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Necessary and sufficient optimality conditions are established for a class of nondifferentiable minimax fractional programming problems with square root terms. Subsequently, we apply the optimality conditions to formulate a parametric dual problem and we prove some duality results.

The paper presents the authors’ contributions for developing a computer code for teaching of descriptive geometry using the computer aided learning techniques. The program was implemented using the programming interface and the 3D modeling capabilities of the AutoCAD system.

Objective: Physician-directed point-of-care ultrasound (PoCUS) is routinely used to identify the etiology of shock and guide therapy in the ICU. We performed a preclinical study to determine what changes are manifested in the femoral vessels during hemorrhagic shock on Duplex imaging and to generate a femoral vessel sonographic profile over the time course of shock., Design & Setting: A preclinical study in swine was performed using a convenience sample of animals that were being used in a Trauma Surgery training lab. The animals developed progressive unregulated hemorrhage during the lab., Subjects: Six anesthetized swine underwent Duplex studies of the femoral vessels prior to any hemorrhage and at two time points after the start of hemorrhage., Interventions: N/A., Measurements: Femoral vessel imaging was performed using a portable ultrasound (Sonosite and Clarius)., Main Results: Femoral arterial peak systolic velocity decreased in all animals with hemorrhage, from a mean (SD) of 77 (27) cm/s pre-hemorrhage to 42 (17) and 32 (16) cm/s at the two post-hemorrhage time points. There were also changes to the arterial waveform morphology. Mean venous velocities also decreased with hemorrhage (20, 11, 7 cm/s). Animals with severe hemorrhage had a cessation of venous flow during positive pressure ventilation., Conclusion: In this preclinical study, both femoral peak systolic velocity and venous velocity decreased with hemorrhage. Femoral vessels represent an easily accessible target for non-invasive hemodynamic monitoring. Changes in femoral vessel Duplex waveforms and velocities should be studied both in a larger sample of animals with controlled hemorrhage and in human trauma patients to determine whether changes appear in early hemorrhage, before the onset of clinically evident hemorrhagic shock., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 Published by Elsevier Ltd.)

Introduction: As medical advances have significantly increased the life expectancy among older adults, the number of older patients requiring trauma care has risen proportionately. Nevertheless, it is unclear among this growing population which sociodemographic and economic factors are associated with decisions to triage and transfer to level I/II centers. This study aims to assess for any association between patient sociodemographic characteristics, triage decisions, and outcomes during acute trauma care presentations., Methods: The National Trauma Data Bank was queried for patients aged 65 and older with an injury severity score > 15 between the years 2007 to 2017. Factors associated with subsequent levels of triage on presentation were assessed using multivariate logistic regression, and associations of levels of triage with outcomes of mortality, morbidity, and hospital length of stay are examined using logistic and linear regression models., Results: Triage of 210,310 older adult trauma patients showed significant findings. American Indian patients had higher odds of being transferred to level I/II centers, while Asian, Black, and Native Hawaiian patients had lower odds of being transferred to level I/II centers when compared to Caucasian patients (P < 0.001). Regarding insurance, self-pay (uninsured) patients were less likely to be transferred to a higher level of care; however, this was also demonstrated in private insurance holders (P < 0.001). Caucasian patients had significantly higher odds of mortality, with Black patients (odds ratio [OR] 0.80 [0.75, 0.85]) and American Indian patients (OR 0.87 [0.72, 1.04]) having significantly lower odds (P < 0.001). Compared to government insurance, private insurance holders (OR 0.82 [0.80, 0.85]) also had significantly lower odds of mortality, while higher odds among self-pay were observed (OR 1.75 [1.62, 1.90]), (P < 0.001)., Conclusions: Access to insurance is associated with triage decisions involving older adults sustaining trauma, with lower access increasing mortality risk. Factors such as race and gender were less likely to be associated with triage decisions. However, due to this study's retrospective design, further prospective analysis is necessary to fully assess the decisions that influence trauma triage decisions in this patient population., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: Advanced directives (ADs) provide a framework from which families may understand patient's wishes. However, end-of-life planning may not be prioritized by everyone. This analysis aimed to determine what populations have ADs and how they affected trauma outcomes., Methods: Adult trauma patients recorded in the American College of Surgeons Trauma Quality Improvement Program (TQIP) from 2013-2015 were included. The primary outcome was presence of an AD. Secondary outcomes included mortality, length of stay (LOS), mechanical ventilation, ICU admission/LOS, withdrawal of life-sustaining measures, and discharge disposition. Multivariable logistic regression models were developed for outcomes., Results: 44 705 patients were included in the analyses. Advanced directives were present in 1.79% of patients. The average age for patients with ADs was 77.8 ± 10.7. African American (odds ratio (OR) .53, confidence intervals [CI] .36-.79) and Asian (OR .22, CI .05-.91) patients were less likely to have ADs. Conversely, Medicaid (OR 1.70, CI 1.06-2.73) and Medicare (OR 1.65, CI 1.25-2.17) patients were more likely to have ADs as compared to those with private insurance. The presence of ADs was associated with increased hospital mortality (OR 2.84, CI 2.19-3.70), increased transition to comfort measures (OR 2.87, CI 2.08-3.95), and shorter LOS (CO -.74, CI -1.26-.22). Patients with ADs had an increased odds of hospice care (OR 4.24, CI 3.18-5.64)., Conclusion: Advanced directives at admission are uncommon, particularly among African Americans and Asians. The presence of ADs was associated with increased mortality, use of mechanical ventilation, admission to the ICU, withdrawal of life-sustaining measures, and hospice. Future research should target expansion of ADs among minority populations to alleviate disparities in end-of-life treatment.

Objective: In this narrative review, we aim to provide a definition of traumatic tracheo-bronchial injuries as well as an approach to their diagnosis and management, including operative and non-operative strategies., Background: Traumatic tracheo-bronchial injuries are relatively uncommon, but are associated with a high mortality, both at the scene and among patients who survive to hospital. Management often requires an emergency airway, usually intubation over a flexible bronchoscope, followed by definitive repair., Methods: The published literature on the diagnosis and management of traumatic airway injuries was searched through PubMed. Additional references were identified from the bibliography of relevant publications identified. The evidence was then summarized in a narrative fashion, incorporating the authors' knowledge, experience, and perspective on the topic., Conclusions: Definitive diagnosis of traumatic tracheo-bronchial injuries usually involves direct visualization through liberal use of bronchoscopy in addition to cross-sectional imaging to evaluate for associated injuries, notably to the great vessels and esophagus. Important considerations for management include concerns for airway obstruction, uncontrolled air leak, and mediastinitis. Early repair of injuries recognized acutely is favored in attempts to prevent the development of airway stenosis. Key operative principles include exposure, conservative debridement to preserve length when possible, creation of a tension-free anastomosis, preservation of the blood supply, and creation of a tracheostomy, particularly in polytrauma patients. An interposition muscle flap is also required, specifically in the setting of combined esophageal and airway injuries. Patients with penetrating injuries tend to have more favorable outcomes, possibly on account of fewer concomitant injuries. Selective non-operative management is also an option in the subset of patients with iatrogenic injuries to the posterior membranous wall of the trachea, and includes broad-spectrum antibiotics and surveillance bronchoscopy., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://med.amegroups.com/article/view/10.21037/med-21-21/coif). The series "Traumatic Injuries of the Mediastinum" was commissioned by the editorial office without any funding or sponsorship. The authors have no other conflicts of interest to declare., (2022 Mediastinum. All rights reserved.)

Introduction: Older adults are more vulnerable to opioid-associated morbidity. The purpose of this study was to determine the frequency and timing of acetaminophen and opioid use in the postoperative period., Methods: Older adult trauma patients (≥65 years) with hip fractures requiring femur or hip fixation were reviewed (Premier Database 2008-2014). We examined rates of acetaminophen use on the day of surgery and prior to receipt of oral opioids. Mixed-effects linear regression models were used to examine the effects of an acetaminophen-first approach on opioid use the day prior to and on the day of discharge., Results: Of the 192 768 patients, 81.6% were Caucasian; 74.0% were female; and the mean age was 82.0 years [± 7.0]. Only 16.8% (32 291) of patients received acetaminophen prior to being prescribed opioids. 27.4% (52 779) received an acetaminophen-opioid combination, and 9.2% (17 730) received opioids without acetaminophen first. Acetaminophen first was associated with reduced opioid use on the day prior to and on the day of discharge (3.52 parenteral morphine equivalent doses (PMEs) less [95% CI: 3.33, 3.70]; P < .0001). A statistically but not clinically significant reduction in length of stay was observed in the acetaminophen-first group., Conclusion: Nearly 37% of older adult patients did not receive acetaminophen as first-line analgesia after hip surgery. Multimodal analgesia, including non-opioid medications as first-line, should be encouraged.

Objective: To describe changes in renal volumes (RV) and renal function after fenestrated-branched endovascular repair (F-BEVAR) for complex aortic aneurysms., Methods: The data from patients enrolled in a physician-sponsored investigational device exemption clinical trial for endovascular treatment of complex aortic aneurysms from July 2012 to April 2017 were retrospectively analyzed. Descriptive statistics were calculated using the mean ± standard deviation. The mean estimated glomerular filtration rate (eGFR) and RV were calculated at baseline and 6, 12, and 18 months after F-BEVAR. Variable distributions were evaluated for skewness, and all models required log-transformation. Linear models using generalized estimating equations were used to assess the association between the RV and eGFR over time after adjustment for relevant covariates. We used Kaplan-Meier life-table analysis to calculate survival and branch patency., Results: A total of 139 patients were followed up for 18 months or until death. The mean age was 71 ± 8 years (70% male). The most common risk factor was hypertension (92%). Chronic kidney disease (CKD; eGFR <60 mL/min) was present in 56 patients (40%). Thirty-one patients (22%) had ≥1 accessory renal artery. Of these 31 accessory arteries, 27 (87%) were embolized or covered. On average, the eGFR had decreased over time compared with baseline, with a median change of -4.4 mL/min (interquartile range [IQR], -11.4 to 4.9 mL/min), -2.6 mL/min (IQR, -11.9 to 6.5 mL/min), and -3.4 mL/min (IQR, -11.9 to 5.5 mL/min) at 6, 12, and 18 months postoperatively, respectively. Similarly, the RV had decreased from baseline by 8% ± 17%, 10% ± 17%, and 11% ± 22% at 6, 12, and 18 months, respectively. An increase in the baseline patient age of 5 years was estimated to be associated with a 3% (95% confidence interval [CI], 0.2%-6.0%) decrease in the mean eGFR during the follow-up period, collapsing over time. This change is similar to the natural history of renal deterioration with age. We estimated that an increase in the log-RV of 1 U would be associated with an estimated 26% (95% CI, 3%-52%) increase in the mean eGFR. Preexisting CKD did not affect the average change in RV. Of the 56 patients with previous CKD, 9 (16.1%) showed improvement in the eGFR to >60 mL/min. The median follow-up period was 17.9 months (IQR, 6.3-24.8). The Kaplan-Meier survival rate at 1 and 2 years was 84.7% (95% CI, 78.3%-91.1%) and 78.8% (95% CI, 71.0%- 86.6%), respectively., Conclusions: The RV and eGFR decreased in patients undergoing repair at the rates expected for patients with complex aortic disease. The eGFR correlated with the RV. Most of the decline in renal function occurred within the first 6 months postoperatively, after which, the renal function had stabilized., (Published by Elsevier Inc.)

Background: Knowledge regarding the barrier properties of human skin is important for understanding skin pathology, developing of transdermal drug delivery systems and computational skin absorption models; however, the molecular pathways through human skin remains to be fully investigated on a nanoscopic level. In particular the nanoscopic pathway of molecules passing the intercellular lipid bilayers separating the corneocytes in the stratum corneum (SC) is not fully elucidated., Methods: Using stimulated emission depletion microscopy (STED) and Förster resonance energy transfer (FRET) the molecular pathways through the SC, the main barrier of the skin, are determined for lipophilic and water-soluble molecules at a nanoscopic resolution., Results: Using STED and confocal microscopy, water-soluble dyes, were observed to be present in both the corneocytes and in the intercellular lipid matrix, whereas the lipophilic dyes were predominately in the intercellular lipid bilayers. FRET was observed in the SC between the lipophilic and water-soluble dyes, the existence of a minimum possible distance between acceptor and donor molecules of 4.0 ± 0.1 nm was found., Conclusions: The results indicate that lipophilic molecules penetrate the stratum corneum via the intercellular lipids bilayers separating the corneocytes in the SC, while the more water-soluble molecules penetrate the stratum corneum via the transcellular route through the corneocytes and intercellular lipid bilayers via the polar head groups of lipid molecules in the bilayers., General Significance: Knowledge of the nanoscopic molecular pathways through human skin will help understand the skin barrier function and will be of use for computational skin absorption models and transdermal drug delivery strategies., (Copyright © 2019. Published by Elsevier B.V.)

Fibromuscular dysplasia (FMD) is a nonatherosclerotic disease that generally affects medium-sized arteries. The distribution typically involves the renal, extracranial carotid/vertebral, and iliac arteries. FMD in other vascular beds is rare. We herein present the case of a 47-year-old female with rapid-onset bilateral digital ischemia. Initial differential diagnosis included vasospastic disorders and vasculitis. An upper extremity arteriogram was suggestive of ulnar and radial FMD. Percutaneous intervention was not successful, and the patient was managed conservatively with symptomatic improvement. This case highlights the important diagnostic and therapeutic considerations in patients with less common etiologies of upper extremity ischemia., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Adherence to topical corticosteroids is low among atopic dermatitis patients and their parents. This can lead to treatment failure and decreased quality of life., Objective: To assess and compare the worries and beliefs concerning topical corticosteroids among parents of children with atopic dermatitis, involved health care professionals, and between different professionals. Also, we identify factors associated with corticosteroid phobia (corticophobia) in professionals., Methods: Parents and health care professionals were invited to complete a questionnaire about corticophobia (Topicop). Higher questionnaire scores, expressed as a percentage, indicate more severe corticophobia. Professionals were asked to answer the questions as though they were using topical corticosteroids on their own child., Results: The scores for 29 parents and 31 public health care nurses were equal: 44%. The score for 51 general practitioners was 39%. The score for 33 public health care physicians and of 47 pediatricians was 31%. The differences between parents and these professionals were statistically significantly different (P = 0.001). Type of profession and having a child with atopic dermatitis were significantly associated factors for the score., Conclusion: Corticophobia is present among parents of children with atopic dermatitis and among health care professionals involved in caring for children with atopic dermatitis. Health care nurses express the same level of corticophobia as parents. The presence of corticophobia among health care professionals may affect parental perspectives and topical corticosteroids adherence negatively., (© 2018 Wiley Periodicals, Inc.)

Dilation throughout the brachial artery in the setting of an arteriovenous fistula is a common occurrence, but focal aneurysmal dilation is not often visualized. Progressive enlargement of a focal arterial segment warrants intervention before negative sequelae. We present the case of a 38-year-old man with history of left upper extremity brachiocephalic fistula who had an enlarged brachial artery and progressive aneurysmal dilation of the distal aspect after ligation and excision of a dilated venous outflow component. The patient was successfully treated with resection and end-to-end reconstruction of the brachial artery, with resolution of pain and improvement in the functionality of his extremity. This case highlights the possible challenges encountered in such situations, when the anatomy is so distorted that it is difficult to clearly delineate on preoperative imaging.

Background: It is well known that suicidal rates vary considerably among European countries and the reasons for this are unknown, although several theories have been proposed. The effect of economic variables has been extensively studied but not that of climate., Methods: Data from 29 European countries covering the years 2000-2012 and concerning male and female standardized suicidal rates (according to WHO), economic variables (according World Bank) and climate variables were gathered. The statistical analysis included cluster and principal component analysis and categorical regression., Results: The derived models explained 62.4 % of the variability of male suicidal rates. Economic variables alone explained 26.9 % and climate variables 37.6 %. For females, the respective figures were 41.7, 11.5 and 28.1 %. Male suicides correlated with high unemployment rate in the frame of high growth rate and high inflation and low GDP per capita, while female suicides correlated negatively with inflation. Both male and female suicides correlated with low temperature., Discussion: The current study reports that the climatic effect (cold climate) is stronger than the economic one, but both are present. It seems that in Europe suicidality follows the climate/temperature cline which interestingly is not from south to north but from south to north-east. This raises concerns that climate change could lead to an increase in suicide rates. The current study is essentially the first successful attempt to explain the differences across countries in Europe; however, it is an observational analysis based on aggregate data and thus there is a lack of control for confounders.

Introduction: Surgery is evolving, and new techniques are introduced to improve "recovery." Postoperative recovery is complex, and evaluating the effectiveness of surgical innovations requires assessment of patient-reported outcomes. The Short-Form-36 (SF-36), a generic health-related quality of life questionnaire, is the most commonly used instrument in this context. The objective of this study was to contribute evidence for the validity of the SF-36 as a metric of postoperative recovery., Methods: Data from 128 patients undergoing planned colorectal surgery at one university hospital between 2005 and 2010 were analyzed. In the absence of a gold standard, the responsiveness and construct validity (known groups and convergent) of the SF-36 were evaluated. Standardized response means were computed for the former and non-parametric tests were used to assess the statistical significance of the changes observed. Multiple linear regression was used to determine whether the SF-36 discriminates between patients with versus without complications and between laparoscopic and open surgery (known groups); correlations between the SF-36 and the 6-min walk test, a measure of functional walking capacity (convergent) was investigated with Spearman's rank correlation., Results: The SF-36 was sensitive to clinically important changes. Scores on six of eight domains and the physical component summary score deteriorated postoperatively (SRM 0.86 for the PCS, p < 0.01) and improved to baseline thereafter. Patients with complications had significantly lower scores on five SF-36 domains (with differences from -9 (-18, -1), p = 0.04 to -18 (-32, -2), p = 0.03), and scores on all subscales were lower than those in a healthy population (p < 0.01 to p = 0.04). The SF-36 did not differentiate between laparoscopic and open surgery. Physical functioning scores correlated with 6MWT distance at 1 and 2 months (Spearman's r = 0.31 and 0.36, p < 0.01)., Conclusions: The SF-36 is responsive to expected physiological changes in the postoperative period, demonstrates construct validity, and thus constitutes a valid measure of postoperative recovery after planned colorectal surgery. The SF-36 did not, however, discriminate between recovery after laparoscopic and open surgery.

Background: Surgical innovations are introduced to improve "recovery," a complex construct often operationalized by the use of patient-reported outcomes. The minimal clinically important difference (MCID) is the smallest change in an outcome sufficiently important to influence management and is crucial for designing and interpreting comparative effectiveness trials. Our objective was to generate MCID estimates for three postoperative recovery metrics., Methods: Prospectively collected data on two cohorts of 281 and 130 adult patients undergoing abdominal surgery were analyzed. At each of three visits, patients had completed the 36-Item Short Form Survey from the RAND Medical Outcomes Study (SF-36) and either Community Healthy Activities Model Program for Seniors (CHAMPS) or the 6-minute walk test (6MWT). The MCID was estimated with an anchor-based approach with random effects linear regression models. Patients' rating of their own health was used to predict SF-36 domain, CHAMPS, and 6MWT scores. Results are reported as MCID (95% confidence interval)., Results: On the SF-36 domains analyzed, MCIDs were consistently smaller for patients rating their health as "excellent" or "very good" (from 8 [6-9] to 15 [12-18]) compared with those for patients rating their health as "fair" or "poor" (from 15 [12-19] to 32 [28-36]). For CHAMPS, the MCID was 8 kcal/kg/week (7-9), and for the 6MWT, 14 meters (9-18)., Conclusion: Plausible MCIDs and ranges around each estimate are provided. These values should be considered when planning and interpreting abdominal surgery clinical trials where patient-reported outcomes are assessed., (Copyright © 2014 Mosby, Inc. All rights reserved.)

Clinically apparent injury to an intercostal nerve associated with paralysis of the upper rectus abdominis is a rare complication of video-assisted thoracoscopic surgery (VATS), with no reports available in the pediatric literature. We present the case of a 16-year-old boy who underwent VATS blebectomy and pleurodesis followed by tube thoracostomy for recurrent spontaneous pneumothorax. Definitive reexpansion of the lung was achieved with no immediate complications, but the child complained of abnormal sensation and motor dysfunction of the left upper rectus at his first follow-up visit 2 weeks after the operation. Isolated muscular paralysis persisted at 2-month follow-up, although there was no associated activity limitation. Video-assisted thoracoscopic surgery is now a common practice and recognized as less morbid than open thoracotomy, but there exists scant literature regarding intercostal nerve injury and associated rectus abdominis paralysis. This report reviews the relevant published literature, with emphasis on the mechanism of nerve injury and avoidance of this complication., (Copyright © 2011 Elsevier Inc. All rights reserved.)