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Alysson R. Carvalho - One of the best experts on this subject based on the ideXlab platform.
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Experimental blunt chest trauma – cardiorespiratory effects of different mechanical Ventilation strategies with high positive end-expiratory pressure: a randomized controlled study
BMC Anesthesiology, 2016Co-Authors: Dierk Schreiter, Alessandro Beda, Peter M. Spieth, Nadja C. Carvalho, Alysson R. Carvalho, Sebastian Katscher, Ludger Mende, Alexander P. Reske, Burkhard Lachmann, Marcelo B. P. AmatoAbstract:Background Uncertainty persists regarding the optimal ventilatory strategy in trauma patients developing acute respiratory distress syndrome (ARDS). This work aims to assess the effects of two mechanical Ventilation strategies with high positive end-expiratory pressure (PEEP) in experimental ARDS following blunt chest trauma. Methods Twenty-six juvenile pigs were anesthetized, tracheotomized and mechanically ventilated. A contusion was applied to the right chest using a bolt-shot device. Ninety minutes after contusion, animals were randomized to two different Ventilation modes, applied for 24 h: Twelve pigs received conventional Pressure-Controlled Ventilation with moderately low tidal volumes (V_T, 8 ml/kg) and empirically chosen high external PEEP (16cmH_2O) and are referred to as the HP-CMV-group. The other group ( n = 14) underwent high-frequency inverse-ratio Pressure-Controlled Ventilation (HFPPV) involving respiratory rate of 65breaths · min^−1, inspiratory-to-expiratory-ratio 2:1, development of intrinsic PEEP and recruitment maneuvers, compatible with the rationale of the Open Lung Concept. Hemodynamics, gas exchange and respiratory mechanics were monitored during 24 h. Computed tomography and histology were analyzed in subgroups. Results Comparing changes which occurred from randomization (90 min after chest trauma) over the 24-h treatment period, groups differed statistically significantly (all P values for group effect
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Pressure support improves oxygenation and lung protection compared to Pressure-Controlled Ventilation and is further improved by random variation of pressure support*
Critical Care Medicine, 2011Co-Authors: Peter M. Spieth, Alessandro Beda, Nadja C. Carvalho, Alysson R. Carvalho, Andreas Güldner, Michael Kasper, René Schubert, Constanze Dassow, Stefan Uhlig, Thea KochAbstract:OBJECTIVES: To explore whether 1) conventional pressure support Ventilation improves lung function and attenuates the pulmonary inflammatory response compared to Pressure-Controlled Ventilation and 2) random variation of pressure support levels (noisy pressure support Ventilation) adds further beneficial effects to pressure support Ventilation. DESIGN: Three-arm, randomized, experimental study. SETTING: University hospital research facility. SUBJECTS: Twenty-four juvenile pigs. INTERVENTIONS: Acute lung injury was induced by surfactant depletion. Animals were randomly assigned to 6 hrs of mechanical Ventilation (n = 8 per group) with either 1) Pressure-Controlled Ventilation, 2) pressure support Ventilation, or 3) noisy pressure support Ventilation. During noisy pressure support Ventilation, the pressure support varied randomly, with values following a normal distribution. In all groups, the driving pressures were set to achieve a mean tidal volume of 6 mL/kg. At the end of experiments, animals were killed and lungs extracted for histologic and biochemical analysis. MEASUREMENTS AND MAIN RESULTS: Respiratory, gas-exchange, and hemodynamics variables were assessed hourly. The diffuse alveolar damage and the inflammatory response of lungs were quantified. Pressure support Ventilation and noisy pressure support Ventilation improved gas exchange and were associated with reduced histologic damage and interleukin-6 concentrations in lung tissue compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange and decreased the inspiratory effort while reducing alveolar edema and inflammatory infiltration compared to pressure support Ventilation. CONCLUSIONS: In this model of acute lung injury, pressure support Ventilation and noisy pressure support Ventilation attenuated pulmonary inflammatory response and improved gas exchange as compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange, reduced the inspiratory effort, and attenuated alveolar edema and inflammatory infiltration as compared to conventional pressure support Ventilation.
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distribution of regional lung aeration and perfusion during conventional and noisy pressure support Ventilation in experimental lung injury
Journal of Applied Physiology, 2011Co-Authors: Alysson R. Carvalho, Alessandro Beda, Peter M. Spieth, Nadja C. Carvalho, Andreas Güldner, Maximilano Cuevas, Stephanie Spieth, Christian Stroczynski, Barbel Wiedemann, Thea KochAbstract:In acute lung injury (ALI), pressure support Ventilation (PSV) may improve oxygenation compared with Pressure-Controlled Ventilation (PCV), and benefit from random variation of pressure support (no...
Thea Koch - One of the best experts on this subject based on the ideXlab platform.
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An adaptive controller for noisy pressure controlled Ventilation
IFMBE Proceedings, 2020Co-Authors: Alessandro Beda, Paolo Pelosi, Peter M. Spieth, Thomas Handzsuj, Nadja C. Carvalho, Edmund Koch, Thea Koch, Marcelo Gama De AbreuAbstract:There is a growing interest in the use of variable Ventilation and pressure controlled Ventilation (PCV). However, the combination of these approaches as “noisy PCV” would require a mechanical Ventilation system that adapts to the respiratory system mechanics. In this work, we evaluated a new control system based on an adaptive least mean squares approach, which automatically tunes the pattern of the driving pressure during PCV to achieve a desired variability pattern of tidal volume (VT). The controller was tested during numerical simulations, applying step changes in respiratory system mechanics and in mechanical Ventilation settings. The time needed to converge (tc) to the desired VT variability pattern after each change, and the difference in minute Ventilation (\(\rm \triangle\)MV) between measured and target pattern of VT during tc were determined. The numerical simulations of the new controller resulted in: 1) tc 25 %; 2) tc only minimally influenced by E*; 3) larger tc when E* was not correctly estimated; 4) absolute value of \(\rm \triangle\)MV < 22.2 %. The new noisy PCV controller had a satisfactory performance and could prove interesting for mechanical Ventilation practice.
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Pressure support improves oxygenation and lung protection compared to Pressure-Controlled Ventilation and is further improved by random variation of pressure support*
Critical Care Medicine, 2011Co-Authors: Peter M. Spieth, Alessandro Beda, Nadja C. Carvalho, Alysson R. Carvalho, Andreas Güldner, Michael Kasper, René Schubert, Constanze Dassow, Stefan Uhlig, Thea KochAbstract:OBJECTIVES: To explore whether 1) conventional pressure support Ventilation improves lung function and attenuates the pulmonary inflammatory response compared to Pressure-Controlled Ventilation and 2) random variation of pressure support levels (noisy pressure support Ventilation) adds further beneficial effects to pressure support Ventilation. DESIGN: Three-arm, randomized, experimental study. SETTING: University hospital research facility. SUBJECTS: Twenty-four juvenile pigs. INTERVENTIONS: Acute lung injury was induced by surfactant depletion. Animals were randomly assigned to 6 hrs of mechanical Ventilation (n = 8 per group) with either 1) Pressure-Controlled Ventilation, 2) pressure support Ventilation, or 3) noisy pressure support Ventilation. During noisy pressure support Ventilation, the pressure support varied randomly, with values following a normal distribution. In all groups, the driving pressures were set to achieve a mean tidal volume of 6 mL/kg. At the end of experiments, animals were killed and lungs extracted for histologic and biochemical analysis. MEASUREMENTS AND MAIN RESULTS: Respiratory, gas-exchange, and hemodynamics variables were assessed hourly. The diffuse alveolar damage and the inflammatory response of lungs were quantified. Pressure support Ventilation and noisy pressure support Ventilation improved gas exchange and were associated with reduced histologic damage and interleukin-6 concentrations in lung tissue compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange and decreased the inspiratory effort while reducing alveolar edema and inflammatory infiltration compared to pressure support Ventilation. CONCLUSIONS: In this model of acute lung injury, pressure support Ventilation and noisy pressure support Ventilation attenuated pulmonary inflammatory response and improved gas exchange as compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange, reduced the inspiratory effort, and attenuated alveolar edema and inflammatory infiltration as compared to conventional pressure support Ventilation.
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distribution of regional lung aeration and perfusion during conventional and noisy pressure support Ventilation in experimental lung injury
Journal of Applied Physiology, 2011Co-Authors: Alysson R. Carvalho, Alessandro Beda, Peter M. Spieth, Nadja C. Carvalho, Andreas Güldner, Maximilano Cuevas, Stephanie Spieth, Christian Stroczynski, Barbel Wiedemann, Thea KochAbstract:In acute lung injury (ALI), pressure support Ventilation (PSV) may improve oxygenation compared with Pressure-Controlled Ventilation (PCV), and benefit from random variation of pressure support (no...
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A novel adaptive control system for noisy Pressure-Controlled Ventilation: a numerical simulation and bench test study.
Intensive Care Medicine, 2009Co-Authors: Alessandro Beda, Paolo Pelosi, Peter M. Spieth, Thomas Handzsuj, Nadja C. Carvalho, Edmund Koch, Thea Koch, Marcelo Gama De AbreuAbstract:There is growing interest in the use of both variable and Pressure-Controlled Ventilation (PCV). The combination of these approaches as “noisy PCV” requires adaptation of the mechanical ventilator to the respiratory system mechanics. Thus, we developed and evaluated a new control system based on the least-mean-squares adaptive approach, which automatically and continuously adjusts the driving pressure during PCV to achieve the desired variability pattern of tidal volume (V T). The controller was tested during numerical simulations and with a physical model reproducing the mechanical properties of the respiratory system. We applied step changes in respiratory system mechanics and mechanical Ventilation settings. The time needed to converge to the desired V T variability pattern after each change (t c) and the difference in minute Ventilation between the measured and target pattern of V T (ΔMV) were determined. During numerical simulations, the control system for noisy PCV achieved the desired variable V T pattern in less than 30 respiratory cycles, with limited influence of the dynamic elastance (E*) on t c, except when E* was underestimated by >25%. We also found that, during tests in the physical model, the control system converged in
Peter M. Spieth - One of the best experts on this subject based on the ideXlab platform.
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An adaptive controller for noisy pressure controlled Ventilation
IFMBE Proceedings, 2020Co-Authors: Alessandro Beda, Paolo Pelosi, Peter M. Spieth, Thomas Handzsuj, Nadja C. Carvalho, Edmund Koch, Thea Koch, Marcelo Gama De AbreuAbstract:There is a growing interest in the use of variable Ventilation and pressure controlled Ventilation (PCV). However, the combination of these approaches as “noisy PCV” would require a mechanical Ventilation system that adapts to the respiratory system mechanics. In this work, we evaluated a new control system based on an adaptive least mean squares approach, which automatically tunes the pattern of the driving pressure during PCV to achieve a desired variability pattern of tidal volume (VT). The controller was tested during numerical simulations, applying step changes in respiratory system mechanics and in mechanical Ventilation settings. The time needed to converge (tc) to the desired VT variability pattern after each change, and the difference in minute Ventilation (\(\rm \triangle\)MV) between measured and target pattern of VT during tc were determined. The numerical simulations of the new controller resulted in: 1) tc 25 %; 2) tc only minimally influenced by E*; 3) larger tc when E* was not correctly estimated; 4) absolute value of \(\rm \triangle\)MV < 22.2 %. The new noisy PCV controller had a satisfactory performance and could prove interesting for mechanical Ventilation practice.
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Experimental blunt chest trauma – cardiorespiratory effects of different mechanical Ventilation strategies with high positive end-expiratory pressure: a randomized controlled study
BMC Anesthesiology, 2016Co-Authors: Dierk Schreiter, Alessandro Beda, Peter M. Spieth, Nadja C. Carvalho, Alysson R. Carvalho, Sebastian Katscher, Ludger Mende, Alexander P. Reske, Burkhard Lachmann, Marcelo B. P. AmatoAbstract:Background Uncertainty persists regarding the optimal ventilatory strategy in trauma patients developing acute respiratory distress syndrome (ARDS). This work aims to assess the effects of two mechanical Ventilation strategies with high positive end-expiratory pressure (PEEP) in experimental ARDS following blunt chest trauma. Methods Twenty-six juvenile pigs were anesthetized, tracheotomized and mechanically ventilated. A contusion was applied to the right chest using a bolt-shot device. Ninety minutes after contusion, animals were randomized to two different Ventilation modes, applied for 24 h: Twelve pigs received conventional Pressure-Controlled Ventilation with moderately low tidal volumes (V_T, 8 ml/kg) and empirically chosen high external PEEP (16cmH_2O) and are referred to as the HP-CMV-group. The other group ( n = 14) underwent high-frequency inverse-ratio Pressure-Controlled Ventilation (HFPPV) involving respiratory rate of 65breaths · min^−1, inspiratory-to-expiratory-ratio 2:1, development of intrinsic PEEP and recruitment maneuvers, compatible with the rationale of the Open Lung Concept. Hemodynamics, gas exchange and respiratory mechanics were monitored during 24 h. Computed tomography and histology were analyzed in subgroups. Results Comparing changes which occurred from randomization (90 min after chest trauma) over the 24-h treatment period, groups differed statistically significantly (all P values for group effect
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Pressure support improves oxygenation and lung protection compared to Pressure-Controlled Ventilation and is further improved by random variation of pressure support*
Critical Care Medicine, 2011Co-Authors: Peter M. Spieth, Alessandro Beda, Nadja C. Carvalho, Alysson R. Carvalho, Andreas Güldner, Michael Kasper, René Schubert, Constanze Dassow, Stefan Uhlig, Thea KochAbstract:OBJECTIVES: To explore whether 1) conventional pressure support Ventilation improves lung function and attenuates the pulmonary inflammatory response compared to Pressure-Controlled Ventilation and 2) random variation of pressure support levels (noisy pressure support Ventilation) adds further beneficial effects to pressure support Ventilation. DESIGN: Three-arm, randomized, experimental study. SETTING: University hospital research facility. SUBJECTS: Twenty-four juvenile pigs. INTERVENTIONS: Acute lung injury was induced by surfactant depletion. Animals were randomly assigned to 6 hrs of mechanical Ventilation (n = 8 per group) with either 1) Pressure-Controlled Ventilation, 2) pressure support Ventilation, or 3) noisy pressure support Ventilation. During noisy pressure support Ventilation, the pressure support varied randomly, with values following a normal distribution. In all groups, the driving pressures were set to achieve a mean tidal volume of 6 mL/kg. At the end of experiments, animals were killed and lungs extracted for histologic and biochemical analysis. MEASUREMENTS AND MAIN RESULTS: Respiratory, gas-exchange, and hemodynamics variables were assessed hourly. The diffuse alveolar damage and the inflammatory response of lungs were quantified. Pressure support Ventilation and noisy pressure support Ventilation improved gas exchange and were associated with reduced histologic damage and interleukin-6 concentrations in lung tissue compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange and decreased the inspiratory effort while reducing alveolar edema and inflammatory infiltration compared to pressure support Ventilation. CONCLUSIONS: In this model of acute lung injury, pressure support Ventilation and noisy pressure support Ventilation attenuated pulmonary inflammatory response and improved gas exchange as compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange, reduced the inspiratory effort, and attenuated alveolar edema and inflammatory infiltration as compared to conventional pressure support Ventilation.
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distribution of regional lung aeration and perfusion during conventional and noisy pressure support Ventilation in experimental lung injury
Journal of Applied Physiology, 2011Co-Authors: Alysson R. Carvalho, Alessandro Beda, Peter M. Spieth, Nadja C. Carvalho, Andreas Güldner, Maximilano Cuevas, Stephanie Spieth, Christian Stroczynski, Barbel Wiedemann, Thea KochAbstract:In acute lung injury (ALI), pressure support Ventilation (PSV) may improve oxygenation compared with Pressure-Controlled Ventilation (PCV), and benefit from random variation of pressure support (no...
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A novel adaptive control system for noisy Pressure-Controlled Ventilation: a numerical simulation and bench test study.
Intensive Care Medicine, 2009Co-Authors: Alessandro Beda, Paolo Pelosi, Peter M. Spieth, Thomas Handzsuj, Nadja C. Carvalho, Edmund Koch, Thea Koch, Marcelo Gama De AbreuAbstract:There is growing interest in the use of both variable and Pressure-Controlled Ventilation (PCV). The combination of these approaches as “noisy PCV” requires adaptation of the mechanical ventilator to the respiratory system mechanics. Thus, we developed and evaluated a new control system based on the least-mean-squares adaptive approach, which automatically and continuously adjusts the driving pressure during PCV to achieve the desired variability pattern of tidal volume (V T). The controller was tested during numerical simulations and with a physical model reproducing the mechanical properties of the respiratory system. We applied step changes in respiratory system mechanics and mechanical Ventilation settings. The time needed to converge to the desired V T variability pattern after each change (t c) and the difference in minute Ventilation between the measured and target pattern of V T (ΔMV) were determined. During numerical simulations, the control system for noisy PCV achieved the desired variable V T pattern in less than 30 respiratory cycles, with limited influence of the dynamic elastance (E*) on t c, except when E* was underestimated by >25%. We also found that, during tests in the physical model, the control system converged in
Alessandro Beda - One of the best experts on this subject based on the ideXlab platform.
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An adaptive controller for noisy pressure controlled Ventilation
IFMBE Proceedings, 2020Co-Authors: Alessandro Beda, Paolo Pelosi, Peter M. Spieth, Thomas Handzsuj, Nadja C. Carvalho, Edmund Koch, Thea Koch, Marcelo Gama De AbreuAbstract:There is a growing interest in the use of variable Ventilation and pressure controlled Ventilation (PCV). However, the combination of these approaches as “noisy PCV” would require a mechanical Ventilation system that adapts to the respiratory system mechanics. In this work, we evaluated a new control system based on an adaptive least mean squares approach, which automatically tunes the pattern of the driving pressure during PCV to achieve a desired variability pattern of tidal volume (VT). The controller was tested during numerical simulations, applying step changes in respiratory system mechanics and in mechanical Ventilation settings. The time needed to converge (tc) to the desired VT variability pattern after each change, and the difference in minute Ventilation (\(\rm \triangle\)MV) between measured and target pattern of VT during tc were determined. The numerical simulations of the new controller resulted in: 1) tc 25 %; 2) tc only minimally influenced by E*; 3) larger tc when E* was not correctly estimated; 4) absolute value of \(\rm \triangle\)MV < 22.2 %. The new noisy PCV controller had a satisfactory performance and could prove interesting for mechanical Ventilation practice.
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Experimental blunt chest trauma – cardiorespiratory effects of different mechanical Ventilation strategies with high positive end-expiratory pressure: a randomized controlled study
BMC Anesthesiology, 2016Co-Authors: Dierk Schreiter, Alessandro Beda, Peter M. Spieth, Nadja C. Carvalho, Alysson R. Carvalho, Sebastian Katscher, Ludger Mende, Alexander P. Reske, Burkhard Lachmann, Marcelo B. P. AmatoAbstract:Background Uncertainty persists regarding the optimal ventilatory strategy in trauma patients developing acute respiratory distress syndrome (ARDS). This work aims to assess the effects of two mechanical Ventilation strategies with high positive end-expiratory pressure (PEEP) in experimental ARDS following blunt chest trauma. Methods Twenty-six juvenile pigs were anesthetized, tracheotomized and mechanically ventilated. A contusion was applied to the right chest using a bolt-shot device. Ninety minutes after contusion, animals were randomized to two different Ventilation modes, applied for 24 h: Twelve pigs received conventional Pressure-Controlled Ventilation with moderately low tidal volumes (V_T, 8 ml/kg) and empirically chosen high external PEEP (16cmH_2O) and are referred to as the HP-CMV-group. The other group ( n = 14) underwent high-frequency inverse-ratio Pressure-Controlled Ventilation (HFPPV) involving respiratory rate of 65breaths · min^−1, inspiratory-to-expiratory-ratio 2:1, development of intrinsic PEEP and recruitment maneuvers, compatible with the rationale of the Open Lung Concept. Hemodynamics, gas exchange and respiratory mechanics were monitored during 24 h. Computed tomography and histology were analyzed in subgroups. Results Comparing changes which occurred from randomization (90 min after chest trauma) over the 24-h treatment period, groups differed statistically significantly (all P values for group effect
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Pressure support improves oxygenation and lung protection compared to Pressure-Controlled Ventilation and is further improved by random variation of pressure support*
Critical Care Medicine, 2011Co-Authors: Peter M. Spieth, Alessandro Beda, Nadja C. Carvalho, Alysson R. Carvalho, Andreas Güldner, Michael Kasper, René Schubert, Constanze Dassow, Stefan Uhlig, Thea KochAbstract:OBJECTIVES: To explore whether 1) conventional pressure support Ventilation improves lung function and attenuates the pulmonary inflammatory response compared to Pressure-Controlled Ventilation and 2) random variation of pressure support levels (noisy pressure support Ventilation) adds further beneficial effects to pressure support Ventilation. DESIGN: Three-arm, randomized, experimental study. SETTING: University hospital research facility. SUBJECTS: Twenty-four juvenile pigs. INTERVENTIONS: Acute lung injury was induced by surfactant depletion. Animals were randomly assigned to 6 hrs of mechanical Ventilation (n = 8 per group) with either 1) Pressure-Controlled Ventilation, 2) pressure support Ventilation, or 3) noisy pressure support Ventilation. During noisy pressure support Ventilation, the pressure support varied randomly, with values following a normal distribution. In all groups, the driving pressures were set to achieve a mean tidal volume of 6 mL/kg. At the end of experiments, animals were killed and lungs extracted for histologic and biochemical analysis. MEASUREMENTS AND MAIN RESULTS: Respiratory, gas-exchange, and hemodynamics variables were assessed hourly. The diffuse alveolar damage and the inflammatory response of lungs were quantified. Pressure support Ventilation and noisy pressure support Ventilation improved gas exchange and were associated with reduced histologic damage and interleukin-6 concentrations in lung tissue compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange and decreased the inspiratory effort while reducing alveolar edema and inflammatory infiltration compared to pressure support Ventilation. CONCLUSIONS: In this model of acute lung injury, pressure support Ventilation and noisy pressure support Ventilation attenuated pulmonary inflammatory response and improved gas exchange as compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange, reduced the inspiratory effort, and attenuated alveolar edema and inflammatory infiltration as compared to conventional pressure support Ventilation.
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distribution of regional lung aeration and perfusion during conventional and noisy pressure support Ventilation in experimental lung injury
Journal of Applied Physiology, 2011Co-Authors: Alysson R. Carvalho, Alessandro Beda, Peter M. Spieth, Nadja C. Carvalho, Andreas Güldner, Maximilano Cuevas, Stephanie Spieth, Christian Stroczynski, Barbel Wiedemann, Thea KochAbstract:In acute lung injury (ALI), pressure support Ventilation (PSV) may improve oxygenation compared with Pressure-Controlled Ventilation (PCV), and benefit from random variation of pressure support (no...
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A novel adaptive control system for noisy Pressure-Controlled Ventilation: a numerical simulation and bench test study.
Intensive Care Medicine, 2009Co-Authors: Alessandro Beda, Paolo Pelosi, Peter M. Spieth, Thomas Handzsuj, Nadja C. Carvalho, Edmund Koch, Thea Koch, Marcelo Gama De AbreuAbstract:There is growing interest in the use of both variable and Pressure-Controlled Ventilation (PCV). The combination of these approaches as “noisy PCV” requires adaptation of the mechanical ventilator to the respiratory system mechanics. Thus, we developed and evaluated a new control system based on the least-mean-squares adaptive approach, which automatically and continuously adjusts the driving pressure during PCV to achieve the desired variability pattern of tidal volume (V T). The controller was tested during numerical simulations and with a physical model reproducing the mechanical properties of the respiratory system. We applied step changes in respiratory system mechanics and mechanical Ventilation settings. The time needed to converge to the desired V T variability pattern after each change (t c) and the difference in minute Ventilation between the measured and target pattern of V T (ΔMV) were determined. During numerical simulations, the control system for noisy PCV achieved the desired variable V T pattern in less than 30 respiratory cycles, with limited influence of the dynamic elastance (E*) on t c, except when E* was underestimated by >25%. We also found that, during tests in the physical model, the control system converged in
Nadja C. Carvalho - One of the best experts on this subject based on the ideXlab platform.
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An adaptive controller for noisy pressure controlled Ventilation
IFMBE Proceedings, 2020Co-Authors: Alessandro Beda, Paolo Pelosi, Peter M. Spieth, Thomas Handzsuj, Nadja C. Carvalho, Edmund Koch, Thea Koch, Marcelo Gama De AbreuAbstract:There is a growing interest in the use of variable Ventilation and pressure controlled Ventilation (PCV). However, the combination of these approaches as “noisy PCV” would require a mechanical Ventilation system that adapts to the respiratory system mechanics. In this work, we evaluated a new control system based on an adaptive least mean squares approach, which automatically tunes the pattern of the driving pressure during PCV to achieve a desired variability pattern of tidal volume (VT). The controller was tested during numerical simulations, applying step changes in respiratory system mechanics and in mechanical Ventilation settings. The time needed to converge (tc) to the desired VT variability pattern after each change, and the difference in minute Ventilation (\(\rm \triangle\)MV) between measured and target pattern of VT during tc were determined. The numerical simulations of the new controller resulted in: 1) tc 25 %; 2) tc only minimally influenced by E*; 3) larger tc when E* was not correctly estimated; 4) absolute value of \(\rm \triangle\)MV < 22.2 %. The new noisy PCV controller had a satisfactory performance and could prove interesting for mechanical Ventilation practice.
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Experimental blunt chest trauma – cardiorespiratory effects of different mechanical Ventilation strategies with high positive end-expiratory pressure: a randomized controlled study
BMC Anesthesiology, 2016Co-Authors: Dierk Schreiter, Alessandro Beda, Peter M. Spieth, Nadja C. Carvalho, Alysson R. Carvalho, Sebastian Katscher, Ludger Mende, Alexander P. Reske, Burkhard Lachmann, Marcelo B. P. AmatoAbstract:Background Uncertainty persists regarding the optimal ventilatory strategy in trauma patients developing acute respiratory distress syndrome (ARDS). This work aims to assess the effects of two mechanical Ventilation strategies with high positive end-expiratory pressure (PEEP) in experimental ARDS following blunt chest trauma. Methods Twenty-six juvenile pigs were anesthetized, tracheotomized and mechanically ventilated. A contusion was applied to the right chest using a bolt-shot device. Ninety minutes after contusion, animals were randomized to two different Ventilation modes, applied for 24 h: Twelve pigs received conventional Pressure-Controlled Ventilation with moderately low tidal volumes (V_T, 8 ml/kg) and empirically chosen high external PEEP (16cmH_2O) and are referred to as the HP-CMV-group. The other group ( n = 14) underwent high-frequency inverse-ratio Pressure-Controlled Ventilation (HFPPV) involving respiratory rate of 65breaths · min^−1, inspiratory-to-expiratory-ratio 2:1, development of intrinsic PEEP and recruitment maneuvers, compatible with the rationale of the Open Lung Concept. Hemodynamics, gas exchange and respiratory mechanics were monitored during 24 h. Computed tomography and histology were analyzed in subgroups. Results Comparing changes which occurred from randomization (90 min after chest trauma) over the 24-h treatment period, groups differed statistically significantly (all P values for group effect
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Pressure support improves oxygenation and lung protection compared to Pressure-Controlled Ventilation and is further improved by random variation of pressure support*
Critical Care Medicine, 2011Co-Authors: Peter M. Spieth, Alessandro Beda, Nadja C. Carvalho, Alysson R. Carvalho, Andreas Güldner, Michael Kasper, René Schubert, Constanze Dassow, Stefan Uhlig, Thea KochAbstract:OBJECTIVES: To explore whether 1) conventional pressure support Ventilation improves lung function and attenuates the pulmonary inflammatory response compared to Pressure-Controlled Ventilation and 2) random variation of pressure support levels (noisy pressure support Ventilation) adds further beneficial effects to pressure support Ventilation. DESIGN: Three-arm, randomized, experimental study. SETTING: University hospital research facility. SUBJECTS: Twenty-four juvenile pigs. INTERVENTIONS: Acute lung injury was induced by surfactant depletion. Animals were randomly assigned to 6 hrs of mechanical Ventilation (n = 8 per group) with either 1) Pressure-Controlled Ventilation, 2) pressure support Ventilation, or 3) noisy pressure support Ventilation. During noisy pressure support Ventilation, the pressure support varied randomly, with values following a normal distribution. In all groups, the driving pressures were set to achieve a mean tidal volume of 6 mL/kg. At the end of experiments, animals were killed and lungs extracted for histologic and biochemical analysis. MEASUREMENTS AND MAIN RESULTS: Respiratory, gas-exchange, and hemodynamics variables were assessed hourly. The diffuse alveolar damage and the inflammatory response of lungs were quantified. Pressure support Ventilation and noisy pressure support Ventilation improved gas exchange and were associated with reduced histologic damage and interleukin-6 concentrations in lung tissue compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange and decreased the inspiratory effort while reducing alveolar edema and inflammatory infiltration compared to pressure support Ventilation. CONCLUSIONS: In this model of acute lung injury, pressure support Ventilation and noisy pressure support Ventilation attenuated pulmonary inflammatory response and improved gas exchange as compared to Pressure-Controlled Ventilation. Noisy pressure support Ventilation further improved gas exchange, reduced the inspiratory effort, and attenuated alveolar edema and inflammatory infiltration as compared to conventional pressure support Ventilation.
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distribution of regional lung aeration and perfusion during conventional and noisy pressure support Ventilation in experimental lung injury
Journal of Applied Physiology, 2011Co-Authors: Alysson R. Carvalho, Alessandro Beda, Peter M. Spieth, Nadja C. Carvalho, Andreas Güldner, Maximilano Cuevas, Stephanie Spieth, Christian Stroczynski, Barbel Wiedemann, Thea KochAbstract:In acute lung injury (ALI), pressure support Ventilation (PSV) may improve oxygenation compared with Pressure-Controlled Ventilation (PCV), and benefit from random variation of pressure support (no...
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A novel adaptive control system for noisy Pressure-Controlled Ventilation: a numerical simulation and bench test study.
Intensive Care Medicine, 2009Co-Authors: Alessandro Beda, Paolo Pelosi, Peter M. Spieth, Thomas Handzsuj, Nadja C. Carvalho, Edmund Koch, Thea Koch, Marcelo Gama De AbreuAbstract:There is growing interest in the use of both variable and Pressure-Controlled Ventilation (PCV). The combination of these approaches as “noisy PCV” requires adaptation of the mechanical ventilator to the respiratory system mechanics. Thus, we developed and evaluated a new control system based on the least-mean-squares adaptive approach, which automatically and continuously adjusts the driving pressure during PCV to achieve the desired variability pattern of tidal volume (V T). The controller was tested during numerical simulations and with a physical model reproducing the mechanical properties of the respiratory system. We applied step changes in respiratory system mechanics and mechanical Ventilation settings. The time needed to converge to the desired V T variability pattern after each change (t c) and the difference in minute Ventilation between the measured and target pattern of V T (ΔMV) were determined. During numerical simulations, the control system for noisy PCV achieved the desired variable V T pattern in less than 30 respiratory cycles, with limited influence of the dynamic elastance (E*) on t c, except when E* was underestimated by >25%. We also found that, during tests in the physical model, the control system converged in