Driving pressure(ΔP)is a core therapeutic component of mechanical ventilation(MV).Varying levels ofΔP have been employed during MV depending on the type of underlying pathology and severity of injury.However,ΔP lev...Driving pressure(ΔP)is a core therapeutic component of mechanical ventilation(MV).Varying levels ofΔP have been employed during MV depending on the type of underlying pathology and severity of injury.However,ΔP levels have also been shown to closely impact hard endpoints such as mortality.Considering this,conducting an in-depth review ofΔP as a unique,outcome-impacting therapeutic modality is extremely important.There is a need to understand the subtleties involved in making sureΔP levels are optimized to enhance outcomes and minimize harm.We performed this narrative review to further explore the various uses ofΔP,the different parameters that can affect its use,and how outcomes vary in different patient populations at different pressure levels.To better utilizeΔP in MV-requiring patients,additional large-scale clinical studies are needed.展开更多
The present paper describes the theoretical treatment performed for the geometrical optimization of advanced and improved-shape waveforms as airways pressure excitation for controlled breathings in dual-controlled ven...The present paper describes the theoretical treatment performed for the geometrical optimization of advanced and improved-shape waveforms as airways pressure excitation for controlled breathings in dual-controlled ventilation applied to anaesthetized or severe brain injured patients, the respiratory mechanics of which can be assumed linear. Advanced means insensitive to patient breathing activity as well as to ventilator settings while improved-shape intends in comparison to conventional square waveform for a progressive approaching towards physiological transpulmonary pressure and respiratory airflow waveforms. Such functional features along with the best ventilation control for the specific therapeutic requirements of each patient can be achieved through the implementation of both diagnostic and compensation procedures effectively carried out by the Advance Lung Ventilation System (ALVS) already successfully tested for square waveform as airways pressure excitation. Triangular and trapezoidal waveforms have been considered as airways pressure excitation. The results shows that the latter fits completely the requirements for a physiological pattern of endoalveolar pressure and respiratory airflow waveforms, while the former exhibits a lower physiological behaviour but it is anyhow periodically recommended for performing adequately the powerful diagnostic procedure.展开更多
The theoretical approach along with the rationale of harmonic excitation modality (HEM) applied as optimal dual controlled ventilation (DCV) to anaesthetized or severe brain injured patients, whose respiretory mechani...The theoretical approach along with the rationale of harmonic excitation modality (HEM) applied as optimal dual controlled ventilation (DCV) to anaesthetized or severe brain injured patients, whose respiretory mechanics can be properly assumed steady and linear, are presented and discussed. The design criteria of an improved version of the Advanced Lung Ventilation System (ALVS), including HEM in its functional features, are described in details. In particular, the elimination of any undesiderable artificial distortion affecting the respiratory and ventilation pattern waveforms is achieved by maintaining continuous forever the airflow inside the ventilation circuit, ensuring also the highest level of safety for patient in any condition. In such a way, the full-time compatibility of controlled breathings with spontaneous breathing activity of patient during continuous positive airways pressure (CPAP) or bilevel positive airways pressure (BiPAP) ventilation modalities and during assisted/controlled ventilation(A/CV), includeing also synchronized or triggered ventilation modalities, is an intrinsic innovative feature of the system available for clinical application. As expected and according to the clinical requirements, HEM provides for physiological respiratory and ventilation pattern waveforms together with optimal “breath to breath” feedback control of lung volume driven by an improved diagnostic measurement procedure, whose outputs are also vital for adapting all the preset ventilation parameters to the current value of the respiratory parameters of patient. The results produced by software simulations concerning both adult and neonatal patients in different clinical conditions are completely consistent with those obtained by the theoretical treatment, showing that HEM reaches the best performances from both clinical and engineering points of view.展开更多
Purpose:To assess the value of the driving pressure variation rate(ΔP%)in predicting the outcome of weaning from invasive mechanical ventilation in patients with acute respiratory distress syndrome.Methods:In this ca...Purpose:To assess the value of the driving pressure variation rate(ΔP%)in predicting the outcome of weaning from invasive mechanical ventilation in patients with acute respiratory distress syndrome.Methods:In this case-control study,a total of 35 patients with moderate-severe acute respiratory distress syndrome were admitted to the intensive care unit between January 2022 and December 2022 and received invasive mechanical ventilation for at least 48 h were enrolled.Patients were divided into successful weaning group and failed weaning group depending on whether they could be removed from ventilator support within 14 days.Outcome measures including driving pressure,PaO2:FiO2,and positive end-expiratory pressure,etc.were assessed every 24 h from day 0 to day 14 until successful weaning was achieved.The measurement data of non-normal distribution were presented as median(Q1,Q3),and the differences between groups were compared by Wilcoxon rank sum test.And categorical data use the Chi-square test or Fisher's exact test to compare.The predictive value ofΔP%in predicting the outcome of weaning from the ventilator was analyzed using receiver operating characteristic curves.Results:Of the total 35 patients included in the study,17 were successful vs.18 failed in weaning from a ventilator after 14 days of mechanical ventilation.The cut-off values of the medianΔP%measured by Operator 1 vs.Operator 2 in the first 4 days were≥4.17%and 4.55%,respectively(p<0.001),with the area under curve of 0.804(sensitivity of 88.2%,specificity of 64.7%)and 0.770(sensitivity of 88.2%,specificity of 64.7%),respectively.There was a significant difference in mechanical ventilation duration between the successful weaning group and the failure weaning group(8(6,13)vs.12(7.5,17.3),p=0.043).The incidence of ventilator-associated pneumonia in the successful weaning group was significantly lower than in the failed weaning group(0.2‰vs.2.3‰,p=0.001).There was a significant difference noted between these 2 groups in the 28-day mortality(11.8%vs.66.7%,p=0.003).Conclusion:The medianΔP%in the first 4 days of mechanical ventilation showed good predictive performance in predicting the outcome of weaning from mechanical ventilation within 14 days.Further study is needed to confirm this finding.展开更多
The standard treatment for acute respiratory distress syndrome(ARDS) is supportive in the form of low tidal volume ventilation applied after significant lung injury has already developed. Nevertheless, ARDS mortality ...The standard treatment for acute respiratory distress syndrome(ARDS) is supportive in the form of low tidal volume ventilation applied after significant lung injury has already developed. Nevertheless, ARDS mortality remains unacceptably high(> 40%). Indeed, once ARDS is established it becomes refractory to treatment, and therefore avoidance is key. However, preventive techniques and therapeutics to reduce the incidence of ARDS in patients at high-risk have not been validated clinically. This review discusses the current data suggesting that preemptive application of the properly adjusted mechanical breath can block progressive acute lung injury and significantly reduce the occurrence of ARDS.展开更多
Mortality from acute respiratory distress syndrome(ARDS) remains unacceptable, approaching 45% in certain high-risk patient populations. Treating fulminant ARDS is currently relegated to supportive care measures only....Mortality from acute respiratory distress syndrome(ARDS) remains unacceptable, approaching 45% in certain high-risk patient populations. Treating fulminant ARDS is currently relegated to supportive care measures only. Thus, the best treatment for ARDS may lie with preventing this syndrome from ever occurring. Clinical studies were examined to determine why ARDS has remained resistant to treatment over the past several decades. In addition, both basic science and clinical studies were examined to determine the impact that early, protective mechanical ventilation may have on preventing the development of ARDS in at-risk patients. Fulminant ARDS is highly resistant to both pharmacologic treatment and methods of mechanical ventilation. However, ARDS is a progressive disease with an early treatment window that can be exploited. In particular, protective mechanical ventilation initiated before the onset of lung injury can prevent the progression to ARDS. Airway pressure release ventilation(APRV) is a novel mechanical ventilation strategy for delivering a protective breath that has been shown to block progressive acute lung injury(ALI) and prevent ALI from progressing to ARDS. ARDS mortality currently remains as high as 45% in some studies. As ARDS is a progressive disease, the key to treatment lies with preventing the disease from ever occurring while it remains subclinical. Early protective mechanical ventilation with APRV appears to offer substantial benefit in this regard and may be the prophylactic treatment of choice for preventing ARDS.展开更多
Objective:To evaluate the efficacy and safety of protective lung ventilation strategy combined with lung recruitment maneuver (RM) in the treatment patients with acute respiratory distress syndrome (ARDS).Methods:Tota...Objective:To evaluate the efficacy and safety of protective lung ventilation strategy combined with lung recruitment maneuver (RM) in the treatment patients with acute respiratory distress syndrome (ARDS).Methods:Totally 74 patients with ARDS admitted to the Department of Intensive Care Unit, Changshu Second People's Hospital in Jiangsu Province between September 2010 and June 2013 were selected and randomly divided into lung recruitment group and non-lung recruitment group, and the initial ventilation solution for both groups was synchronized intermittent mandatory ventilation (SIMV). For RM, SIMV mode (pressure control and pressure support) was adopted. Positive end expiratory pressure (PEEP) was increased by 5 cm H2O every time and maintained for 40-50 s before entering the next increasing period, and the peak airway pressure was kept below 45 cm H2O. After PEEP reached the maximum value, it was gradually reduced by 5 cm H2O every time and finally maintained at 15 cm H2O for 10 min.Results:A total of 74 patients with mean age of (49.0±18.6) years old were enrolled, 36 patients were enrolled in lung recruitment maneuver (RM) group and 38 patients were enrolled into non-lung recruitment maneuver (non-RM) group. 44 were male and accounted for 59.5% of all the patients. For the indicators such as PEEP, pressure support (PS), plateau airway pressure (Pplat), peak airway pressure (Ppeak), vital capacity (VC) and fraction of inspired oxygen (FiO2), no statistical differences in the indicators were found between the RM group and non-RM group on D1, D3 and D7 (P>0.05), except that only FiO2 of RM group on D7 was significantly lower than that of non-RM group (47.2±10.0) vs. (52.2±10.5),P<0.05]. For the indicators of blood gas analysis, including pH, arterial oxygen pressure (PaO2), arterial carbon dioxide pressure (PaCO2) and oxygenation index (PaO2/FiO2), PaO2 and PaO2/FiO2 of RM group were significantly higher than those of non-RM group on D7, and the values were [(90.2±16.1) mmHg vs. (76.4±11.3) mmHg,P<0.05] and [(196.5±40.7) mmHg vs. (151.7±37.3) mmHg,P<0.05] respectively. There was no statistical difference in heart rate (HR), cardiac index (CI), central venous pressure (CVP) or mean arterial pressure (MAP) between RM group and non-RM group on D1, D3 and D7 (P>0.05). 28-day mortality, ICU mortality and in-hospital mortality were 25% vs. 28.9%, 25% vs. 26.3% and 36.1% vs. 39.5% respectively between RM group and non-RM group (allP>0.05).Conclusion:Protective lung ventilation strategy combined with lung recruitment maneuver can improve the indicators such as PaO2, FiO2 and PaO2/FiO2 on D7, but failed to improve the final outcomes such as 28-day mortality, ICU mortality and in-hospital mortality.展开更多
Several clinical and experimental studies have shown that lung injury occurs shortly after brain damage. The responsible mechanisms involve neurogenic pulmonary edema, inflammation, the harmful action of neurotransmit...Several clinical and experimental studies have shown that lung injury occurs shortly after brain damage. The responsible mechanisms involve neurogenic pulmonary edema, inflammation, the harmful action of neurotransmitters, or autonomic system dysfunction. Mechanical ventilation, an essential component of life support in brain-damaged patients(BD), may be an additional traumatic factor to the already injured or susceptible to injury lungs of these patients thus worsening lung injury, in case that non lung protective ventilator settings are applied. Measurement of respiratory mechanics in BD patients, as well as assessment of their evolution during mechanical ventilation, may lead to preclinical lung injury detection early enough, allowing thus the selection of the appropriate ventilator settings to avoid ventilatorinduced lung injury. The aim of this review is to explore the mechanical properties of the respiratory system in BD patients along with the underlying mechanisms, and to translate the evidence of animal and clinical studies into therapeutic implications regarding the mechanical ventilation of these critically ill patients.展开更多
Expiratory flow limitation(EFL), that is the inability of expiratory flow to increase in spite of an increase of the driving pressure, is a common and unrecognized occurrence during mechanical ventilation in a variety...Expiratory flow limitation(EFL), that is the inability of expiratory flow to increase in spite of an increase of the driving pressure, is a common and unrecognized occurrence during mechanical ventilation in a variety of intensive care unit conditions. Recent evidence suggests that the presence of EFL is associated with an increase in mortality, at least in acute respiratory distress syndrome(ARDS) patients, and in pulmonary complications in patients undergoing surgery. EFL is a major cause of intrinsic positive end-expiratory pressure(PEEPi), which in ARDS patients is heterogeneously distributed, with a consequent increase of ventilation/perfusion mismatch and reduction of arterial oxygenation. Airway collapse is frequently concomitant to the presence of EFL.When airways close and reopen during tidal ventilation, abnormally high stresses are generated that can damage the bronchiolar epithelium and uncouple small airways from the alveolar septa, possibly generating the small airways abnormalities detected at autopsy in ARDS. Finally, the high stresses and airway distortion generated downstream the choke points may contribute to parenchymal injury, but this possibility is still unproven. PEEP application can abolish EFL, decrease PEEPi heterogeneity, and limit recruitment/derecruitment.Whether increasing PEEP up to EFL disappearance is a useful criterion for PEEP titration can only be determined by future studies.展开更多
文摘Driving pressure(ΔP)is a core therapeutic component of mechanical ventilation(MV).Varying levels ofΔP have been employed during MV depending on the type of underlying pathology and severity of injury.However,ΔP levels have also been shown to closely impact hard endpoints such as mortality.Considering this,conducting an in-depth review ofΔP as a unique,outcome-impacting therapeutic modality is extremely important.There is a need to understand the subtleties involved in making sureΔP levels are optimized to enhance outcomes and minimize harm.We performed this narrative review to further explore the various uses ofΔP,the different parameters that can affect its use,and how outcomes vary in different patient populations at different pressure levels.To better utilizeΔP in MV-requiring patients,additional large-scale clinical studies are needed.
文摘The present paper describes the theoretical treatment performed for the geometrical optimization of advanced and improved-shape waveforms as airways pressure excitation for controlled breathings in dual-controlled ventilation applied to anaesthetized or severe brain injured patients, the respiratory mechanics of which can be assumed linear. Advanced means insensitive to patient breathing activity as well as to ventilator settings while improved-shape intends in comparison to conventional square waveform for a progressive approaching towards physiological transpulmonary pressure and respiratory airflow waveforms. Such functional features along with the best ventilation control for the specific therapeutic requirements of each patient can be achieved through the implementation of both diagnostic and compensation procedures effectively carried out by the Advance Lung Ventilation System (ALVS) already successfully tested for square waveform as airways pressure excitation. Triangular and trapezoidal waveforms have been considered as airways pressure excitation. The results shows that the latter fits completely the requirements for a physiological pattern of endoalveolar pressure and respiratory airflow waveforms, while the former exhibits a lower physiological behaviour but it is anyhow periodically recommended for performing adequately the powerful diagnostic procedure.
文摘The theoretical approach along with the rationale of harmonic excitation modality (HEM) applied as optimal dual controlled ventilation (DCV) to anaesthetized or severe brain injured patients, whose respiretory mechanics can be properly assumed steady and linear, are presented and discussed. The design criteria of an improved version of the Advanced Lung Ventilation System (ALVS), including HEM in its functional features, are described in details. In particular, the elimination of any undesiderable artificial distortion affecting the respiratory and ventilation pattern waveforms is achieved by maintaining continuous forever the airflow inside the ventilation circuit, ensuring also the highest level of safety for patient in any condition. In such a way, the full-time compatibility of controlled breathings with spontaneous breathing activity of patient during continuous positive airways pressure (CPAP) or bilevel positive airways pressure (BiPAP) ventilation modalities and during assisted/controlled ventilation(A/CV), includeing also synchronized or triggered ventilation modalities, is an intrinsic innovative feature of the system available for clinical application. As expected and according to the clinical requirements, HEM provides for physiological respiratory and ventilation pattern waveforms together with optimal “breath to breath” feedback control of lung volume driven by an improved diagnostic measurement procedure, whose outputs are also vital for adapting all the preset ventilation parameters to the current value of the respiratory parameters of patient. The results produced by software simulations concerning both adult and neonatal patients in different clinical conditions are completely consistent with those obtained by the theoretical treatment, showing that HEM reaches the best performances from both clinical and engineering points of view.
文摘Purpose:To assess the value of the driving pressure variation rate(ΔP%)in predicting the outcome of weaning from invasive mechanical ventilation in patients with acute respiratory distress syndrome.Methods:In this case-control study,a total of 35 patients with moderate-severe acute respiratory distress syndrome were admitted to the intensive care unit between January 2022 and December 2022 and received invasive mechanical ventilation for at least 48 h were enrolled.Patients were divided into successful weaning group and failed weaning group depending on whether they could be removed from ventilator support within 14 days.Outcome measures including driving pressure,PaO2:FiO2,and positive end-expiratory pressure,etc.were assessed every 24 h from day 0 to day 14 until successful weaning was achieved.The measurement data of non-normal distribution were presented as median(Q1,Q3),and the differences between groups were compared by Wilcoxon rank sum test.And categorical data use the Chi-square test or Fisher's exact test to compare.The predictive value ofΔP%in predicting the outcome of weaning from the ventilator was analyzed using receiver operating characteristic curves.Results:Of the total 35 patients included in the study,17 were successful vs.18 failed in weaning from a ventilator after 14 days of mechanical ventilation.The cut-off values of the medianΔP%measured by Operator 1 vs.Operator 2 in the first 4 days were≥4.17%and 4.55%,respectively(p<0.001),with the area under curve of 0.804(sensitivity of 88.2%,specificity of 64.7%)and 0.770(sensitivity of 88.2%,specificity of 64.7%),respectively.There was a significant difference in mechanical ventilation duration between the successful weaning group and the failure weaning group(8(6,13)vs.12(7.5,17.3),p=0.043).The incidence of ventilator-associated pneumonia in the successful weaning group was significantly lower than in the failed weaning group(0.2‰vs.2.3‰,p=0.001).There was a significant difference noted between these 2 groups in the 28-day mortality(11.8%vs.66.7%,p=0.003).Conclusion:The medianΔP%in the first 4 days of mechanical ventilation showed good predictive performance in predicting the outcome of weaning from mechanical ventilation within 14 days.Further study is needed to confirm this finding.
文摘The standard treatment for acute respiratory distress syndrome(ARDS) is supportive in the form of low tidal volume ventilation applied after significant lung injury has already developed. Nevertheless, ARDS mortality remains unacceptably high(> 40%). Indeed, once ARDS is established it becomes refractory to treatment, and therefore avoidance is key. However, preventive techniques and therapeutics to reduce the incidence of ARDS in patients at high-risk have not been validated clinically. This review discusses the current data suggesting that preemptive application of the properly adjusted mechanical breath can block progressive acute lung injury and significantly reduce the occurrence of ARDS.
文摘Mortality from acute respiratory distress syndrome(ARDS) remains unacceptable, approaching 45% in certain high-risk patient populations. Treating fulminant ARDS is currently relegated to supportive care measures only. Thus, the best treatment for ARDS may lie with preventing this syndrome from ever occurring. Clinical studies were examined to determine why ARDS has remained resistant to treatment over the past several decades. In addition, both basic science and clinical studies were examined to determine the impact that early, protective mechanical ventilation may have on preventing the development of ARDS in at-risk patients. Fulminant ARDS is highly resistant to both pharmacologic treatment and methods of mechanical ventilation. However, ARDS is a progressive disease with an early treatment window that can be exploited. In particular, protective mechanical ventilation initiated before the onset of lung injury can prevent the progression to ARDS. Airway pressure release ventilation(APRV) is a novel mechanical ventilation strategy for delivering a protective breath that has been shown to block progressive acute lung injury(ALI) and prevent ALI from progressing to ARDS. ARDS mortality currently remains as high as 45% in some studies. As ARDS is a progressive disease, the key to treatment lies with preventing the disease from ever occurring while it remains subclinical. Early protective mechanical ventilation with APRV appears to offer substantial benefit in this regard and may be the prophylactic treatment of choice for preventing ARDS.
文摘Objective:To evaluate the efficacy and safety of protective lung ventilation strategy combined with lung recruitment maneuver (RM) in the treatment patients with acute respiratory distress syndrome (ARDS).Methods:Totally 74 patients with ARDS admitted to the Department of Intensive Care Unit, Changshu Second People's Hospital in Jiangsu Province between September 2010 and June 2013 were selected and randomly divided into lung recruitment group and non-lung recruitment group, and the initial ventilation solution for both groups was synchronized intermittent mandatory ventilation (SIMV). For RM, SIMV mode (pressure control and pressure support) was adopted. Positive end expiratory pressure (PEEP) was increased by 5 cm H2O every time and maintained for 40-50 s before entering the next increasing period, and the peak airway pressure was kept below 45 cm H2O. After PEEP reached the maximum value, it was gradually reduced by 5 cm H2O every time and finally maintained at 15 cm H2O for 10 min.Results:A total of 74 patients with mean age of (49.0±18.6) years old were enrolled, 36 patients were enrolled in lung recruitment maneuver (RM) group and 38 patients were enrolled into non-lung recruitment maneuver (non-RM) group. 44 were male and accounted for 59.5% of all the patients. For the indicators such as PEEP, pressure support (PS), plateau airway pressure (Pplat), peak airway pressure (Ppeak), vital capacity (VC) and fraction of inspired oxygen (FiO2), no statistical differences in the indicators were found between the RM group and non-RM group on D1, D3 and D7 (P>0.05), except that only FiO2 of RM group on D7 was significantly lower than that of non-RM group (47.2±10.0) vs. (52.2±10.5),P<0.05]. For the indicators of blood gas analysis, including pH, arterial oxygen pressure (PaO2), arterial carbon dioxide pressure (PaCO2) and oxygenation index (PaO2/FiO2), PaO2 and PaO2/FiO2 of RM group were significantly higher than those of non-RM group on D7, and the values were [(90.2±16.1) mmHg vs. (76.4±11.3) mmHg,P<0.05] and [(196.5±40.7) mmHg vs. (151.7±37.3) mmHg,P<0.05] respectively. There was no statistical difference in heart rate (HR), cardiac index (CI), central venous pressure (CVP) or mean arterial pressure (MAP) between RM group and non-RM group on D1, D3 and D7 (P>0.05). 28-day mortality, ICU mortality and in-hospital mortality were 25% vs. 28.9%, 25% vs. 26.3% and 36.1% vs. 39.5% respectively between RM group and non-RM group (allP>0.05).Conclusion:Protective lung ventilation strategy combined with lung recruitment maneuver can improve the indicators such as PaO2, FiO2 and PaO2/FiO2 on D7, but failed to improve the final outcomes such as 28-day mortality, ICU mortality and in-hospital mortality.
文摘Several clinical and experimental studies have shown that lung injury occurs shortly after brain damage. The responsible mechanisms involve neurogenic pulmonary edema, inflammation, the harmful action of neurotransmitters, or autonomic system dysfunction. Mechanical ventilation, an essential component of life support in brain-damaged patients(BD), may be an additional traumatic factor to the already injured or susceptible to injury lungs of these patients thus worsening lung injury, in case that non lung protective ventilator settings are applied. Measurement of respiratory mechanics in BD patients, as well as assessment of their evolution during mechanical ventilation, may lead to preclinical lung injury detection early enough, allowing thus the selection of the appropriate ventilator settings to avoid ventilatorinduced lung injury. The aim of this review is to explore the mechanical properties of the respiratory system in BD patients along with the underlying mechanisms, and to translate the evidence of animal and clinical studies into therapeutic implications regarding the mechanical ventilation of these critically ill patients.
文摘Expiratory flow limitation(EFL), that is the inability of expiratory flow to increase in spite of an increase of the driving pressure, is a common and unrecognized occurrence during mechanical ventilation in a variety of intensive care unit conditions. Recent evidence suggests that the presence of EFL is associated with an increase in mortality, at least in acute respiratory distress syndrome(ARDS) patients, and in pulmonary complications in patients undergoing surgery. EFL is a major cause of intrinsic positive end-expiratory pressure(PEEPi), which in ARDS patients is heterogeneously distributed, with a consequent increase of ventilation/perfusion mismatch and reduction of arterial oxygenation. Airway collapse is frequently concomitant to the presence of EFL.When airways close and reopen during tidal ventilation, abnormally high stresses are generated that can damage the bronchiolar epithelium and uncouple small airways from the alveolar septa, possibly generating the small airways abnormalities detected at autopsy in ARDS. Finally, the high stresses and airway distortion generated downstream the choke points may contribute to parenchymal injury, but this possibility is still unproven. PEEP application can abolish EFL, decrease PEEPi heterogeneity, and limit recruitment/derecruitment.Whether increasing PEEP up to EFL disappearance is a useful criterion for PEEP titration can only be determined by future studies.
