Respiratory system mechanics during noninvasive proportional assist ventilation: A model study.

Purpose: To assess the accuracies of airway resistance (Raw) and compliance (Crs) calculations using the expiratory time constant (RCexp) method as well as the accuracy of Pmus estimation in obstructive lung models.

Methods: A Respironics V60 ventilator was connected to an active lung simulator. The driving pressure was maintained at 5-10 cmH2O and positive end-expiration pressure (PEEP) was 5 cmH2O.

Continuous estimation of respiratory system compliance and airway resistance during pressure-controlled ventilation without end-inspiration occlusion.

Background: Assessing mechanical properties of the respiratory system (C) during mechanical ventilation necessitates an end-inspiration flow of zero, which requires an end-inspiratory occlusion maneuver. This lung model study aimed to observe the effect of airflow obstruction on the accuracy of respiratory mechanical properties during pressure-controlled ventilation (PCV) by analyzing dynamic signals.

Methods: A Hamilton C3 ventilator was attached to a lung simulator that mimics lung mechanics in healthy, acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD) models.

Accuracy of the estimations of respiratory mechanics using an expiratory time constant in passive and active breathing conditions: a bench study.

Background: Respiratory mechanics monitoring provides useful information for guiding mechanical ventilation, but many measuring methods are inappropriate for awake patients. This study aimed to evaluate the accuracy of dynamic mechanics estimation using expiratory time constant (RC) calculation during noninvasive pressure support ventilation (PSV) with air leak in different lung models.

Methods: A Respironics V60 ventilator was connected to an active breathing simulator for modeling five profiles: normal adult, restrictive, mildly and severely obstructive, and mixed obstructive/restrictive.

[Development of an Active Mechanical Lung for Simulating Human Pulmonary Ventilation].

At present, the passive simulated lung including the splint lung is an important device for hospitals and manufacturers in testing the functions of a respirator. However, the human respiration simulated by this passive simulated lung is quite different from the actual respiration. And it is not able to simulate the spontaneous breathing.

[Modeling the noninvasive bi-level positive airway pressure ventilation therapy system and simulated application].

Without artificial airway though oral, nasal or airway incision, the bi-level positive airway pressure (Bi-PAP) has been widely employed for respiratory patients. In an effort to investigate the therapeutic effects and measures for the respiratory patients under the noninvasive Bi-PAP ventilation, a therapy system model was designed for virtual ventilation experiments. In this system model, it includes a sub-model of noninvasive Bi-PAP respirator, a sub-model of respiratory patient, and a sub-model of the breath circuit and mask.

Bistable insulin response: The win-win solution for glycemic control.

To satisfy both the safety and rapidity of glycemic control, muscles' insulin response must be bistable, as theoretically predicted. Here, we test the bistability hypothesis by combining cellular experiments (to measure the threshold values ) with mathematical modeling (to test the relevance of bistability ). We examine bistability in C2C12 myotubes by both single-cell analysis (Fӧrster resonance energy transfer) and cultured cells analysis (immunoblot).

Modeling the therapy system of noninvasive pressure support ventilation with the respiratory patient in COPD and ARDS.

The noninvasive pressure support ventilation (NPSV) has been one of mechanical ventilation widely applied for the respiratory patients in chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), etc. To investigate and develop the technologies in NPSV conveniently and in low-cost, in this article, a therapy system model of NPSV was designed with developing the mathematical submodels of NPSV respirator and respiratory patient in COPD and ARDS. By simulating the respirator, breath circuit, mask and respiratory patients, a MATLAB-based virtual experimental platform was developed for virtual ventilations.

Gas Exchange Mechanism of High Frequency Ventilation: A Brief Narrative Review and Prospect.

The high frequency ventilation (HFV) can well support the breathing of respiratory patient with 20%-40% of normal tidal volume. Now as a therapy of rescue ventilation when conversional ventilation failed, the HFV has been applied in the treatments of severe patients with acute respiratory failure (ARF), acute respiratory distress syndrome (ARDS), etc. However, the gas exchange mechanism (GEM) of HFV is still not fully understood by researchers.

[Circuit Designed for Driving Blower in Non-invasive Positive Airway Pressure Respirator].

One of critical technologies in a non-invasive positive airway pressure respirator is to output the airflow for meeting the requirement of respiratory patient in breath. In order to develop a safe and reliable blower driving system, a circuit based on the special chips MC33035 and MC33039 was designed. The linear relationship between the input control voltage and the output air flow was achieved.

Continuous estimation of airway resistance in non-invasive ventilation.

Background: This study aimed to evaluate the accuracy of expiratory time constant (RC) to continuously calculate the airway resistance (R).

Material And Methods: A Respironics V60 ventilator was connected to a lung simulator for modeling different profiles of respiratory mechanics.

Results: During assisted ventilation, the respiratory system compliance (C) calculation was always overestimated in most lung models.

[Prospects and developments in the technologies of high frequency oscillatory ventilation].

The high frequency oscillatory ventilation (HFOV) is characterized with low tidal volume and low mean airway pressure, and can well support the breathing of the patients with respiratory diseases. Since the HFOV was proposed, it has been widely concerned by medical and scientific researchers. About the HFOV, this paper discussed its current research status and prospected its future development in technologies.

Accuracy of the dynamic signal analysis approach in respiratory mechanics during noninvasive pressure support ventilation: a bench study.

Objective: To evaluate the accuracy of respiratory mechanics using dynamic signal analysis during noninvasive pressure support ventilation (PSV).

Methods: A Respironics V60 ventilator was connected to an active lung simulator to model normal, restrictive, obstructive, and mixed obstructive and restrictive profiles. The PSV was adjusted to maintain tidal volumes (V) that achieved 5.

Comparison of Inspiratory Effort, Workload and Cycling Synchronization Between Non-Invasive Proportional-Assist Ventilation and Pressure-Support Ventilation Using Different Models of Respiratory Mechanics.

BACKGROUND This study assessed lung models for the influence of respiratory mechanics and inspiratory effort on breathing pattern and simulator-ventilator cycling synchronization in non-invasive ventilation. MATERIAL AND METHODS A Respironics V60 ventilator was connected to an active lung simulator modeling mildly restrictive, severely restrictive, obstructive and mixed obstructive/restrictive profiles. Pressure-support ventilation (PSV) and proportional-assist ventilation (PAV) were set to obtain similar tidal volume (VT).

Seeking mTORC1 Inhibitors Through Molecular Dynamics Simulation of Arginine Analogs Inhibiting CASTOR1.

Background: Hyperactivity of the mechanistic target of rapamycin complex 1 (mTORC1) is implicated in a variety of diseases such as cancer and diabetes. Treatment may benefit from effective mTORC1 inhibition, which can be achieved by preventing arginine from disrupting the cytosolic arginine sensor for mTORC1 subunit 1 (CASTOR1)-GTPase-activating proteins toward RAGS subcomplex 2 (GATOR2) complex through binding with CASTOR1. An attractive idea is to determine analogues of arginine that are as competent as arginine in binding with CASTOR1, but without disrupting the CASTOR1-GATOR2 interaction.

[Investigating the mechanism of the high frequency ventilation for the oscillation airflow between left and right lungs].

Traditionally, adequate tidal volume is considered to be a necessary condition to support respiratory patient breathing. But the high frequency ventilation (HFV) with a small tidal volume can still support the respiratory patient breathing well. In order to further explore the mechanisms of HFV, the pendelluft ventilation between left and right lungs was proposed in this paper.

A noninvasive high frequency oscillation ventilator: Achieved by utilizing a blower and a valve.

After the High Frequency Oscillatory Ventilation (HFOV) has been applied in the invasive ventilator, the new technique of noninvasive High Frequency Oscillatory Ventilation (nHFOV) which does not require opening the patient's airway has attracted much attention from the field. This paper proposes the design of an experimental positive pressure-controlled nHFOV ventilator which utilizes a blower and a special valve and has three ventilation modes: spontaneous controlled ventilation combining HFOV, time-cycled ventilation combining HFOV (T-HFOV), and continuous positive airway pressure ventilation combining HFOV. Experiments on respiratory model are conducted and demonstrated the feasibility of using nHFOV through the control of fan and valve.