Deventilation Syndrome in Patients with Chronic Obstructive Pulmonary Disease Using Nocturnal Noninvasive Ventilation: What Are the Underlying Mechanisms?

INTRODUCTION: Patients with chronic obstructive pulmonary disease (COPD) commonly experience severe dyspnea after discontinuation of nocturnal noninvasive ventilation (NIV), known as deventilation syndrome (DVS), which negatively affects quality of life. Despite various hypotheses, the precise mechanisms of DVS remain unknown. METHODS: An observational pilot study was performed monitoring 16 stable COPD patients before, during, and after an afternoon nap on NIV. Seven patients experienced DVS (Borg Dyspnea Scale ≥5), while nine served as controls (Borg Dyspnea Scale ≤2). Hyperinflation was evaluated through inspiratory capacity (IC) measurements and end-expiratory lung impedance (EELI) via electrical impedance tomography. Respiratory muscle activity was assessed by diaphragmatic surface electromyography (sEMG). RESULTS: Post-NIV dyspnea scores were significantly higher in the DVS group (5 [3-7] vs. 0 [0-1.5], p < 0.001). IC values were lower in the DVS group compared to controls, both pre-NIV (54 [41-63] vs. 88 [72-94] %pred., p = 0.006) and post-NIV (45 [40-59] vs. 76 [65-82] %pred., p = 0.005), while no intergroup difference was seen in IC changes pre- and post-NIV. EELI values after NIV indicated a tendency towards lower values in controls and higher values in DVS patients. sEMG amplitudes were higher in the DVS group within the first 5-min post-NIV (221 [112-294] vs. 100 [58-177]% of baseline, p = 0.030). CONCLUSION: This study suggests that it is unlikely that DVS originates from the inability to create diaphragmatic muscle activity after NIV. Instead, NIV-induced hyperinflation in individuals with static hyperinflation may play a significant role. Addressing hyperinflation holds promise in preventing DVS symptoms in COPD patients.

Noninvasive Assessment of Neuromechanical Coupling and Mechanical Efficiency of Parasternal Intercostal Muscle during Inspiratory Threshold Loading.

This study aims to investigate noninvasive indices of neuromechanical coupling (NMC) and mechanical efficiency (MEff) of parasternal intercostal muscles. Gold standard assessment of diaphragm NMC requires using invasive techniques, limiting the utility of this procedure. Noninvasive NMC indices of parasternal intercostal muscles can be calculated using surface mechanomyography (sMMGpara) and electromyography (sEMGpara). However, the use of sMMGpara as an inspiratory muscle mechanical output measure, and the relationships between sMMGpara, sEMGpara, and simultaneous invasive and noninvasive pressure measurements have not previously been evaluated. sEMGpara, sMMGpara, and both invasive and noninvasive measurements of pressures were recorded in twelve healthy subjects during an inspiratory loading protocol. The ratios of sMMGpara to sEMGpara, which provided muscle-specific noninvasive NMC indices of parasternal intercostal muscles, showed nonsignificant changes with increasing load, since the relationships between sMMGpara and sEMGpara were linear (R2 = 0.85 (0.75-0.9)). The ratios of mouth pressure (Pmo) to sEMGpara and sMMGpara were also proposed as noninvasive indices of parasternal intercostal muscle NMC and MEff, respectively. These indices, similar to the analogous indices calculated using invasive transdiaphragmatic and esophageal pressures, showed nonsignificant changes during threshold loading, since the relationships between Pmo and both sEMGpara (R2 = 0.84 (0.77-0.93)) and sMMGpara (R2 = 0.89 (0.85-0.91)) were linear. The proposed noninvasive NMC and MEff indices of parasternal intercostal muscles may be of potential clinical value, particularly for the regular assessment of patients with disordered respiratory mechanics using noninvasive wearable and wireless devices.

Electromyography-Based Respiratory Onset Detection in COPD Patients on Non-Invasive Mechanical Ventilation.

To optimize long-term nocturnal non-invasive ventilation in patients with chronic obstructive pulmonary disease, surface diaphragm electromyography (EMGdi) might be helpful to detect patient-ventilator asynchrony. However, visual analysis is labor-intensive and EMGdi is heavily corrupted by electrocardiographic (ECG) activity. Therefore, we developed an automatic method to detect inspiratory onset from EMGdi envelope using fixed sample entropy (fSE) and a dynamic threshold based on kernel density estimation (KDE). Moreover, we combined fSE with adaptive filtering techniques to reduce ECG interference and improve onset detection. The performance of EMGdi envelopes extracted by applying fSE and fSE with adaptive filtering was compared to the root mean square (RMS)-based envelope provided by the EMG acquisition device. Automatic onset detection accuracy, using these three envelopes, was evaluated through the root mean square error (RMSE) between the automatic and mean visual onsets (made by two observers). The fSE-based method provided lower RMSE, which was reduced from 298 ms to 264 ms when combined with adaptive filtering, compared to 301 ms provided by the RMS-based method. The RMSE was negatively correlated with the proposed EMGdi quality indices. Following further validation, fSE with KDE, combined with adaptive filtering when dealing with low quality EMGdi, indicates promise for detecting the neural onset of respiratory drive.

The Practice of Compounding, Associated Compounding Regulations, and the Impact on Dermatologists.

Medication compounding gained national attention in the fall of 2012 after contaminated compounded medications produced in the New England Compounding Center infected 800 people with fungal meningitis and led to several fatalities. This prompted Congress to pass regulations on compounding through the Drug Quality and Security Act (DQSA) in 2013. The act increased oversight of patient-specific drug compounding taking place in compounding pharmacies, created 503(b) outsourcing facilities to obtain compounded drugs, and added regulations for obtaining compounded drugs from traditional 503(a) pharmacies. These regulations also had a broader overall impact by triggering federal and state-specific policies, which have ultimately limited a physician's ability to perform low-risk, in-office compounding. This article provides an overview of the different types of compounding restrictions, reviews the current federal and state regulations and/or guidelines, discusses how newly proposed policies may affect the practice of dermatology, and presents an algorithm on how the practicing dermatologist should approach compounding. J Drugs Dermatol. 2018;17(7 Suppl):s17-22.

Cultural competence for the 21st century dermatologist practicing in the United States.

Significant health disparities exist among under-represented minorities in the Unites States, which can partially be accounted for by the quality of patient-physician interaction. A distinguishing factor of this interaction is the ability of the provider to demonstrate cultural competence, or address the social, cultural, and community influences on healthcare behaviors and incorporate these elements into patient care. However, this practice has yet to be universally implemented in our healthcare system. These factors become even more important as the racial, ethnic and cultural distribution of the United States population changes. Multiple studies have suggested that cultural competence of the health care provider and staff leads to improved patient adherence, satisfaction, and ultimately, health outcome. Cultural competence in the workplace also leads to efficient and cost-effective healthcare and better community integration into healthcare systems. The purpose of this review is to help dermatologists understand the benefits of culturally competent care for their patients and themselves and identify methods and resources to achieve this goal.

ASDS Cosmetic Dermatologic Surgery Fellowship Milestones.

BACKGROUND: The American Council of Graduate Medical Education, which oversees much of postgraduate medical education in the United States, has championed the concept of "milestones," standard levels of achievement keyed to particular time points, to assess trainee performance during residency. OBJECTIVE: To develop a milestones document for the American Society for Dermatologic Surgery (ASDS) Cosmetic Dermatologic Surgery (CDS) fellowship program. METHODS: An ad hoc milestone drafting committee was convened that included members of the ASDS Accreditation Work Group and program directors of ASDS-approved Cosmetic Dermatologic Surgery (CDC) fellowship training programs. Draft milestones were circulated through email in multiple rounds until consensus was achieved. RESULTS: Thirteen milestones were developed in the 6 Accreditation Council for Graduate Medical Education (ACGME) competency areas, with 8 of these being patient-care milestones. Additional instructions for milestone administration more specific to the CDS fellowship than general ACGME instructions were also approved. Implementation of semiannual milestones was scheduled for the fellowship class entering in July 2018. CONCLUSION: Milestones are now available for CDS fellowship directors to implement in combination with other tools for fellow evaluation.

Influence of the Fuzzy Function on the Estimation of the Fuzzy Sample Entropy with Fixed Tolerance Values for the Evaluation of Surface EMG Muscle Activity.

Fixed sample entropy (fSampEn) is a technique that has demonstrated superior performance to other amplitude estimators for assessing respiratory muscle electromyographic activity. This technique is based on the calculation of sample entropy (SampEn) using fixed tolerance thresholds. Fuzzy entropy (FuzzyEn) introduces an improvement to the SampEn algorithm based on the use of a fuzzy measure to evaluate the similarity between vectors. However, several fuzzy functions have been used to calculate the FuzzyEn, and not all of them allow an effective comparison with the SampEn calculation parameters. In the present work, an analysis of the different fuzzy functions previously used has been carried out and a new sigmoid fuzzy function for the calculation of FuzzyEn with fixed tolerance thresholds (fFuzzyEn) has been proposed. The results show that the proposed fuzzy function outperformed both fSampEn and previously proposed FuzzyEn-based algorithms. These results suggest that fFuzzyEn could improve the assessment of muscle activity providing potentially useful diagnostic information.Clinical Relevance- This sets out the appropriate use of the fuzzy function for the estimation of the fuzzy sample entropy with fixed tolerance thresholds (fFuzzyEn). The use of fFuzzyEn could improve methods for detecting the onset and offset of respiratory electromyographic (EMG) signals, as well as the assessment of EMG activation level.

Reducing Legal Risks and Social Media Issues for Cosmetic Surgery.

It is important to understand the legal malpractice risks and strategies to reduce them in facial plastic surgery. Cosmetic procedures and the use of social media introduces additional risks that should be considered by practicing facial plastic surgeons. Strategies should be implemented to protect yourself and your patients, which include an emphasis on informed consent as it relates to using photos on social media platforms, removing photos from social media, and addressing online reviews. By understanding the risks and using adequate strategies, facial plastic surgeons can minimize the risk of litigation when performing cosmetic procedures.

Systemic antioxidants and skin health.

Most dermatologists agree that antioxidants help fight free radical damage and can help maintain healthy skin. They do so by affecting intracellular signaling pathways involved in skin damage and protecting against photodamage, as well as preventing wrinkles and inflammation. In today's modern world of the rising nutraceutical industry, many people, in addition to applying topical skin care products, turn to supplementation of the nutrients missing in their diets by taking multivitamins or isolated, man-made nutraceuticals, in what is known as the Inside-Out approach to skin care. However, ingestion of large quantities of isolated, fragmented nutrients can be harmful and is a poor representation of the kind of nutrition that can be obtained from whole food sources. In this comprehensive review, it was found that few studies on oral antioxidants benefiting the skin have been done using whole foods, and that the vast majority of current research is focused on the study of compounds in isolation. However, the public stands to benefit greatly if more research were to be devoted toward the impact that physiologic doses of antioxidants (obtained from fruits, vegetables, and whole grains) can have on skin health, and on health in general.

A Retrospective Review of Histopathologic Features Associated with Increased Risk of Recurrence of Non-melanoma Skin Cancer After Mohs Micrographic Surgery.

Objective: Mohs micrographic surgery (MMS) is the gold standard treatment for non-melanoma skin cancer (NMSC). However, NMSC recurrence may occur in a small proportion of patients. The aim of this study was to identify histopathologic features seen on the final stage of previous MMS, which may increase the risk of NMSC recurrence. Methods: This was a single-institution retrospective study of 39 recurrent basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs), which were treated with MMS. Slides from the final stage of previous MMS were reviewed by two board-certified dermatopathologists for the following histopathologic features: perineural inflammation, dense inflammation, mucin, ruptured follicle, actinic keratosis, and missing tissue. Results: Twenty recurrent BCCs and 19 recurrent SCCs were included. Histopathologic features identified on the final stage of previous MMS included missing tissue from the epidermis, dermis, and/or subcutis (69%), actinic keratosis (51%), perineural inflammation (10%), and dense inflammation (8%). Ruptured follicle was present in one BCC case, and mucin was not identified in any cases. Limitations: Limitations include retrospective study design, small number of recurrent cases, single institution, and lack of a control group consisting of NMSC cases which did not recur after MMS. Conclusion: Mohs surgeons should carefully evaluate NMSC frozen sections for the presence of missing tissue, actinic keratosis, perineural inflammation, and dense inflammation as these histopathologic features may be associated with tumor recurrence. It is of paramount importance to acquire high quality frozen sections for thorough margin evaluation.

Noninvasive Assessment of Neuromechanical and Neuroventilatory Coupling in COPD.

This study explored the use of parasternal second intercostal space and lower intercostal space surface electromyogram (sEMG) and surface mechanomyogram (sMMG) recordings (sEMGpara and sMMGpara, and sEMGlic and sMMGlic, respectively) to assess neural respiratory drive (NRD), neuromechanical (NMC) and neuroventilatory (NVC) coupling, and mechanical efficiency (MEff) noninvasively in healthy subjects and chronic obstructive pulmonary disease (COPD) patients. sEMGpara, sMMGpara, sEMGlic, sMMGlic, mouth pressure (Pmo), and volume (Vi) were measured at rest, and during an inspiratory loading protocol, in 16 COPD patients (8 moderate and 8 severe) and 9 healthy subjects. Myographic signals were analyzed using fixed sample entropy and normalized to their largest values (fSEsEMGpara%max, fSEsMMGpara%max, fSEsEMGlic%max, and fSEsMMGlic%max). fSEsMMGpara%max, fSEsEMGpara%max, and fSEsEMGlic%max were significantly higher in COPD than in healthy participants at rest. Parasternal intercostal muscle NMC was significantly higher in healthy than in COPD participants at rest, but not during threshold loading. Pmo-derived NMC and MEff ratios were lower in severe patients than in mild patients or healthy subjects during threshold loading, but differences were not consistently significant. During resting breathing and threshold loading, Vi-derived NVC and MEff ratios were significantly lower in severe patients than in mild patients or healthy subjects. sMMG is a potential noninvasive alternative to sEMG for assessing NRD in COPD. The ratios of Pmo and Vi to sMMG and sEMG measurements provide wholly noninvasive NMC, NVC, and MEff indices that are sensitive to impaired respiratory mechanics in COPD and are therefore of potential value to assess disease severity in clinical practice.

Assessment of the Non-linear Response of the fSampEn on Simulated EMG Signals.

Fixed sample entropy (fSampEn) is a promising technique for the analysis of respiratory electromyographic (EMG) signals. Its use has shown outperformance of amplitude-based estimators such as the root mean square (RMS) in the evaluation of respiratory EMG signals with cardiac noise and a high correlation with respiratory signals, allowing changes in respiratory muscle activity to be tracked. However, the relationship between the fSampEn response to a given muscle activation has not been investigated. The aim of this study was to analyze the nature of the fSampEn measurements that are produced as the EMG activity increases linearly. Simulated EMG signals were generated and increased linearly. The effect of the parameters r and the size of the moving window N of the fSampEn were evaluated and compared with those obtained using the RMS. The RMS showed a linear trend throughout the study. A non-linear, sigmoidal-like behavior was found when analyzing the EMG signals using the fSampEn. The lower the values of r, the higher the non-linearity observed in the fSampEn results. Greater moving windows reduced the variation produced by too small values of r.Clinical Relevance- Understanding the inherent non-linear relationship produced when using the fSampEn in EMG recordings will contribute to the improvement of the respiratory muscle activation assessment at different levels of respiratory effort in patients with respiratory conditions, particularly during the inspiratory phase.

Shear wave dispersion as a potential biomarker for cervical remodeling during pregnancy: evidence from a non-human primate model.

Shear wave dispersion (variation of phase velocity with frequency) occurs in tissues with layered and anisotropic microstructure and viscous components, such as the uterine cervix. This phenomenon, mostly overlooked in previous applications of cervical Shear Wave Elasticity Imaging (SWEI) for preterm birth risk assessment, is expected to change drastically during pregnancy due to cervical remodeling. Here we demonstrate the potential of SWEI-based descriptors of dispersion as potential biomarkers for cervical remodeling during pregnancy. First, we performed a simulation-based pre-selection of two SWEI-based dispersion descriptors: the ratio R of group velocities computed with particle-velocity and particle-displacement, and the slope S of the phase velocity vs. frequency. The pre-selection consisted of comparing the contrast-to-noise ratio (CNR) of dispersion descriptors in materials with different degrees of dispersion with respect to a low-dispersive medium. Shear waves induced in these media by SWEI were simulated with a finite-element model of Zener viscoelastic solids. The pre-selection also considered two denoising strategies to improve CNR: a low-pass filter with automatic frequency cutoff determination, and singular value decomposition of shear wave displacements. After pre-selection, the descriptor-denoising combination that produced the largest CNR was applied to SWEI cervix data from 18 pregnant Rhesus macaques acquired at weeks 10 (mid-pregnancy stage) and 23 (late pregnancy stage) of the 24.5-week full pregnancy. A maximum likelihood linear mixed-effects model (LME) was used to evaluate the dependence of the dispersion descriptor on pregnancy stage, maternal age, parity and other experimental factors. The pre-selection study showed that descriptor S combined with singular value decomposition produced a CNR 11.6 times larger than the other descriptor and denoising strategy combinations. In the Non-Human Primates (NHP) study, the LME model showed that descriptor S significantly decreased from mid to late pregnancy (-0.37 ± 0.07 m/s-kHz per week, p <0.00001) with respect to the base value of 15.5 ± 1.9 m/s-kHz. This change was more significant than changes in other SWEI features such as the group velocity previously reported. Also, S varied significantly between the anterior and posterior portions of the cervix (p =0.02) and with maternal age (p =0.008). Given the potential of shear wave dispersion to track cervical remodeling, we will extend its application to ongoing longitudinal human studies.

Evaluation of Respiratory Muscle Activity by Means of Concentric Ring Electrodes.

Surface electromyography (sEMG) can be used for the evaluation of respiratory muscle activity. Recording sEMG involves the use of surface electrodes in a bipolar configuration. However, electrocardiographic (ECG) interference and electrode orientation represent considerable drawbacks to bipolar acquisition. As an alternative, concentric ring electrodes (CREs) can be used for sEMG acquisition and offer great potential for the evaluation of respiratory muscle activity due to their enhanced spatial resolution and simple placement protocol, which does not depend on muscle fiber orientation. The aim of this work was to analyze the performance of CREs during respiratory sEMG acquisitions. Respiratory muscle sEMG was applied to the diaphragm and sternocleidomastoid muscles using a bipolar and a CRE configuration. Thirty-two subjects underwent four inspiratory load spontaneous breathing tests which was repeated after interchanging the electrode positions. We calculated parameters such as (1) spectral power and (2) median frequency during inspiration, and power ratios of inspiratory sEMG without ECG in relation to (3) basal sEMG without ECG (Rins/noise), (4) basal sEMG with ECG (Rins/cardio) and (5) expiratory sEMG without ECG (Rins/exp). Spectral power, Rins/noise and Rins/cardio increased with the inspiratory load. Significantly higher values (p < 0.05) of Rins/cardio and significantly higher median frequencies were obtained for CREs. Rins/noise and Rins/exp were higher for the bipolar configuration only in diaphragm sEMG recordings, whereas no significant differences were found in the sternocleidomastoid recordings. Our results suggest that the evaluation of respiratory muscle activity by means of sEMG can benefit from the remarkably reduced influence of cardiac activity, the enhanced detection of the shift in frequency content and the axial isotropy of CREs which facilitates its placement.

Endophytic Fungi: Biological Control and Induced Resistance to Phytopathogens and Abiotic Stresses.

Plant diseases cause losses of approximately 16% globally. Thus, management measures must be implemented to mitigate losses and guarantee food production. In addition to traditional management measures, induced resistance and biological control have gained ground in agriculture due to their enormous potential. Endophytic fungi internally colonize plant tissues and have the potential to act as control agents, such as biological agents or elicitors in the process of induced resistance and in attenuating abiotic stresses. In this review, we list the mode of action of this group of microorganisms which can act in controlling plant diseases and describe several examples in which endophytes were able to reduce the damage caused by pathogens and adverse conditions. This is due to their arsenal of molecules generated during the interaction by which they form a kind of biological shield in the plant. Furthermore, considering that endophytic fungi can be an important tool in managing for biotic and abiotic stresses due to the large amount of biologically active substances produced, bioprospecting this class of microorganisms is tending to increase and generate valuable products for agriculture.