Colloidal Nanoparticles of High Entropy Materials: Capabilities, Challenges, and Opportunities in Synthesis and Characterization.

Materials referred to as "high entropy" contain a large number of elements randomly distributed on the lattice sites of a crystalline solid, such that a high configurational entropy is presumed to contribute significantly to their formation and stability. High temperatures are typically required to achieve entropy stabilization, which can make it challenging to synthesize colloidal nanoparticles of high entropy materials. Nonetheless, strategies are emerging for the synthesis of colloidal high entropy nanoparticles, which are of interest for their synergistic properties and unique catalytic functions that arise from the large number of constituent elements and their interactions. In this Perspective, we highlight the classes of materials that have been made as colloidal high entropy nanoparticles as well as insights into the synthetic methods and the pathways by which they form. We then discuss the concept of "high entropy" within the context of colloidal materials synthesized at much lower temperatures than are typically required for entropy to drive their formation. Next, we identify and address challenges and opportunities in the field of high entropy nanoparticle synthesis. We emphasize aspects of materials characterization that are especially important to consider for nanoparticles of high entropy materials, including powder X-ray diffraction and elemental mapping with scanning transmission electron microscopy, which are among the most commonly used techniques in laboratory settings. Finally, we share perspectives on emerging opportunities and future directions involving colloidal nanoparticles of high entropy materials, with an emphasis on synthesis, characterization, and fundamental knowledge that is needed for anticipated advances in key application areas.

Handheld Magnetometer-Assisted Localization and Removal of a Foreign Body From the Chest Wall.

Foreign bodies fully embedded in soft tissues present a unique challenge to surgeons attempting excision. Small fragments can be nonpalpable, and many prove difficult to visualize intra-operatively by means of classic radiologic techniques. A 35-year-old active duty soldier presented requesting excision of ballistic fragment embedded in his chest wall that had previously failed a previous attempt at removal. The metallic foreign body was successfully localized intra-operatively using a handheld magnetometer probe and removed without complication. This case demonstrates the utility and cost-effectiveness of the handheld magnetometry for intra-operative localization of metallic foreign bodies. Metallic foreign bodies may be localized intra-operatively using inexpensive and reusable equipment that does not require radiation or bulky radiographic imaging equipment.

Soft Chemistry of Hard Materials: Low-Temperature Pathways to Bulk and Nanostructured Layered Metal Borides.

Conspectus"Synthesis by design" is often considered to be the primary goal of chemists who make molecules and materials. Synthetic chemists usually have in mind a target they want to make, and they want to be able to design a pathway that can get them to that target as quickly and efficiently as possible. Chemists who synthesize refractory solids, which have melting points above 1000 °C and are often chemically inert at these high temperatures, have access to only a small number of synthetic strategies due to the need to overcome solid-state diffusion, which is the rate-limiting step in such reactions. The use of extremely high temperatures to facilitate diffusion among two or more refractory solids, which precedes any chemical reaction that must occur, generally drives the system to form only the product that is the most thermodynamically stable-the global minimum on an energy landscape-for a certain combination of elements. When trying to target a different product in the same system, one generally cannot rely on thermally driven reactions. Lower-temperature reactions that side step this diffusion limitation can succeed where high temperatures fail by providing access to local minima on an energy landscape. These local minima represent metastable phases that are primed for synthesis, but only if an appropriate pathway and set of reactions can be identified. It is therefore important to develop and understand low-temperature, or "soft", chemical reactions in "hard" refractory systems. These reactions allow us to apply the retrosynthetic framework that molecular chemists rely on to systems where chemists have not previously had such control over reactions, reactivities, and metastable product formation.In this Account, we discuss the development of soft chemical reactions of hard materials in the context of a class of layered, refractory metal borides that are precursors to an emerging family of two-dimensional nanomaterials. Layered ternary metal boride phases such as MoAlB have layers of metal borides, which are chemically unreactive, interleaved with layers of aluminum, which are reactive. Some of the interlayer aluminum can be deintercalated at room temperature in dilute aqueous sodium hydroxide, transforming stable MoAlB into destabilized MoAl1-xB. Mild thermal treatment of submicrometer grains of this destabilized MoAl1-xB sample allows it to traverse the energy landscape and crystallize as Mo2AlB2, a metastable compound. Further thermal treatment transforms Mo2AlB2 into a Mo2AlB2-alumina nanolaminate and ultimately mesoporous MoB, all through continued traversing of the energy landscape using mild chemical and thermal treatments. Similar topochemical manipulations, which maintain structure but change composition, are emerging for other MAB phases and are opening the door to new types of metastable compounds and nanostructured materials in traditionally refractory systems.

Synthesis and Magnetic, Optical, and Electrocatalytic Properties of High-Entropy Mixed-Metal Tungsten and Molybdenum Oxides.

High-entropy oxides (HEOs) are of interest for their unique physical and chemical properties. Significant lattice distortions, strain, and tolerance for high-vacancy concentrations set HEOs apart from single-metal or mixed-metal oxides. Herein, we synthesized and characterized the structures and compositions, along with the optical, magnetic, and electrocatalytic properties, of two families of high-entropy mixed-metal tungsten and molybdenum oxides, AWO4 and B2Mo3O8, where A and B are 3d transition metals. The HEOs A6WO4 (A = Mn, Fe, Co, Ni, Cu, and Zn) and B25Mo3O8 (B = Mn, Fe, Co, Ni, and Zn), as well as all accessible single-metal AWO4 and B2Mo3O8 parent compounds, were synthesized using high-temperature solid-state methods. X-ray photoelectron spectroscopy analysis of the surfaces revealed that the HEOs largely had the metal oxidation states expected from the bulk chemical formulas, but in some cases they were different than in the parent compounds. A6WO4 exhibited antiferromagnetic (AFM) ordering with a Néel temperature of 30 K, which is less than the average of its AFM parent compounds, and had a narrow band gap of 0.24 eV, which is much lower than all of its parent compounds. B25Mo3O8 was paramagnetic, despite the existence of AFM and ferromagnetic ordering in several of its parent compounds and had no observable band gap, which is analogous to its parent compounds. Both A6WO4 and B25Mo3O8 exhibited superior catalytic activity relative to the parent compounds for the oxygen evolution reaction, the oxidation half reaction of overall water splitting, under alkaline conditions, based on the overpotential required to reach the benchmark surface area normalized current density. Consistent with literature predictions of OER durability for ternary tungsten and molybdenum oxides, A6WO4 and B25Mo3O8 also exhibited stable performance without significant dissolution during 10 h stability experiments at a constant current.

Formation and Transformation of Cu2-xSe1-yTey Nanoparticles Synthesized by Tellurium Anion Exchange of Copper Selenide.

Ion exchange reactions of colloidal nanoparticles post-synthetically modify the composition while maintaining the morphology and crystal structure and therefore are important for tuning properties and producing otherwise inaccessible and/or metastable materials. Reactions involving anion exchange of metal chalcogenides are particularly interesting, as they involve the replacement of the sublattice that defines the structure while also requiring high temperatures that can be disruptive. Here, we show that the tellurium anion exchange of weissite Cu2-xSe nanoparticles using a trioctylphosphine-tellurium complex (TOP═Te) yields weissite Cu2-xSe1-yTey solid solutions, rather than complete exchange to weissite Cu2-xTe, with compositions that are tunable based on the amount of TOP═Te used. Upon storage at room temperature in either solvent or air, tellurium-rich Cu2-xSe1-yTey solid solution nanoparticles transform, over the span of several days, to a selenium-rich Cu2-xSe1-yTey composition. The tellurium that is expelled from the solid solution during this process migrates to the surface and forms a tellurium oxide shell, which correlates with the onset of particle agglomeration due to the change in surface chemistry. Collectively, this study demonstrates tunable composition during tellurium anion exchange of copper selenide nanoparticles along with unusual post-exchange reactivity that transforms the composition, surface chemistry, and colloidal dispersibility due to the apparent metastable nature of the solid solution product.

Case Volume and Readiness to Deploy: Clinical Opportunities for Active-Duty Surgeons Outside of Military Hospitals.

BACKGROUND: The Military Health System (MHS) uses a readiness program that identifies the knowledge, skills, and abilities (KSAs) necessary for surgeons to provide combat casualty care. Operative productivity is assigned an objective score based on case type and complexity and totaled to assess overall readiness. As of 2019, only 10.1% of surgeons met goal readiness threshold. At one tertiary military treatment facility (MTF), leadership has taken an aggressive approach toward increasing readiness by forming military training agreements (MTAs) and allowing Off Duty Employment (ODE). We sought to quantify the efficacy of this approach. STUDY DESIGN: Operative logs from 2021 were obtained from surgeons assigned to the MTF. Operations were assigned CPT codes and processed through the KSA calculator (Deloitte; London, UK). Each surgeon was then surveyed to identify time away from clinical duties for deployment or military training. RESULTS: Nine surgeons were present in 2021 and spent an average of 10.1 weeks (19.5%) abroad. Surgeons performed 2,348 operations (Average [Avg] 261 ± 95) including 1,575 (Avg 175; 67.1%) at the MTF, 606 (Avg 67.3; 25.8%) at MTAs, and 167 (Avg 18.6, 7.1%) during ODE. Adding MTA and ODE caseloads increased KSA scores by 56% (17,765 ± 7,889 vs 11,391 ± 8,355). Using the MHS threshold of 14,000, 3 of 9 (33.3%) surgeons met the readiness threshold from MTF productivity alone. Including all operations, 7 of 9 (77.8%) surgeons met threshold. CONCLUSIONS: Increased use of MTAs and ODE significantly augments average caseloads. These operations provide considerable benefit and result in surgeon readiness far exceeding the MHS average. Military leadership can maximize the chances of meeting readiness goals by encouraging clinical opportunities outside the MTF.

Intermuscular coherence of plantar and dorsiflexor muscles in older adults with Parkinson's disease and age-matched controls during bipedal and unipedal stance.

Introduction: Postural instability increases with age and is exacerbated in neurological disorders such as Parkinson's disease (PD). Reducing the base of support from bipedal to unipedal stance increases center of pressure (CoP) parameters and intermuscular coherence in lower-leg muscles of healthy older adults. To further develop an understanding of postural control in an altered state of neurological impairment, we explored intermuscular coherence in lower-leg muscles and CoP displacement in older adults with PD. Methods: This study measured surface EMG from the medial (MG) and lateral (LG) gastrocnemii, soleus (SOL), and tibialis anterior (TA), and examined EMG amplitude and intermuscular coherence during bipedal and unipedal stance on a force plate with firm (no foam) and compliant (standing on foam) surface conditions in nine older adults with PD (70±5 years, 6 females) and 8 age-matched non-Parkinsonian older adults (5 females). Intermuscular coherence was analyzed between agonist-agonist and agonist-antagonist muscle pairs in the alpha (8-13 Hz) and beta (15-35 Hz) frequency bands. Results: CoP parameters increased from bipedal to unipedal stance in both groups (p < 0.01), but did not increase from the firm to compliant surface condition (p > 0.05). During unipedal stance, CoP path length was shorter in older adults with PD (2027.9 ± 1074.1 mm) compared to controls (3128.5 ± 1198.7 mm) (p < 0.01). Alpha and beta agonist-agonist and agonist-antagonist coherence increased by 28% from bipedal to unipedal stance (p > 0.05), but did not differ between older adults with PD (0.09 ± 0.07) and controls (0.08 ± 0.05) (p > 0.05). The older adults with PD also had greater normalized EMG amplitude of the LG (63.5 ± 31.7%) and TA (60.6 ± 38.4%) during the balance tasks (p > 0.05) than the non-Parkinsonian counterparts. Discussion: Older adults with PD had shorter path lengths during unipedal stance and required greater muscle activation than older adults without PD to perform the tasks, but intermuscular coherence did not differ between the groups. This may be attributable to their early disease stage and high motor function.

Band Gap Narrowing in a High-Entropy Spinel Oxide Semiconductor for Enhanced Oxygen Evolution Catalysis.

High-entropy oxides (HEOs), which contain five or more metal cations that are generally thought to be randomly mixed in a crystalline oxide lattice, can exhibit unique and enhanced properties, including improved catalytic performance, due to synergistic effects. Here, we show that band gap narrowing emerges in a high-entropy aluminate spinel oxide, (Fe0.2Co0.2Ni0.2Cu0.2Zn0.2)Al2O4 (A5Al2O4). The 0.9 eV band gap of A5Al2O4 is narrower than the band gaps of all parent spinel oxides. First-principles calculations for multicomponent AAl2O4 spinels indicate that the band gap narrowing arises from the broadening of the energy distribution of the 3d states due to variations in the electronegativities and crystal field splitting across the 3d transition-metal series. As a catalyst for the oxygen evolution reaction in an alkaline electrolyte, A5Al2O4 reaches a current density of 10 mA/cm2 at an overpotential of 400 mV, outperforming all of the single-metal end members at an applied potential of 1.7 V vs RHE. Catalyst deactivation occurs after 5 h at 10 mA/cm2 and is attributed, based on elemental analysis and grazing-incidence X-ray diffraction, to the formation of a passivating layer that blocks the high-entropy oxide surface. This result helps to validate that the HEO is the active catalyst. The observation of band gap narrowing in A5Al2O4 expands the scope of synergistic properties exhibited by high-entropy materials and offers insight into the question of how the electronic structure of multicomponent oxide materials can be engineered via a high-entropy approach to achieve enhanced catalytic properties.

Introducing Porosity into Refractory Molybdenum Boride through Controlled Decomposition of a Metastable Mo-Al-B Precursor.

The high temperatures typically required to synthesize refractory compounds preclude the formation of high-energy morphological features, including nanoscopic pores that are beneficial for applications, such as catalysis, that require higher surface areas. Here, we demonstrate a low-temperature multistep pathway to engineer mesoporosity into a catalytic refractory material. Mesoporous molybdenum boride, α-MoB, forms through the controlled thermal decomposition of nanolaminate-containing sheets of the metastable MAB (metal-aluminum-boron) phase Mo2AlB2 and amorphous alumina. Upon heating, the Mo2AlB2 layers of the Mo2AlB2-AlOx nanolaminate, which is derived from MoAlB, begin to bridge and decompose, forming inclusions of alumina in a framework of α-MoB. The alumina can be dissolved in aqueous sodium hydroxide in an autoclave, forming α-MoB with empty and accessible pores. Statistical analysis of the morphologies and dimensions of the pores reveals a correlation with grain size, which relates to the pathway by which the alumina inclusions form. The transformation of Mo2AlB2 to α-MoB is topotactic due to crystal structure relationships, resulting in a high density of stacking faults that can be modeled to account for the observed experimental diffraction data. Porosity was validated by comparing surface areas and demonstrating catalytic viability for the hydrogen evolution reaction.

Preoperative angioembolisation of a mediastinal accessory ectopic spleen: A case report and review of the literature.

A 50-year-old male presented to our institution for embolization of an incidentally detected mediastinal mass prior to surgical resection. The patient had undergone extensive pre-procedural imaging as well as bronchoscopy and mediastinoscopy. Ultimately, resection was required for a definitive diagnosis of congenital ectopic mediastinal accessory spleen. This case represents the first reported incidence of ectopic splenic tissue in this location and illustrates the difficulties in establishing a pre-operative diagnosis with often confounding imaging findings.

Resting Tendon Cross-Sectional Area Underestimates Biceps Brachii Tendon Stress: Importance of Measuring During a Contraction.

Force produced by the muscle during contraction is applied to the tendon and distributed through the cross-sectional area (CSA) of the tendon. This ratio of force to the tendon CSA is quantified as the tendon mechanical property of stress. Stress is traditionally calculated using the resting tendon CSA; however, this does not take into account the reductions in the CSA resulting from tendon elongation during the contraction. It is unknown if calculating the tendon stress using instantaneous CSA during a contraction significantly increases the values of in vivo distal biceps brachii (BB) tendon stress in humans compared to stress calculated with the resting CSA. Nine young (22 ± 1 years) and nine old (76 ± 4 years) males, and eight young females (21 ± 1 years) performed submaximal isometric elbow flexion tracking tasks at force levels ranging from 2.5 to 80% maximal voluntary contraction (MVC). The distal BB tendon CSA was recorded on ultrasound at rest and during the submaximal tracking tasks (instantaneous). Tendon stress was calculated as the ratio of tendon force during contraction to CSA using the resting and instantaneous measures of CSA, and statistically evaluated with multi-level modeling (MLM) and Johnson-Neyman regions of significance tests to determine the specific force levels above which the differences between calculation methods and groups became statistically significant. The tendon CSA was greatest at rest and decreased as the force level increased (p < 0.001), and was largest in young males (23.0 ± 2.90 mm2) followed by old males (20.87 ± 2.0 mm2) and young females (17.08 ± 1.54 mm2) (p < 0.001) at rest and across the submaximal force levels. Tendon stress was greater in the instantaneous compared with the resting CSA condition, and young males had the greatest difference in the values of tendon stress between the two conditions (20 ± 4%), followed by old males (19 ± 5%), and young females (17 ± 5%). The specific force at which the difference between the instantaneous and resting CSA stress values became statistically significant was 2.6, 6.6, and 10% MVC for old males, young females, and young males, respectively. The influence of using the instantaneous compared to resting CSA for tendon stress is sex-specific in young adults, and age-specific in the context of males. The instantaneous CSA should be used to provide a more accurate measure of in vivo tendon stress in humans.

Focused Changes in Opioid Prescribing Yield Far-reaching Benefits Through Culture Change and Attention to Opioid Minimization.

OBJECTIVE: Standardization of prescriptions after specific procedures (laparoscopic appendectomy, cholecystectomy, inguinal/umbilical hernia repair) significantly reduces opioid prescriptions for these targeted procedures. We sought to determine the impact of increased attention to responsible opioid prescribing in the absence of protocolization. DESIGN: Prescription practices of Laparoscopic Sleeve Gastrectomies and Roux-en-y Gastric Bypasses at a tertiary medical center (October 1, 2016-September 30, 2018) were retrospectively reviewed. Patients were grouped into whether surgical intervention took place before or after institution of an unrelated opioid protocol in November 2017. Patients with chronic opioid use or extended hospital stay (>4 days) were excluded. Discharge prescriptions, oral morphine equivalents (OME), and need for repeat prescriptions were compared. SETTING: This study was set at Madigan Army Medical Center in Tacoma, Washington. PARTICIPANTS: All general surgery residents engaged in clinical duties at our institution during the dates of the study were included. RESULTS: Study population included 187 patients, with 91 patients undergoing surgery prior to the protocol and 88 post-protocol. Preprotocol patients were provided an average of 413 OME (SD 103) and 5.5% required repeat opioid prescriptions within 3 months of surgery. The most common opioid prescription was 300 mL of oxycodone elixir (450 OME, 88%). Postprotocol, opioid prescriptions fell 61% to an average of 161 OME (SD 71, p < 0.001). Repeat opioid requirements remained statistically unchanged (8.0%, p = 0.562). The most common opioid prescription postprotocol included 20 oxycodone tablets (150 OME, 76%). CONCLUSIONS: Opioid reduction efforts reap benefits beyond those procedures specifically targeted. Focus on responsible opioid prescribing through standardization, even when limited to certain procedures, may result in a hospital culture change with global opioid prescription reduction.

Importance of Maximal Strength and Muscle-Tendon Mechanics for Improving Force Steadiness in Persons with Parkinson's Disease.

Although plantar flexion force steadiness (FS) is reduced in persons with Parkinson's disease (PD), the underlying causes are unknown. The aim of this exploratory design study was to ascertain the influence of maximal voluntary contraction (MVC) force and gastrocnemius-Achilles muscle-tendon unit behaviour on FS in persons with PD. Nine persons with PD and nine age- and sex-matched non-PD controls (~70 years, 6 females per group) performed plantar flexion MVCs and sub-maximal tracking tasks at 5, 10, 25, 50 and 75% MVC. Achilles tendon elongation and medial gastrocnemius fascicle lengths were recorded via ultrasound during contraction. FS was quantified using the coefficient of variation (CV) of force. Contributions of MVC and tendon mechanics to FS were determined using multiple regression analyses. Persons with PD were 35% weaker during MVC (p = 0.04) and had 97% greater CV (p = 0.01) with 47% less fascicle shortening (p = 0.004) and 38% less tendon elongation (p = 0.002) than controls. Reduced strength was a direct contributor to lower FS in PD (ß = 0.631), and an indirect factor through limiting optimal muscle-tendon unit interaction. Interestingly, our findings indicate an uncoupling between fascicle shortening and tendon elongation in persons with PD. To better understand limitations in FS and muscle-tendon unit behavior, it is imperative to identify the origins of MVC decrements in persons with PD.

Validation of a novel partial resuscitative endovascular balloon occlusion of the aorta device in a swine hemorrhagic shock model: Fine tuning flow to optimize bleeding control and reperfusion injury.

OBJECTIVES: Partial restoration of aortic flow during resuscitative endovascular balloon occlusion of the aorta (REBOA) is advocated by some to mitigate distal ischemia. Our laboratory has validated the mechanics and optimal partial REBOA (pREBOA) flow rates using a prototype device. We hypothesize that pREBOA will increase survival when compared with full REBOA (fREBOA) in prolonged nonoperative management of hemorrhagic shock. METHODS: Twenty swine underwent placement of aortic flow probes, zone 1 REBOA placement, and 20% blood volume hemorrhage. They were randomized to either solid organ or abdominal vascular injury. The pREBOA arm (10 swine) underwent full inflation for 10 minutes and then deflation to a flow rate of 0.5 L/min for 2 hours. The fREBOA arm (10 swine) underwent full inflation for 60 minutes, followed by deflation/resuscitation. The primary outcome is survival, and secondary outcomes are serologic/pathologic signs of ischemia-reperfusion injury and quantity of hemorrhage. RESULTS: Two of 10 swine survived in the fREBOA group (2/5 solid organ injury; 0/5 abdominal vascular injury), whereas 7 of 10 swine survived in the pREBOA group (3/5 solid organ injury, 4/5 abdominal vascular injury). Survival was increased (p = 0.03) and hemorrhage was higher in the pREBOA group (solid organ injury, 1.36 ± 0.25 kg vs. 0.70 ± 0.33 kg, p = 0.007; 0.86 ± 0.22 kg vs. 0.71 ± 0.28 kg, not significant). Serum evidence of ischemia was greater with fREBOA, but this was not significant (e.g., lactate, 16.91 ± 3.87 mg/dL vs. 12.96 ± 2.48 mg/dL at 120 minutes, not significant). Swine treated with pREBOA that survived demonstrated trends toward lower alanine aminotransferase, lower potassium, and higher calcium. The potassium was significantly lower in survivors at 60 minutes and 90 minutes time points (5.97 ± 0.60 vs. 7.53 ± 0.90, p = 0.011; 6.67 ± 0.66 vs. 8.15 ± 0.78, p = 0.029). Calcium was significantly higher at 30 minutes, 60 minutes, and 90 minutes (8.56 ± 0.66 vs. 7.50 ± 0.40, p = 0.034; 8.63 ± 0.62 vs. 7.15 ± 0.49, p = 0.019; 8.96 ± 0.64 vs. 7.00, p = 0.028). CONCLUSION: Prolonged pREBOA at a moderate distal flow rate provided adequate hemorrhage control, improved survival, and had evidence of decreased ischemic injury versus fREBOA. Prophylactic aggressive calcium supplementation may have utility before and during the reperfusion phase.

Influence of preoperative psychotropic medications on opioid requirements and outcomes following bariatric surgery.

INTRODUCTION: Opioid use continues to impose a substantial burden on the healthcare system. Multiple studies suggest that depression and psychosis increase the risk of chronic opioid use. We hypothesized that patients' pharmacologic profiles would affect postoperative opioid requirements following bariatric surgery. MATERIALS AND METHODS: Retrospective analysis identified patients who underwent laparoscopic bariatric surgery at a high-volume center from 2014 to 2016. Prescriptions from one year prior through 3 months after surgery were collected. Patients with complicated operative courses were excluded. RESULTS: A total of 201 patients met inclusion criteria. Forty-six patients(23%) required an opioid refill within 3 months of surgery. Opioid exposure was strongly associated with need for repeat opioid prescription(OR 3.1, p = 0.001). When controlled for preoperative opioid exposure, antidepressant and antipsychotic use showed no such association. Patients using antipsychotics were significantly more likely to have complicated postoperative courses(OR 2.25, p = 0.043). CONCLUSIONS: Opioid exposure increased the risk of chronic opioid requirements after surgery, but other psychotropic medications showed no such effect. Patients using anti-psychotics may be prone to surgical complications making them vulnerable to chronic opioid use.

Senior surgical resident autonomy and teaching assistant cases: A prospective observational study.

INTRODUCTION: Teaching assistant (TA) cases allow senior residents (SR) to gain autonomy. We compared the safety profiles of TA cases performed under direct vs. indirect staff supervision. METHODS: Prospective observational study of operative cases where a SR served as the TA between 7/2014-6/2017 (n = 161). Patient/operative characteristics, 30-day outcomes, and SR survey data were compared by level of supervision. RESULTS: Case mix included 68 laparoscopic appendectomies (42%), 49 laparoscopic cholecystectomies (30%), 10 I&Ds (6%), 10 umbilical hernia repairs (6%), 4 port placements (3%), and 11 others. Indirectly supervised cases were shorter (61 vs. 76 min, p < 0.01), with less blood loss (11 vs. 24 ml, p < 0.05), and lower conversion rates (0% vs. 5.7%, p < 0.05). Perceived difficulty was high in 20% of cases with indirect vs. 49% with direct supervision (p < 0.01). Mean SR comfort was high (4.4 vs. 4.6 out of 5) regardless of level of staff supervision. 30-day complications did not differ for indirect vs. direct supervision (all p = NS). DISCUSSION: Carefully selected TA cases offer SRs opportunities to practice autonomy without sacrificing operative time or patient safety.

An Evaluation of a Novel Medical Device Versus Standard Interventions in the Treatment of Tension Pneumothorax in a Swine Model (Sus scrofa).

INTRODUCTION: Tension pneumothorax is a common cause of preventable death in trauma. Needle decompression is the traditional first-line intervention but has high failure rates. We sought to evaluate the effectiveness and expedience of needle thoracostomy, surgical tube thoracostomy, and Reactor™ thoracostomy - a novel spring-loaded trocar insertion device. MATERIALS AND METHODS: Yorkshire swine underwent controlled thoracic insufflation to create tension pneumothorax physiology for device comparison. Additional experiments were performed by increasing insufflation pressures to achieve pulseless electrical activity. Intervention was randomized to needle thoracostomy (14 gauge), tube thoracostomy (32Fr), or Reactor™ thoracostomy (36Fr). Air leak was simulated throughout intervention with 40-80 mL/kg/min insufflation. Intrathoracic pressure monitoring and hemodynamic parameters were obtained at 1 and 5 minutes. RESULTS: Tension physiology and tension-induced pulseless electrical activity were created in all iterations. Needle thoracostomy (n = 28) was faster at 7.04 ± 3.04 seconds than both Reactor thoracostomy (n = 32), 11.63 ± 5.30 (p < 0.05) and tube thoracostomy (n = 32), 27.06 ± 10.73 (p < 0.01); however, Reactor™ thoracostomy was faster than tube thoracostomy (p < 0.001). Physiological decompression was achieved in all patients treated with Reactor™ and tube thoracostomy, but only 14% of needle thoracostomy. Cardiac recovery to complete physiologic baseline occurred in only 21% (6/28) of those treated with needle thoracostomy whereas Reactor™ or tube thoracostomy demonstrated 88% (28/32) and 94% (30/32) response rates. When combined, needle thoracostomy successfully treated tension pneumothorax in only 4% (1/28) of subjects as compared to 88% (28/32) with Reactor™ thoracostomy and 94% (30/32) with tube thoracostomy (p < 0.01). CONCLUSIONS: Needle thoracostomy provides a rapid intervention for tension pneumothorax, but is associated with unacceptably high failure rates. Reactor™ thoracostomy was effective, expedient, and may provide a useful and technically simpler first-line treatment for tension pneumothorax or tension-induced pulseless electrical activity.

Stemming the Tide of Opioid Addiction-Dramatic Reductions in Postoperative Opioid Requirements Through Preoperative Education and a Standardized Analgesic Regimen.

INTRODUCTION: Surgery is a known gateway to opioid use that may result in long-term morbidity. Given the paucity of evidence regarding the appropriate amount of postoperative opioid analgesia and variable prescribing education, we investigated prescribing habits before and after institution of a multimodal postoperative pain management protocol. MATERIALS AND METHODS: Laparoscopic appendectomies, laparoscopic cholecystectomies, inguinal hernia repairs, and umbilical hernia repairs performed at a tertiary military medical center from 01 October 2016 until 30 September 2017 were examined. Prescriptions provided at discharge, oral morphine equivalents (OME), repeat prescriptions, and demographic data were obtained. A pain management regimen emphasizing nonopioid analgesics was then formulated and implemented with patient education about expected postoperative outcomes. After implementation, procedures performed from 01 November 2017 until 28 February 2018 were then examined and analyzed. Additionally, a patient satisfaction survey was provided focusing on efficacy of postoperative pain control. RESULTS: Preprotocol, 559 patients met inclusion criteria. About 97.5% were provided an opioid prescription, but prescriptions varied widely (256 OME, standard deviation [SD] 109). Acetaminophen was prescribed often (89.5%), but nonsteroidal anti-inflammatory drug (NSAID) prescriptions were rare (14.7%). About 6.1% of patients required repeat opioid prescriptions. After implementation, 181 patients met inclusion criteria. Initial opioid prescriptions decreased 69.8% (77 OME, SD 35; P < 0.001), while repeat opioid prescriptions remained statistically unchanged (2.79%; P = 0.122). Acetaminophen prescribing rose to 96.7% (P = 0.002), and NSAID utilization increased to 71.0% (P < 0.001). Postoperative survey data were obtained in 75 patients (41.9%). About 68% stated that they did not use all of the opioids prescribed and 81% endorsed excellent or good pain control throughout their postoperative course. CONCLUSIONS: Appropriate preoperative counseling and utilization of nonopioid analgesics can dramatically reduce opioid use while maintaining high patient satisfaction. Patient-reported data suggest that even greater reductions may be possible.

Preperitoneal balloon tamponade and resuscitative endovascular balloon occlusion of the aorta: Alternatives to open packing for pelvic fracture-associated hemorrhage.

BACKGROUND: The objective of this study was to compare the efficacy of preperitoneal balloon tamponade (PPB), resuscitative endovascular balloon occlusion of the orta (REBOA), and open preperitoneal packing (OP) in a realistic animal model of pelvic fracture-associated hemorrhage. METHODS: Thirty-nine swine underwent creation of open-book pelvic fracture and iliac vascular injury. Animals were randomized to no intervention (n = 7), OP (n = 10), PPB (n = 9), zone 1 REBOA (n = 7), and zone 3 REBOA (n = 6) at a mean arterial pressure less than 40 mm Hg from uncontrolled hemorrhage. Primary outcome was survival at 1 hour. Secondary outcomes included survival in the immediate 10 m following intervention reversal, peak preperitoneal pressure (PP), blood loss, bleed rate, and peak lactate. RESULTS: Prior to injury, no difference was measured between groups for weight, hemodynamics, lactate, and hematocrit (all p = NS). The injury was uniformly lethal without intervention, with survival time (mean) of 5 m, peak PP of 14 mm Hg, blood loss of 960 g, bleed rate of 450 g/m, and peak lactate of 2.6 mmol/L. Survival time (m) was extended to 44 with OP, 60 with PPB, and 60 with REBOA (p < 0.01). Peak PP (mm Hg) was 19 with OP, 23 with PPB, 10 with zone 1 REBOA, and 6 with zone 3 REBOA (p < 0.05). Blood loss (g) was 850 with OP, 930 with PPB, 610 with zone 1 REBOA, and 370 with zone 3 REBOA (p < 0.01). Peak lactate (mmol/L) was 3.3 with OP, 4.3 with PPB, 13.4 with zone 1 REBOA, and 5.3 with zone 3 REBOA (p < 0.01). Only 33% of zone 1 REBOA animals survived the initial 10 m after balloon deflation, compared to 60% for OP, 67% for PPB, and 100% for zone 3 REBOA (p < 0.01). CONCLUSION: Preperitoneal balloon tamponade and zone 3 REBOA are effective alternatives to OP in this animal model of lethal pelvic fracture-associated hemorrhage. Zone 1 REBOA extends survival time but with high mortality upon reversal.