Pressure and Volume Control of a Non-invasive Mechanical Ventilator: a PI and LQR Approach

AbstractWearable sensors to continuously measure blood pressure (BP) and derived cardiovascular variables have the potential to revolutionize patient monitoring. Current wearable methods analyzing time components (e.g., pulse transit time) still lack clinical accuracy, whereas existing technologies for direct BP measurement are too bulky. Here we present a new art of continuous non-invasive arterial blood pressure monitoring (CNAP2GO). It directly measures BP by using a new “volume control technique” and could be used for small wearable sensors integrated in a finger ring. As a software prototype, CNAP2GO showed excellent BP measurement performance in comparison with invasive BP in 46 patients having surgery. The resulting pulsatile BP signal carries information to derive cardiac output and other hemodynamic variables. We show that CNAP2GO can be miniaturized for wearable approaches. CNAP2GO potentially constitutes the breakthrough for wearable sensors for blood pressure and flow monitoring in both ambulatory and in-hospital clinical settings.

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Toilet bronchoscopy in the ICU

10.1093/med/9780199600830.003.0122 ◽

2016 ◽

Author(s):

Gianluigi Li Bassi ◽

Carles Agusti

Keyword(s):

Critically Ill ◽

Critically Ill Patients ◽

Control Ventilation ◽

Volume Control ◽

Non Invasive ◽

Non Invasive Ventilation ◽

Volume Control Ventilation ◽

Baseline Values ◽

Topical Anaesthetics ◽

Pressure Controlled

Critically-ill patients retain respiratory secretions. Toilet bronchoscopy is applied to aspirate retained secretions and revert lung atelectasis. Toilet bronchoscopy is particularly indicated when retained secretions are visible during the procedureand air-bronchograms are not present at the chest radiograph. Yet, toilet bronchoscopy should only be applied when other less invasive methods of secretion removal have failed. Ventilatory settings during the intervention, the inspiratory fraction of oxygen should be increased to 100%. In volume control ventilation, the pressure limit alarm needs to be increased; during pressure-controlled ventilation, the set inspiratory pressure should be increased. The external PEEP should be decreased to at least 50% of the baseline values, to prevent barotrauma. The use of sedatives, analgesics, and topical anaesthetics is mandatory to achieve favourable procedural condition. Toilet bronchoscopy is also feasible and safe in critically-ill patients undergoing non-invasive ventilation.

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VEMERS UC: A Clinically Validated Emergency Mechanical Ventilator for Covid-19 and Post Pandemic Use in Low Resource Communities

Journal of Medical Devices ◽

10.1115/1.4051246 ◽

2021 ◽

Author(s):

Luciano E. Chiang ◽

Felipe Castro Niklitschek

Keyword(s):

Low Cost ◽

Rapid Development ◽

Control Mode ◽

Volume Control ◽

The Novel ◽

Mechanical Ventilator ◽

Mechanical Ventilators ◽

Industrial Markets ◽

Safety Features ◽

Technical Features

Abstract In this article we present a clinically validated invasive emergency mechanical ventilator developed in Chile called VEMERS UC. It has been clinically tested and validated in intubated Covid19 patients. Once the pandemic hit Chilean soil in March 2020, it was clear that the number of mechanical ventilators available would not be enough. As in other parts of the world many initiatives sprung, most of them naively simple. Chilean medical societies joined engineering specialists and agreed early on in an organized and regulated open process for validating emergency mechanical ventilators, thus allowing for rapid development but with the required functionality, reliability, and safety features. VEMERS UC was one of few that completed successfully all stages of the validating process, the final test being on five critically-ill intubated COVID-19 patients for eight hours each. VEMERS UC is based on an electro-pneumatic circuit architecture and its components are all low cost, off-the-shelf pneumatic and electronic products easily obtained in industrial markets. It works in continuous mandatory volume control mode. The novel technical features of VEMERS UC are discussed here as well as the results obtained in each stage of the validating process. The validating process carried out in Chile is noteworthy by itself, and it could be used as an example in other developing countries. Furthermore, VEMERS UC can be used as a guiding design reference in other countries as well, since this design has already been thoroughly tested in human patients and has proven to work successfully.

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An Unusual Cause of Stridor After Decannulation of a Tracheostomised Patient

Global Journal of Medical Research ◽

10.34257/gjmrdvol20is1pg21 ◽

2020 ◽

pp. 21-23

Author(s):

Sailaja Kambhampati ◽

Meghana Yadav

Keyword(s):

Granulation Tissue ◽

Heart Block ◽

Rare Case ◽

Positive Pressure Ventilation ◽

Complete Heart Block ◽

Hemodynamic Instability ◽

Positive Pressure ◽

Inferior Wall ◽

Mechanical Ventilator ◽

Non Invasive

Stridor is commonly seen post decannulation in a tracheostomised patient. Usually it occurs due to airway obstruction secondary to tracheal stenosis, granulation tissue, tracheomalacia. We report a rare case of stridor due to dynamic pharyngeal collapse after decannulation. A 68- year - old male who presented with inferior wall MI and Complete Heart Block had to be put on a mechanical ventilator for hemodynamic instability and subsequently tracheostomised. Post decannulation he developed stridor and breathlessness. CT scan of neck revealed a supraglottic narrowing which on bronchoscopy showed a dynamic collapsibility of supraglottic area. This dynamic collapse was treated with non invasive positive pressure ventilation.

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X-ray microtomography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107058 ◽

1988 ◽

Vol 46 ◽

pp. 998-999

Author(s):

H.W. Deckman ◽

B.F. Flannery ◽

J.H. Dunsmuir ◽

K.D' Amico

Keyword(s):

Computed Tomography ◽

Internal Structure ◽

Imaging Technique ◽

Three Dimensional ◽

Tissue Structure ◽

Individual Element ◽

X Ray ◽

Non Invasive ◽

Panoramic Imaging ◽

Three Dimensional Images

We have developed a new X-ray microscope which produces complete three dimensional images of samples. The microscope operates by performing X-ray tomography with unprecedented resolution. Tomography is a non-invasive imaging technique that creates maps of the internal structure of samples from measurement of the attenuation of penetrating radiation. As conventionally practiced in medical Computed Tomography (CT), radiologists produce maps of bone and tissue structure in several planar sections that reveal features with 1mm resolution and 1% contrast. Microtomography extends the capability of CT in several ways. First, the resolution which approaches one micron, is one thousand times higher than that of the medical CT. Second, our approach acquires and analyses the data in a panoramic imaging format that directly produces three-dimensional maps in a series of contiguous stacked planes. Typical maps available today consist of three hundred planar sections each containing 512x512 pixels. Finally, and perhaps of most import scientifically, microtomography using a synchrotron X-ray source, allows us to generate maps of individual element.

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