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Kondili, Eumorfia, Demosthenes Makris, Dimitrios Georgopoulos, Nikoletta Rovina, Anastasia Kotanidou et Antonia Koutsoukou. « COVID-19 ARDS : Points to Be Considered in Mechanical Ventilation and Weaning ». Journal of Personalized Medicine 11, no 11 (28 octobre 2021) : 1109. http://dx.doi.org/10.3390/jpm11111109.
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The COVID-19 disease can cause hypoxemic respiratory failure due to ARDS, requiring invasive mechanical ventilation. Although early studies reported that COVID-19-associated ARDS has distinctive features from ARDS of other causes, recent observational studies have demonstrated that ARDS related to COVID-19 shares common clinical characteristics and respiratory system mechanics with ARDS of other origins. Therefore, mechanical ventilation in these patients should be based on strategies aiming to mitigate ventilator-induced lung injury. Assisted mechanical ventilation should be applied early in the course of mechanical ventilation by considering evaluation and minimizing factors associated with patient-inflicted lung injury. Extracorporeal membrane oxygenation should be considered in selected patients with refractory hypoxia not responding to conventional ventilation strategies. This review highlights the current and evolving practice in managing mechanically ventilated patients with ARDS related to COVID-19.
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Mammel, Mark C., Janice P. Ophoven, Patrick K. Lewallen, Margaret J. Gordon, Marylyn C. Sutton et Stephen J. Boros. « High-Frequency Ventilation and Tracheal Injuries ». Pediatrics 77, no 4 (1 avril 1986) : 608–13. http://dx.doi.org/10.1542/peds.77.4.608.
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Recent reports linking serious tracheal injuries to various forms of high-frequency ventilation prompted this study. We compared the tracheal histopathology seen following standard-frequency, conventional mechanical ventilation with that seen following high-frequency, conventional mechanical ventilation, and two different forms of high-frequency jet ventilation. Twenty-six adult cats were examined. Each was mechanically ventilated for 16 hours. Seven received standard-frequency, conventional mechanical ventilation at 20 breaths per minute. Seven received high-frequency, conventional mechanical ventilation at 150 breaths per minute. Six received high-frequency jet ventilation at 250 breaths per minute via the Instrument Development Corporation VS600 jet ventilator (IDC). Six received high-frequency jet ventilation at 400 breaths per minute via the Bunnell Life Pulse jet ventilator (BLP). A semiquantitative histopathologic scoring system graded tracheal tissue changes. All forms of high-frequency ventilation produced significant inflammation (erosion, necrosis, and polymorphonuclear leukocyte infiltration) in the trachea in the region of the endotracheal tube tip. Conventional mechanical ventilation produced less histopathology than any form of high-frequency ventilation. Of all of the ventilators examined, the BLP, the ventilator operating at the fastest rate, produced the greatest loss of surface cilia and depletion of intracellular mucus. IDC high-frequency jet ventilation and high-frequency, conventional mechanical ventilation produced nearly identical histologic injuries. In this study, significant tracheal damage occurred with all forms of high-frequency ventilation. The tracheal damage seen with high-frequency, conventional mechanical ventilation suggests that ventilator frequency, not delivery system, may be responsible for the injuries.
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Shi, Yan, Shuai Ren, Maolin Cai et Weiqing Xu. « Modelling and Simulation of Volume Controlled Mechanical Ventilation System ». Mathematical Problems in Engineering 2014 (2014) : 1–7. http://dx.doi.org/10.1155/2014/271053.
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Volume controlled mechanical ventilation system is a typical time-delay system, which is applied to ventilate patients who cannot breathe adequately on their own. To illustrate the influences of key parameters of the ventilator on the dynamics of the ventilated respiratory system, this paper firstly derived a new mathematical model of the ventilation system; secondly, simulation and experimental results are compared to verify the mathematical model; lastly, the influences of key parameters of ventilator on the dynamics of the ventilated respiratory system are carried out. This study can be helpful in the VCV ventilation treatment and respiratory diagnostics.
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Lozano-Zahonero, Sara, Matthias Schneider, Sashko Spassov et Stefan Schumann. « A novel mechanical ventilator providing flow-controlled expiration for small animals ». Laboratory Animals 54, no 6 (19 février 2020) : 568–75. http://dx.doi.org/10.1177/0023677220906857.
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For investigating the effects of mechanical ventilation on the respiratory system, experiments in small mammal models are used. However, conventional ventilators for small animals are usually limited to a specific ventilation mode, and in particular to passive expiration. Here, we present a computer-controlled research ventilator for small animals which provides conventional mechanical ventilation as well as new type ventilation profiles. Typical profiles of conventional mechanical ventilation, as well as flow-controlled expiration and sinusoidal ventilation profiles can be generated with our new ventilator. Flow control during expiration reduced the expiratory peak flow rate by 73% and increased the mean airway pressure by up to 1 mbar compared with conventional ventilation without increasing peak pressure and end-expiratory pressure. Our new ventilator for small animals allows for the application of various ventilation profiles. We could analyse the effects of applying conventional ventilation profiles, pressure-controlled ventilation and volume-controlled ventilation, as well as the novel flow-controlled ventilation profile. This new approach enables studying the mechanical properties of the respiratory system with an increased freedom for choosing independent ventilation parameters.
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Bubshait, Khlood, et Yasmine Alabbasi. « Influence of Spontaneous and Mechanical Ventilation on Frequency-Based Measures of Heart Rate Variability ». Critical Care Research and Practice 2021 (26 décembre 2021) : 1–9. http://dx.doi.org/10.1155/2021/8709262.
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Frequency-based measures of heart rate variability have been shown to be a useful physiological marker in both clinical and research settings providing insight into the functioning of the autonomic nervous system. Ongoing interactions between the autonomic nervous system control of the heart and lung occurs during each ventilation cycle because of their anatomical position within the closed thoracic cavity. Mechanical ventilation and subsequent removal change the normal ventilator mechanics producing alterations in the tidal volume, intrathoracic pressure, and oxygen delivery. A noninvasive method called heart rate variability (HRV) can be used to evaluate this interaction during ventilation and can be quantified by applying frequency-based measures of the variability between heartbeats. Although HRV is a reliable method to measure alteration of the autonomic nervous system (ANS) function and cardiopulmonary interaction, there have been limited reports concerning the changes in the frequency-based measure of HRV during both spontaneous and mechanical ventilation. The purpose of this methodological study is therefore to describe the physiological influence of both spontaneous and mechanical ventilation on frequency-based measures of HRV.
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Imanaka, Hideaki, Dean Hess, Max Kirmse, Luca M. Bigatello, Robert M. Kacmarek, Wolfgang Steudel et William E. Hurford. « Inaccuracies of Nitric Oxide Delivery Systems during Adult Mechanical Ventilation ». Anesthesiology 86, no 3 (1 mars 1997) : 676–88. http://dx.doi.org/10.1097/00000542-199703000-00021.
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Background Various systems to administer inhaled nitric oxide (NO) have been used in patients and experimental animals. We used a lung model to evaluate five NO delivery systems during mechanical ventilation with various ventilatory patterns. Methods An adult mechanical ventilator was attached to a test lung configured to separate inspired and expired gases. Four injection systems were evaluated with NO injected either into the inspiratory circuit 90 cm proximal to the Y piece or directly at the Y piece and delivered either continuously or only during the inspiratory phase. Alternatively, NO was mixed with air using a blender and delivered to the high-pressure air inlet of the ventilator. Nitric oxide concentration was measured from the inspiratory limb of the ventilator circuit and the tracheal level using rapid- and slow-response chemiluminescence analyzers. The ventilator was set for constant-flow volume control ventilation, pressure control ventilation, pressure support ventilation, or synchronized intermittent mandatory ventilation. Tidal volumes of 0.5 l and 1 l were evaluated with inspiratory times of 1 s and 2 s. Results The system that premixed NO proximal to the ventilator was the only one that maintained constant NO delivery regardless of ventilatory pattern. The other systems delivered variable NO concentration during pressure control ventilation and spontaneous breathing modes. Systems that injected a continuous flow of NO delivered peak NO concentrations greater than the calculated dose. These variations were not apparent when a slow-response chemiluminescence analyzer was used. Conclusions NO delivery systems that inject NO at a constant rate, either continuously or during inspiration only, into the inspiratory limb of the ventilator circuit produce highly variable and unpredictable NO delivery when inspiratory flow is not constant. Such systems may deliver a very high NO concentration to the lungs, which is not accurately reflected by measurements performed with slow-response analyzers.
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Hao, Liming, Shuai Ren, Yan Shi, Na Wang, Yixuan Wang, Zujin Luo, Fei Xie, Meng Xu, Jian Zhang et Maolin Cai. « A Novel Method to Evaluate Patient-Ventilator Synchrony during Mechanical Ventilation ». Complexity 2020 (15 septembre 2020) : 1–15. http://dx.doi.org/10.1155/2020/4828420.
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The synchrony of patient-ventilator interaction affects the process of mechanical ventilation which is clinically applied for respiratory support. The occurrence of patient-ventilator asynchrony (PVA) not only increases the risk of ventilator complications but also affects the comfort of patients. To solve the problem of uncertain patient-ventilator interaction in the mechanical ventilation system, a novel method to evaluate patient-ventilator synchrony is proposed in this article. Firstly, a pneumatic model is established to simulate the mechanical ventilation system, which is verified to be accurate by the experiments. Then, the PVA phenomena are classified and detected based on the analysis of the ventilator waveforms. On this basis, a novel synchrony index SIhao is established to evaluate the patient-ventilator synchrony. It not only solves the defects of previous evaluation indexes but also can be used as the response parameter in the future research of ventilator control algorithms. The accurate evaluation of patient-ventilator synchrony can be applied to the adjustment of clinical strategies and the pathological analyses of patients. This research can also reduce the burden on clinicians and help to realize the adaptive control of the mechanical ventilation and weaning process in the future.
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Pinsky, Michael R. « Mechanical ventilation and the cardiovascular system ». Current Opinion in Critical Care 2, no 5 (octobre 1996) : 391–95. http://dx.doi.org/10.1097/00075198-199610000-00010.
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Wang, Yi, Yan Qiu Huang, Zhi Peng Li, Le Wang et Jie Gao. « Study on the Pollutant Control of Industrial Buildings with Mechanical Ventilation ». Advanced Materials Research 243-249 (mai 2011) : 4949–55. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.4949.
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The aim of this paper is to study the control effects of pollutants with different ventilation methods in industrial buildings. Comparative researches are conducted between the push-pull ventilation system and displacement ventilation system. Formaldehyde (HCHO) is selected as the main pollutant in the industrial buildings in this paper. The computational fluid dynamics (CFD) is used to analysis the space distribution of pollutant concentrations with the pollution sources at different locations. Through comparative study，the pollutants distribution with the same supply air volume and pollutants diffusion intensity are evaluated from the following two aspects. Firstly, when the height of the pollutant source is 1.2 m in the industrial building, the average concentration of the contaminant at the space section with push-pull ventilation system is relatively higher than that with displacement ventilation system. Secondly, the average concentration with push-pull ventilation system is 0.00058 kmol/m3 while displacement ventilation system is 0.00097 kmol/m3 when the height of the pollutant source is 0.6 m. And when it is 0.3 m, they are 0.00016 kmol/m3 and 0.0017 kmol/m3 respectively. Thus, the concentration of the contaminant in displacement ventilation is higher than the push-pull ventilation’s with the location of the pollution source continuously declining in the height direction.
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Shen, Dongkai, Qian Zhang et Yan Shi. « Dynamic Characteristics of Mechanical Ventilation System of Double Lungs with Bi-Level Positive Airway Pressure Model ». Computational and Mathematical Methods in Medicine 2016 (2016) : 1–13. http://dx.doi.org/10.1155/2016/9234537.
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In recent studies on the dynamic characteristics of ventilation system, it was considered that human had only one lung, and the coupling effect of double lungs on the air flow can not be illustrated, which has been in regard to be vital to life support of patients. In this article, to illustrate coupling effect of double lungs on flow dynamics of mechanical ventilation system, a mathematical model of a mechanical ventilation system, which consists of double lungs and a bi-level positive airway pressure (BIPAP) controlled ventilator, was proposed. To verify the mathematical model, a prototype of BIPAP system with a double-lung simulators and a BIPAP ventilator was set up for experimental study. Lastly, the study on the influences of key parameters of BIPAP system on dynamic characteristics was carried out. The study can be referred to in the development of research on BIPAP ventilation treatment and real respiratory diagnostics.
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Shi, Yan, Shuai Ren, Maolin Cai, Weiqing Xu et Qiyou Deng. « Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator ». Computational and Mathematical Methods in Medicine 2014 (2014) : 1–10. http://dx.doi.org/10.1155/2014/761712.
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Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems.
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VanKoevering, Kyle K., Pratyusha Yalamanchi, Catherine T. Haring, Anne G. Phillips, Stephen Lewis Harvey, Alvaro Rojas-Pena, David A. Zopf et Glenn E. Green. « Delivery system can vary ventilatory parameters across multiple patients from a single source of mechanical ventilation ». PLOS ONE 15, no 12 (10 décembre 2020) : e0243601. http://dx.doi.org/10.1371/journal.pone.0243601.
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Background Current limitations in the supply of ventilators during the Covid19 pandemic have limited respiratory support for patients with respiratory failure. Split ventilation allows a single ventilator to be used for more than one patient but is not practicable due to requirements for matched patient settings, risks of cross-contamination, harmful interference between patients and the inability to individualize ventilator support parameters. We hypothesized that a system could be developed to circumvent these limitations. Methods and findings A novel delivery system was developed to allow individualized peak inspiratory pressure settings and PEEP using a pressure regulatory valve, developed de novo, and an inline PEEP ‘booster’. One-way valves, filters, monitoring ports and wye splitters were assembled in-line to complete the system and achieve the design targets. This system was then tested to see if previously described limitations could be addressed. The system was investigated in mechanical and animal trials (ultimately with a pig and sheep concurrently ventilated from the same ventilator). The system demonstrated the ability to provide ventilation across clinically relevant scenarios including circuit occlusion, unmatched physiology, and a surgical procedure, while allowing significantly different pressures to be safely delivered to each animal for individualized support. Conclusions In settings of limited ventilator availability, systems can be developed to allow increased delivery of ventilator support to patients. This enables more rapid deployment of ventilator capacity under constraints of time, space and financial cost. These systems can be smaller, lighter, more readily stored and more rapidly deployable than ventilators. However, optimizing ventilator support for patients with individualized ventilation parameters will still be dependent upon ease of use and the availability of medical personnel.
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Coleman, Denise M., H. William Kelly, Bennie C. Mcwilliams, Annette Pérez et Marc M. Perreault. « Therapeutic Aerosol Delivery during Mechanical Ventilation ». Annals of Pharmacotherapy 30, no 6 (juin 1996) : 644–55. http://dx.doi.org/10.1177/106002809603000613.
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Objective To provide an overview of aerosol drug delivery during mechanical ventilation in the pediatric and adult populations. Data Sources Published articles and abstracts identified in a MEDLINE search (1984–July 1994) were reviewed. Study Selection All articles and abstracts found, including review articles, in vivo and in vitro studies, case reports, and case series pertaining to issues involving aerosol delivery during mechanical ventilation, were reviewed. No predetermined selection criteria were used to exclude studies. Data Extraction Percent delivery of the starting dose to either the patients or the various in vitro lung models, as well as each variable possibly affecting delivery for each study, were tabulated for each study reviewed. Data Synthesis The delivery of therapeutic aerosols to endotracheally intubated and mechanically ventilated patients presents a unique challenge for healthcare providers. Delivery can be affected by the diameter of the endotracheal tube and ventilator circuitry, type of ventilator, ventilator modes, type of delivery device, and how the delivery device is operated and introduced into the ventilator circuitry. The drug being aerosolized may behave differently from one delivery system to another. The proper operation of each device requires attention to positioning in the ventilator circuit as well as the mode of ventilation. Conclusions No apparent advantage exists for metered-dose inhalers with a large-volume adapter over jet nebulizers, as each method of delivery is capable of similar efficiency (5–15%). Sufficient attention to detail, including the use of an efficient nebulizer and/or adapter and proper placement and operating method, is required to provide optimal delivery. For bronchodilator administration, careful monitoring of outcomes will provide the most optimal dosing schedule.
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Pomprapa, Anake, Danita Muanghong, Marcus Köny, Steffen Leonhardt, Philipp Pickerodt, Onno Tjarks, David Schwaiberger et Burkhard Lachmann. « Artificial intelligence for closed-loop ventilation therapy with hemodynamic control using the open lung concept ». International Journal of Intelligent Computing and Cybernetics 8, no 1 (9 mars 2015) : 50–68. http://dx.doi.org/10.1108/ijicc-05-2014-0025.
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Purpose – The purpose of this paper is to develop an automatic control system for mechanical ventilation therapy based on the open lung concept (OLC) using artificial intelligence. In addition, mean arterial blood pressure (MAP) is stabilized by means of a decoupling controller with automated noradrenaline (NA) dosage to ensure adequate systemic perfusion during ventilation therapy for patients with acute respiratory distress syndrome (ARDS). Design/methodology/approach – The aim is to develop an automatic control system for mechanical ventilation therapy based on the OLC using artificial intelligence. In addition, MAP is stabilized by means of a decoupling controller with automated NA dosage to ensure adequate systemic perfusion during ventilation therapy for patients with ARDS. Findings – This innovative closed-loop mechanical ventilation system leads to a significant improvement in oxygenation, regulates end-tidal carbon dioxide for appropriate gas exchange and stabilizes MAP to guarantee proper systemic perfusion during the ventilation therapy. Research limitations/implications – Currently, this automatic ventilation system based on the OLC can only be applied in animal trials; for clinical use, such a system generally requires a mechanical ventilator and sensors with medical approval for humans. Practical implications – For implementation of a closed-loop ventilation system, reliable signals from the sensors are a prerequisite for successful application. Originality/value – The experiment with porcine dynamics demonstrates the feasibility and usefulness of this automatic closed-loop ventilation therapy, with hemodynamic control for severe ARDS. Moreover, this pilot study validated a new algorithm for implementation of the OLC, whereby all control objectives are fulfilled during the ventilation therapy with adequate hemodynamic control of patients with ARDS.
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Kostuganov, Arman, Yuri Vytchikov et Andrey Prilepskiy. « Self-contained ventilation system of civil buildings built into window structures ». MATEC Web of Conferences 196 (2018) : 02007. http://dx.doi.org/10.1051/matecconf/201819602007.
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The article describes development and application of self-contained ventilation systems in civil buildings. It suggests several models of air exchange within the building, compares these models and points out the variant of ventilating with self-contained mechanical systems with utilization of heat. The researchers conclude that structurally self-contained systems of mechanical ventilation with utilization of heat are most efficiently built into window constructions. This installation variant makes it possible to keep the interior, avoid building construction strengthening, shorten time and labor input of construction-assembling works, allow rational use of the vertical building envelopes area without extra space using. The paper key issue is the development of constructive solutions of self-contained ventilation systems main elements to ensure the possibility of their use in window structures. This research stage was developed with account of previous results of field tests and of such ventilation systems theoretical descriptions. The authors assess limit dimensions of the systems suitable for installment into window constructions of civil buildings in the view of modern Russian requirements to thermal protection. The research suggests a general constructive solution of such a ventilation system and a heat exchanger model which can be used as an air heat utilizer in these systems.
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PAVLIDOU (Κ. ΠΑΥΛΙΔΟΥ), K., I. SAVVAS (Ι. ΣΑΒΒΑΣ) et T. ANAGNOSTOU (Τ. ΑΝΑΓΝΩΣΤΟΥ). « Mechanical ventilation. Part II : Basic principles and function of ventilators. » Journal of the Hellenic Veterinary Medical Society 62, no 4 (13 novembre 2017) : 334. http://dx.doi.org/10.12681/jhvms.14864.
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Mechanical ventilation is the process of supporting respiration by manual or mechanical means. When normal breathing is inefficient or has stopped, mechanical ventilation is life-saving and should be applied at once. The ventilator increases the patient's ventilation by inflating the lungs with oxygen or a mixture of air and oxygen. Ventilators play an important role in the anaesthetic management of patients, as well as in the treatment of patients in the ICU. However, there are differences between the anaesthetic ventilators and the ventilators in ICU. The main indication for mechanical ventilation is difficulty in ventilation and/or oxygenation of the patient because of any respiratory or other disease. The aims of mechanical ventilation are to supply adequate oxygen to patients with a limited vital capacity, to treat ventilatory failure, to reduce dyspnoea and to facilitate rest of fatigued breathing muscles. Depression of the central nervous system function is a pre-requirement for mechanical ventilation. Some times, opioids or muscle relaxants can be used in order to depress patient's breathing. Mechanical ventilation can be applied using many different modes: assisted ventilation, controlled ventilation, continuous positive pressure ventilation, intermittent positive pressure ventilation and jet ventilation. Furthermore, there are different types of automatic ventilators built to provide positive pressure ventilation in anaesthetized or heavily sedated or comatose patients: manual ventilators (Ambu-bag), volumecontrolled ventilators with pressure cycling, volume-controlled ventilators with time cycling and pressure-controlled ventilators. In veterinary practice, the ventilator should be portable, compact and easy to operate. The controls on most anaesthetic ventilators include settings for tidal volume, inspiratory time, inspiratory pressure, respiratory rate and inspiration: expiration (I:E) ratio. The initial settings should be between 10-20 ml/kg for tidal volume, 12-30 cmH2 0 for the inspiratory pressure and 8-15 breaths/min for the respiratory rate. Mechanical ventilation is a very important part of treatment in the ICU, but many problems may arise during application of mechanical ventilation in critically ill patients. All connections should be checked in advance and periodically for mechanical problems like leaks. Moreover, complications like lung injury, pneumonia, pneumothorax, myopathy and respiratory failure can occur during the course of mechanical ventilation causing difficulty in weaning.
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Flechelles, Olivier, Annie Ho, Patrice Hernert, Guillaume Emeriaud, Nesrine Zaglam, Farida Cheriet et Philippe A. Jouvet. « Simulations for Mechanical Ventilation in Children : Review and Future Prospects ». Critical Care Research and Practice 2013 (2013) : 1–8. http://dx.doi.org/10.1155/2013/943281.
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Mechanical ventilation is a very effective therapy, but with many complications. Simulators are used in many fields, including medicine, to enhance safety issues. In the intensive care unit, they are used for teaching cardiorespiratory physiology and ventilation, for testing ventilator performance, for forecasting the effect of ventilatory support, and to determine optimal ventilatory management. They are also used in research and development of clinical decision support systems (CDSSs) and explicit computerized protocols in closed loop. For all those reasons, cardiorespiratory simulators are one of the tools that help to decrease mechanical ventilation duration and complications. This paper describes the different types of simulators described in the literature for physiologic simulation and modeling of the respiratory system, including a new simulator (SimulResp), and proposes a validation process for these simulators.
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Richter, Andre J., Christian Schnabel, Peter Spieth et Emdund Koch. « Development of a compact stand-alone esophageal pressure measurement device ». Current Directions in Biomedical Engineering 4, no 1 (1 septembre 2018) : 355–58. http://dx.doi.org/10.1515/cdbme-2018-0085.
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AbstractMechanical ventilation requires optimal parameter setting for every single patient. For instance sufficient positive end-expiratory pressure (PEEP) may ensure oxygenation and prevent overdistension of lungs or alveolar collapse. To find optimal PEEP, transpulmonary pressure (airway pressure minus pleural pressure) guides as an indicator for both, chest wall mechanics and lung characteristic. Since measurement of pleural pressure is impractical in clinical routine, esophageal pressure can be used to estimate pleural pressure and may help to assure protective mechanical ventilation. We developed a PESO (derived from PESO = esophageal pressure) measurement system, which provides a compact stand-alone device to measure the esophageal pressure during mechanical ventilation of patients. In addition to the esophageal pressure, air way pressure is also measured to provide the synchronized data independent of the ventilator manufacturer. The device works with two commercial pressure transducers, whose signals are conditioned and digitized with an Arduino Nano microcontroller, which samples data with 62 kHz and transmits averaged data with 100 Hz to a mobile tablet PC, which acts as process, display and record unit. The compact system provides a working time of 5 hours. Therefore, the system supports the progress for mechanical ventilation research. This paper describes technical details as well as functionality.
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Rahman, Haolia, Agus Sukandi, Nasruddin Nasruddin, Arnas Arnas et Remon Lapisa. « Mechanical Ventilation Control Based on Estimated occupancy using a Carbon Dioxide Sensor ». TEKNIK 41, no 3 (23 novembre 2020) : 232–38. http://dx.doi.org/10.14710/teknik.v41i3.33416.
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Ventilation is an important aspect to maintain good indoor air quality in a building. However, excessive ventilation causing high energy consumption of the HVAC system. The ASHRAE Standard provides a guideline to set the ventilation rate that depends on the occupants' number and space. Thus, quantification of the number of occupants is required to regulate the ventilation rate. In this study, the estimated number of occupants was estimated using a Bayesian MCMC method based on CO2 levels. The mass balance equation of the CO2 is used as a model for the calculation of Bayesian MCMC. The Bayesian method for estimating the occupants' number is tested in a 96,7 m3 office room equipped with a ventilation system. Thus the occupancy estimation and control of ventilation can be done in real-time. The test also includes conventional ventilation control based on CO2 levels directly without converting to the occupants' number. The ventilation rate based on the number of occupants at the present test chamber refers to ASHRAE 62.1. The test results show that ventilation controlled by the estimated number of occupants using the Bayesian method successfully conducted with ventilation rate per occupant closer to the ASHRAE 62.1 standard over conventional ventilation method
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Repessé, Xavier, Cyril Charron, Guillaume Geri, Alix Aubry, Alexis Paternot, Julien Maizel, Michel Slama et Antoine Vieillard-Baron. « Impact of positive pressure ventilation on mean systemic filling pressure in critically ill patients after death ». Journal of Applied Physiology 122, no 6 (1 juin 2017) : 1373–78. http://dx.doi.org/10.1152/japplphysiol.00958.2016.
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Mean systemic filling pressure (Pms) defines the pressure measured in the venous-arterial system when the cardiac output is nil. Its estimation has been proposed in patients with beating hearts by building the venous return curve, using different pairs of right atrial pressure/cardiac output during mechanical ventilation. We raised the hypothesis according to which the Pms is altered by tidal ventilation and positive end-expiratory pressure (PEEP), which would challenge this extrapolation method based on cardiopulmonary interactions. We conducted a two-center, noninterventional, observational, and prospective study, using an arterial and a venous catheter to measure the pressure in the circulatory system at the time of death in critically ill, mechanically ventilated patients with a PEEP. Arterial (Part) and venous pressures (Pra) were recorded in five conditions: at end expiration and end inspiration with and without PEEP and finally once the ventilator was disconnected. Part and Pra did not differ in any experimental conditions. Tidal ventilation increased Pra and Part by 2.4 and 1.9 mmHg, respectively, whereas PEEP increased both values by 1.2 and 1 mmHg, respectively. After disconnection of the ventilator, Pra and Part were 10.0 ± 4.2 and 9.9 ± 4.2 mmHg, respectively. Pms increases during mechanical ventilation, with an effect of tidal ventilation and PEEP. This calls into question the validity of its evaluation in heart-beating patients using cardiopulmonary interactions during mechanical ventilation. NEW & NOTEWORTHY The physiology of the mean systemic filling pressure (Pms) is not well understood in human beings. This study is the first report of a tidal ventilation- and positive end-expiratory pressure-related increase in Pms in critically ill patients. The results challenge the utility and the value estimating Pms in heart-beating patients by reconstruction of the venous return curve using varying inflation pressures.
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Kim, Kristin M., Sandro Cinti, Steven Gay, Susan Goold, Andrew Barnosky et Marie Lozon. « Triage of Mechanical Ventilation for Pediatric Patients During a Pandemic ». Disaster Medicine and Public Health Preparedness 6, no 2 (juin 2012) : 131–37. http://dx.doi.org/10.1001/dmp.2012.19.
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ABSTRACTObjective: The novel H1N1 influenza pandemic renewed the concern that during a severe pandemic illness, critical care and mechanical ventilation resources will be inadequate to meet the needs of patients. Several published protocols address the need to triage patients for access to ventilator resources. However, to our knowledge, none of these has addressed the pediatric populations.Methods: We used a systematic review of the pediatric critical care literature to evaluate pediatric critical care prognosis and multisystem organ failure scoring systems. We used multiple search engines, including MEDLINE and EMBASE, using a search for terms and key words including including multiple organ failure, multiple organ dysfunction, PELOD, PRISM III, pediatric risk of mortality score, pediatric logistic organ dysfunction, pediatric index of mortality pediatric multiple organ dysfunction score, “child+multiple organ failure + scoring system. ” Searches were conducted in the period January 2010-February 2010.Results: Of the 69 papers reviewed, 22 were used. Five independently derived scoring systems were evaluated for use in a respiratory pandemic ventilator triage protocol. The Pediatric Logistic Organ Dysfunction (PELOD) scoring system was the most appropriate for use in such a triage protocol.Conclusions: We present a pediatric-specific ventilator triage protocol using the PELOD scoring system to complement the NY State adult triage protocol. Further evaluation of pediatric scoring systems is imperative to ensure appropriate triage of pediatric patients.(Disaster Med Public Health Preparedness. 2012;6:131–137)
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Jansen, J. R., E. Hoorn, J. Van Goudoever et A. Versprille. « A computerized respiratory system including test functions of lung and circulation ». Journal of Applied Physiology 67, no 4 (1 octobre 1989) : 1687–91. http://dx.doi.org/10.1152/jappl.1989.67.4.1687.
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The design of a microcomputer-controlled ventilator for automatic performance of lung function and circulatory tests has been described. It incorporates the characteristics of normal mechanical ventilation and also allows one to perform a multitude of test procedures for lung function and circulatory studies in paralyzed animals. The major components of the setup are a pump assembly with solenoid valves to direct gas flow, an electromechanical servo system, and a MS-DOS microcomputer system. The pump assembly has been constructed as a relatively simple device. Great versatility is created by the use of a microcomputer for the control of the ventilator. The software can be easily adapted to several other types of experimental studies. Besides the keyboard input the ventilator can be controlled by a remote computer system. This allows one to run an experimental protocol automatically and to use it in closed-loop servo ventilation. The flexibility in the choice of the respiratory parameters makes the ventilator suitable for lung function and circulatory studies during artificial ventilation. The ventilator has been successfully used in different animal studies during the last 6 yr.
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Tschopp, M., et C. Lovis. « Towards Clinically Available Closed-loop Systems for Mechanical Ventilation in the Intensive Care Unit ». Yearbook of Medical Informatics 18, no 01 (août 2009) : 75–80. http://dx.doi.org/10.1055/s-0038-1638642.
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Summary Objective To provide an overview of the state-of-the-art of closedloop systems in the field of mechanical ventilation. Methods This survey is reviewing the literature and proposes an overview of existing closed-loop systems, in different areas of mechanical ventilation. It discusses the key points that guided their development and addresses specific issues such as their performance and penetration at the bedside. Results Much research has been undertaken in the hope of improving patient-ventilator interaction and shortening the weaning process. This led to the development of new modes of ventilation and expert weaning systems that are starting to achieve a wider clinical audience. Conclusion Intensive care unit personnel are facing increasing work load during care for patients with severe, multi-system illness, using sophisticated equipments that generate high information flows requiring quick processing. Mechanical ventilation is a good example of a process that requires skilful and timely management of multiple parameters that could be delegated to closed-loop systems. Availability of commercial offerings, validated by randomized controlled trials in a well-defined set of clinical situations, is starting to fulfill the promise of intelligent systems skillfully assisting caregivers at the bedside.
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Ng, Lisa C., Stephen Zimmerman, Jeremy Good, Brian Toll, Steven J. Emmerich et Andrew K. Persily. « Estimating real-time infiltration for use in residential ventilation control ». Indoor and Built Environment 29, no 4 (26 août 2019) : 508–26. http://dx.doi.org/10.1177/1420326x19870229.
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Minimum outdoor air ventilation rates specified in standards such as ASHRAE Standard 62.2–2016 are generally based on envelope airtightness, building floor area, geographical location and number of occupants. ASHRAE Standard 62.2–2016 allows for a constant infiltration credit, which reduces the required mechanical ventilation. However, infiltration rates vary based on the weather and system operation. Thus, mechanical systems could potentially operate less if the real-time (RT) infiltration rate was known and used to adjust the mechanical ventilation rate. CONTAM models of two test houses on the campus of the National Institute of Standards and Technology were verified with measurements and used to simulate hourly infiltration rates in three cities. The infiltration rates were passed to a theoretical controller that changed the hourly mechanical ventilation rate to meet the ventilation requirement. Simulated energy use and relative annual occupant exposure for this RT control strategy were compared with ventilation at a constant rate. Implementation of the RT control strategy resulted in annual average energy savings of $66USD across both houses and three cities without increasing the annual occupant exposure compared with ventilating continuously at a constant rate. The authors discuss the advantages and limitations of the proposed RT ventilation control strategy.
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Janiga, Julia, Joanna Krzempka et Aleksandra Szczerbińska. « Identifying mechanical ventilation issues in classrooms ». E3S Web of Conferences 44 (2018) : 00055. http://dx.doi.org/10.1051/e3sconf/20184400055.
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This article focuses on the issues of indoor air quality in mechanically ventilated classrooms. The aim of the study was to determine the reasons for inadequate air quality reported by occupants. Two different ventilation systems were assessed by measuring CO2 and VOC concentrations in classrooms during operating time. Results showed that in both cases, CO2 levels in the air, even though mostly acceptable, were exceeded throughout the measuring periods on occasion. Based on obtained data, in both cases probable causes for reported ventilation system malfunctions were proposed.
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Edriss, Hawa, Shengping Yang, Edna Juarez, Joshua Crane, Michelle Lear, Asley Sanchez et Kenneth Nugent. « The Association Between the Mechanical Ventilator Pressures and Outcomes in a Cohort of Patients with Acute Respiratory Failure ». Clinical Medicine Insights : Circulatory, Respiratory and Pulmonary Medicine 14 (janvier 2020) : 117954842096624. http://dx.doi.org/10.1177/1179548420966246.
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Background: Pressures measured during mechanical ventilation provide important information about the respiratory system mechanics and can help predict outcomes. Methods: The electronic medical records of patients hospitalized between 2010 and 2016 with sepsis who required mechanical ventilation were reviewed to collect demographic information, clinical information, management requirements, and outcomes, such as mortality, ICU length of stay, and hospital length of stay. Mechanical ventilation pressures were recorded on the second full day of hospitalization. Results: This study included 312 adult patients. The mean age is 59.1 ± 16.3 years; 57.4% were men. The mean BMI was 29.3 ± 10.7. Some patients had pulmonary infections (46.2%), and some patients had extrapulmonary infections (34.9%). The overall mortality was 42.6%. In a multi-variable model that included age, gender, number of comorbidities, APACHE 2 score, and PaO2/FiO2 ratio, peak pressure, plateau pressure, driving pressure, and PEEP all predicted mortality when entered into the model separately. There was an increase in peak pressure, plateau pressure, and driving pressure across BMI categories ranging from underweight to obese. Conclusions: This study demonstrates that ventilator pressure measurements made early during the management of patients with acute respiratory failure requiring mechanical ventilation provide prognostic information regarding outcomes, including mortality. Patients with high mechanical ventilator pressures during the early course of their acute respiratory failure require more attention to identify reversible disease processes when possible. In addition, increased BMIs are associated with increased ventilator pressures, and this increases the complexity of the clinical evaluation in the management of obese patients.
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Gayan-Ramirez, Ghislaine N., et Marc L. Decramer. « Diaphragm antioxidant system in controlled mechanical ventilation in piglets : short term vs. prolonged mechanical ventilation response ». Intensive Care Medicine 31, no 10 (22 juillet 2005) : 1303–5. http://dx.doi.org/10.1007/s00134-005-2693-2.
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Berquist, Justin, Carsen Banister et Mathieu Pellissier. « Comparison of Heat Recovery Ventilator Frost Control Techniques in the Canadian Arctic : Preheat and Recirculation ». E3S Web of Conferences 246 (2021) : 11010. http://dx.doi.org/10.1051/e3sconf/202124611010.
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Air-to-air heat/energy recovery ventilators can effectively reduce the cost associated with ventilating a home. However, high indoor moisture levels, in conjunction with extreme temperature differences between the outdoor and indoor air can cause frost accumulation in the mechanical equipment, leading to performance degradation or failure. In this research, a demonstration house using a heat recovery ventilation system in Iqaluit, Nunavut, Canada was used to compare the performance of two frost control techniques: recirculation and electrical preheat. The advantages and disadvantages of each method are outlined to highlight the need to adapt southern strategies to ensure system functionality in the Arctic. The system was equipped with a heat recovery ventilator (HRV) with built-in recirculation technology to defrost the HRV, as well as two electric preheaters that can be used instead of recirculation and prevent frost formation. Between December 2018 and April 2019 the ventilation system’s performance was monitored for seven weeks while using either recirculation or electrical preheat. The experiments showed the ventilation system equipment consumed more absolute energy with electrical preheat than with recirculation as the frost control technique. However, when using recirculation, the ventilation system experienced more losses throughout the ventilation system, causing the whole building to consume more energy due to an increase in energy consumption by the home’s heating system. Moreover, the quantity of outdoor air that was restricted while using recirculation made electrical preheat the superior option for this ventilation system design. The energy use of the ventilation system with electric preheat enabled was 35% lower on a per volume of outdoor air basis. Contrary to some belief that preheating is a poor approach for frost control in heat/energy recovery ventilators, this research finds that preheating can be a more energy efficient method to provide ventilation if controlled well.
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Guerin, Claude, et Jean-Christophe Richard. « Measurement of respiratory system resistance during mechanical ventilation ». Intensive Care Medicine 33, no 6 (25 avril 2007) : 1046–49. http://dx.doi.org/10.1007/s00134-007-0652-9.
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Tehrani, Fleur T., et James H. Roum. « Flex : A New Computerized System for Mechanical Ventilation ». Journal of Clinical Monitoring and Computing 22, no 2 (7 mars 2008) : 121–30. http://dx.doi.org/10.1007/s10877-008-9113-4.
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Su, Marissa, et ehab daoud. « Effect of respiratory effort on target minute ventilation during Adaptive Support Ventilation. » Journal of Mechanical Ventilation 2, no 2 (1 juin 2021) : 53–58. http://dx.doi.org/10.53097/jmv.10022.
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Background: Adaptive support ventilation (ASV) is an intelligent mode of mechanical ventilation protocol which uses a closed-loop control between breaths. The algorithm states that for a given level of alveolar ventilation, there is a particular respiratory rate and tidal volume which achieve a lower work of breathing. The mode allows the clinician to set a desired minute ventilation percentage (MV%) while the ventilator automatically selects the target ventilatory pattern base on these inputs and feedback from the ventilator monitoring system. The goal is to minimize the work of breathing and reduce complications by allowing the ventilator to adjust the breath delivery taking into account the patient’s respiratory mechanics (Resistance, and Compliance). In this study we examine the effect of patients’ respiratory effort on target tidal volume (VT) and Minute Ventilation (V̇e) during ASV using breathing simulator. Methods: A bench study was performed by using the ASL 5000 breathing simulator to compare the target ventilator to actual VT and V̇e value in simulated patients with various level of respiratory effort during ASV on the Hamilton G5 ventilator. The clinical scenario involves simulated adult male with IBW 70kg and normal lung mechanics: respiratory compliance of 70 mL/cm H2O, and airway resistance of 9 cm H2O/L/s. Simulated patients were subjected to five different level of muscle pressure (Pmus): 0 (Passive), -5, -10, -15, -25 (Active) cm H2O at a set respiratory rate of 10 (below targeted VT) set at three different levels of minute ventilation goals: 100%, 200%, and 300%, with a PEEP of 5 cm H2O. Fifty breaths were analyzed in every experiment. Means and standard deviations (SD) of variables were calculated. One way analysis of variants was done to compare the values. Pearson correlation coefficient test was used to calculate the correlation between the respiratory effort and the VT, V̇e, and peak inspiratory pressure (PIP). Results: The targeted VT and V̇e were not significant in the passive patient when no effort was present, however were significantly higher in the active states at all levels of Pmus on the 100%, 200% and the 300 MV%. The VT and V̇e increase correlated with the muscle effort in the 100 and 200 MV% but did not in the 300%. Conclusions: Higher inspiratory efforts resulted in significantly higher VT and V̇e than targeted ones. Estimating patients’ effort is important during setting ASV. Keywords: Mechanical ventilation, ASV, InteliVent, Pmus, tidal volume, percent minute ventilation
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Zhang, Chenchen, et Hejiang Sun. « Analysis and Modeling of Mechanical Ventilation Operation Behaviors of Occupants in Cold Regions of North China ». Applied Sciences 12, no 10 (19 mai 2022) : 5143. http://dx.doi.org/10.3390/app12105143.
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Mechanical ventilation has a great impact on building simulation performance, such as indoor environment quality and building energy consumption. However, there is still a lack of accurate mechanical ventilation models established from long-term field data that can effectively predict building performance. In this study, one-year measurements on mechanical ventilation operation behavior were collected from 85 apartments, which were conducted with a mechanical ventilation system of the same brand in cold regions of North China. This permitted statistical analysis and clustering of the mechanical ventilation operation behavior by using the K-means method, leading to five behavior patterns. The results showed that 24% households operated mechanical ventilation system nearly all day, and there was a large difference in usage behaviors between the split system and the centralized system. Furthermore, two classes of models based on random forest and logistic regression were developed for predicting mechanical ventilation system operation (on/off) behavior. The models based on random forest showed high accuracy as it resulted in a 0.992 average in predictions. These models using field data can guide the selection of accurate input boundary conditions of mechanical ventilation and improve the accuracy of dwelling numerical simulations.
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Whalley, R., et A. Abdul-Ameer. « Ventilation system airflow dynamics ». Proceedings of the Institution of Mechanical Engineers, Part I : Journal of Systems and Control Engineering 224, no 3 (25 mars 2010) : 305–20. http://dx.doi.org/10.1243/09596518jsce960.
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Lin, Shyan Lung, San Shan Hung, Ching Kun Chen et Hsing Cheng Chang. « A Novel and Experimental Design for Mechanical Ventilation with Optimal Spontaneous Flow Pattern and WOB Feedback Control ». Applied Mechanics and Materials 284-287 (janvier 2013) : 2189–93. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.2189.
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In this study, we proposed an innovative design for mechanical ventilation by applying the previously implemented optimal respiratory control simulator as the controller of an experimental ventilation device. Instead of providing a fixed airflow pattern, an optimal spontaneous flow pattern was optimized by the simulator based on patient’s estimated respiratory mechanics and was applied to drive a ventilation device. We also implemented an experimental ventilation control system, including the simulator, a ventilation device, an artificial lung, and a feedback control mechanism to attain minimum work of breathing during mechanical ventilation. The experiments were elaborated to verify that once patient’s respiratory physiology was significant changed, the breathing signals and measured respiratory mechanics were instantaneously monitored, and the optimization process was renewed by the simulator under the feedback control strategy.
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Wilkens, MD, MPH, Eric P., et Gary M. Klein, MD, MPH, MBA. « Mechanical ventilation in disaster situations : A new paradigm using the AGILITIES Score System ». American Journal of Disaster Medicine 5, no 6 (1 novembre 2010) : 369–84. http://dx.doi.org/10.5055/ajdm.2010.0043.
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Background: The failure of life-critical systems such as mechanical ventilators in the wake of a pandemic or a disaster may result in death, and therefore, state and federal government agencies must have precautions in place to ensure availability, reliability, and predictability through comprehensive preparedness and response plans.Methods: All 50 state emergency preparedness response plans were extensively examined for the attention given to the critically injured and ill patient population during a pandemic or mass casualty event. Public health authorities of each state were contacted as well.Results: Nine of 51 state plans (17.6 percent) included a plan or committee for mechanical ventilation triage and management in a pandemic influenza event. All 51 state plans relied on the Centers for Disease Control and Prevention Flu Surge 2.0 spreadsheet to provide estimates for their influenza planning. In the absence of more specific guidance, the authors have developed and provided guidelines recommended for ventilator triage and the implementation of the AGILITIES Score in the event of a pandemic, mass casualty event, or other catastrophic disaster.Conclusions: The authors present and describe the AGILITIES Score Ventilator Triage System and provide related guidelines to be adopted uniformly by government agencies and hospitals.This scoring system and the set of guidelines are to be used in disaster settings, such as Hurricane Katrina, and are based on three key factors: relative health, duration of time on mechanical ventilation, and patients’ use of resources during a disaster. For any event requiring large numbers of ventilators for patients, the United States is woefully unprepared. The deficiencies in this aspect of preparedness include (1) lack of accountability for physical ventilators, (2) lack of understanding with which healthcare professionals can safely operate these ventilators, (3) lack of understanding from where additional ventilator resources exist, and (4) a triage strategy to provide ventilator support to those patients with the greatest chances of survival.
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Wilkens, MD, MPH, Eric P., et Gary M. Klein, MD, MPH, MBA. « Mechanical ventilation in disaster situations : A new paradigm using the AGILITIES Score System ». American Journal of Disaster Medicine 14, no 4 (1 octobre 2019) : 311–26. http://dx.doi.org/10.5055/ajdm.2019.0347.
Texte intégralRésumé :
Background: The failure of life-critical systems such as mechanical ventilators in the wake of a pandemic or a disaster may result in death, and therefore, state and federal government agencies must have precautions in place to ensure availability, reliability, and predictability through comprehensive preparedness and response plans.Methods: All 50 state emergency preparedness response plans were extensively examined for the attention given to the critically injured and ill patient population during a pandemic or mass casualty event. Public health authorities of each state were contacted as well.Results: Nine of 51 state plans (17.6 percent) included a plan or committee for mechanical ventilation triage and management in a pandemic influenza event. All 51 state plans relied on the Centers for Disease Control and Prevention Flu Surge 2.0 spreadsheet to provide estimates for their influenza planning. In the absence of more specific guidance, the authors have developed and provided guidelines recommended for ventilator triage and the implementation of the AGILITIES Score in the event of a pandemic, mass casualty event, or other catastrophic disaster.Conclusions: The authors present and describe the AGILITIES Score Ventilator Triage System and provide related guidelines to be adopted uniformly by government agencies and hospitals. This scoring system and the set of guidelines are to be used in disaster settings, such as Hurricane Katrina, and are based on three key factors: relative health, duration of time on mechanical ventilation, and patients’ use of resources during a disaster. For any event requiring large numbers of ventilators for patients, the United States is woefully unprepared. The deficiencies in this aspect of preparedness include (1) lack of accountability for physical ventilators, (2) lack of understanding with which healthcare professionals can safely operate these ventilators, (3) lack of understanding from where additional ventilator resources exist, and (4) a triage strategy to provide ventilator support to those patients with the greatest chances of survival.
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Birtürk, Aslı, Orhan Ekren, Sinan Aktakka, Özdem Özel et Macit Toksoy. « Solar Powered Mechanical Ventilation : A case study ». E3S Web of Conferences 111 (2019) : 01058. http://dx.doi.org/10.1051/e3sconf/201911101058.
Texte intégralRésumé :
In this study, a solar powered mechanical ventilation unit has investigated and tested in terms of efficiency and performance. Test unit can be divided into two parts, the first one is ventilation unit with 370 m3/h max airflow rate and max 167 W fan power provides fresh air for a residency and recovers heat from the climatized exhaust air. Total area is 70 m2 for the residency and total occupant is four. The second part of the test system is solar energy power system with two 325 W polycrystalline photovoltaic panels, an inverter and two batteries. The mechanical ventilation unit has energized by a solar photovoltaic system; if the solar energy is not available then ventilation unit has connected to the national electricity grid. This is an alternative option to consumers to use electricity by the grid in case the PV system does not produce enough energy because of the usage or the technical problems or the weather conditions based on the seasons. On the other hand, in some cities, number of photovoltaic panels rolled up upper number according to solar energy potential and therefore resulted excess electricity has assumed to sell to the national grid. According to the results, the test system is able to operate at maximum ventilation necessity and power consumption without grid connection in Izmir. Furthermore, we have compared Izmir and Romania in accordance with feasibility for the same mechanical ventilation system at max flow rate and required ventilation rate is determined depends on daily usage scenario of the room.
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Lichtwarck-Aschoff, Michael, Bela Suki, Anders Hedlund, Ulf H. Sjöstrand, Agneta Markström, Rafael Kawati, Göran Hedenstierna et Josef Guttmann. « Decreasing size of cardiogenic oscillations reflects decreasing compliance of the respiratory system during long-term ventilation ». Journal of Applied Physiology 96, no 3 (mars 2004) : 879–84. http://dx.doi.org/10.1152/japplphysiol.00532.2003.
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Part of the energy produced by the heartbeat is transferred to the lung and promotes intrapulmonary gas mixing. It is likely that this transmission in the form of local mechanical disturbances affects and reflects respiratory mechanics. The effects of the cardiogenic oscillations were studied in seven piglets during 7 h of monotonous mechanical ventilation. During the 1st h of ventilation, every heartbeat triggered a noticeable transient increase in lung volume of 14 ml (95% confidence interval = 10-17 ml). After 7 h, the increase in lung volume due to heartbeat significantly decreased to 7 ml (95% confidence interval = 2-9 ml, P < 0.05). During the course of ventilation, overall lung compliance and gas exchange were progressively compromised. We conclude that 1) sufficient mechanical energy is transferred from the beating heart to the lung to increase lung volume, and 2) the ability of the heartbeats to help increase lung volume is reduced during long-term ventilation, which reflects the changes in lung compliance.
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Smith, Barbara K., David D. Fuller, A. Daniel Martin, Lawrence Lottenberg, Saleem Islam, Lee Ann Lawson, Raymond P. Onders et Barry J. Byrne. « Diaphragm Pacing as a Rehabilitative Tool for Patients With Pompe Disease Who Are Ventilator-Dependent : Case Series ». Physical Therapy 96, no 5 (1 mai 2016) : 696–703. http://dx.doi.org/10.2522/ptj.20150122.
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Background and Purpose Pompe disease is an inherited disorder notable for severe, progressive ventilatory compromise. Although ventilatory failure has been attributed to myofiber dysfunction secondary to diaphragmatic glycogen accumulation, neural involvement of the phrenic motor system is also a prominent feature. Direct diaphragm pacing supplements respiratory function in other disorders of the phrenic motor system. Accordingly, it is hypothesized that augmented neuromuscular activity via diaphragm pacing would promote weaning from mechanical ventilation in patients with Pompe disease who are unresponsive to conventional, muscle-directed treatments. Case Description Three patients with Pompe disease developed diaphragm paresis that resulted in chronic mechanical ventilation dependence. After preoperative inspiratory muscle strengthening exercises failed to improve function, fine-wire pacing electrodes were laparoscopically implanted into the diaphragm. Diaphragm conditioning was initiated the first postoperative week and consisted of gradual increases in stimulation parameters, lengthening of stimulation sessions, and ventilator weaning. Ventilation and intramuscular electromyographic activity were recorded periodically during conditioning to quantify diaphragm neuromuscular function. Outcomes During paced breathing without mechanical ventilation, tidal volumes increased, and 2 patients were weaned from daytime ventilator dependence within the first 3 months of pacing, which has been sustained over the long-term. A third patient reduced reliance on daytime ventilation, but weaning was delayed by malacia of the large airways. In all patients, pacing appeared to facilitate spontaneous phrenic motor unit activity during independent breathing without ventilator or pacer support. Discussion The findings are consistent with the view that diaphragm pacing has potential rehabilitative value to reduce reliance on mechanical ventilation in people with Pompe disease, but further study is needed. Diaphragm pacing represents a paradigm shift in the management of respiratory insufficiency for Pompe disease that warrants further controlled examination.
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Kurniawan Taufiq Kadafi, Erviani Maulidya, William Prayogo Susanto et Saptadi Yuliarto. « Mechanical ventilation practice of pediatric patients with Covid-19 in Indonesian tertiary hospital ». Pediatrics Sciences Journal 2, no 1 (3 février 2022) : 15–19. http://dx.doi.org/10.51559/pedscij.v2i1.22.
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Background: Coronavirus Disease-2019 (COVID-19) in children tend to have milder clinical manifestation. However, some develop critical conditions and require mechanical ventilation in the Pediatric Intensive Care Unit (PICU). Various modalities are recommended for mechanical ventilation, such as High Flow Nasal Cannula (HFNC), Continuous Positive Airway Pressure (CPAP), or invasive ventilation with intubation. This study aims to describe the clinical feature, ventilation modalities usage, and the outcome of children with critical COVID-19.
Methods: This is a retrospective study in COVID-19 children with respiratory distress who were treated in the COVID-19 isolation PICU room of Saiful Anwar General Hospital for one year. The data was gained from the medical record and analyzed descriptively. Data were analyzed using Ms. Excel for Windows.
Results: A total of 51 children with COVID-19 were admitted to Saiful Anwar general Hospital in one year period, with 12 of them in critical condition and 6 children require mechanical ventilation. The main signs developed were fever and dyspnea. Invasive mechanical ventilation applicated in 5 patients, and only 1 patient received Non-Invasive Ventilation (NIV). The mean of PEEP used in invasive ventilation is 7-9 cmH2O, lower than ESPNIC’s recommendation of 8-10 cmH2O. Length of ventilator usage is 2-21 days, with 2 patients passed away, both with a comorbid and organ system injury.
Conclusion: The mechanical ventilation setting must be determined individually based on the patients’ condition, despite several guidelines providing the recommendation.
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Ku, Jae-Hyun. « A Study on Characteristic Analysis for Indoor Ventilation Performance of Mechanical Ventilation System ». Journal of the Korean Institute of Gas 16, no 2 (30 avril 2012) : 31–37. http://dx.doi.org/10.7842/kigas.2012.16.2.31.
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Hayashi, Motoya, Hoon kim, Yoshinori Honma et Junichiro Matsunaga. « Feasibility of a Passive Ventilation System with a Thermal Damper - Simulations and measurement results of an experimental house in a mild region of Japan - ». E3S Web of Conferences 111 (2019) : 06047. http://dx.doi.org/10.1051/e3sconf/201911106047.
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In order to retain good indoor air quality through the year in detached houses with passive ventilation systems, the authors investigated a mechanical control air-supply method. Firstly, indoor environments in houses with passive ventilation systems with thermal dampers, were examined using a simulation program (Fresh). Secondly, a passive ventilation system with a thermal damper, an under-floorheating system with a heat pump and were installed in an airtight house at Maebashi in Japan and measurements on its ventilation characteristics and indoor air quality were made. The simulation results showed that if the thermal damper is well tuned, this mechanically controlled air-supply opening keeps ventilation rates adequate through the year especially in airtight houses. The measurement results showed that the ventilation rates were kept above the required level through the year and the TVOC concentration decreases from 3000 to 200 μg/m3 in 5 months after the construction.
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Savchenko, Olena, Vasyl Zhelykh et Hendrik Voll. « Analysis of the systems of ventilation of residential houses of Ukraine and Estonia ». Selected Scientific Papers - Journal of Civil Engineering 12, no 2 (1 décembre 2017) : 23–30. http://dx.doi.org/10.1515/sspjce-2017-0015.
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Abstract The most common ventilation system in residential buildings in Ukraine is natural ventilation. In recent years, due to increased tightness of structures, an increase in the content of synthetic finishing materials in them, the quality of microclimate parameters deteriorated. One of the measures to improve the parameters of indoor air in residential buildings is the use of mechanical inflow and exhaust ventilation system. In this article the regulatory documents concerning the design of ventilation systems in Ukraine and Estonia and the requirements for air exchange in residential buildings are considered. It is established that the existing normative documents in Ukraine are analogous to European norms, which allow design the system of ventilation of residential buildings according to European standards. However, the basis for the design of ventilation systems in Ukraine is the national standards, in which mechanical ventilation, unfortunately, is provided only for the design of high-rise buildings. To maintain acceptable microclimate parameters in residential buildings, it is advisable for designers to apply the requirements for designing ventilation systems in accordance with European standards.
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Ju, Fa-Li, Qinrong Sun, Changlei Hou, Xue Huang, Xiaoping Yu et Liying Liu. « Test and analysis of air flow rate adaptive performance in a distributed fan ventilation system ». Building Services Engineering Research and Technology 42, no 2 (6 janvier 2021) : 223–36. http://dx.doi.org/10.1177/0143624420986000.
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In this study, adaptive branch fan performance in a distributed fan ventilation system was tested. The results demonstrate that the adaptive branch fan stabilises the branch air flow rate within a certain air pressure range corresponding to the branch duct inlet, and this range becomes increasingly narrow as the fan control signal is adjusted to reduce the speed of the fan. The adaptive branch fan is less affected by the main fan and other branch fans in the distributed fan ventilation system because it has a good self-adaptive ability of ventilation duct resistance characteristics and anti-interference ability of the air flow rate. Furthermore, the hydraulic characteristics of the branch fans in the distributed fan ventilation system were analysed. The new performance characterisation parameters and method for modifying the engineering design for the adaptive branch fan were presented. Practical application: This study investigates the adaptive performance of the branch fan in a distributed fan ventilation system. Our results demonstrate that the new branch fan can stabilise the air flow rate in a mechanical ventilation system. More importantly, we not only propose performance characterisation parameters of the adaptive branch fan that are important for understanding the operation of a mechanical ventilation system, but also present a method of engineering design application. This study can guide the design and operation of mechanical ventilation systems.
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KARTACHI, YOUNES, et ABDELLAH MECHAQRANE. « NUMERICAL SIMULATION AND PARAMETRIC STUDIES FOR EVALUATION OF BALANCED VENTILATION AND EARTH AIR EXCHANGERS SYSTEM COUPLED TO A DOMESTIC BUILDING ». International Journal of Air-Conditioning and Refrigeration 21, no 01 (mars 2013) : 1350002. http://dx.doi.org/10.1142/s2010132513500028.
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In this study, we analyze the impact of ventilation heat recovery with the heating and cooling potential of earth air heat exchanger in real climatic conditions in domestic buildings in the Middle Atlas region. In our case study, we calculate the primary energy used by a domestic building built as per the conventional house design parameters required by the Moroccan regulation. We use climate data for the city of Fes in Northern Moroccan. Three system configurations were considered. The first was the mechanical extract ventilation system both with and without heat recovery. The second was the mechanical extract ventilation system with earth to air heat exchanger system (EAHEX), and the third system was the mechanical balanced ventilation system coupled with EAHEX system. Primary energy use strongly influences natural resources efficiency and the environmental impacts of energy supply activities. In this study we explore the primary energy implications of the mechanical balanced ventilation system coupled with the EAHEX system in residential buildings. The results of this study shows that the use of a balanced ventilation system, with a high efficiency instead of a mechanical extract ventilation system, decreases the final and primary energy consumption. Moreover, it decreases or increases the CO2 emission depending on the primary energy sources.
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Ambos, Edgar C., Evan Neil V. Ambos et Lanndon A. Ocampo. « Modeling the Applicability of a Displacement Ventilation System ». International Journal of Manufacturing, Materials, and Mechanical Engineering 11, no 1 (janvier 2021) : 63–89. http://dx.doi.org/10.4018/ijmmme.2021010105.
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Due to its significant role in improving indoor air quality, displacement ventilation system is widely adopted in current literature. This paper proposes a displacement ventilation system for room conditions with ceilings that are relatively low, internal heat load could be high, walls could be sunlit, and occupants doing the low physical activity. These conditions are prevalent in the Philippines, being a tropical country. Input parameters to the design process such as heat load, the height of the ceiling, comfort, and indoor air quality requirements were generated, and the main output parameters are the stratification height and ventilation airflow rate. To demonstrate the proposed displacement ventilation system, four cases were generated. Results show that the ventilation airflow rates obtained from the four cases were greater than the minimum outdoor air requirements for health in conference rooms and large assembly areas which are 17.5 and 3.5 liters/sec*person respectively, for smoking and no smoking rooms.
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Chatburn, Robert. « Four Truths of Mechanical Ventilation and the Ten-Fold Path to Enlightenment ». Journal of Mechanical Ventilation 2, no 3 (15 septembre 2021) : 73–78. http://dx.doi.org/10.53097/jmv.10028.
Texte intégralRésumé :
The Four Truths 1. The truth of confusion 2. The truth of the origin of confusion 3. The truth of the cessation of confusion 4. The truth of the path leading to the cessation of confusion The 10-Fold Path 1. A breath is one cycle of positive flow (inspiration) and negative flow (expiration) defined in terms of the flow-time curve. 2. A breath is assisted if the ventilator does work on the patient. 3. A ventilator assists breathing using either pressure control or volume control based on the equation of motion for the respiratory system. 4. Breaths are classified by the criteria that trigger (start) and cycle (stop) inspiration 5. Trigger and cycle events can be initiated by the patient or the machine. 6. Breaths are classified as spontaneous or mandatory based on both the trigger and cycle events. 7. There are 3 breath sequences: Continuous mandatory ventilation (CMV), Intermittent Mandatory Ventilation (IMV), and Continuous Spontaneous Ventilation (CSV). 8. There are 5 basic ventilatory patterns: VC-CMV, VC-IMV, PC-CMV, PC-IMV, and PC-CSV: 9. Within each ventilatory pattern there are several variations that can be distinguished by their targeting scheme(s). 10. A mode of ventilation is classified according to its control variable, breath sequence, and targeting scheme(s). Keywords: Breath. Trigger, Cycle, Breath sequences, Ventilatory patterns, Mode of ventilation
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Qi, Yue, Junjie Liu, Xilei Dai, Lei Zhao, Dayi Lai et Shen Wei. « Investigation of Ventilation Behaviors in Mechanically Ventilated Residential Buildings in China ». E3S Web of Conferences 111 (2019) : 06048. http://dx.doi.org/10.1051/e3sconf/201911106048.
Texte intégralRésumé :
Mechanical ventilation system provides a more reliable, controllable, and comfortable way of ventilation than natural ventilation through an opened window. However, the operation of mechanical ventilation system cost energy. This study investigated the usage of natural and mechanical ventilation in 46 apartments in ten cities across five different climate zones in China by on-site monitoring and questionnaire survey. On average, the daily natural and mechanical ventilation durations were 11 hours and 7.2 hours, respectively. Large differences existed among climate regions and seasons. From north to south, as the climate became warmer, the usage of natural ventilation increased. From seasonal perspectives, natural ventilation duration was the longest in summer and the shortest in winter. The trend of mechanical ventilation usage was opposite to that of natural ventilation. Generally, as the outdoor air temperature increased, the duration of natural ventilation increased and the duration of mechanical ventilation decreased. This study proposed an outline to use thermal comfort, health, and energy saving as three motivations to analyze ventilation behaviors. Based on the obtained results, suggestions were made for achieving healthy, thermally comfortable, and energy efficient ventilation in residential buildings.
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Kjonegaard, Rebecca, Willa Fields et Major L. King. « Current Practice in Airway Management : A Descriptive Evaluation ». American Journal of Critical Care 19, no 2 (1 mars 2010) : 168–73. http://dx.doi.org/10.4037/ajcc2009803.
Texte intégralRésumé :
Background Ventilator-associated pneumonia, a common complication of mechanical ventilation, could be reduced if health care workers implemented evidence-based practices that decrease the risk for this complication. Objectives To determine current practice and differences in practices between registered nurses and respiratory therapists in managing patients receiving mechanical ventilation. Methods A descriptive comparative design was used. A convenience sample of 41 registered nurses and 25 respiratory therapists who manage critical care patients treated with mechanical ventilation at Sharp Grossmont Hospital, La Mesa, California, completed a survey on suctioning techniques and airway management practices. Descriptive and inferential statistics were used to analyze the data. Results Significant differences existed between nurses and respiratory therapists for hyperoxygenation before suctioning (P =.03). In the 2 groups, nurses used the ventilator for hyper-oxygenation more often, and respiratory therapists used a bag-valve device more often (P =.03). Respiratory therapists instilled saline (P <.001) and rinsed the closed system with saline after suctioning (P =.003) more often than nurses did. Nurses suctioned oral secretions (P <.001) and the nose of orally intubated patients (P =.01), brushed patients’ teeth with a toothbrush (P<.001), and used oral swabs to clean the mouth (P <.001) more frequently than respiratory therapists did. Conclusion Nurses and respiratory therapists differed significantly in the management of patients receiving mechanical ventilation. To reduce the risk of ventilator-associated pneumonia, both nurses and respiratory therapists must be consistent in using best practices when managing patients treated with mechanical ventilation.
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METE, Cem, Gülfer AKÇA, Ünal AKÇA et Nazik YENER. « Pediatric intensive care unit tracheostomy experiences in Ondokuz Mayıs University Faculty of Medicine ». Journal of Experimental and Clinical Medicine 39, no 2 (18 mars 2022) : 403–8. http://dx.doi.org/10.52142/omujecm.39.2.18.
Texte intégralRésumé :
In this study; patients who underwent conventional tracheostomy while being followed up on a mechanical ventilator with endotracheal intubation in their pediatric intensive care unit were evaluated retrospectively. It was aimed to share the positive changes observed in clinical-mechanical ventilator parameters with the literature. Study data were obtained from the hospital information management system and recorded in the "Child Patient Evaluation Form with Tracheostomy" as follows: Demographic data, diagnosis of admission to pediatric intensive care unit, indications for mechanical ventilation and tracheostomy, changes in post-procedure mechanical ventilation parameters, tracheostomy complications, decannulation, survival and death rates etc. Post-discharge medical records were created by telephone interviews with parents. IBM SPSS 21 (Statistical Package for Social Sciences) program was used for statistical analysis. In our study; the most common indication (67.0%) for tracheostomy was the need for prolonged mechanical ventilation. Peak inspiratory pressure requirement on mechanical ventilator decreased statistically and tidal volume increased significantly in those who underwent tracheostomy due to prolonged mechanical ventilation requirement (both p<0.001). On the other hand, the mean length of stay in the pediatric intensive care unit after the procedure was statistically significantly shorter (p<0.001). Decannulation success was statistically significantly higher in those who underwent tracheostomy due to upper airway obstruction (p<0.02). In our study; only four (6.2%) patients died due to tracheotomy (cannula occlusion, unplanned decannulation, etc.). Clinicians should consider tracheostomy if extubation cannot be achieved in children and adolescents who have been given mechanical ventilation for a long time (>2-4 weeks) due to progressive primary disease. Tracheotomy should definitely be performed within appropriate medical indications in order to shorten the length of stay in the hospital/Pediatric intensive care unit and to provide medical care outside the hospital (e.g.; a suitable home environment) in order to create general psychosocial-physical well-being in the patients.