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.

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.

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.

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.

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.

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.

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.

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.

Traffic stops do not prevent traffic deaths.

OBJECTIVES: Amid growing calls for police reform, it is imperative to reassess whether police actions designed to improve public safety are associated with injury prevention. This study aims to examine the relationship between the police traffic stops (PTSs) and motor vehicle crash (MVC) deaths at the state level. We hypothesize that increased PTSs would be associated with reduced MVC deaths. METHODS: We retrospectively analyzed PTSs and MVC deaths at the state level from 2004 to 2016. Police traffic stops data were from 33 state patrols from the Stanford Open Policing Project. The MVC deaths data were collected from the National Highway Traffic Safety Administration. The vehicle miles traveled data were from the Federal Highway Administration Office of Highway Policy Information. All data were adjusted per 100 million vehicle miles traveled (100MVMT) and were analyzed as state-level time series cross-sectional data. The dependent variable was MVC deaths per 100MVMT, and the independent variable was number of PTSs per 100MVMT. We performed panel data analysis accounting for random and fixed state effects and changes over time. RESULTS: Thirty-three state patrols with 235 combined years were analyzed, with a total of 161,153,248 PTSs. The PTS rate varied by state and year. Nebraska had the highest PTS rate (3,637/100MVMT in 2004), while Arizona had the lowest (0.17/100MVMT in 2009). Motor vehicle crash deaths varied by state and year, with the highest death rate occurring in South Carolina in 2005 (2.2/100MVMT) and the lowest in Rhode Island in 2015 (0.57/100MVMT). After accounting for year and state-level variability, no association was found between PTS and the MVC death rates. CONCLUSION: State patrol traffic stops are not associated with reduced MVC deaths. Strategies to reduce death from MVC should consider alternative strategies, such as motor vehicle modifications, community-based safety initiatives, improved access to health care, or prioritizing trauma system. LEVEL OF EVIDENCE: Retrospective epidemiological study, level IV.

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.

Chemical Profiling of Volatile Organic Compounds in the Headspace of Algal Cultures as Early Biomarkers of Algal Pond Crashes.

Algae ponds used in industrial biomass production are susceptible to pathogen or grazer infestation, resulting in pond crashes with high economic costs. Current methods to monitor and mitigate unhealthy ponds are hindered by a lack of early indicators that precede culture crash. We used solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) to identify volatiles emitted from healthy and rotifer infested cultures of Microchloropsis salina. After 48 hours of algal growth, marine rotifers, Brachionus plicatilis, were added to the algae cultures and volatile organic compounds (VOC) were sampled from the headspace using SPME fibers. A GC-MS approach was used in an untargeted analysis of VOCs, followed by preliminary identification. The addition of B. plicatilis to healthy cultures of M. salina resulted in decreased algal cell numbers, relative to uninfected controls, and generated trans-ß-ionone and ß-cyclocitral, which were attributed to carotenoid degradation. The abundances of the carotenoid-derived VOCs increased with rotifer consumption of algae. Our results indicate that specific VOCs released by infected algae cultures may be early indicators for impending pond crashes, providing a useful tool to monitor algal biomass production and pond crash prevention.

A Viable Lyopreserved Amniotic Membrane Modulates Diabetic Wound Microenvironment and Accelerates Wound Closure.

Objective: Wound healing is a complex process involving the dynamic interplay of various types of cells and bioactive factors. Impaired wound healing is characterized by a loss in synchronization of the process, resulting in non-healing chronic wounds. Human amniotic membrane (AM) has been shown to be effective in the management of chronic wounds. Recently, a viable lyopreserved AM (VLAM) has been developed. The VLAM retains the structural, molecular, and functional properties of fresh AM with the advantage of a long shelf life for living tissue at ambient temperatures. The objective of this study was to evaluate the effects of VLAM on the impaired wound microenvironment and wound closure in db/db mice. Approach: VLAM or saline gel (control) was applied weekly to 7-mm excisional wounds in diabetic (db/db) mice. Wound appearance and size were assessed weekly. Inflammation and redox state in wounds were tested by cytokine gene and protein expression, and by catalase and glutathione peroxidase activities, respectively. Wound tissue granulation and neovascularization were assessed histologically. Results: Diabetic wounds treated with VLAM closed faster than control wounds. On an average, VLAM-treated wounds closed 4 days faster than the control wounds, with a significantly faster rate of closure at days 7 and 14 as compared with control wounds. The faster closure correlated with a decrease in the expression of proinflammatory factors and oxidative stress, and an increase in angiogenesis and dermal thickness. Innovation: Effects of VLAM on a chronic wound microenvironment and underlying molecular mechanisms were investigated for the first time. Conclusion: VLAM accelerates wound closure in db/db mice by decreasing inflammation and oxidative stress and supporting wound tissue granulation, neovascularization, and re-epithelialization.

Among Trauma Patients, Younger Men with Ventilator-Associated Pneumonia Have Worse Outcomes Compared to Older Men-An Exploratory Study.

BACKGROUND: Ventilator-associated pneumonia is associated with significant morbidity. Although the association of gender with outcomes in trauma patients has been debated for years, recently, certain authors have demonstrated a difference. We sought to compare the outcomes of younger men and women to older men and women, among critically ill trauma patients with ventilator-associated pneumonia (VAP). METHODS: We reviewed our trauma data base for trauma patients with ventilator-associated pneumonia admitted to our trauma intensive care unit between January 2016 and June 2018. Data collected included demographics, injury mechanism and severity (ISS), admission vital signs and laboratory data and outcome measures including hospital length of stay, ICU stay and survival. Patients were also divided into younger (<50) and older (≥50) to account for hormonal status. Linear regression and binary logistic regression models were performed to compare younger men to older men and younger women to older women, and to examine the association between gender and hospital length of stay (LOS), ICU stay (ICUS), and survival. RESULTS: Forty-five trauma patients admitted to our trauma intensive care unit during the study period (January 2016 to August 2018) had ventilator-associated pneumonia. The average age was 58.9 ± 19.6 years with mean ISS of 18.2 ± 9.8. There were 32 (71.1%) men, 27 (60.0%) White, and 41 (91.1%) had blunt trauma. Mean ICU stay was 14.9 ± 11.4 days and mean total hospital length of stay (LOS) was 21.5 ± 14.6 days. Younger men with VAP had longer hospital LOS 28.6 ± 17.1 days compared to older men 16.7 ± 6.6 days, (p < 0.001) and longer intensive care unit stay 21.6 ± 15.6 days compared to older men 11.9 ± 7.3 days (p = 0.02), there was no significant difference in injury severity (ISS was 22.2 ± 8.4 vs. 17 ± 8, p = 0.09). CONCLUSIONS: Among trauma patients with VAP, younger men had longer hospital length of stay and a trend towards longer ICU stay. Further research should focus on the mechanisms behind this difference in outcome using a larger database.

Thermodynamic Studies on a Hydrogen Bonded Acidic 3,5-Bis(trifluoromethyl)phenol-functionalized Polymer as a Gas Chromatography Stationary Phase for Selectively Speciating Chemical Warfare Agents.

We describe for the first time hydrogen bonded acid (HBA) polymer, poly{methyl[3-(2-hydroxyl, 4,6-bistrifluoromethyl)phenyl]propylsiloxane}, (DKAP), as stationary phase for gas chromatography (µGC) of organophosphate (OP), chemical warfare agent (CWA) surrogates, dimethylmethylphosphonate (DMMP), diisopropylmethylphosphonate (DIMP), diethylmethylphosphonate (DEMP), and trimethylphosphate (TMP), with high selectivity. Absorption of OPs to DKAP was one-to-several orders of magnitude higher relative to commercial polar, mid-polar, and nonpolar stationary phases. We also present for the first-time thermodynamic studies on the absorption of OP vapors and quantitative binding energy data for interactions with various stationary phases. These data help to identify the best pair of hetero-polar columns for a two-dimensional GC system, employing a nonpolar stationary phase as GC1 and DKAP as the GC2 stationary phase, for selective and rapid field detection of CWAs.

Viable cryopreserved umbilical tissue (vCUT) reduces post-operative adhesions in a rabbit abdominal adhesion model.

Post-operative adhesions, a common complication of surgery, cause pain, impair organ functionality, and often require additional surgical interventions. Control of inflammation, protection of injured tissue, and rapid tissue repair are critical for adhesion prevention. Adhesion barriers are biomaterials used to prevent adhesions by physical separation of opposing injured tissues. Current adhesion barriers have poor anti-inflammatory and tissue regenerative properties. Umbilical cord tissue (UT), a part of the placenta, is inherently soft, conforming, biocompatible, and biodegradable, with antimicrobial, anti-inflammatory, and antifibrotic properties, making it an attractive alternative to currently available adhesion barriers. While use of fresh tissue is preferable, availability and short storage time limit its clinical use. A viable cryopreserved UT (vCUT) "point of care" allograft has recently become available. vCUT retains the extracellular matrix, growth factors, and native viable cells with the added advantage of a long shelf life at -80 °C. In this study, vCUT's anti-adhesion property was evaluated in a rabbit abdominal adhesion model. The cecum was abraded on two opposing sides, and vCUT was sutured to the abdominal wall on the treatment side; whereas the contralateral side of the abdomen served as an internal untreated control. Gross and histological evaluation was performed at 7, 28, and 67 days post-surgery. No adhesions were detectable on the vCUT treated side at all time points. Histological scores for adhesion, inflammation, and fibrosis were lower on the vCUT treated side as compared to the control side. In conclusion, the data supports the use of vCUT as an adhesion barrier in surgical procedures.