in remote prehospital settings, given its potential benefits in reducing blood loss and mortality, long storage at ambient temperatures, high portability, and rapid reconstitution for transfusion in austere environments. Here we assess the ex vivo characteristics of a novel Terumo's freeze-dried plasma product (TFDP).

STUDY DESIGN AND METHODS

Rotational thromboelastometry (ROTEM) tests (INTEM, EXTEM, and FIBTEM) were conducted on plasma samples at 37°C with a ROTEM delta-machine using standard reagents and procedures. The following samples were analyzed: pooled plasma to produce TFDP, TFDP reconstituted, and stored immediately at -80°C, reconstituted TFDP stored at 4°C for 24 h and room temperature (RT) for 4 h before freezing at -80°C. Analysis of plasma concentrations of selected cytokines, chemokines, and vascular molecules was performed using a multiplex immunoassay system. One-way ANOVA with post hoc tests assessed differences in hemostatic and inflammatory properties.

RESULTS

No significant differences in ROTEM variables (coagulation time [CT], clot formation time, α-angle, maximum clot firmness, and lysis index 30) between the TFDP-producing plasma and reconstituted TFDP samples were observed. Compared to control plasma, reconstituted TFDP stored at 4°C for 24 h or RT for 4 h showed a longer INTEM CT. Levels of immuno-inflammatory mediators were similar between frozen plasma and TFDP.

CONCLUSIONS

TFDP is equivalent to frozen plasma with respect to global hemostatic and immuno-inflammatory mediator profiles. Further investigations of TFDP in trauma-induced coagulopathy models and bleeding patients are warranted.

Rare Use of Posterolateral Thoracotomy in an Austere Environment

A 25-year-old local national male presented to a split Forward Surgical Team after impalement of the posterior chest with a metal fragment. The patient was hemodynamically normal, but no imaging was available to determine the depth of penetration or the size of the internal portion of the fragment. This case represents a rare indication for posterolateral thoracotomy in an austere trauma setting.

Thoracic trauma in military settings: a review of current practices and recommendations

PURPOSE OF REVIEW

To examine current literature on thoracic trauma related to military combat and to explore its relevance to the civilian population.

RECENT FINDINGS

Damage control resuscitation (DCR) has improved the management of hemorrhaging trauma patients. Permissive hypotension below 110 mmHg and antifibrinolytic use during DCR is widely accepted, whereas the use of freeze-dried plasma and whole blood is gaining popularity. The Modified Physiologic Triaging Tool can be used for primary triage and it may have applications in civilian trauma systems. Although Tactical Combat Casualty Care protocol recommends the Cric-Key device for surgical cricothyroidotomies, other devices may offer comparable performance. Recommendations for regional anesthesia after blunt trauma are not well defined. Increasing amounts of evidence favor the use of extracorporeal membrane oxygenation for refractory hypoxemia and resuscitative endovascular balloon occlusion of the aorta (REBOA) for severe hemorrhage. REBOA outcomes are potentially improved by partial occlusion and small 7 Fr catheters.

SUMMARY

The Global War on Terror has provided opportunities to better understand and treat thoracic trauma in military settings. Trauma registries and other data sources have contributed to significant advancements in the management of thoracic trauma in military and civilian populations.