Register transitions in an in vivo canine model as a function of intrinsic laryngeal muscle stimulation, fundamental frequency, and sound pressure level

Phonatory instabilities and involuntary register transitions can occur during singing. However, little is known regarding the mechanisms which govern such transitions. To investigate this phenomenon, we systematically varied laryngeal muscle activation and airflow in an in vivo canine larynx model during phonation. We calculated voice range profiles showing average nerve activations for all combinations of fundamental frequency (F0) and sound pressure level (SPL). Further, we determined closed-quotient (CQ) and minimum-posterior-area (MPA) based on high-speed video recordings. While different combinations of muscle activation favored different combinations of F0 and SPL, in the investigated larynx there was a consistent region of instability at about 400 Hz which essentially precluded phonation. An explanation for this region may be a larynx specific coupling between sound source and subglottal tract or an effect based purely on larynx morphology. Register transitions crossed this region, with different combinations of cricothyroid and thyroarytenoid muscle (TA) activation stabilizing higher or lower neighboring frequencies. Observed patterns in CQ and MPA dependent on TA activation reproduced patterns found in singers in previous work. Lack of control of TA stimulation may result in phonation instabilities, and enhanced control of TA stimulation may help to avoid involuntary register transitions, especially in the singing voice.

International Multi-Institutional Experience with Presentation and Management of Aortic Arch Laterality in Aberrant Subclavian Artery and Kommerell's Diverticulum

BACKGROUND

Aberrant subclavian artery (ASA) with or without Kommerell's diverticulum (KD) is a rare anatomic aortic arch anomaly that can cause dysphagia and/or life-threatening rupture. The objective of this study is to compare outcomes of ASA/KD repair in patients with a left versus right aortic arch.

METHODS

Using the Vascular Low Frequency Disease Consortium methodology, a retrospective review was performed of patients ≥18 years old with surgical treatment of ASA/KD from 2000 to 2020 at 20 institutions.

RESULTS

288 patients with ASA with or without KD were identified; 222 left-sided aortic arch (LAA), and 66 right-sided aortic arch (RAA). Mean age at repair was younger in LAA 54 vs. 58 years (P = 0.06). Patients in RAA were more likely to undergo repair due to symptoms (72.7% vs. 55.9%, P = 0.01), and more likely to present with dysphagia (57.6% vs. 39.1%, P < 0.01). The hybrid open/endovascular approach was the most common repair type in both groups. Rates of intraoperative complications, death within 30 days, return to the operating room, symptom relief and endoleaks were not significantly different. For patients with symptom status follow-up data, in LAA, 61.7% had complete relief, 34.0% had partial relief and 4.3% had no change. In RAA, 60.7% had complete relief, 34.4% had partial relief and 4.9% had no change.

CONCLUSIONS

In patients with ASA/KD, RAA patients were less common than LAA, presented more frequently with dysphagia, had symptoms as an indication for intervention, and underwent treatment at a younger age. Open, endovascular and hybrid repair approaches appear equally effective, regardless of arch laterality.

Lipoedema – myths and facts, Part 5

The four previous articles in this series addressed the myths and facts surrounding lipoedema. We have shown that there is no scientific evidence at all for the key statements made about lipoedema – which are published time and time again. The main result of this “misunderstanding” of lipoedema is a therapeutic concept that misses the mark. The patient’s real problems are overlooked.

The national and especially the international response to the series, which can be read in both German and English, has been immense and has exceeded all our expectations. The numerous reactions to our articles make it clear that in other countries, too, the fallacies regarding lipoedema have led to an increasing discrepancy between the experience of healthcare workers and the perspective of patients and self-help groups, based on misinformation mostly generated by the medical profession.

Parts 1 to 4 in this series of articles on the myths surrounding lipoedema have made it clear that we have to radically change the view of lipoedema that has been held for decades. Changing our perspective means getting away from the idea of “oedema in lipoedema” – and hence away from the dogma that decongestion is absolutely necessary – and towards the actual problems faced by our patients with lipoedema. Such a paradigm shift in a disease that has been described in the same way for decades cannot be left to individuals but must be put on a much broader footing. For this reason, the lead author of this series of articles invited renowned lipoedema experts from various European countries to discussions on the subject. Experts from seven different countries took part in the two European Lipoedema Forums, with the goal of establishing a consensus. The consensus reflects the experts’ shared view on the disease, having scrutinized the available literature, and having taken into account the many years of clinical practice with this particular patient group. Appropriate to the clinical complexity of lipoedema, participants from different specialties provided an interdisciplinary approach. Nearly all of the participants in the European Lipoedema Forum had already published work on lipoedema, had been involved in drawing up their national lipoedema guidelines, or were on the executive board of their respective specialty society.

In this fifth and final part of our series on lipoedema, we will summarise the relevant findings of this consensus, emphasising the treatment of lipoedema as we now recommend it. As the next step, the actual consensus paper “European Best Practice of Lipoedema” will be issued as an international publication.

Instead of looking at the treatment of oedema, the consensus paper will focus on treatment of the soft tissue pain, as well as the psychological vulnerability of patients with lipoedema. The relationship between pain perception and the patient’s mental health is recognised and dealt with specifically. The consensus also addresses the problem of self-acceptance, and this plays a prominent role in the new therapeutic concept. The treatment of obesity provides a further pillar of treatment. Obesity is recognised as being the most common comorbid condition by far and an important trigger of lipoedema. Bariatric surgery should therefore also be considered for patients with lipoedema who are morbidly obese. The expert group upgraded the importance of compression therapy and appropriate physical activity, as the demonstrated anti-inflammatory effects directly improve the patients’ symptoms. Patients will be provided with tools for personalised self-management in order to sustain sucessful treatment. Should conservative therapy fail to improve the symptoms, liposuction may be considered in strictly defined circumstances.

The change in the view of lipoedema that we describe here brings the patients’ actual symptoms to the forefront. This approach allows us to focus on more comprehensive treatment that is not only more effective but also more sustainable than focusing on the removal of non-existent oedema.

Analysis of focused ultrasound-induced blood-brain barrier permeability in a mouse model of Alzheimer's disease using two-photon microscopy

Transcranial focused ultrasound (FUS) can cause temporary, localized increases in blood-brain barrier (BBB) permeability for effective drug delivery to the brain. In pre-clinical models of Alzheimer's disease, FUS has successfully been used to deliver therapeutic agents and endogenous therapeutic molecules to the brain leading to plaque reduction and improved behavior. However, prior to moving to clinic, questions regarding how the compromised vasculature in Alzheimer's disease responds to FUS need to be addressed. Here, we used two-photon microscopy to study changes in FUS-mediated BBB permeability in transgenic (TgCRND8) mice and their non-transgenic littermates. A custom-built ultrasound transducer was attached to the skull, covering a cranial window. Methoxy-X04 was used to visualize amyloid deposits in vivo. Fluorescent intravascular dyes were used to identify leakage from the vasculature after the application of FUS. Dye leakage occurred in both transgenic and non-transgenic mice at similar acoustic pressures but exhibited different leakage kinetics. Calculation of the permeability constant demonstrated that the vasculature in the transgenic mice was much less permeable after FUS than the non-transgenic littermates. Further analysis demonstrated that the change in vessel diameter following FUS was lessened in amyloid coated vessels. These data suggest that changes in vessel diameter may be directly related to permeability and the presence of amyloid plaque may reduce the permeability of a vessel after FUS. This study indicates that the FUS parameters used for the delivery of therapeutic agents to the brain may need to be adjusted for application in Alzheimer's disease.

Clinical trials needed to evaluate compression therapy in breast cancer related lymphedema (BCRL). Proposals from an expert group

AIM

A mainstay of lymphedema management involves the use of compression therapy. Compression therapy application is variable at different levels of disease severity. Evidence is scant to direct clinicians in best practice regarding compression therapy use. Further, compression clinical trials are fragmented and poorly extrapolable to the greater population. An ideal construct for conducting clinical trials in regards to compression therapy will promote parallel global initiatives based on a standard research agenda. The purpose of this article is to review current evidence in practice regarding compression therapy for BCRL management and based on this evidence, offer an expert consensus recommendation for a research agenda and prescriptive trials. Recommendations herein focus solely on compression interventions.

METHODS

This document represents the proceedings of a session organized by the International Compression Club (ICC) in June 2009 in Ponzano (Veneto, Italy). The purpose of the meeting was to enable a group of experts to discuss the existing evidence for compression treatment in breast cancer related lymphedema (BCRL) concentrating on areas where randomized controlled trials (RCTs) are lacking.

RESULTS

The current body of research suggests efficacy of compression interventions in the treatment and management of lymphedema. However, studies to date have failed to adequately address various forms of compression therapy and their optimal application in BCRL. We offer recommendations for standardized compression research trials for prophylaxis of arm lymphedema and for the management of chronic BCRL. Suggestions are also made regarding; inclusion and exclusion criteria, measurement methodology and additional variables of interest for researchers to capture.

CONCLUSION

This document should inform future research trials in compression therapy and serve as a guide to clinical researchers, industry researchers and lymphologists regarding the strengths, weaknesses and shortcomings of the current literature. By providing this construct for research trials, the authors aim to support evidence-based therapy interventions, promote a cohesive, standardized and informative body of literature to enhance clinical outcomes, improve the quality of future research trials, inform industry innovation and guide policy related to BCRL.

Self-inflicted wounding. 2: Identification, assessment and management

The spectrum of conditions associated with self-inflicted wounding and their presenting features were outlined in the first part of this article (Moffatt, 1999). In part two, the assessment and management of self-wounding patients is discussed. Manipulative behaviour can be a barrier to treatment, as well as a disruptive force within the healthcare team. Awareness of its effects are essential to the successful development of a therapeutic relationship. However, the current possibilities for effective treatment of self-wounding are limited, and there is an urgent need for more research into both its causes and the various management options available.

Issues in the assessment of leg ulceration

A discussion on the type of assessments frequently performed by nurses prior to the application of compression therapy

Collaboration in improving care for patients: how can we find out what we haven't been able to figure out yet?

BACKGROUND

Questions, or what the physicist and learning expert Reginald Revans called "insightful inquiry," are essential to learning. People remember and use what they discover themselves. But many habits and activities in front-line workplaces of patient care have not promoted frank discussions of what we haven't figured out yet about improving care for patients. Leaders are no longer defined by having the right answers. Leaders will be the ones who have the right questions and who promote local learning with the right questions. SUGGESTIONS FOR GETTING STARTED IN COLLABORATION. The authors suggest questions to ask to get collaborative inquiry going and cite examples they have collected. The questions and examples are grouped in seven thematic categories: Listening to and appreciating others; Thinking across disciplines and roles; Sharing ideas and linking those shared ideas to execution and deployment of change; Appreciating systems and interdependencies; Using research (including local research) to inform our practices; Using methods, skills, and techniques as facilitators of collaboration; and Working across organizational boundaries.

The principles of assessment prior to compression therapy

This article focuses on the type of assessment frequently performed by nurses although the patient with a leg ulcer requires the skills of the whole health-care team. A priority of assessment is to determine the underlying aetiology of the leg ulcer, but the assessment process is often complicated by the multifactorial health needs of this vulnerable group of older patients.

Know how. Four-layer bandaging

The concept of four-layer bandaging originated in the 1980s at Charing Cross Hospital, London. Since then, a second four-layer system in kit form has been developed. The results of a recent trial involving 232 patients showed that the two systems have equivalent healing. Today, four-layer bandaging is a popular compression regime, and is used in a wide range of health-care settings. Ease of application of the bandages, and reproducibility, mean that it is not only a therapeutic technique but a very safe one.

Compression Bandaging: Selection and Evidence

The use of effective compression has been shown to heal venous leg ulcers¹ and prevent their recurrence² whereas inappropriate compression may lead to skin damage and, in extreme cases, amputation³. It is therefore important to differentiate between appropriate and inappropriate compression. Compression is palliative rather than curative, and hence needs to be worn for as long as the patient's venous disease is present: in most cases this means a lifetime. Compression should be applied only after a clinician with appropriate training has excluded the possibility of arterial disease.

Graduated compression hosiery for venous ulceration

An update on compression hosiery for the management of venous leg ulcers

Ankle pulses are not sufficient to detect impaired arterial circulation in patients with leg ulcers

Much debate has taken place on the use of Doppler ultrasound in the community setting. A sequential study of patients attending a community ulcer clinic was undertaken to identify community nurses' ability to detect arterial disease by palpation of pedal pulses and to compare these figures with the recording of a resting pressure index. A total of 462 patients (553 limbs) were studied; 167 (31%) had no detectable pulses at the ankle. Of the 93 limbs with a reduced resting pressure index (< 0.9), 37% had detectable pulses. Of the 440 with a normal resting index (> or = 0.9), 25% had no detectable ankle pulses. A number of risk factors were identified. Palpation of pedal pulses alone by community nurses is a poor prediction of arterial disease and should be accompanied by the recording of a resting pressure index.

Letters

THE DIFFICULTY OF SECURING RESEARCH FUNDING POSTNATAL CARE THE DANGERS OF WATER-FILLED GLOVES.

Community leg ulcer clinics: cost-effectiveness

This study investigates the cost-effectiveness and efficacy of a new service provided by community leg ulcer clinics, and compares it with treatment in existing hospital-based venous ulcer care clinics. Data were provided prospectively from district nurses and retrospectively from patients. Success in treatment was assessed as a percentage of ulcers completely healed after 12 weeks of treatment, analysed by the up-table method. Treatment success of 22% at 12 weeks using existing methods compared with 80% in community clinics. Costs were estimated to be 433,600 pounds and 169,000 pounds respectively. These findings indicate that community leg ulcer clinics were more effective and less expensive than the previous system of care.

Oxerutins in the prevention of recurrence in chronic venous ulceration: randomized controlled trial

The value of oxerutins [O-(beta-hydroxyethyl)-rutosides] in the prevention of venous ulcer recurrence was investigated in a double-blind randomized controlled trial of 138 patients with recently healed chronic venous ulcers. Oxerutins in the form of Paroven 500 mg twice daily or identical placebo were given, and all patients were provided with elastic compression stockings. At follow-up 3 months later, patients were assessed for re-ulceration and for tablet and stocking compliance. Oxerutins (n = 69) and placebo (n = 69) groups were well matched for age, sex, duration of previous ulceration and deep vein thrombosis. Cumulative re-ulceration by life-table analysis at 12 and 18 months was 22 and 32 per cent respectively for placebo, and 23 and 34 per cent respectively for oxerutins (P = 0.93). Recurrence was more frequent in patients who complied with both tablets and stockings, suggesting that compliance was influenced by continued symptoms (P = 0.006). This trial failed to demonstrate that oxerutins influenced ulcer recurrence.

Effect of premedication on arterial blood gases prior to cardiac surgery

The effect of premedication on arterial blood gas tensions was studied in thirty adult surgical patients with valvular disease. They were divided into three groups, each group having a different premedication regimen. Blood gas tensions were compared in these patients when awake on the night before surgery, asleep, after premedication and just prior to induction of anaesthesia. Samples were taken while the patient breathed air and each patient acted as his/her own control. The patients were randomised into one of three premedication regimens: 1. intramuscular lorazepam, 2. intramuscular morphine and hyoscine (scopolamine) and 3. oral lorazepam plus intramuscular morphine and hyoscine. There was a statistically significant though not clinically significant rise in PaCO2 and fall in pH following premedication with lorazepam, morphine and hyoscine. There was also a significant fall in PaO2 associated with morphine and hyoscine premedication which was greater than that which occurred with unsedated sleep. Patients who are to undergo cardiac valvular surgery should receive supplementary oxygen following premedication and during transfer to the operating room.