A mathematical model of mechanical ventilator describes its behavior during artificial ventilation. This paper purposes to create and simulate Mathematical Model (MM) of Pressure Controlled Ventilator (PCV) signal. Th...A mathematical model of mechanical ventilator describes its behavior during artificial ventilation. This paper purposes to create and simulate Mathematical Model (MM) of Pressure Controlled Ventilator (PCV) signal. This MM represents the respiratory activities and an important controlled parameter during mechanical ventilation—Positive End Expiration Pressure (PEEP). The MM is expressed and modelled using periodic functions with inequalities to control the beginning of inspiration and expiration durations. The created MM of PCV signal is combined with an existing multi compartmental model of respiratory system that is modified and developed in the internal parameters—compliances (C) to test created MM. The created MM and model of respiratory system are constructed and simulated using Simulink package in MATLAB platform. The obtained simulator of mechnical ventilation system could potentially represent the pressure signal of PVC as a complete respiratory cycle and continuance waveform. This simulator is also able to reflect a respiratory mechanic by changing some input variables such as inspiration pressure (IP), PEEP and C, which are monitored in volume, flow, pressure and PV loop waveforms. The obtained simulator has provided a simple environment for testing and monitoring PCV signal and other parameters (volume, flow and dynamic compliance) during artificial ventilation. Furthermore, the simulator may be used for studying in the laboratory and training ventilator’s operators.展开更多
A pressure controlled mechanical ventilator with an automatic secretion clearance function can improve secretion clearance safely and efficiently.Studies on secretion clearance by pressure controlled systems show that...A pressure controlled mechanical ventilator with an automatic secretion clearance function can improve secretion clearance safely and efficiently.Studies on secretion clearance by pressure controlled systems show that these are suited for clinical applications.However,these studies are based on a single lung electric model and neglect the coupling between the two lungs.The research methods applied are too complex for the analysis of a multi-parameter system.In order to understand the functioning of the human respiratory system,this paper develops a dimensionless mathematical model of doublelung mechanical ventilation system with a secretion clearance function.An experiment is designed to verify the mathematical model through comparison of dimensionless experimental data and dimensionless simulation data.Finally,the coupling between the two lungs is studied,and an orthogonal experiment designed to identify the impact of each parameter on the system.展开更多
The present paper describes the theoretical treatment performed for the geometrical optimization of advanced and improved-shape waveforms as airways pressure excitation for controlled breathings in dual-controlled ven...The present paper describes the theoretical treatment performed for the geometrical optimization of advanced and improved-shape waveforms as airways pressure excitation for controlled breathings in dual-controlled ventilation applied to anaesthetized or severe brain injured patients, the respiratory mechanics of which can be assumed linear. Advanced means insensitive to patient breathing activity as well as to ventilator settings while improved-shape intends in comparison to conventional square waveform for a progressive approaching towards physiological transpulmonary pressure and respiratory airflow waveforms. Such functional features along with the best ventilation control for the specific therapeutic requirements of each patient can be achieved through the implementation of both diagnostic and compensation procedures effectively carried out by the Advance Lung Ventilation System (ALVS) already successfully tested for square waveform as airways pressure excitation. Triangular and trapezoidal waveforms have been considered as airways pressure excitation. The results shows that the latter fits completely the requirements for a physiological pattern of endoalveolar pressure and respiratory airflow waveforms, while the former exhibits a lower physiological behaviour but it is anyhow periodically recommended for performing adequately the powerful diagnostic procedure.展开更多
The theoretical approach along with the rationale of harmonic excitation modality (HEM) applied as optimal dual controlled ventilation (DCV) to anaesthetized or severe brain injured patients, whose respiretory mechani...The theoretical approach along with the rationale of harmonic excitation modality (HEM) applied as optimal dual controlled ventilation (DCV) to anaesthetized or severe brain injured patients, whose respiretory mechanics can be properly assumed steady and linear, are presented and discussed. The design criteria of an improved version of the Advanced Lung Ventilation System (ALVS), including HEM in its functional features, are described in details. In particular, the elimination of any undesiderable artificial distortion affecting the respiratory and ventilation pattern waveforms is achieved by maintaining continuous forever the airflow inside the ventilation circuit, ensuring also the highest level of safety for patient in any condition. In such a way, the full-time compatibility of controlled breathings with spontaneous breathing activity of patient during continuous positive airways pressure (CPAP) or bilevel positive airways pressure (BiPAP) ventilation modalities and during assisted/controlled ventilation(A/CV), includeing also synchronized or triggered ventilation modalities, is an intrinsic innovative feature of the system available for clinical application. As expected and according to the clinical requirements, HEM provides for physiological respiratory and ventilation pattern waveforms together with optimal “breath to breath” feedback control of lung volume driven by an improved diagnostic measurement procedure, whose outputs are also vital for adapting all the preset ventilation parameters to the current value of the respiratory parameters of patient. The results produced by software simulations concerning both adult and neonatal patients in different clinical conditions are completely consistent with those obtained by the theoretical treatment, showing that HEM reaches the best performances from both clinical and engineering points of view.展开更多
Background: Abdominoplasty is a commonly requested procedure for aesthetic improvement of the affected soft tissue layers of skin, fat, and muscle through the slightest incision feasible. The degree of plicature gener...Background: Abdominoplasty is a commonly requested procedure for aesthetic improvement of the affected soft tissue layers of skin, fat, and muscle through the slightest incision feasible. The degree of plicature generates an increase in intraabdominal pressure that causes an increase in intrathoracic pressure. Pressure, volume, flow, and respiratory rate are components of a unique physical variable, the mechanical power (MP), and is an integrated variable linked to most factors related to postoperative pulmonary complications. Purpose: To assess the effect of rectus plication (RP) during abdominoplasty on lung pressures and the contribution to increasing the MP. Method: A open-label study was conducted at TJ Plast Advanced Center for Plastic Surgery in Tijuana, México, from September 2021 to May 2022. The study included forty-six female patients subjected to abdominoplasty or liposuction with abdominoplasty. After the induction of general anesthesia and neuromuscular blockade, they were allocated into two groups: Group 1 pressure control ventilation-volume guaranteed (PCV-VG) and Group 2 volume control ventilation (VCV). Respiratory pressures and MP were assessed before and after RP. Results: During VCV, patients had a greater increase in peak pressure (PIP) (P 0.000). Plateau pressure (P<sub>plat</sub>) increased 1.78 ± 0.35 cmH<sub>2</sub>O in group 2 after RP (P = 0.001). MP had a greater increase in group 2 after RP (P 0.01). Conclusion: This prospective study showed that RP is related to an increase in PIP and P<sub>plat</sub> and an increase in the MP better controlled with PCV-VG ventilation.展开更多
Background:Conventional pressure support ventilation(PSP)is triggered and cycled off by pneumatic signals such as flow.Patient-ventilator asynchrony is common during pressure support ventilation,thereby contributing t...Background:Conventional pressure support ventilation(PSP)is triggered and cycled off by pneumatic signals such as flow.Patient-ventilator asynchrony is common during pressure support ventilation,thereby contributing to an increased inspiratory effort.Using diaphragm electrical activity,neurally controlled pressure support(PSN)could hypothetically eliminate the asynchrony and reduce inspiratory effort.The purpose of this study was to compare the differences between PSN and PSP in terms of patient-ventilator synchrony,inspiratory effort,and breathing pattern.Methods:Eight post-operative patients without respiratory system comorbidity,eight patients with acute respiratory distress syndrome(ARDS)and obvious restrictive acute respiratory failure(ARF),and eight patients with chronic obstructive pulmonary disease(COPD)and mixed restrictive and obstructive ARF were enrolled.Patient-ventilator interactions were analyzed with macro asynchronies(ineffective,double,and auto triggering),micro asynchronies(inspiratory trigger delay,premature,and late cycling),and the total asynchrony index(AI).Inspiratory efforts for triggering and total inspiration were analyzed.Results:Total AI of PSN was consistently lower than that of PSP in COPD(3%vs.93%,P=0.012 for 100%support level;8%vs.104%,P=0.012 for 150%support level),ARDS(8%vs.29%,P=0.012 for 100%support level;16%vs.41%,P=0.017 for 150%support level),and post-operative patients(21%vs.35%,P=0.012 for 100%support level;15%vs.50%,P=0.017 for 150%support level).Improved support levels from 100%to 150%statistically increased total AI during PSP but not during PSN in patients with COPD or ARDS.Patients’inspiratory efforts for triggering and total inspiration were significantly lower during PSN than during PSP in patients with COPD or ARDS under both support levels(P<0.05).There was no difference in breathing patterns between PSN and PSP.Conclusions:PSN improves patient-ventilator synchrony and generates a respiratory pattern similar to PSP independently of any level of support in patients with different respiratory system mechanical properties.PSN,which reduces the trigger and total patient’s inspiratory effort in patients with COPD or ARDS,might be an alternative mode for PSP.Trial Registration:ClinicalTrials.gov,NCT01979627;https://clinicaltrials.gov/ct2/show/record/NCT01979627.展开更多
文摘A mathematical model of mechanical ventilator describes its behavior during artificial ventilation. This paper purposes to create and simulate Mathematical Model (MM) of Pressure Controlled Ventilator (PCV) signal. This MM represents the respiratory activities and an important controlled parameter during mechanical ventilation—Positive End Expiration Pressure (PEEP). The MM is expressed and modelled using periodic functions with inequalities to control the beginning of inspiration and expiration durations. The created MM of PCV signal is combined with an existing multi compartmental model of respiratory system that is modified and developed in the internal parameters—compliances (C) to test created MM. The created MM and model of respiratory system are constructed and simulated using Simulink package in MATLAB platform. The obtained simulator of mechnical ventilation system could potentially represent the pressure signal of PVC as a complete respiratory cycle and continuance waveform. This simulator is also able to reflect a respiratory mechanic by changing some input variables such as inspiration pressure (IP), PEEP and C, which are monitored in volume, flow, pressure and PV loop waveforms. The obtained simulator has provided a simple environment for testing and monitoring PCV signal and other parameters (volume, flow and dynamic compliance) during artificial ventilation. Furthermore, the simulator may be used for studying in the laboratory and training ventilator’s operators.
文摘A pressure controlled mechanical ventilator with an automatic secretion clearance function can improve secretion clearance safely and efficiently.Studies on secretion clearance by pressure controlled systems show that these are suited for clinical applications.However,these studies are based on a single lung electric model and neglect the coupling between the two lungs.The research methods applied are too complex for the analysis of a multi-parameter system.In order to understand the functioning of the human respiratory system,this paper develops a dimensionless mathematical model of doublelung mechanical ventilation system with a secretion clearance function.An experiment is designed to verify the mathematical model through comparison of dimensionless experimental data and dimensionless simulation data.Finally,the coupling between the two lungs is studied,and an orthogonal experiment designed to identify the impact of each parameter on the system.
文摘The present paper describes the theoretical treatment performed for the geometrical optimization of advanced and improved-shape waveforms as airways pressure excitation for controlled breathings in dual-controlled ventilation applied to anaesthetized or severe brain injured patients, the respiratory mechanics of which can be assumed linear. Advanced means insensitive to patient breathing activity as well as to ventilator settings while improved-shape intends in comparison to conventional square waveform for a progressive approaching towards physiological transpulmonary pressure and respiratory airflow waveforms. Such functional features along with the best ventilation control for the specific therapeutic requirements of each patient can be achieved through the implementation of both diagnostic and compensation procedures effectively carried out by the Advance Lung Ventilation System (ALVS) already successfully tested for square waveform as airways pressure excitation. Triangular and trapezoidal waveforms have been considered as airways pressure excitation. The results shows that the latter fits completely the requirements for a physiological pattern of endoalveolar pressure and respiratory airflow waveforms, while the former exhibits a lower physiological behaviour but it is anyhow periodically recommended for performing adequately the powerful diagnostic procedure.
文摘The theoretical approach along with the rationale of harmonic excitation modality (HEM) applied as optimal dual controlled ventilation (DCV) to anaesthetized or severe brain injured patients, whose respiretory mechanics can be properly assumed steady and linear, are presented and discussed. The design criteria of an improved version of the Advanced Lung Ventilation System (ALVS), including HEM in its functional features, are described in details. In particular, the elimination of any undesiderable artificial distortion affecting the respiratory and ventilation pattern waveforms is achieved by maintaining continuous forever the airflow inside the ventilation circuit, ensuring also the highest level of safety for patient in any condition. In such a way, the full-time compatibility of controlled breathings with spontaneous breathing activity of patient during continuous positive airways pressure (CPAP) or bilevel positive airways pressure (BiPAP) ventilation modalities and during assisted/controlled ventilation(A/CV), includeing also synchronized or triggered ventilation modalities, is an intrinsic innovative feature of the system available for clinical application. As expected and according to the clinical requirements, HEM provides for physiological respiratory and ventilation pattern waveforms together with optimal “breath to breath” feedback control of lung volume driven by an improved diagnostic measurement procedure, whose outputs are also vital for adapting all the preset ventilation parameters to the current value of the respiratory parameters of patient. The results produced by software simulations concerning both adult and neonatal patients in different clinical conditions are completely consistent with those obtained by the theoretical treatment, showing that HEM reaches the best performances from both clinical and engineering points of view.
文摘Background: Abdominoplasty is a commonly requested procedure for aesthetic improvement of the affected soft tissue layers of skin, fat, and muscle through the slightest incision feasible. The degree of plicature generates an increase in intraabdominal pressure that causes an increase in intrathoracic pressure. Pressure, volume, flow, and respiratory rate are components of a unique physical variable, the mechanical power (MP), and is an integrated variable linked to most factors related to postoperative pulmonary complications. Purpose: To assess the effect of rectus plication (RP) during abdominoplasty on lung pressures and the contribution to increasing the MP. Method: A open-label study was conducted at TJ Plast Advanced Center for Plastic Surgery in Tijuana, México, from September 2021 to May 2022. The study included forty-six female patients subjected to abdominoplasty or liposuction with abdominoplasty. After the induction of general anesthesia and neuromuscular blockade, they were allocated into two groups: Group 1 pressure control ventilation-volume guaranteed (PCV-VG) and Group 2 volume control ventilation (VCV). Respiratory pressures and MP were assessed before and after RP. Results: During VCV, patients had a greater increase in peak pressure (PIP) (P 0.000). Plateau pressure (P<sub>plat</sub>) increased 1.78 ± 0.35 cmH<sub>2</sub>O in group 2 after RP (P = 0.001). MP had a greater increase in group 2 after RP (P 0.01). Conclusion: This prospective study showed that RP is related to an increase in PIP and P<sub>plat</sub> and an increase in the MP better controlled with PCV-VG ventilation.
基金National Science and Technology Major Project(No.2020ZX09201015)Clinical Science and Technology Specific Projects of Jiangsu Province(Nos.BE2018743,BE2019749)+3 种基金National Natural Science Foundation of China(Nos.81870066,81670074,81930058)Natural Science Foundation of Jiangsu Province(No.BK20171271)Jiangsu Provincial Medical Youth Talent(No.QNRC 2016807)Third Level Talents of the"333 High Level Talents Training Project"in the fifth phase in Jiangsu(No.LGY2016051)。
文摘Background:Conventional pressure support ventilation(PSP)is triggered and cycled off by pneumatic signals such as flow.Patient-ventilator asynchrony is common during pressure support ventilation,thereby contributing to an increased inspiratory effort.Using diaphragm electrical activity,neurally controlled pressure support(PSN)could hypothetically eliminate the asynchrony and reduce inspiratory effort.The purpose of this study was to compare the differences between PSN and PSP in terms of patient-ventilator synchrony,inspiratory effort,and breathing pattern.Methods:Eight post-operative patients without respiratory system comorbidity,eight patients with acute respiratory distress syndrome(ARDS)and obvious restrictive acute respiratory failure(ARF),and eight patients with chronic obstructive pulmonary disease(COPD)and mixed restrictive and obstructive ARF were enrolled.Patient-ventilator interactions were analyzed with macro asynchronies(ineffective,double,and auto triggering),micro asynchronies(inspiratory trigger delay,premature,and late cycling),and the total asynchrony index(AI).Inspiratory efforts for triggering and total inspiration were analyzed.Results:Total AI of PSN was consistently lower than that of PSP in COPD(3%vs.93%,P=0.012 for 100%support level;8%vs.104%,P=0.012 for 150%support level),ARDS(8%vs.29%,P=0.012 for 100%support level;16%vs.41%,P=0.017 for 150%support level),and post-operative patients(21%vs.35%,P=0.012 for 100%support level;15%vs.50%,P=0.017 for 150%support level).Improved support levels from 100%to 150%statistically increased total AI during PSP but not during PSN in patients with COPD or ARDS.Patients’inspiratory efforts for triggering and total inspiration were significantly lower during PSN than during PSP in patients with COPD or ARDS under both support levels(P<0.05).There was no difference in breathing patterns between PSN and PSP.Conclusions:PSN improves patient-ventilator synchrony and generates a respiratory pattern similar to PSP independently of any level of support in patients with different respiratory system mechanical properties.PSN,which reduces the trigger and total patient’s inspiratory effort in patients with COPD or ARDS,might be an alternative mode for PSP.Trial Registration:ClinicalTrials.gov,NCT01979627;https://clinicaltrials.gov/ct2/show/record/NCT01979627.
