Early Repair of Rib Fractures Is Associated with Superior Length of Stay and Total Hospital Cost: A Propensity Matched Analysis of the National Inpatient Sample.

Background and Objectives: Previous studies have suggested that early scheduling of the surgical stabilization of rib fractures (SSRF) is associated with superior outcomes. It is unclear if these data are reproducible at other institutions. We hypothesized that early SSRF would be associated with decreased morbidity, length of stay, and total charges. Materials and Methods: Adult patients who underwent SSRF for multiple rib fractures or flail chest were identified in the National Inpatient Sample (NIS) by ICD-10 code from the fourth quarter of 2015 to 2016. Patients were excluded for traumatic brain injury and missing study variables. Procedures occurring after hospital day 10 were excluded to remove possible confounding. Early fixation was defined as procedures which occurred on hospital day 0 or 1, and late fixation was defined as procedures which occurred on hospital days 2 through 10. The primary outcome was a composite outcome of death, pneumonia, tracheostomy, or discharge to a short-term hospital, as determined by NIS coding. Secondary outcomes were length of hospitalization (LOS) and total cost. Chi-square and Wilcoxon rank-sum testing were performed to determine differences in outcomes between the groups. One-to-one propensity matching was performed using covariates known to affect the outcome of rib fractures. Stuart-Maxwell marginal homogeneity and Wilcoxon signed rank matched pair testing was performed on the propensity-matched cohort. Results: Of the 474 patients who met the inclusion criteria, 148 (31.2%) received early repair and 326 (68.8%) received late repair. In unmatched analysis, the composite adverse outcome was lower among early fixation (16.2% vs. 40.2%, p < 0.001), total hospital cost was less (USD114k vs. USD215k, p < 0.001), and length of stay was shorter (6 days vs. 12 days) among early SSRF patients. Propensity matching identified 131 matched pairs of early and late SSRF. Composite adverse outcomes were less common among early SSRF (18.3% vs. 32.8%, p = 0.011). The LOS was shorter among early SSRF (6 days vs. 10 days, p < 0.001), and total hospital cost was also lower among early SSRF patients (USD118k vs. USD183k late, p = 0.001). Conclusion: In a large administrative database, early SSRF was associated with reduced adverse outcomes, as well as improved hospital length of stay and total cost. These data corroborate other research and suggest that early SSRF is preferred. Studies of outcomes after SSRF should stratify analyses by timing of procedure.

Energetics of high temperature degradation of fentanyl into primary and secondary products.

Fentanyl is a synthetic opioid used for managing chronic pain. Due to its higher potency (50-100×) than morphine, fentanyl is also an abused drug. A sensor that could detect illicit fentanyl by identifying its thermally degraded fragments would be helpful to law enforcement. While experimental studies have probed the thermal degradation of fentanyl, little theoretical work has been done to understand the mechanism. Here, we studied the thermal degradation pathways of fentanyl using extensive ab initio molecular dynamics simulations combined with enhanced sampling via multiple-walker metadynamics. We calculated the free energy profile for each bond suggested earlier as a potential degradation point to map the thermodynamic driving forces. We also estimated the forward attempt rate of each bond degradation reaction to gain information about degradation kinetics.

Factors Predictive of Ventilator-associated Pneumonia in Critically Ill Trauma Patients.

BACKGROUND: Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation. We sought to investigate factors associated with the development of VAP in critically ill trauma patients. METHODS: We conducted a retrospective review of trauma patients admitted to our trauma intensive care unit between 2016 and 2018. Patients with ventilator-associated pneumonia were identified from the trauma database. Data collected from the trauma database included demographics (age, gender and race), mechanism of injury (blunt, penetrating), injury severity (injury severity score "ISS"), the presence of VAP, transfused blood products and presenting vital signs. RESULTS: A total of 1403 patients were admitted to the trauma intensive care unit (TICU) during the study period; of these, 45 had ventilator-associated pneumonia. Patients with VAP were older (p = 0.030), and they had a higher incidence of massive transfusion (p = 0.015) and received more packed cells in the first 24 h of admission (p = 0.028). They had a higher incidence of face injury (p = 0.001), injury to sternum (p = 0.011) and injury to spine (p = 0.024). Patients with VAP also had a higher incidence of acute kidney injury (AKI) (p < 0.001) and had a longer ICU (p < 0.001) and hospital length of stay (p < 0.001). Multiple logistic regression models controlling for age and injury severity (ISS) showed massive transfusion (p = 0.017), AKI (p < 0.001), injury to face (p < 0.001), injury to sternum (p = 0.007), injury to spine (p = 0.047) and ICU length of stay (p < 0.001) to be independent predictors of VAP. CONCLUSIONS: Among critically ill trauma patients, acute kidney injury, injury to the spine, face or sternum, massive transfusion and intensive care unit length of stay were associated with VAP.

Evaluation and management of blunt traumatic aortic injury: a practice management guideline from the Eastern Association for the Surgery of Trauma.

BACKGROUND: Blunt traumatic aortic injury (BTAI) is the second most common cause of death in trauma patients. Eighty percent of patients with BTAI will die before reaching a trauma center. The issues of how to diagnose, treat, and manage BTAI were first addressed by the Eastern Association for the Surgery of Trauma (EAST) in the practice management guidelines on this topic published in 2000. Since that time, there have been advances in the management of BTAI. As a result, the EAST guidelines committee decided to develop updated guidelines for this topic using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework recently adopted by EAST. METHODS: A systematic review of the MEDLINE database using PubMed was performed. The search retrieved English language articles regarding BTAI from 1998 to 2013. Letters to the editor, case reports, book chapters, and review articles were excluded. Topics of investigation included imaging to diagnose BTAI, type of operative repair, and timing of operative repair. RESULTS: Sixty articles were identified. Of these, 51 articles were selected to construct the guidelines. CONCLUSION: There have been changes in practice since the publication of the previous guidelines in 2000. Computed tomography of the chest with intravenous contrast is strongly recommended to diagnose clinically significant BTAI. Endovascular repair is strongly recommended for patients without contraindications. Delayed repair of BTAI is suggested, with the stipulation that effective blood pressure control must be used in these patients.

Ultra Long-term Follow-up of the Autologous Pubovaginal Sling for Stress Incontinence: Results at 23 Years.

OBJECTIVE: To examine the efficacy, safety, and long-term durability of the autologous pubovaginal sling for stress incontinence over a 29-year period. METHODS: A total of 192 consecutive female patients with stress urinary incontinence who underwent autologous pubovaginal sling from 1993 through 1999 were analyzed over a 29-year period. Intermediate and ultra long-term follow-up were obtained at a mean of 4 and 23 years, respectively. A total of 51 patients had sufficient data at both time intervals and were evaluated using a standardized questionnaire for resolution of stress incontinence, the primary endpoint, as well as resolution of urge incontinence, overall dryness, and voiding dysfunction. RESULTS: At intermediate-term follow-up (mean 45.3 months), 96% of 51 patients reported no stress incontinence. In addition, 76% of patients experienced resolution of their preoperative urge incontinence. Overall dryness occurred in 84%. At ultra long-term follow-up (mean 22.9 years), 84% reported no stress incontinence and an overall dryness rate of 53%. Postoperative voiding dysfunction included de novo urge incontinence (3 patients) and persistent urinary obstruction requiring urethrolysis (1 patient). CONCLUSION: The autologous pubovaginal sling is effective, safe, and durable at a mean of 23 years, the longest known follow-up in the literature. Given the U.S. Food and Drug Administration (FDA) warnings regarding transvaginal mesh and growing concerns with the synthetic midurethral sling, the autologous pubovaginal sling should be offered as an option to those women seeking treatment for stress urinary incontinence.

Benefit of balance? Odds of survival by unit transfused: Retrospective analysis of the ACS-TQIP database.

BACKGROUND: The critical blood shortage in January 2022 threatened the availability of blood. Utility of transfusion per unit was reported in a previous study, revealing patients receiving balanced transfusion are more likely to die after 16 units of packed red blood cells. We aimed to validate this study using a larger database. METHODS: Retrospective analysis utilizing the American College of Surgeons Trauma Quality Improvement Program was performed. Trauma patients aged ≥16 receiving transfusion within 4 hours of arrival were included and excluded if they died in the emergency department, received <2 units of packed red blood cells, did not receive fresh frozen plasma, or were missing data. Primary outcome was mortality. Subgroups were balanced transfusion if receiving ≤2:1 ratio of packed red blood cells:fresh frozen plasma, and unbalanced transfusion if >2:1 ratio. RESULTS: A total of 17,047 patients were evaluated with 28% mortality (4,822/17,408). Multivariable logistic regression identified advancing age (odds ratio 1.03 95% confidence interval 1.03-1.04), higher ISS (odds ratio 1.04, 95% confidence interval 1.03-1.04), and lower GCS (odds ratio 0.82, 95% confidence interval 0.82-0.83) as risk factors for mortality. Protective factors were balanced transfusion (odds ratio 0.81 95% confidence interval 0.71-0.93), male sex (odds ratio 0.90, 95% confidence interval 0.81-0.99), and blunt mechanism (odds ratio 0.74, 95% confidence interval 0.67-0.81). At 11 units of packed red blood cells, balanced transfusion patients were more likely to die (odds ratio 0.88, 95% confidence interval 0.80-0.98). Balanced transfusion patients survived at a higher rate for each unit of packed red blood cells, between 6 and 23 units of packed red blood cells. CONCLUSION: Mortality increases with each unit of packed red blood cell transfused. At 11 units of packed red blood cells, mortality is the more likely outcome. Balanced transfusion improves the chance of survival through 23 units of packed red blood cells.

Retained bullets: to remove or not to remove? Lessons from two clinical scenarios with intracardiac bullet embolization.

Firearm-related injuries in the USA are increasing, with over 105,000 cases annually. Gunshot wounds (GSWs), especially those involving retained bullets, present complex challenges due to bullet trajectories and embolization risks. This study reviews two cases of bullet emboli, focusing on bullet localization strategies and timing of removal. Imaging techniques such as chest X-ray, CT scan, intraoperative fluoroscopy, and transesophageal echocardiogram were employed for localization. In Case 1, a stable patient with a left-back GSW had a bullet embolism from the inferior vena cava to the right ventricle, necessitating prompt removal. In Case 2, an unstable patient with thoracoabdominal GSWs experienced a delayed embolism to the aortic root, requiring multiple surgeries. Effective management of retained bullets involves diverse imaging and timely surgical intervention, especially for stable patients, emphasizing individualized and proactive strategies to enhance outcomes in bullet embolization cases.

Lost and found: a unique foregut gastrointestinal bullet embolism.

Bullet embolism is a rare phenomenon where a bullet migrates from its original point of entry to a distant site within the body. This brief report describes a case of a bullet embolism entering the gastrointestinal (GI) tract through the posterior oropharynx. The patient initially presented with a gunshot wound to the left scapula, and the bullet was later identified in the GI tract. The patient was managed with a combination of endoscopic techniques and serial imaging, avoiding unnecessary surgical intervention. This case underscores the importance of comprehensive diagnostic strategies and tailored management in GI bullet embolism. It also emphasizes the utility of endoscopy in detecting GI tract injuries and highlights the successful use of non-operative management in specific scenarios.

Case report: Selective operative management of zone 3 carotid artery transection.

INTRODUCTION: Penetrating carotid artery injury is rare and particularly uncommon in zone 3 of the vessel. Due to anatomical challenges to open operative management in zone 3, there are minimal treatment recommendations for this highly morbid condition. The urgency associated with understanding proper management of this traumatic injury is further supported by the nearly 100 % rate of fatality in untreated penetrating carotid artery injuries. PRESENTATION OF CASE: A 17-year-old male presented with a bullet wound to the right temple. He was intubated for airway protection given left-sided tracheal deviation secondary to a right neck hematoma. His Glasgow Coma Scale (GCS) was 11 on initial presentation, E3V2M6. The patient remained hemodynamically stable and underwent a CT angiogram of the head and neck. Imaging revealed a complete transection of the cervical (zone III) right internal carotid artery (RICA), a large pseudoaneurysm of the RICA distal to carotid bifurcation, and comminuted mandibular fracture. Collateral blood flow was preserved to the right hemisphere. Multi-disciplinary discussions deemed risks of operative intervention outweighed the benefits in the immediate peri-trauma period as the increased risk of hemispheric stroke, exsanguination, and death was thought to be prohibitive. Therefore, treatment of delayed intervascular stenting of the RICA was performed as opposed to emergent open RICA ligation or repair. DISCUSSION: Treatment decisions for zone 3 CAI rely on the patient's hemodynamic stability, with surgical ligation favored for immediate hemorrhage control in unstable cases, while stable patients may undergo observation or delayed endovascular intervention. Balancing the need for hemostasis to prevent further blood loss with the potential benefits of anticoagulation to maintain cerebral perfusion underscores the decision-making required in managing such cases. CONCLUSION: The rarity and challenge of ICA injury at this anatomical location presents unique challenges. Our description of observation and delayed revascularization outlines the precarious, yet validated, treatment method for hemodynamically stable patients.

Optimal Management of Traumatic Abdominal Wall Hernias Remains Unclear.

High-energy, blunt force trauma to the abdomen results in an abdominal wall injury (AWI) in up to 9% of patients. In 1% of blunt abdominal trauma, they result in a traumatic abdominal wall hernia (TAWH). Optimal management of these injuries remains unclear. Because they are the result of a high-energy mechanism, concomitant serious abdominal organ injuries are common. This has prompted some to advocate that the presence of a TAWH on physical exam mandates exploratory laparotomy. However, delayed repairs have better outcomes and nontherapeutic celiotomy should be avoided. Similarly debated is the expanding use of minimally invasive techniques and the use of mesh for hernia repairs. Overall, the presence of a TAWH is likely not an absolute indication for emergency surgery. Rather, it is an indicator of high-energy impact and associated with a high rate of visceral injury. These patients require a close observation for clinical decline and development of typical indicators for laparotomy.

Three-dimensional modeling and simulation of DNA hybridization kinetics and mass transport as functions of temperature in a microfluidic channel.

A 3D finite element model was developed to optimize the kinetics and mass transfer characteristics of low concentration, 18 bp ssDNA targets in bulk media solution, to 18 bp complimentary oligonucleotide probes immobilized on electrochemical detection electrodes positioned along the length of a microfluidic channel. Conditions considered in the model were fluid flow rate, diffusion time, DNA melting temperature, number of matching base pairs, and temperature of the fluid in the channel. System optimization was based on maximizing the uniformity and surface concentration of the specifically bound hybridized DNA, minimizing waste volume generation and the hybridization time. With the coupled simulation method used, the total experiment time was reduced from 150 to 60 min and the simulated results were consistent with experimental results found in the literature. A stopped flow procedure was investigated as a means to improve hybridization. This procedure can not only improve uniformity and capture efficiency, and reduce waste, but can also decrease overall signal intensity relative to continuous flow operation. Finally, the use of temperature in reducing mismatched hybridization and improving duplex stability was also successfully modeled and simulated.

Surgical subspecialization is associated with higher rate of rib fracture stabilization: a retrospective database analysis.

Background: Surgical stabilization of rib fractures (SSRF) is performed on only a small subset of patients who meet guideline-recommended indications for surgery. Although previous studies show that provider specialization was associated with SSRF procedural competency, little is known about the impact of provider specialization on SSRF performance frequency. We hypothesize that provider specialization would impact performance of SSRF. Methods: The Premier Hospital Database was used to identify adult patients with rib fractures from 2015 and 2019. The outcome of interest was performance of SSRF, defined using International Classification of Diseases-10th Revision Procedure Coding System coding. Patients were categorized as receiving their procedures from a thoracic, general surgeon, or orthopedic surgeon. Patients with missing or other provider types were excluded. Multivariate modeling was performed to evaluate the effect of surgical specialization on outcomes of SSRF. Given a priori assumptions that trauma centers may have different practice patterns, a subgroup analysis was performed excluding patients with 'trauma center' admissions. Results: Among 39 733 patients admitted with rib fractures, 2865 (7.2%) received SSRF. Trauma center admission represented a minority (1034, 36%) of SSRF procedures relative to other admission types (1831, 64%, p=0.15). In a multivariable analysis, thoracic (OR 6.94, 95% CI 5.94-8.11) and orthopedic provider (OR 2.60, 95% CI 2.16-3.14) types were significantly more likely to perform SSRF. In further analyses of trauma center admissions versus non-trauma center admissions, this pattern of SSRF performance was found at non-trauma centers. Conclusion: The majority of SSRF procedures in the USA are being performed by general surgeons and at non-trauma centers. 'Subspecialty' providers in orthopedics and thoracic surgery are performing fewer total SSRF interventions, but are more likely to perform SSRF, especially at non-trauma centers. Provider specialization as a barrier to SSRF may be related to competence in the SSRF procedures and requires further study. Type: Therapeutic/care management. Level of evidence: IV.

When is enough enough? Odds of survival by unit transfused.

BACKGROUND: Balanced transfusion is lifesaving for hemorrhagic shock. The American Red Cross critical blood shortage in 2022 threatened the immediate availability of blood. To eliminate waste, we reviewed the utility of transfusions per unit to define expected mortality at various levels of balanced transfusion. METHODS: A retrospective study of 296 patients receiving massive transfusion on presentation at a level 1 trauma center was performed from January 2018 to December 2021. Units of packed red blood cells (PRBCs), fresh frozen plasma (FFP), and platelets received in the first 4 hours were recorded. Patients were excluded if they died in the emergency department, died on arrival, received <2 U PRBCs or FFP, or received PRBC/FFP >2:1. Primary outcomes were mortality and odds of survival to discharge. Subgroups were defined as transfused if receiving 2 to 9 U PRBCs, massive transfusion for 10 to 19 U PRBCs, and ultramassive transfusion for ≥20 U PRBCs. RESULTS: A total of 207 patients were included (median age, 32 years; median Injury Severity Score, 25; 67% with penetrating mechanism). Mortality was 29% (61 of 207 patients). Odds of survival is equal to odds of mortality at 11 U PRBCs (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.50-1.79). Beyond 16 U PRBCs, odds of mortality exceed survival (OR, 0.36; 95% CI, 0.16-0.82). Survival approaches zero >36 U PRBCs (OR, 0.09; 95% CI, 0.00-0.56). Subgroup mortality rates increased with unit transfused (16% transfused vs. 36% massive transfusion, p = 0.003; 36% massive transfusion vs. 67% ultramassive transfusion, p = 0.006). CONCLUSION: Mortality increases with each unit balanced transfusion. Surgeons should view efforts heroic beyond 16 U PRBCs/4 hours and near futile beyond 36 U PRBCs/4 hours. While extreme outliers can survive, consider cessation of resuscitation beyond 36 U PRBCs. This is especially true if hemostasis has not been achieved or blood supplies are limited. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level IV.

Multi-System Inflammatory Syndrome Presenting as Non-Specific Colitis: A Medical Diagnosis with a Surgical Presentation.

A 20-year-old woman with previous COVID-19 diagnosis presented with abdominal pain and colitis on CT scan. She was admitted in septic shock, with etiology of colitis unclear. After resuscitation, antibiotics, and steroids, she clinically deteriorated. Worsening Clostridioides difficile infection was most likely and she was taken to the operating room. Intraoperatively, only a segment of transverse colon appeared abnormal on gross and endoscopic evaluation. Total colectomy was deferred in favor of segmental resection. Given her unusual disease pattern and recent COVID-19 infection, diagnosis of MIS-C was considered. Steroids were continued and treatment broadened to include heparin and IVIG. The patient returned to the operating room for planned reexploration, endoscopy, and end colostomy. On hospital day three, the patient had an acute mental status change. Computed tomography demonstrated acute cerebral edema with brainstem herniation. The family chose comfort-care measures. Final pathology from the transverse colon demonstrated COVID-19-associated vasculitis.

Age as a Barrier to Surgical Stabilization of Rib Fractures in Patients with Flail Chest.

INTRODUCTION: Although randomized trials demonstrate a benefit to surgical stabilization of rib fractures (SSRF), SSRF is rarely performed. We hypothesized older patients were less likely to receive SSRF nationally. METHODS: The 2016 National Inpatient Sample was used to identify adults with flail chest. Comorbidities and receipt of SSRF were categorized by ICD-10 code. Univariable testing and Multivariable regression were performed to determine the association of demographic characteristics and comorbidities to receipt of SSRF. RESULTS: 1021 patients with flail chest were identified, including 244 (23.9%) who received SSRF. Patients ≥70 years were less likely to receive SSRF. (<70 yrs 201/774 [26.0%] vs ≥70 43/247 [17.4%], P = .006) and had higher risk of death (<70 yrs 39/774 [5.0%] vs ≥70 33/247 [13.4%], P < .001) In multivariable modeling, only age ≥70 years was associated with SSRF (OR .591, P = .005). CONCLUSION: Despite guideline-based support of SSRF in flail chest, SSRF is performed in <25% of patients. Age ≥70 years is associated with lower rate of SSRF and higher risk of death. Future study should examine barriers to SSRF in older patients.

Contemporary management and outcomes of penetrating colon injuries: Validation of the 2020 AAST Colon Organ Injury Scale.

INTRODUCTION: The American Association for the Surgery of Trauma Colon Organ Injury Scale (OIS) was updated in 2020 to include a separate OIS for penetrating colon injuries and included imaging criteria. In this multicenter study, we describe the contemporary management and outcomes of penetrating colon injuries and hypothesize that the 2020 OIS system correlates with operative management, complications, and outcomes. METHODS: This was a retrospective study of patients presenting to 12 Level 1 trauma centers between 2016 and 2020 with penetrating colon injuries and Abbreviated Injury Scale score of <3 in other body regions. We assessed the association of the new OIS with surgical management and clinical outcomes and the association of OIS imaging criteria with operative criteria. Bivariate analysis was done with χ 2 , analysis of variance, and Kruskal-Wallis, where appropriate. Multivariable models were constructed in a stepwise selection fashion. RESULTS: We identified 573 patients with penetrating colon injuries. Patients were young and predominantly male; 79% suffered a gunshot injury, 11% had a grade V destructive injury, 19% required ≥6 U of transfusion, 24% had an Injury Severity Score of >15, and 42% had moderate-to-large contamination. Higher OIS was independently associated with a lower likelihood of primary repair, higher likelihood of resection with anastomosis and/or diversion, need for damage-control laparotomy, and higher incidence of abscess, wound infection, extra-abdominal infections, acute kidney injury, and lung injury. Damage control was independently associated with diversion and intra-abdominal and extra-abdominal infections. Preoperative imaging in 152 (27%) cases had a low correlation with operative findings ( κ coefficient, 0.13). CONCLUSION: This is the largest study to date of penetrating colon injuries and the first multicenter validation of the new OIS specific to these injuries. While imaging criteria alone lacked strong predictive value, operative American Association for the Surgery of Trauma OIS colon grade strongly predicted type of interventions and outcomes, supporting use of this grading scale for research and clinical practice. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level III.

In situ dissolution or deposition of Ytterbium (Yb) metal in microhotplate wells for a miniaturized atomic clock.

Current atomic clocks are burdened by size, weight, power and portability limitations to satisfy a broad range of potential applications. One critical need in the fabrication of a miniaturized atomic clock is small, low-power metallic sources. Exploiting the relatively high vapor pressure of ytterbium (Yb) and its dissolution in anhydrous ammonia, we report two independent techniques for depositing Yb inside a well micromachined into a microhotplate. Subsequent in situ evaporation of Yb from the microhotplate well serves as a low-power metallic source suitable for atomic clocks. The deposition and evaporation of Yb were confirmed using a variety of physicochemical techniques including quartz crystal microbalance, scanning electron microscopy, energy dispersive X-ray spectroscopy, and laser fluorescence. We also describe the fabrication of the microhotplate device, an integral component of our Yb-based miniature atomic clock. The Yb deposition/evaporation on a microhotplate well is thus useful as a low power Yb source during the fabrication of a miniaturized atomic clock, and this technique could be used for other applications requiring a vapor of a metal that has a moderate vapor pressure.

Thermally-activated pentanol delivery from precursor poly(p-phenylenevinylene)s for MEMS lubrication.

The synthesis of two new polyphenylene vinylene (PPV) precursor polymers which can be thermally induced to eliminate pentanol is presented. Pentanol has recently been discovered to be a very useful lubricant in MicroElectroMechanical Systems. The utilization of the elimination reaction of precursor polymers to PPV as a small molecule delivery platform has, to the best of our knowledge, not been previously reported. The elimination reactions were examined using thermal gravimetric analysis, gas chromatography, and UV-Vis spectroscopy. Using PPV precursors allows for (1) a high loading of lubricant (one molecule per monomeric unit), (2) a platform that requires relatively high temperatures (>145 °C) to eliminate the lubricant, and (3) a non-volatile, mechanically and chemically stable by-product of the elimination reaction (PPV).

Iatrogenic rib fractures and the associated risks of mortality.

PURPOSE: Rib fractures, though typically associated with blunt trauma, can also result from complications of medical or surgical care, including cardiopulmonary resuscitation. The purpose of this study is to describe the demographics and outcomes of iatrogenic rib fractures. METHODS: Patients with rib fractures were identified in the 2016 National Inpatient Sample. Mechanism of injury was defined as blunt traumatic rib fracture (BTRF) or iatrogenic rib fracture (IRF). IRF was identified as fractures from the following mechanisms: complications of care, drowning, suffocation, and poisoning. Differences between BTRF and IRF were compared using rank-sum test, Chi-square test, and multivariable regression. RESULTS: 34,644 patients were identified: 33,464 BTRF and 1180 IRF. IRF patients were older and had higher rates of many comorbid medical disorders. IRF patients were more likely to have flail chest (6.1% versus 3.1%, p < 0.001). IRF patients were more likely to have in-hospital death (20.7% versus 4.2%, p < 0.001) and longer length of hospitalization (11.8 versus 6.9 days, p < 0.001). IRF patients had higher rates of tracheostomy (30.2% versus 9.1%, p < 0.001). In a multivariable logistic regression of all rib fractures, IRF was independently associated with death (OR 3.13, p < 0.001). A propensity matched analysis of IRF and BTRF groups corroborated these findings. CONCLUSION: IRF injuries are sustained in a subset of extremely ill patients. Relative to BTRF, IRF is associated with greater mortality and other adverse outcomes. This population is understudied. The etiology of worse outcomes in IRF compared to BTRF is unclear. Further study of this population could address this disparity.

A monolithically-integrated µGC chemical sensor system.

Gas chromatography (GC) is used for organic and inorganic gas detection with a range of applications including screening for chemical warfare agents (CWA), breath analysis for diagnostics or law enforcement purposes, and air pollutants/indoor air quality monitoring of homes and commercial buildings. A field-portable, light weight, low power, rapid response, micro-gas chromatography (µGC) system is essential for such applications. We describe the design, fabrication and packaging of µGC on monolithically-integrated Si dies, comprised of a preconcentrator (PC), µGC column, detector and coatings for each of these components. An important feature of our system is that the same mechanical micro resonator design is used for the PC and detector. We demonstrate system performance by detecting four different CWA simulants within 2 min. We present theoretical analyses for cost/power comparisons of monolithic versus hybrid µGC systems. We discuss thermal isolation in monolithic systems to improve overall performance. Our monolithically-integrated µGC, relative to its hybrid cousin, will afford equal or slightly lower cost, a footprint that is 1/2 to 1/3 the size and an improved resolution of 4 to 25%.