The HEV Ventilator: at the interface between particle physics and biomedical engineering.

A high-quality, low-cost ventilator, dubbed HEV, has been developed by the particle physics community working together with biomedical engineers and physicians around the world. The HEV design is suitable for use both in and out of hospital intensive care units, provides a variety of modes and is capable of supporting spontaneous breathing and supplying oxygen-enriched air. An external air supply can be combined with the unit for use in situations where compressed air is not readily available. HEV supports remote training and post market surveillance via a Web interface and data logging to complement standard touch screen operation, making it suitable for a wide range of geographical deployment. The HEV design places emphasis on the ventilation performance, especially the quality and accuracy of the pressure curves, reactivity of the trigger, measurement of delivered volume and control of oxygen mixing, delivering a global performance which will be applicable to ventilator needs beyond the COVID-19 pandemic. This article describes the conceptual design and presents the prototype units together with a performance evaluation.

Diaphragm dysfunction and peripheral muscle wasting in septic shock patients: Exploring their relationship over time using ultrasound technology (the MUSiShock protocol).

BACKGROUND: Intensive Care Unit (ICU) patients are known to lose muscle mass and function during ICU stay. Ultrasonography (US) application for the assessment of the skeletal muscle is a promising tool and might help detecting muscle changes and thus several dysfunctions during early stages of ICU stay. MUSiShock is a research project aiming to investigate structure and function of diaphragm and peripheral muscles using ultrasound techniques in septic shock patients, and to assess their relevance in several clinical outcomes such as the weaning process. METHODS AND DESIGN: This is a research protocol from an observational prospective cohort study. We plan to assess eighty-four septic shock patients during their ICU stay at the following time-points: at 24 hours of ICU admission, then daily until day 5, then weekly, at extubation time and at ICU discharge. At each time-point, we will measure the quadriceps rectus femoris and diaphragm muscles, using innovative US muscle markers such as Shear-Wave Elastography (SWE). In parallel, the Medical Research Council (MRC) sum score for muscle testing and the Airway occlusion pressure (P0.1) will also be collected. We will describe the association between SWE assessment and other US markers for each muscle. The association between the changes in both diaphragm and rectus femoris US markers over time will be explored as well; finally, the analysis of a combined model of one diaphragm US marker and one limb muscle US marker to predict weaning success/failure will be tested. DISCUSSION: By using muscle ultrasound at both diaphragm and limb levels, MUSiShock aims to improve knowledge in the early detection of muscle dysfunction and weakness, and their relationship with muscle strength and MV weaning, in critically ill patients. A better anticipation of these short-term muscle structure and function outcomes may allow clinicians to rapidly implement measures to counteract it. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04550143. Registered on 16 September 2020.

[Cardiac rehabilitation : a multidisciplinary program of cardiovascular prevention of essential importance]. / La réadaptation cardiaque : un programme multidisciplinaire de prévention cardiovasculaire indispensable.

Cardiovascular diseases and especially coronary artery disease remain the first cause of mortality in Switzerland. Comprehensive cardiac rehabilitation is a validated multidisciplinary intervention, which represents the most appropriate strategy of implementing an effective secondary cardiovascular prevention to reduce the impact of cardiovascular diseases. However, less than half of patients after a myocardial infarction and a tiny proportion of patients with heart failure participate in a rehabilitation program in our country. This article summarizes the current state of cardiac rehabilitation in Switzerland, as well as future developments of cardiac tele-rehabilitation that have accelerated due to the COVID-19 pandemic.

Les maladies cardiovasculaires, et en premier lieu la maladie coronarienne, restent la première cause de mortalité en Suisse. La réadaptation cardiaque intégrée est une intervention multidisciplinaire validée représentant le meilleur moyen de mettre en place une stratégie de prévention cardiovasculaire secondaire efficace pour réduire l'impact des maladies cardiovasculaires. Pourtant, moins de la moitié des patients victimes d'un infarctus du myocarde et une proportion infime de patients atteints d'une insuffisance cardiaque participent à un programme de réadaptation cardiaque dans notre pays. Cet article résume l'état actuel de la réadaptation cardiaque en Suisse ainsi que les futurs développements de téléréadaptation cardiaque qui se sont accélérés dans le contexte de la pandémie de Covid-19.

Can proportional ventilation modes facilitate exercise in critically ill patients? A physiological cross-over study : Pressure support versus proportional ventilation during lower limb exercise in ventilated critically ill patients.

BACKGROUND: Early exercise of critically ill patients may have beneficial effects on muscle strength, mass and systemic inflammation. During pressure support ventilation (PSV), a mismatch between demand and assist could increase work of breathing and limit exercise. A better exercise tolerance is possible with a proportional mode of ventilation (Proportional Assist Ventilation, PAV+ and Neurally Adjusted Ventilatory Assist, NAVA). We examined whether, in critically ill patients, PSV and proportional ventilation have different effects on respiratory muscles unloading and work efficiency during exercise. METHODS: Prospective pilot randomized cross-over study performed in a medico-surgical ICU. Patients requiring mechanical ventilation >48 h were enrolled. At initiation, the patients underwent an incremental workload test on a cycloergometer to determine the maximum level capacity. The next day, 2 15-min exercise, at 60% of the maximum capacity, were performed while patients were randomly ventilated with PSV and PAV+ or NAVA. The change in oxygen consumption (ΔVO2, indirect calorimetry) and the work efficiency (ratio of ΔVO2 per mean power) were computed. RESULTS: Ten patients were examined, 6 ventilated with PSV/PAV+ and 4 with PSV/NAVA. Despite the same mean inspiratory pressure at baseline between the modes, baseline VO2 (median, IQR) was higher during proportional ventilation (301 ml/min, 270-342) compared to PSV (249 ml/min, 206-353). Exercise with PSV was associated with a significant increase in VO2 (ΔVO2, median, IQR) (77.6 ml/min, 59.9-96.5), while VO2 did not significantly change during exercise with proportional modes (46.3 ml/min, 5.7-63.7, p < 0.05). As a result, exercise with proportional modes was associated with a better work efficiency than with PSV. The ventilator modes did not affect patient's dyspnea, limb fatigue, distance, hemodynamics and breathing pattern. CONCLUSIONS: Proportional ventilation during exercise results in higher work efficiency and less increase in VO2 compared to ventilation with PSV. These preliminary findings suggest that proportional ventilation could enhance the training effect and facilitate rehabilitation.

[Early exercise training after exacerbation in patients with chronic respiratory failure]. / Réentraînement a l'effort précoce chez l'insuffisant respiratoire après décompensation aiguë.

Patients who suffered from an exacerbation of a chronic respiratory disorder are often very limited in terms of their exercise capacity because of severe dyspnea and amyotrophy of peripheral muscles. Early implementation of pulmonary rehabilitation may help these patients to avoid the complications of a prolonged bedridden period, and increase more rapidly their mobility. Early rehabilitation has become more frequent, but requires special skills from the care givers (chest therapists). Techniques which enhance muscular performance and motility of patients who are recovering from an exacerbation such as electromoystimulation or mobilisation under non-invasive ventilation, give encouraging results; their impact on length of hospital stay requires further studies.