Cric in the Dark: Surgical Cricothyrotomy in Low Light Tactical Environments.

BACKGROUND: Surgical cricothyrotomy (SC) is a difficult procedure with high failure rates in the battlefield environment. The difficulty of this procedure is compounded in a low-light tactical environment in which white light cannot be used. This study compared the use of red-green (RG) light and red (R) light in the performance of SC in a low-light environment. MATERIALS AND METHODS: Tactical Combat Casualty Care-certified navy corpsmen (n = 33) were provided 15 minutes of standardized instruction followed by hands-on practice with the Tactical CricKit and the H&H bougie-assisted Emergency Cricothyrotomy Kit. Participants acclimated to a dark environment for 30 minutes before performing SC on a mannequin with both devices using both R and RG light in a randomized order. Application time, success, participant preference, and participant confidence were analyzed. RESULTS: There were similarly high levels of successful placement (>87.5%) in all four cohorts. Light choice did not appear to affect placement time with either of the two kits. On Likert-scale surveys, participants reported that RG decreased difficulty (p < .0001) and increased confidence (p < .0001) in performing the procedure. CONCLUSION: RG light increased confidence and decreased perceived difficulty when performing SC, though no differences in placement time or success were observed.

Red-Green Tactical Lighting Is Preferred for Suturing Wounds in a Simulated Night Environment.

BACKGROUND: Delivering medical care in nighttime conditions is challenging, as 25% of Special Operations medical Operators have reported that problems with lighting contributed to poor casualty outcomes. Red light is often used in nighttime operations but makes blood detection difficult and diminishes depth perception and visual acuity. Red-green combination lighting may be superior for differentiating blood from tissue and other fluids but had not been tested versus red-only or green-only lighting for combat-related medical procedures, such as wound suturing. METHODS: Dark-adapted medical resident physicians (N = 24) sutured 6cm long, 3cm deep, full-thickness lacerations in deceased swine under red-only, green-only, and red-green lighting provided by a tactical flashlight using a randomized within-subjects design. Time to suture completion, suture quality, user ratings, and user preference data were contrasted at p < .05. This study was approved by Naval Medical Center Portsmouth IRB. RESULTS: Suture completion time and suture quality were similar across all lighting conditions. Participants rated red-green lighting as significantly easier for identifying blood, identifying instruments, and performing suturing (p < .01). Red-green lighting was preferred by 83% of participants compared to 8% each for red-only and green-only (p < .001). CONCLUSIONS: Pending further study under tactical conditions, red-green lighting is tentatively recommended for treating battlefield wounds in low-light environments.

Intravenous and Intraosseous Blood Transfusion With Three Different Pediatric Pressure Transfusion Strategies in an Immature Swine (Sus scrofa) Model of Hemorrhagic Shock: A Pilot Study.

INTRODUCTION: Exsanguination remains the leading cause of preventable death in military conflicts, and pediatric casualties are common. Transfusion is crucial to preserve life, but vascular access is challenging in children, so intraosseous (IO) access is often required. However, the optimal transfusion method is unclear. There was therefore the need for feasibility testing of a model for contrasting the efficacy of blood infusion devices via intravenous (IV) and IO access in immature swine with bone densities similar to children. MATERIALS AND METHODS: Eighteen immature swine (21 ± 1 kg) were bled 31% of estimated blood volume and then received autologous blood delivered by pressure bag, push-pull (PP), or LifeFlow Rapid Infuser via IO (15-gauge IO needle placed in the humeral head) or IV (auricular 20-gauge), with monitoring for 60 minutes. RESULTS: Flow rates for LifeFlow (172 ± 28 mL/kg) were 4-fold higher than pressure bag (44 ± 13 mL/kg, P < 0.001) and 80% higher than PP (95 ± 28 mL/kg, P < 0.02). However, higher hemolysis was evident in the IV LifeFlow condition, with 6-fold more plasma-free hemoglobin than other conditions (P < 0.0001). CONCLUSIONS: IV LifeFlow conferred higher flows, but higher hemolysis in this pilot study demonstrates the feasibility of an immature swine model toward determining optimal methods for resuscitating children with hemorrhagic shock.

Impact of Marine Exposure on Hemostatic Gauzes Using Thromboelastography.

BACKGROUND: Military forces render emergency care in marine environments, where care for exsanguination is challenging. However, the effect of saltwater on the functionality of hemostatic agents is unknown. In this study, we used thromboelastography (TEG) to quantify the effect of saltwater on the efficacy of five gauze products. METHODS: Blood from 24 healthy adult men was diluted by 30% with hetastarch to mimic hemodilution. Dry and saltwater-soaked Kerlix™, ChitoGauze®, Combat Gauze®, NuStat™, and WoundClot™ were contrasted in terms of the TEG parameters of speed of clot initiation (R), clot amplification (K), α angle (i.e., clot formation rate), and maximum amplitude of clot (MA), using repeated-measures analysis of variance at the p < .05 statistical significance threshold. RESULTS: Compared with untreated dilute blood, R was significantly faster when any dry or wet gauze was added, with the fastest R values recorded for Combat Gauze. K and α angle findings were mixed. MA was greater than diluted blood for dry hemostatic gauze, but in the wet condition, only the MA for Combat Gauze was significantly greater than that of diluted blood. CONCLUSION: Gauze products, wet or dry, improved clotting compared to diluted blood without gauze. Saltwater exposure did not significantly detract from this benefit. Our findings suggest that Combat Gauze may be the choice hemostatic gauze for maritime environments.

Randomized Comparative Assessment of Three Surgical Cricothyrotomy Devices on Airway Mannequins.

BACKGROUND: Airway obstruction is the second leading cause of preventable battlefield death, at least in part because surgical cricothyrotomy (SC) failure rates remain unacceptably high. Ideally, SC should be a rapid, simple, easily-learned, and reliably-performed procedure. Currently, 3 SC devices meet Tactical Combat Casualty Care (TCCC) standards: The Tactical CricKit® (TCK), Control-CricTM(CC), and Bougie-assisted Technique (BAT). However, no previous studies have compared these devices in application time, application success, user ratings, and user preference. METHODS: United States Navy Corpsmen (N = 25) were provided 15 minutes of standardized instruction, followed by hands-on practice with each device on airway mannequins. Participants then performed SC with each of the 3 devices in a randomly assigned sequence. In this within-subjects design, application time, application success, participant ratings, and participant preference data were analyzed using repeated-measures ANOVA, regression, and non-parametric statistics at p < 0.05. RESULTS: Application time for CC (M = 184 sec, 95% CI 144-225 sec) was significantly slower than for BAT (M = 135 sec, 95% CI 113-158 sec, p < 0.03) and TCK (M = 117 sec, 95% CI 93-142 sec, p < 0.005). Success was significantly greater for BAT (76%) than for TCK (40%, p < 0.02) and trended greater than CC (48%, p = 0.07). CC was rated significantly lower than TCK and BAT in ease of application, effectiveness, and reliability (each p < 0.01). User preference was significantly (p < 0.01) higher for TCK (58%) and BAT (42%) than for CC (0%). Improved CC blade design was the most common user suggestion. CONCLUSION: While this study was limited by the use of mannequins in a laboratory environment, present results indicate that none of these devices was ideal for performing SC. Based on slow application times, low success rates, and user feedback, the Control-CricTM cannot be recommended until improvements are made to the blade design.

Comparison of Three Junctional Tourniquets Using a Randomized Trial Design.

BACKGROUND: Hemorrhage remains a leading cause of death in both civilian and military settings. Of preventable deaths from hemorrhage, a significant portion occurs from junctional wounds that are not amenable to traditional extremity tourniquets. Junctional tourniquets (JTQs) can potentially provide hemorrhage control by compressing the arteries at the junction of the trunk and extremities. The FDA has cleared 3 JTQ products: The Combat Ready Clamp (CRoC®), the Junctional Emergency Treatment Tool (JETT™), and the SAM® Junctional Tourniquet (SJT). However, little is known regarding which of these JTQs is superior in application time, effectiveness in pulse elimination, effectiveness during transport, and user preference. METHODS: Active duty corpsmen (N = 49) were given standardized instruction and hands-on training with the CRoC®, JETT™, and SJT, then sequentially applied each JTQ unilaterally to a fellow study participant in a randomized order. Pulse elimination was determined by Doppler ultrasound at the dorsalis pedis immediately then reevaluated after a short transport. User preference data were collected following testing. Data were analyzed using repeated measures ANOVA and non-parametric statistics at p < 0.05. RESULTS: The CRoC® was significantly slower in application time than the JETT™ and SJT. Effectiveness was similar for CRoC®, JETT™, and SJT. Effectiveness during transport was significantly higher for SJT than for the JETT™, but no JTQ performed well during transport (24-48% effectiveness). SJT ranked first in perceived ease of use, stability, and reliability, and in user trust and overall preference. Participants provided cogent suggestions for product improvement. CONCLUSIONS: All JTQ devices performed poorly during transport. Combined, present findings highlight the potential of JTQ products for saving lives threatened by junctional wounds, but also highlight the need for specific product improvements towards fostering JTQ performance in patient transport.

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.

Clinician Attitudes, Screening Practices, and Interventions to Reduce Firearm-Related Injury.

Firearm injury is a leading cause of injury-related morbidity and mortality in the United States. We sought to systematically identify and summarize existing literature on clinical firearm injury prevention screening and interventions. We conducted a systematic search of PubMed, Web of Science, Cumulative Index of Nursing and Allied Health Literature (CINAHL), PsycInfo, and ClinicalTrials.gov for English-language original research (published 1992-2014) on clinical screening methods, patient-level firearm interventions, or patient/provider attitudes on the same. Unrelated studies were excluded through title, abstract, and full-text review, and the remaining articles underwent data abstraction and quality scoring. Of a total of 3,260 unique titles identified, 72 were included in the final review. Fifty-three articles examined clinician attitudes/practice patterns; prior training, experience, and expectations correlated with clinicians' regularity of firearm screening. Twelve articles assessed patient interventions, of which 6 were randomized controlled trials. Seven articles described patient attitudes; all were of low methodological quality. According to these articles, providers rarely screen or counsel their patients-even high-risk patients-about firearm safety. Health-care-based interventions may increase rates of safe storage of firearms for pediatric patients, suicidal patients, and other high-risk groups. Some studies show that training clinicians can increase rates of effective firearm safety screening and counseling. Patients and families are, for the most part, accepting of such screening and counseling. However, the current literature is, by and large, not high quality. Rigorous, large-scale, adequately funded studies are needed.