scholarly journals Simulated Ventilation of Two Patients With a Single Ventilator in a Pandemic Setting

2021 ◽  
Author(s):  
Pascal Schepat ◽  
Benjamin Kober ◽  
Martin Eble ◽  
Volker Wenzel ◽  
Holger Herff
Keyword(s):  
Gas Flow ◽  
Minute Ventilation ◽  
Clinical Situation ◽  
Flow Sensor ◽  
Laboratory Simulation ◽  
Flow Limitation ◽  
Controlled Ventilation ◽  
Pressure Controlled Ventilation ◽  
3D Printed ◽  
Pressure Controlled

Abstract Background: Simultaneous ventilation of two patients, e.g., due to a shortage of ventilators in a pandemic, may result in hypoventilation in one patient and hyperinflation in the other patient. Methods: In a simulation of double patient ventilation using artificial lungs with equal compliances (70mL∙mbar-1), we tried to voluntarily direct gas flow to one patient by using 3D-printed y-adapters and stenosis adapters during volume-, and pressure-controlled ventilation. Subsequently, we modified the model using a special one-way valve on the limited flow side and measured in pressure-controlled ventilation with the flow sensor adjusted on either side in a second and third setup. In the last setup, we also measured with different lung compliances.Results: Volume- or pressure-controlled ventilation using standard connection tubes with the same compliance in each lung resulted in comparable minute volumes in both lungs, even if one side was obstructed to 3mm (6.6±0.2vs.6.5±0.1L for volume-controlled ventilation, p=.25 continuous severe alarm and 7.4±0.1vs.6.1±0.1L for pressure-controlled ventilation, p=.02 no alarm). In the second setup, pressure-controlled ventilation resulted at a 3mm flow limitation in minute ventilation of 9.4±0.3vs3.5±0.1L∙min-1, p=.001. In a third setup using the special one-way valve and the flow sensor on the unobstructed side, pressure-controlled ventilation resulted at a 3mm flow limitation in minute ventilation of 7.4±0.2vs3±0L∙min-1, at the compliance of 70mL∙mbar-1 for both lungs, 7.2±0vs4.1±0L∙ min-1, at the compliances of 50 vs. 70mL∙mbar-1, and 7.2±0.2vs5.7±0L∙ min-1, at the compliance of 30 vs. 70mL∙mbar-1 (all p=.001).Conclusions: Overriding a modern intensive care ventilator's safety features are possible, thereby ventilating two lungs with one ventilator simultaneously in a laboratory simulation using 3D-printed y-adapters. Directing tidal volumes in different pulmonary conditions towards one lung using 3D-printed flow limiters with diameters <6mm was also possible. While this ventilation setting was technically feasible in a bench model, it would be volatile, if not dangerous in a clinical situation.

scholarly journals Simulated Ventilation of two Patients with a Single Ventilator in a Pandemic Setting

2021 ◽  
Author(s):  
Pascal Schepat ◽  
Benjamin Kober ◽  
Martin Eble ◽  
Volker Wenzel ◽  
Holger Herff
Keyword(s):  
Gas Flow ◽  
Minute Ventilation ◽  
Clinical Situation ◽  
Flow Sensor ◽  
Laboratory Simulation ◽  
Flow Limitation ◽  
Controlled Ventilation ◽  
Pressure Controlled Ventilation ◽  
3D Printed ◽  
Pressure Controlled

Abstract Background: Simultaneous ventilation of two patients, e.g. due to a shortage of ventilators in a pandemic, may result in hypoventilation in one patient and hyperinflation in the other patient. Methods: In a simulation of double patient ventilation using artificial lungs with equal compliances (70mL∙mbar-1), we tried to voluntarily direct gas flow to one patient by using 3D-printed y-adapters and stenosis adapters during volume-, and pressure-controlled ventilation. Subsequently, we modified the model using a special one-way valve on the limited flow side and measured in pressure-controlled ventilation with the flow sensor adjusted to either side in a second and third setup. In the last setup, we also measured with different lung compliances.Results: Volume- or pressure-controlled ventilation using standard connection tubes with the same compliance in each lung resulted in comparable minute volumes in both lungs, even if one side was obstructed to 3mm (6.6±0.2vs.6.5±0.1L for volume-controlled ventilation, p=.25 continuous severe alarm and 7.4±0.1vs.6.1±0.1L for pressure-controlled ventilation, p=.02 no alarm). In the second setup, pressure-controlled ventilation resulted at 3mm flow limitation in minute ventilation of 9.4±0.3vs3.5±0.1L∙min-1, p=.001. In a third setup using the special one-way valve and the flow sensor on the unobstructed side, pressure-controlled ventilation resulted at 3mm flow limitation in minute ventilation of 7.4±0.2vs3±0L∙min-1, at the compliance of 70mL∙mbar-1 for both lungs, 7.2±0vs4.1±0L∙ min-1, at the compliances of 50 vs. 70mL∙mbar-1, and 7.2±0.2vs5.7±0L∙ min-1, at the compliance of 30 vs. 70mL∙mbar-1 (all p=.001).Conclusions: Overriding a modern intensive care ventilator's safety features are possible, thereby ventilating two lungs with one ventilator simultaneously in a laboratory simulation using 3D-printed y-adapters. Directing tidal volumes in different pulmonary conditions towards one lung using 3D-printed flow limiters with diameters <6mm was also possible. While this ventilation setting was technically feasible in a bench model, it would be volatile, if not dangerous in a clinical situation.

Crisis Ventilator: A 3D Printed Option for Pressure Controlled Ventilation

2020 ◽  
Author(s):  
Alex Brito ◽  
Evan Fontaine ◽  
S. James El Haddi ◽  
Albert Chi MD FACS
Keyword(s):  
Raw Materials ◽  
Tension Pneumothorax ◽  
Pressure Control ◽  
Control Ventilation ◽  
Pressure Control Ventilation ◽  
Controlled Ventilation ◽  
Pressure Controlled Ventilation ◽  
Clinical Scenarios ◽  
3D Printed ◽  
Pressure Controlled

Abstract During the Coronavirus-19, or COVID-19, pandemic there was an early shortage of available ventilators. Domestic production was limited by dependence on overseas sources of raw materials despite partnering with automotive manufacturers. Our group has developed a 3D printed alternative called the CRISIS ventilator. Its design is similar to existing resuscitator devices on the market and uses a modified Pressure-Control ventilation. Here we compare the performance of the device on a simulated ARDS lung and handling of different clinical scenarios included tension pneumothorax and bronchospasm.

Comparison of mathematical and mechanical models of pressure-controlled ventilation

1993 ◽  
Vol 74 (2) ◽  
pp. 922-933 ◽  
Author(s):  
W. C. Burke ◽  
P. S. Crooke ◽  
T. W. Marcy ◽  
A. B. Adams ◽  
J. J. Marini
Keyword(s):  
Respiratory System ◽  
Minute Ventilation ◽  
Pressure Fluctuations ◽  
Applied Pressure ◽  
Flow Profile ◽  
Alveolar Pressure ◽  
Controlled Ventilation ◽  
Pressure Controlled Ventilation ◽  
Impedance Conditions ◽  
Pressure Controlled

Recent evidence that volume-cycled mechanical ventilation may itself produce lung injury has focused clinical attention on the pressure waveform applied to the respiratory system. There has been an increasing use of pressure-controlled ventilation (PCV), because it limits peak cycling pressure and provides a decelerating flow profile that may improve gas exchange. In this mode, however, the relationships are of machine adjustments to ventilation and alveolar pressure are not straightforward. Consequently, setting selection remains largely an empirical process. In previous work, we developed a biexponential model of PCV that provides a conceptual framework for understanding these interactions (J. Appl. Physiol. 67: 1081–1092, 1989). We tested the validity of this mathematical model in a single-compartment analogue of the respiratory system across wide ranges of clinician-set variables (frequency, duty cycle, applied pressure) and impedance conditions (inspiratory and expiratory resistance and system compliance). Our data confirm the quantitative validity of the proposed model when approximately rectilinear waves of pressure are applied and appropriate values for impedance are utilized. Despite a fixed-circuit configuration, however, resistance proved to be a function of each clinician-set variable, requiring remeasurement of system impedance as adjustments in these variables were made. With further modification, this model may provide a practical as well as a conceptual basis for understanding minute ventilation and alveolar pressure fluctuations during PCV in the clinical setting.

scholarly journals Comparison of Volume-Guaranteed or -Targeted, Pressure-Controlled Ventilation with Volume-Controlled Ventilation during Elective Surgery: A Systematic Review and Meta-Analysis

2021 ◽  
Vol 10 (6) ◽  
pp. 1276
Author(s):  
Volker Schick ◽  
Fabian Dusse ◽  
Ronny Eckardt ◽  
Steffen Kerkhoff ◽  
Simone Commotio ◽  
...  
Keyword(s):  
Systematic Review ◽  
Elective Surgery ◽  
Meta Analysis ◽  
Lung Ventilation ◽  
One Lung Ventilation ◽  
Controlled Ventilation ◽  
Pressure Controlled Ventilation ◽  
Volume Controlled Ventilation ◽  
Volume Controlled ◽  
Pressure Controlled

For perioperative mechanical ventilation under general anesthesia, modern respirators aim at combining the benefits of pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) in modes typically named “volume-guaranteed” or “volume-targeted” pressure-controlled ventilation (PCV-VG). This systematic review and meta-analysis tested the hypothesis that PCV-VG modes of ventilation could be beneficial in terms of improved airway pressures (Ppeak, Pplateau, Pmean), dynamic compliance (Cdyn), or arterial blood gases (PaO2, PaCO2) in adults undergoing elective surgery under general anesthesia. Three major medical electronic databases were searched with predefined search strategies and publications were systematically evaluated according to the Cochrane Review Methods. Continuous variables were tested for mean differences using the inverse variance method and 95% confidence intervals (CI) were calculated. Based on the assumption that intervention effects across studies were not identical, a random effects model was chosen. Assessment for heterogeneity was performed with the χ2 test and the I2 statistic. As primary endpoints, Ppeak, Pplateau, Pmean, Cdyn, PaO2, and PaCO2 were evaluated. Of the 725 publications identified, 17 finally met eligibility criteria, with a total of 929 patients recruited. Under supine two-lung ventilation, PCV-VG resulted in significantly reduced Ppeak (15 studies) and Pplateau (9 studies) as well as higher Cdyn (9 studies), compared with VCV [random effects models; Ppeak: CI −3.26 to −1.47; p < 0.001; I2 = 82%; Pplateau: −3.12 to −0.12; p = 0.03; I2 = 90%; Cdyn: CI 3.42 to 8.65; p < 0.001; I2 = 90%]. For one-lung ventilation (8 studies), PCV-VG allowed for significantly lower Ppeak and higher PaO2 compared with VCV. In Trendelenburg position (5 studies), this effect was significant for Ppeak only. This systematic review and meta-analysis demonstrates that volume-targeting, pressure-controlled ventilation modes may provide benefits with respect to the improved airway dynamics in two- and one-lung ventilation, and improved oxygenation in one-lung ventilation in adults undergoing elective surgery.

Lung regional stress and strain as a function of posture and ventilatory mode

2011 ◽  
Vol 110 (5) ◽  
pp. 1374-1383 ◽  
Author(s):  
Gaetano Perchiazzi ◽  
Christian Rylander ◽  
Antonio Vena ◽  
Savino Derosa ◽  
Debora Polieri ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Volume Control ◽  
Dynamic Strain ◽  
Positive Pressure ◽  
Stress And Strain ◽  
Prone Positioning ◽  
Ventilatory Mode ◽  
Controlled Ventilation ◽  
Pressure Controlled Ventilation ◽  
Pressure Controlled

During positive-pressure ventilation parenchymal deformation can be assessed as strain (volume increase above functional residual capacity) in response to stress (transpulmonary pressure). The aim of this study was to explore the relationship between stress and strain on the regional level using computed tomography in anesthetized healthy pigs in two postures and two patterns of breathing. Airway opening and esophageal pressures were used to calculate stress; change of gas content as assessed from computed tomography was used to calculate strain. Static stress-strain curves and dynamic strain-time curves were constructed, the latter during the inspiratory phase of volume and pressure-controlled ventilation, both in supine and prone position. The lung was divided into nondependent, intermediate, dependent, and central regions: their curves were modeled by exponential regression and examined for statistically significant differences. In all the examined regions, there were strong but different exponential relations between stress and strain. During mechanical ventilation, the end-inspiratory strain was higher in the dependent than in the nondependent regions. No differences between volume- and pressure-controlled ventilation were found. However, during volume control ventilation, prone positioning decreased the end-inspiratory strain of dependent regions and increased it in nondependent regions, resulting in reduced strain gradient. Strain is inhomogeneously distributed within the healthy lung. Prone positioning attenuates differences between dependent and nondependent regions. The regional effects of ventilatory mode and body positioning should be further explored in patients with acute lung injury.

scholarly journals Effect of mechanical pressure-controlled ventilation in patients with disturbed respiratory function during laparoscopic cholecystectomy

2013 ◽  
Vol 70 (1) ◽  
pp. 9-15
Author(s):  
Maja Surbatovic ◽  
Zoran Vesic ◽  
Dragan Djordjevic ◽  
Sonja Radakovic ◽  
Snjezana Zeba ◽  
...  
Keyword(s):  
Laparoscopic Cholecystectomy ◽  
Respiratory Function ◽  
Respiratory Diseases ◽  
Positive Pressure ◽  
Time Interval ◽  
Time Intervals ◽  
Controlled Ventilation ◽  
Arterial Blood ◽  
Pressure Controlled Ventilation ◽  
Pressure Controlled

Background/Aim: Laparoscopic cholecystectomy is considered to be the gold standard for laparoscopic surgical procedures. In ASA III patients with concomitant respiratory diseases, however, creation of pneumoperitoneum and the position of patients during surgery exert additional negative effect on intraoperative respiratory function, thus making a higher challenge for the anesthesiologist than for the surgeon. The aim of this study was to compare the effect of intermittent positive pressure ventilation (IPPV) and pressure controlled ventilation (PCV) during general anesthesia on respiratory function in ASA III patients submitted to laparoscopic cholecystectomy. Methods. The study included 60 patients randomized into two groups depending on the mode of ventilation: IPPV or PCV. Respiratory volume (VT), peak inspiratory pressure (PIP), compliance (C), end-tidal CO2 pressure (PETCO2), oxygen saturation (SpO2), partial pressures of O2, CO2 (PaO2 and PaCO2) and pH of arterial blood were recorded within four time intervals. Results. There were no statistically significant differences in VT, SpO2, PaO2, PaCO2 and pH values neither within nor between the two groups. In time interval t1 there were no statistically significant differences in PIP, C, PETCO2 values between the IPPV and the PCV group. But, in the next three time intervals there was a difference in PIP, C, and PETCO2 values between the two groups which ranged from statistically significant to highly significant; PIP was lower, C and PETCO2 were higher in the PCV group. Conclusion. Pressure controlled ventilation better maintains stability regarding intraoperative ventilatory parameters in ASA III patients with concomitant respiratory diseases during laparoscopic cholecystectomy.

Pressure-controlled ventilation versus controlled mechanical ventilation with decelerating inspiratory flow

1993 ◽  
Vol 21 (8) ◽  
pp. 1143-1148 ◽  
Author(s):  
JAVIER MUÑOZ ◽  
JOSE EUGENIO GUERRERO ◽  
JOSE LUIS ESCALANTE ◽  
RICARDO PALOMINO ◽  
BRAULIO DE LA CALLE
Keyword(s):  
Mechanical Ventilation ◽  
Inspiratory Flow ◽  
Controlled Ventilation ◽  
Pressure Controlled Ventilation ◽  
Controlled Mechanical Ventilation ◽  
Pressure Controlled
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