Novel Essential Amino Acid Supplements Following Resistance Exercise Induce Aminoacidemia and Enhance Anabolic Signaling Irrespective of Age: A Proof-of-Concept Trial.

We investigated the effects of ingesting a leucine-enriched essential amino acid (EAA) gel alone or combined with resistance exercise (RE) versus RE alone (control) on plasma aminoacidemia and intramyocellular anabolic signaling in healthy younger (28 ± 4 years) and older (71 ± 3 years) adults. Blood samples were obtained throughout the three trials, while muscle biopsies were collected in the postabsorptive state and 2 h following RE, following the consumption of two 50 mL EAA gels (40% leucine, 15 g total EAA), and following RE with EAA (combination (COM)). Protein content and the phosphorylation status of key anabolic signaling proteins were determined via immunoblotting. Irrespective of age, during EAA and COM peak leucinemia (younger: 454 ± 32 µM and 537 ± 111 µM; older: 417 ± 99 µM and 553 ± 136 µM) occurred ~60-120 min post-ingestion (younger: 66 ± 6 min and 120 ± 60 min; older: 90 ± 13 min and 78 ± 12 min). In the pooled sample, the area under the curve for plasma leucine and the sum of branched-chain amino acids was significantly greater in EAA and COM compared with RE. For intramyocellular signaling, significant main effects were found for condition (mTOR (Ser2481), rpS6 (Ser235/236)) and age (S6K1 (Thr421/Ser424), 4E-BP1 (Thr37/46)) in age group analyses. The phosphorylation of rpS6 was of similar magnitude (~8-fold) in pooled and age group data 2 h following COM. Our findings suggest that a gel-based, leucine-enriched EAA supplement is associated with aminoacidemia and a muscle anabolic signaling response, thus representing an effective means of stimulating muscle protein anabolism in younger and older adults following EAA and COM.

Skeletal muscle, haematological and splenic volume characteristics of elite breath-hold divers.

PURPOSE: The aim of the study was to provide an evaluation of the oxygen transport, exchange and storage capacity of elite breath-hold divers (EBHD) compared with non-divers (ND). METHODS: Twenty-one healthy males' (11 EBHD; 10 ND) resting splenic volumes were assessed by ultrasound and venous blood drawn for full blood count analysis. Percutaneous skeletal muscle biopsies were obtained from the m. vastus lateralis to measure capillarisation, and fibre type-specific localisation and distribution of myoglobin and mitochondrial content using quantitative immunofluorescence microscopy. RESULTS: Splenic volume was not different between groups. Reticulocytes, red blood cells and haemoglobin concentrations were higher (+ 24%, p < 0.05; + 9%, p < 0.05; + 3%, p < 0.05; respectively) and mean cell volume was lower (- 6.5%, p < 0.05) in the EBHD compared with ND. Haematocrit was not different between groups. Capillary density was greater (+ 19%; p < 0.05) in the EBHD. The diffusion distance (R95) was lower in type I versus type II fibres for both groups (EBHD, p < 0.01; ND, p < 0.001), with a lower R95 for type I fibres in the EBHD versus ND (- 13%, p < 0.05). Myoglobin content was higher in type I than type II fibres in EBHD (+ 27%; p < 0.01) and higher in the type I fibres of EBHD than ND (+ 27%; p < 0.05). No fibre type differences in myoglobin content were observed in ND. Mitochondrial content was higher in type I than type II fibres in EBHD (+ 35%; p < 0.05), with no fibre type differences in ND or between groups. CONCLUSIONS: In conclusion, EBDH demonstrate enhanced oxygen storage in both blood and skeletal muscle and a more efficient oxygen exchange capacity between blood and skeletal muscle versus ND.

The NATO Special Operations Surgical Team Development Course A Program Overview.

The Special Operations Surgical Team Development Course (SOSTDC) is a 5-day course held two or three times a year at the North Atlantic Treaty Organization (NATO) training facility within the Special Operations Medical Branch (SOMB) of the Allied Centre for Medical Education (ACME). Its aim is to teach, train, develop, and encourage NATO partner nations to provide robust, hardened, and clinically able surgical resuscitation teams that are capable of providing close support to Special Operations Forces (SOF).

The Potential Use of the Abdominal Aortic Junctional Tourniquet® in a Military Population: A Review of Requirement, Effectiveness, and Usability.

Uncontrolled hemorrhage is the leading cause of preventable prehospital death on the battlefield; 20% is junctional. This is a challenge to manage in the forward and prehospital military environment. With the widespread use of body armor, peripheral tourniquets and continued asymmetric warfare this consistent figure is unlikely to reduce. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an often-quoted potential solution; however, this invasive strategy requires a high skill level alongside a significant failure and complication rate. The Abdominal Aortic Junctional Tourniquet® (AAJT) is a noninvasive potential adjunct for the management of hemorrhage below the level of the aortic bifurcation with published case reports of successful use in prehospital blast and gunshot wounds. When placed at the level of the aortic bifurcation, alongside a pelvic binder, it can be used to control pelvic hemorrhage, buying time until definitive management. Importantly it has a low training burden and is easy to use. The AAJT has potential use as a prehospital device in the exsanguinating patient, those in traumatic cardiac arrest, as a bridging device, and as fluid conserving device in resource-limited environments. The evidence surrounding the AAJT is reviewed, and potential uses in the military setting are suggested.

The Combat Application Tourniquet Versus the Tactical Mechanical Tourniquet.

BACKGROUND: Exsanguination from limb injury is an important battlefield consideration that is mitigated with the use of emergency tourniquets. The Combat Application Tourniquet (C-A-T®) is the current British military standard tourniquet. METHODS: We tested the self-application of a newer tourniquet system, the Tactical Mechanical Tourniquet (TMT), against self-application of the C-A-T. A total of 24 healthy British military volunteers self-applied the C-A-T and the TMT to their mid thigh in a randomized, sequential manner. Popliteal artery flow was monitored with a portable ultrasound machine, and time until arterial occlusion was measured. Pain scores were also recorded. Results The volunteers allowed testing on their lower limbs (n = 48 legs). The C-A-T was applied successfully to 22 volunteers (92%), and the TMT was successfully applied to 17 (71%). Median time to reach complete arterial occlusion was 37.5 (interquartile range [IQR], 27-52) seconds with the C-A-T, and 35 (IQR, 29-42) seconds with the TMT. The 2.5-second difference in median times was not significant (ρ = .589). The 1-in-10 difference in median pain score was also not significant (ρ = .656). The success or failure of self-application between the two tourniquet models as assessed by contingency table was not significant (p= .137). CONCLUSION: The TMT is effective when self-applied at the mid thigh. It does not offer an efficacy advantage over the C-A-T.

Working Memory Capacity and Surgical Performance While Exposed to Mild Hypoxic Hypoxemia.

INTRODUCTION: Medical Emergency Response Team (MERT) helicopters fly at altitudes of 3000 m in Afghanistan (9843 ft). Civilian hospitals and disaster-relief surgical teams may have to operate at such altitudes or even higher. Mild hypoxia has been seen to affect the performance of novel tasks at flight levels as low as 5000 ft. Aeromedical teams frequently work in unpressurized environments; it is important to understand the implications of this mild hypoxia and investigate whether supplementary oxygen systems are required for some or all of the team members. METHODS: Ten UK orthopedic surgeons were recruited and in a double blind randomized experimental protocol, were acutely exposed for 45 min to normobaric hypoxia [fraction of inspired oxygen (FIo2) ∼14.1%, equivalent to 3000 m (10,000 ft)] or normobaric normoxia (sea-level). Basic physiological parameters were recorded. Subjects completed validated tests of verbal working memory capacity (VWMC) and also applied an orthopedic external fixator (Hoffmann® 3, Stryker, UK) to a plastic tibia under test conditions. RESULTS: Significant hypoxia was induced with the reduction of FIo2 to ∼14.1% (Spo2 87% vs. 98%). No effect of hypoxia on VWMC was observed. The pin-divergence score (a measure of frame asymmetry) was significantly greater in hypoxic conditions (4.6 mm) compared to sea level (3.0 mm); there was no significant difference in the penetrance depth (16.9 vs. 17.2 mm). One hypoxic frame would have failed early. DISCUSSION: We believe that surgery at an altitude of 3000 m, when unacclimated individuals are acutely exposed to atmospheric hypoxia for 45 min, can likely take place without supplemental oxygen use but further work is required.Parker PJ, Manley AJ, Shand R, O'Hara JP, Mellor A. Working memory capacity and surgical performance while exposed to mild hypoxic hypoxemia. Aerosp Med Hum Perform. 2017; 88(10):918-923.

Combat Trousers as Effective Improvised Pelvic Binders A Comparative Cadaveric Study.

BACKGROUND: Improvised explosive devices and landmines can cause pelvic fractures, which, in turn, can produce catastrophic hemorrhage. This cadaveric study compared the intrapelvic pressure changes that occurred with the application of an improvised pelvic binder adapted from the combat trousers worn by British military personnel with the commercially available trauma pelvic orthotic device (TPOD). METHODS: Six unembalmed cadavers (three male, three female) were used to simulate an unstable pelvic fracture with complete disruption of the posterior arch (AO/OTA 61-C1) by dividing the pelvic ring anteriorly and posteriorly. A 3-4cm manometric balloon filled with water was placed in the retropubic space and connected to a 50mL syringe and water manometer via a three-way tap. A baseline pressure of 8cm H2O (average central venous pressure) was set. The combat trouser binder (CTB) and TPOD were applied to each cadaver in a random sequence and the steady intrapelvic pressure changes were recorded. Statistical analysis was performed using the Wilcoxon rank-sum test and a paired t test depending on the normality of the data to determine impact on the intrapelvic pressure of each intervention compared with baseline. RESULTS: The median steady intrapelvic pressure achieved after application of the CTB was 16cm H2O and after application of the TPOD binder was 18cm H2O, both of which were significantly greater than the baseline pressure (ρ < .01 and .036, respectively) but not significantly different from each other (ρ > .05). CONCLUSION: Pelvic injuries are increasingly common in modern theaters of war. The CTB is a novel, rapidly deployable, yet effective, method of pelvic binding adapted from the clothes the casualty is already wearing. This technique may be used in austere environments to tamponade and control intrapelvic hemorrhage.

What Is the Optimal Device Length and Insertion Site for Needle Thoracostomy in UK Military Casualties? A Computed Tomography Study.

Significant lessons to inform best practice in trauma care should be learned from the last decade of conflict in Afghanistan and Iraq. This study used radiological data collated in the UK Military Hospital in Camp Bastion, Afghanistan, to investigate the most appropriate device length for needle chest decompression of tension pneumothorax (TP). We reviewed the optimal length of device and site needed for needle decompression of a tension pneumothorax in a UK military population and found no significant difference between sites for needle chest decompression (NCD). As a result, we do not recommend use of devices longer than 60mm for UK service personnel.

The evaluation of an abdominal aortic tourniquet for the control of pelvic and lower limb hemorrhage.

Despite improved body armor, hemorrhage remains the leading cause of preventable death on the battlefield. Trauma to the junctional areas such as pelvis, groin, and axilla can be life threatening and difficult to manage. The Abdominal Aortic Tourniquet (AAT) is a prehospital device capable of preventing pelvic and proximal lower limb hemorrhage by means of external aortic compression. The aim of the study was to evaluate the efficacy of the AAT. Serving soldiers under 25 years old were recruited. Basic demographic data, height, weight, blood pressure, and abdominal girth were recorded. Doppler ultrasound was used to identify blood flow in the common femoral artery (CFA). The AAT was applied while the CFA flow was continuously monitored. The balloon was inflated until flow in the CFA ceased or the maximum pressure of the device was reached. A total of 16 soldiers were recruited. All participants tolerated the device. No complications were reported. Blood flow in the CFA was eliminated in 15 out of 16 participants. The one unsuccessful subject was above average height, weight, body mass index, and abdominal girth. This study shows the AAT to be effective in the control of blood flow in the pelvis and proximal lower limb and potentially lifesaving.

An evaluation of two tourniquet systems for the control of prehospital lower limb hemorrhage.

BACKGROUND: Hemorrhage remains the main cause of preventable death on the modern battlefield. As Improvised Explosive Devices in Afghanistan become increasingly powerful, more proximal limb injuries occur. Significant concerns now exist about the ability of the windlass tourniquet to control distal hemorrhage after mid-thigh application. To evaluate the efficacy of the Combat Application Tourniquet (CAT) windlass tourniquet in comparison to the newer Emergency and Military Tourniquet (EMT) pneumatic tourniquet. METHODS: Serving soldiers were recruited from a military orthopedic outpatient clinic. Participants' demographics, blood pressure, and body mass index were recorded. Doppler ultrasound was used to identify the popliteal pulses bilaterally. The CAT was randomly self-applied by the participant at mid-thigh level, and the presence or absence of the popliteal pulse on Doppler was recorded. The process was repeated on the contralateral leg with the CAT now applied by a trained researcher. Finally, the EMT tourniquet was applied to the first leg and popliteal pulse change Doppler recorded again. RESULTS: A total of 25 patients were recruited with 1 participant excluded. The self-applied CAT occluded popliteal flow in only four subjects (16.6%). The CAT applied by a researcher occluded popliteal flow in two subjects (8.3%). The EMT prevented all popliteal flow in 18 subjects (75%). This was a statistically significant difference at p < 0.001 for CAT versus EMT. CONCLUSION: This study demonstrates that the CAT tourniquet is ineffective in controlling arterial blood flow when applied at mid-thigh level. The EMT was successful in a significantly larger number of participants.

Skill sets and competencies for the modern military surgeon: lessons from UK military operations in Southern Afghanistan.

INTRODUCTION: British military forces remain heavily committed on combat operations overseas. UK military operations in Afghanistan (Operation HERRICK) are currently supported by a surgical facility at Camp Bastion, in Helmand Province, in the south of the country. There have been no large published series of surgical workload on Operation HERRICK. The aim of this study is to evaluate this information in order to determine the appropriate skill set for the modern military surgical team. METHOD: A retrospective analysis of operating theatre records between 1st May 2006 and 1st May 2008 was performed. Data was collated on a monthly basis and included patient demographics, operation type and time of operation. RESULTS: During the study period 1668 cases required 2210 procedures. Thirty-two per cent were coalition forces (ISAF), 27% were Afghan security forces (ANSF) and 39% were civilians. Paediatric casualties accounted for 14.7% of all cases. Ninety-three per cent of cases were secondary to battle injury and of these 51.3% were emergencies. The breakdown of procedures, by specialty, was 66% (1463) orthopaedic, 21% (465) general surgery, 6% (139) head and neck, 5% (104) burns surgery and a further 4% (50) non-battle, non-emergency procedures. There was an almost twofold increase in surgical workload in the second year (1103 cases) compared to the first year of the deployment (565 cases, p<0.05). DISCUSSION: Surgical workload over the study period has clearly increased markedly since the initial deployment of ISAF forces to Helmand Province. A 6-week deployment to Helmand Province currently provides an equivalent exposure to penetrating trauma as 3 years trauma experience in the UK NHS. The spectrum of injuries seen and the requisite skill set that the military surgeon must possess is outside that usually employed within the NHS. A number of different strategies; including the deployment of trainee specialist registrars to combat hospitals, more focused pre-deployment military surgery training courses, and wet-laboratory work are proposed to prepare for future generations of surgeons operating in conflict environments.

Casualty evacuation timelines: an evidence-based review.

There is no tri-modal death distribution demonstrable in modern military conflict. Recent UK, Palestinian and Israeli data suggests that nine out of every ten injured soldiers that die do so within minutes of wounding from insurvivable, unsalvagable trauma. Having the surgeon on the battlefield with the soldier has been shown to make no difference to these survival rates. Early definitive airway control using rapid sequence induction and intubation is of benefit to the head and airway injured. Once this airway is secured, these early survivors may be transported for up to 2 hours receiving intensive care level treatment: Hypotensive resuscitation with blood transfusion, administration of adjunctive clotting factors, hypothermia mitigation, administration of antibiotics, analgesics, novel haemostatics, splintage, FAST scanning can all be performed in flight. The second peak of death comes from truncal bleeding and CNS injury. Those with truncal (or junctional) bleeding require significant surgical, logistic and haemostatic support. Those with CNS injury require CT scanning and specialized neurosurgical care. These subgroups do best in large well-resourced hospital units which have the infrastructure, blood, climate control, knowledge and staffing levels to deal with them. Stopping elsewhere en-route to these larger centres is of uncertain benefit. Our resources must be optimised to save the many that could be saved, rather than dispersed for the few who will not. Wounded soldiers need to be undergoing surgery in the operating theatres of these large centres within three hours of wounding.

Damage control surgery and casualty evacuation: techniques for surgeons, lessons for military medical planners.

Damage Control Surgery (DCS) is a three-phase team-based approach to maximal injury penetrating abdominal trauma. In Phase I, the hypothermic, coagulopathic, acidotic, hypotensive casualty undergoes a proactively planned one-hour time limited laparotomy by an appropriately trained surgical trauma team. In phase II physiological stabilization takes place in the Intensive Care Unit. In phase III--definitive repair occurs. DCS is extremely resource intensive but will save lives on the battlefield. A military DCS patient will perioperatively require fourteen units of blood and seven units of fresh frozen plasma--half the blood stock of a light-scaled FST. Two DCS patients will in one day, exhaust this FSTs oxygen supply. We know that hypothermic patients with an iliac vascular injury (initial core temp < 34 degrees C) suffer four-fold increases in their mortality, yet we cannot heat our tents above 20 degrees C during a mild British winter. Our primary casualty retrieval is excessively slow. A simple casevac request has to go to too much 'middle-management' before a flight decision is made. In Vietnam, wounded soldiers arrived in hospital within twenty-five minutes of injury. In Iraq in 2005, that figure is over one hundred and ten minutes. We use support or anti-tank helicopters that are re-roled on an adhoc basis for the critical care and transport of our sickest patients. We still do not have a dedicated all-weather military helicopter evacuation fleet despite significant evidence that intensive care unit level military evacuation is safe and eminently achievable in both in the primary and secondary care setting. Should we not be asking why?