When Minutes Matter: A Comparison of Whole Blood Collection Techniques.

BACKGROUND: Fast and reliable blood collection is critical to emergency walking blood banks (WBB) because mortality significantly declines when blood is quickly administered to a warfighter with hemorrhagic shock. Phlebotomy for WBB is accomplished via either the "straight stick" (SS) or "ruggedized lock" (RL) method. SS comprises a 16-gauge phlebotomy needle connected to a blood collection bag via tubing. The RL device collects blood through the same apparatus, but has a capped, intravenous (IV) catheter between the needle and the donor's arm. This is the first study to compare these two methods in battlefield-relevant metrics. METHODS: Military first responders and licensed medical providers (N=86) were trained in SS and RL as part of fresh whole blood training exercises. Outcomes included venipuncture success rates, time to IV access, blood collection times, total time, and user preferences, using a within-subjects crossover design. Data were analyzed using ANOVA and nonparametric statistics at p<0.05. RESULTS: SS outperformed RL in first venipuncture success rates (76% vs. 64%, p=0.07), IV access times (448 [standard error of the mean; SE 23] vs. 558 [SE 31] s, p<0.01), and blood collection bag fill times (573 [SE 48] vs. 703 [SE 44] s, p<0.05), resulting in an approximate 3.5-minute faster time overall. Survey data were mixed, with users perceiving SS as simpler and faster, but RL as more reliable and secure. CONCLUSION: SS is optimal when timely collection is imperative, while RL may be preferable when device stability or replacing the collection bag is a consideration.

Prescreened Whole O Blood Group Walking Blood Bank Capabilities for Nontraditional Maritime Medical Receiving Platforms: A Case Series.

BACKGROUND: Tactical Combat Casualty Care (TCCC) guidelines recognize low-titer group O whole blood (LTOWB) as the resuscitative fluid of choice for combat wounded. Utilization of prescreened LTOWB in a walking blood bank (WBB) format has been well described by the Ranger O low-titer blood (ROLO) and the United States Marine Corps Valkyrie programs, but it has not been applied to the maritime setting. METHODS: We describe three WBB experiences of an expeditionary resuscitative surgical system (ERSS) team, attached to three nontraditional maritime medical receiving platforms, over 6 months. RESULTS: Significant variations were identified in the number of screened eligible donors, the number of LTOWB donors, and the timely arrival at WBB activation sites between the platforms. Overall, 95% and 84% of the screened eligible group O blood donors on the Arleigh Burke Class Destroyer (DDG) and Nimitz Class Aircraft Carrier (CVN), respectively, were determined to be LTOWB. However, only 37% of the eligible screened group O blood donors aboard the Harper's Ferry Class Dock Landing Ship (LSD) were found to be LTOWB. Of the eligible donors, 66% did not complete screening, with 52% citing a correctable reason for nonparticipation. CONCLUSION: LTOWB attained through WBBs may be the only practical resuscitative fluid on maritime platforms without inherent blood product storage capabilities to perform remote damage control resuscitation. Future efforts should focus on optimizing WBBs through capability development, education, and training efforts.

Feasibility of Obtaining Intraosseous and Intravenous Access Using Night Vision Goggle Focusing Adaptors.

BACKGROUND: The optimal tactical lighting for performing medical procedures under low-light conditions is unclear. METHODS: United States Navy medical personnel (N = 23) performed intravenous (IV) and intraosseous (IO) procedures on mannequins using a tactical headlamp, night vision goggles (NVGs), and night vision goggles with focusing adaptors (NVG+A) utilizing a randomized within-subjects design. Procedure success, time to completion, and user preferences were analyzed using analysis of variance (ANOVA) and nonparametric statistics at p < .05. RESULTS: IV success rates were significantly greater for the headlamp (74%) than for NVG (35%; p < .03) and somewhat greater than for NVG+A (52%; p = .18). IO success rates were high under each lighting condition (96% to 100%). Time to completion was significantly faster using headlamp (IV, 106 ± 28 s; IO, 47 ± 11 s) than NVG (IV, 168 ± 80 s; IO, 56 ± 17 s) or NVG-A (IV, 157 ± 52 s; IO, 59 ± 27 s; each p < .01). Posttesting confidence on a 1-to-5 scale was somewhat higher for NVG+A (IV, 2.9 ± 0.2; IO, 4.2 ± 0.2) than for NVG (IV, 2.6 ± 0.2; IO, 4.0 ± 0.2). Participants cited concerns with NVG+A depth perception and with adjusting the adaptors, and that the adaptors were not integrated into the NVG. CONCLUSION: While this mannequin study was limited by laboratory conditions and by the lack of practice opportunities, we found some small advantages of focusing adaptors over NVG alone but not over headlamp for IV and IO access in low-light conditions.

Fluid Resuscitation in Tactical Combat Casualty Care; TCCC Guidelines Change 21-01. 4 November 2021.

Hemorrhagic shock in combat trauma remains the greatest life threat to casualties with potentially survivable injuries. Advances in external hemorrhage control and the increasing use of damage control resuscitation have demonstrated significant success in decreasing mortality in combat casualties. Presently, an expanding body of literature suggests that fluid resuscitation strategies for casualties in hemorrhagic shock that include the prehospital use of cold-stored or fresh whole blood when available, or blood components when whole blood is not available, are superior to crystalloid and colloid fluids. On the basis of this recent evidence, the Committee on Tactical Combat Casualty Care (TCCC) has conducted a review of fluid resuscitation for the combat casualty who is in hemorrhagic shock and made the following new recommendations: (1) cold stored low-titer group O whole blood (CS-LTOWB) has been designated as the preferred resuscitation fluid, with fresh LTOWB identified as the first alternate if CS-LTOWB is not available; (2) crystalloids and Hextend are no longer recommended as fluid resuscitation options in hemorrhagic shock; (3) target systolic blood pressure (SBP) resuscitation goals have been redefined for casualties with and without traumatic brain injury (TBI) coexisting with their hemorrhagic shock; and (4) empiric prehospital calcium administration is now recommended whenever blood product resuscitation is required.

Case Series on 2g Tranexamic Acid Flush From the 75th Ranger Regiment Casualty Database.

Early tranexamic acid (TXA) administration for resuscitation of critically injured warfighters provides a mortality benefit. The 2019 Tactical Combat Casualty Care (TCCC) recommendations of a 1g drip over 10 minutes, followed by 1g drip over 8 hours, is intended to limit potential TXA side effects, including hypotension, seizures, and anaphylaxis. However, this slow and cumbersome TXA infusion protocol is difficult to execute in the tactical care environment. Additionally, the side effect cautions derive from studies of elderly or cardiothoracic surgery patients, not young healthy warfighters. Therefore, the 75th Ranger Regiment developed and implemented a 2g intravenous or intraosseous (IV/IO) TXA flush protocol. We report on the first six cases of this protocol in the history of the Regiment. After-action reports (AARs) revealed no incidences of post-TXA hypotension, seizures, or anaphylaxis. Combined, the results of this case series are encouraging and provide a foundation for larger studies to fully determine the safety of the novel 2g IV/IO TXA flush protocol toward preserving the lives of traumatically injured warfighters.

The Use of Tranexamic Acid in Tactical Combat Casualty Care: TCCC Proposed Change 20-02.

The literature continues to provide strong support for the early use of tranexamic acid (TXA) in severely injured trauma patients. Questions persist, however, regarding the optimal medical and tactical/logistical use, timing, and dose of this medication, both from the published TXA literature and from the TCCC user community. The use of TXA has been explored outside of trauma, new dosing strategies have been pursued, and expansion of retrospective use data has grown as well. These questions emphasize the need for a reexamination of TXA by the CoTCCC. The most significant updates to the TCCC Guidelines are (i) including significant traumatic brain injury (TBI) as an indication for TXA, (ii) changing the dosing protocol to a single 2g IV/IO administration, and (iii) recommending TXA administration via slow IV/IO push.

The Joint Emergency Medicine Exercise: A Capstone Training Evolution of a Military Unique Curriculum for Emergency Medicine Residents.

INTRODUCTION: The role of the Emergency Medicine (EM) physician in the U.S. military continues to expand, and current Accreditation Council for Graduate Medical Education general training requirements do not optimally prepare military EM graduates to be successful in postresidency operational assignments. To address this gap, the Naval Medical Center San Diego EM residency program introduced a Military Unique Curriculum (MUC) culminating in a capstone event, the Joint Emergency Medicine Exercise (JEMX). METHODS: Part of an approved Quality Improvement project, annual survey results from 2012 to 2017 evaluated graduate opinion on the strengths and weaknesses of the MUC. We describe a pilot project conceived by tri-service EM physicians to evaluate the feasibility of the JEMX. RESULTS: Forty-eight graduate residents responded to surveys, 18 of which were administered pre-MUC implementation. With a 100% response rate from graduate residents, overall trends showed greater perceived readiness for postresidency operational assignments after MUC implementation. Written comments received cited the MUC as areas where the Naval Medical Center San Diego EM program excelled and the successful JEMX evolutions as the most valuable curricular component of the MUC. CONCLUSION: An integrated MUC with a capstone exercise, such as our JEMX, provides a feasible and effective educational experience that improves operational readiness of graduating EM residents.

Risk Associated With Autologous Fresh Whole Blood Training.

Fresh whole blood (FWB) is increasingly being recognized as the ideal resuscitative fluid for hemorrhagic shock. Because of this, military units are working to establish the capability to give FWB from a walking blood bank donor in environments that are unsupported by conventional blood bank services. Therefore, many military units are performing autologous blood transfusion training. In this training, a volunteer has a unit of blood collected and then transfused back into the same donor. The authors report their experience performing an estimated 3408 autologous transfusions in training and report no instances of hemolytic transfusion reactions or other major complications. With appropriate control measures in place, autologous FWB training is low-risk training.

A Pilot Study of Four Intraosseous Blood Transfusion Strategies.

BACKGROUND: Intraosseous (IO) access is used by military first responders administering fluids, blood, and medications. Current IO transfusion strategies include gravity, pressure bags, rapid transfusion devices, and manual push-pull through a three-way stopcock. In a swine model of hemorrhagic shock, we compared flow rates among four different IO blood transfusion strategies. METHODS: Nine Yorkshire swine were placed under general anesthesia. We removed 20 to 25mL/kg of each animal's estimated blood volume using flow of gravity. IO access was obtained in the proximal humerus. We then autologously infused 10 to 15mL/kg of the animal's estimated blood volume through one of four randomly assigned treatment arms. RESULTS: The average weight of the swine was 77.3kg (interquartile range, 72.7kg-88.8kg). Infusion rates were as follows: gravity, 5mL/min; Belmont rapid infuser, 31mL/min; single-site pressure bag, 78mL/min; double-site pressure bag, 103mL/min; and push-pull technique, 109mL/min. No pulmonary arterial fat emboli were noted. CONCLUSION: The optimal IO transfusion strategy for injured Servicemembers appears to be single-site transfusion with a 10mL to 20mL flush of normal saline, followed immediately by transfusion under a pressure bag. Further study, powered to detect differences in flow rate and clinical complications. is required.

Barotrauma with extreme pressures in sport: from scuba to skydiving.

The human body is well adapted to dealing with small variations in atmospheric pressure. However when our pursuit of sport and recreation takes us to extreme altitudes or ocean depths, the change in surrounding pressure has the potential to cause significant morbidity. Sports with more extreme changes in atmospheric pressure such as skydiving and scuba diving commonly place the athlete at risk for barotrauma injuries, especially in the middle ear and sinuses. Middle ear barotrauma occurs when a pressure differential develops between the middle ear and the pressure outside of the tympanic membrane. Early symptoms include ear pain, dizziness, and muffled hearing. When extreme pressure gradients are not relieved, middle ear effusions and rupture of the tympanic membrane can occur. A similar mechanism and injury pattern occurs in the sinuses as well. With proper training and prevention strategies, athletes in these sports can protect themselves from most barotrauma injuries.

Bilateral compartment syndrome of the anterior thigh following functional fitness exercises: a case report.

We present a case of delayed, acute bilateral exertional compartment syndrome of the anterior thigh induced by callisthenic exercise. Symptoms consisted of pain out of proportion to examination findings, inability to ambulate, and severe pain with knee flexion. Treatment consisted of bilateral thigh fasciotomies and supportive therapy for concomitant rhabdomyolysis. Full strength, range of motion, and return to all military duties were achieved by 4 months postinjury.

Injury profile for airborne operations utilizing the SF-10A maneuverable parachute.

PURPOSE: The purpose of this investigation was to determine the injury profile of the steerable, SF-10A, static-line parachute. METHODS: The investigation evaluated prospectively 972 low-level static-line training jumps for major injuries that required CASEVAC from the drop zone and for minor injuries that allowed the jumpers to continue with their training mission. RESULTS: The investigation found overall injury rates to be 8.23 per 1000 jumps, with 2.03 per 1000 jumps requiring CASEVAC. CONCLUSIONS: Overall attrition rates of the steerable SF-10A parachute were below those of previously reported non-steerable parachutes, suggesting further evaluation is warranted of maneuverable parachutes in all military services.