scholarly journals Potential for the Lung Recruitment and the Risk of Lung Overdistension During 21 Days of Mechanical Ventilation in Patients With COVID-19 After Noninvasive Ventilation Failure: the COVID-VENT Observational Trial

2021 ◽  
Author(s):  
Andrey Yaroshetskiy ◽  
Sergey N. Avdeev ◽  
Mikhail E. Politov ◽  
Pavel V. Nogtev ◽  
Victoria G. Beresneva ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Gas Exchange ◽  
Tidal Volume ◽  
Time Course ◽  
Respiratory Mechanics ◽  
Peep Level ◽  
Driving Pressure ◽  
Number Of Patients ◽  
Lung Overdistension ◽  
Ventilation Failure

Abstract Background: Data on the lung respiratory mechanics and gas exchange in the time course of COVID-19-associated respiratory failure is limited. This study aimed to explore respiratory mechanics and gas exchange, the lung recruitability and risk of overdistension during the time course of mechanical ventilation. Methods: This was a prospective observational study in critically ill mechanically ventilated patients (n=116) with COVID-19 admitted into Intensive Care Units of Sechenov University. The primary endpoints were: «optimum» positive end-expiratory pressure (PEEP) level balanced between the lowest driving pressure and the highest SpO2 and number of patients with recruitable lung on Days 1 and 7 of mechanical ventilation. We measured driving pressure at different levels of PEEP (14, 12, 10 and 8 cmH2O) with preset tidal volume, and with the increase of tidal volume by 100 ml and 200 ml at preset PEEP level, and calculated static respiratory system compliance (CRS), PaO2/FiO2, alveolar dead space and ventilatory ratio on Days 1, 3, 5, 7, 10, 14 and 21.Results: The «optimum» PEEP levels on Day 1 were 11.0 (10.0-12.8) cmH2O and 10.0 (9.0-12.0) cmH2O on Day 7. Positive response to recruitment was observed on Day 1 in 27.6% and on Day 7 in 9.2% of patients. PEEP increase from 10 to 14 cmH2O and VT increase by 100 and 200 ml led to a significant decrease in CRS from Day 1 to Day 14 (p<0.05). Ventilatory ratio was 2.2 (1.7-2,7) in non-survivors and in 1.9 (1.6-2.6) survivors on Day 1 and decreased on Day 7 in survivors only (p<0.01). PaO2/FiO2 was 105.5 (76.2-141.7) mmHg in non-survivors on Day 1 and 136.6 (106.7-160.8) in survivors (p=0.002). In survivors, PaO2/FiO2 rose on Day 3 (p=0.008) and then between Days 7 and 10 (p=0.046). Conclusion: Lung recruitability was low in COVID-19 and decreased during the course of the disease, but lung overdistension occurred at «intermediate» PEEP and VT levels. In survivors gas exchange improvements after Day 7 mismatched CRS.Trial registration: ClinicalTrials.gov, NCT04445961. Registered 24 June 2020 - Retrospectively registered, http://https://clinicaltrials.gov/ct2/show/NCT04445961?cond=COVID-19&cntry=RU&city=Moscow&draw=3&rank=23

Time-course of respiratory mechanics and gas exchange during mechanical ventilation in a case of near-fatal asthma

1991 ◽  
Vol 17 (8) ◽  
pp. 506-507 ◽  
Author(s):  
L. Blanch ◽  
R. Fernandez ◽  
A. Ferrer ◽  
F. Baigorri ◽  
A. Artigas
Keyword(s):  
Mechanical Ventilation ◽  
Gas Exchange ◽  
Time Course ◽  
Respiratory Mechanics ◽  
Fatal Asthma ◽  
Near Fatal Asthma

Respiratory Failure and the Indications for Mechanical Ventilation

2017 ◽  
Author(s):  
John W. Kreit
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory Failure ◽  
Gas Exchange ◽  
Disease Process ◽  
Upper Airway ◽  
Lower Airway ◽  
Vital Functions ◽  
Refractory Hypoxemia ◽  
Ventilation Failure ◽  
Underlying Pathophysiology

Respiratory failure occurs when a disease process significantly interferes with the respiratory system’s vital functions and causes arterial hypoxemia, hypercapnia, or both. Typically, respiratory failure is divided into three categories based on the underlying pathophysiology: ventilation failure, oxygenation failure, and oxygenation-ventilation failure. With severe disturbances in gas exchange, mechanical ventilation is often needed to assist the respiratory system and restore the PaCO2, PaO2, or both, to normal. Respiratory Failure and the Indications for Mechanical Ventilation defines and describes the three types of respiratory failure and reviews the four indications for intubation and mechanical ventilation—acute or acute-on-chronic hypercapnia, refractory hypoxemia, inability to protect the lower airway, and upper airway obstruction.

scholarly journals Ultra-protective mechanical ventilation without extra-corporeal carbon dioxide removal for acute respiratory distress syndrome

2018 ◽  
Vol 20 (1) ◽  
pp. 40-45 ◽  
Author(s):  
Hariharan Regunath ◽  
Nathanial Moulton ◽  
Daniel Woolery ◽  
Mohammed Alnijoumi ◽  
Troy Whitacre ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Mechanical Ventilation ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Tidal Volume ◽  
Distress Syndrome ◽  
Carbon Dioxide Removal ◽  
Driving Pressure ◽  
Protective Mechanical Ventilation

Background Tidal hyperinflation can still occur with mechanical ventilation using low tidal volume (LVT) (6 mL/kg predicted body weight (PBW)) in acute respiratory distress syndrome (ARDS), despite a well-demonstrated reduction in mortality. Methods Retrospective chart review from August 2012 to October 2014. Inclusion: Age >18years, PaO2/FiO2<200 with bilateral pulmonary infiltrates, absent heart failure, and ultra-protective mechanical ventilation (UPMV) defined as tidal volume (VT) <6 mL/kg PBW. Exclusion: UPMV use for <24 h. Demographics, admission Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, arterial blood gas, serum bicarbonate, ventilator parameters for pre-, during, and post-UPMV periods including modes, VT, peak inspiratory pressure (PIP), plateau pressure (Pplat), driving pressure, etc. were gathered. We compared lab and ventilator data for pre-, during, and post-UPMV periods. Results Fifteen patients (male:female = 7:8, age 42.13 ± 11.29 years) satisfied criteria, APACHEII 20.6 ± 7.1, mean days in intensive care unit and hospitalization were 18.5 ± 8.85 and 20.81 ± 9.78 days, 9 (60%) received paralysis and 7 (46.67%) required inotropes. Eleven patients had echocardiogram, 7 (63.64%) demonstrated right ventricular volume or pressure overload. Eleven patients (73.33%) survived. During-UPMV, VT ranged 2–5 mL/kg PBW(3.99 ± 0.73), the arterial partial pressure of carbon dioxide (PaCO2) was higher than pre-UPMV values (84.81 ± 18.95 cmH2O vs. 69.16 ± 33.09 cmH2O), but pH was comparable and none received extracorporeal carbon dioxide removal (ECCO2-R). The positive end-expiratory pressure (14.18 ± 7.56 vs. 12.31 ± 6.84 cmH2O), PIP (38.21 ± 12.89 vs. 32.59 ± 9.88), and mean airway pressures (19.98 ± 7.61 vs. 17.48 ± 6.7 cm H2O) were higher during UPMV, but Pplat and PaO2/FiO2 were comparable during- and pre-UPMV. Driving pressure was observed to be higher in those who died than who survived (24.18 ± 12.36 vs. 13.42 ± 3.25). Conclusion UPMV alone may be a safe alternative option for ARDS patients in centers without ECCO2-R.

scholarly journals Radiological pattern in ARDS patients: partitioned respiratory mechanics, gas exchange and lung recruitability

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Silvia Coppola ◽  
Tommaso Pozzi ◽  
Martina Gurgitano ◽  
Alessandro Liguori ◽  
Ejona Duka ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Respiratory System ◽  
Respiratory Mechanics ◽  
Recruitment Maneuver ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Driving Pressure ◽  
Lung Weight ◽  
Focal Pattern ◽  
Lung Ct

Abstract Background The ARDS is characterized by different degrees of impairment in oxygenation and distribution of the lung disease. Two radiological patterns have been described: a focal and a diffuse one. These two patterns could present significant differences both in gas exchange and in the response to a recruitment maneuver. At the present time, it is not known if the focal and the diffuse pattern could be characterized by a difference in the lung and chest wall mechanical characteristics. Our aims were to investigate, at two levels of PEEP, if focal vs. diffuse ARDS patterns could be characterized by different lung CT characteristics, partitioned respiratory mechanics and lung recruitability. Methods CT patterns were analyzed by two radiologists and were classified as focal or diffuse. The changes from 5 to 15 cmH2O in blood gas analysis and partitioned respiratory mechanics were analyzed. Lung CT scan was performed at 5 and 45 cmH2O of PEEP to evaluate lung recruitability. Results One-hundred and ten patients showed a diffuse pattern, while 58 showed a focal pattern. At 5 cmH2O of PEEP, the driving pressure and the elastance, both the respiratory system and of the lung, were significantly higher in the diffuse pattern compared to the focal (14 [11–16] vs 11 [9–15 cmH2O; 28 [23–34] vs 21 [17–27] cmH2O/L; 22 [17–28] vs 14 [12–19] cmH2O/L). By increasing PEEP, the driving pressure and the respiratory system elastance significantly decreased in diffuse pattern, while they increased or did not change in the focal pattern (Δ15-5: − 1 [− 2 to 1] vs 0 [− 1 to 2]; − 1 [− 4 to 2] vs 1 [− 2 to 5]). At 5 cmH2O of PEEP, the diffuse pattern had a lower lung gas (743 [537–984] vs 1222 [918–1974] mL) and higher lung weight (1618 [1388–2001] vs 1222 [1059–1394] g) compared to focal pattern. The lung recruitability was significantly higher in diffuse compared to focal pattern 21% [13–29] vs 11% [6–16]. Considering the median of lung recruitability of the whole population (16.1%), the recruiters were 65% and 22% in the diffuse and focal pattern, respectively. Conclusions An early identification of lung morphology can be useful to choose the ventilatory setting. A diffuse pattern has a better response to the increase of PEEP and to the recruitment maneuver.

scholarly journals Low sensitivity of measurements of respiratory mechanics in detecting lung edema from high tidal volume mechanical ventilation

Critical Care ◽  
2007 ◽  
Vol 11 (Suppl 2) ◽  
pp. P189
Author(s):  
N Maniatis ◽  
S Orfanos ◽  
H Roussos ◽  
A Armaganidis ◽  
A Kotanidou
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Respiratory Mechanics ◽  
High Tidal Volume ◽  
Lung Edema ◽  
Low Sensitivity

scholarly journals Can you calculate the total respiratory, lung, and chest wall respiratory mechanics?

2020 ◽  
Vol 1 (1) ◽  
pp. 24-26
Author(s):  
Mia Shokry ◽  
Kimiyo Yamasaki ◽  
Ehab Daoud
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Chest Wall ◽  
Airway Pressure ◽  
Respiratory Mechanics ◽  
Peak Inspiratory Pressure ◽  
Esophageal Pressure ◽  
Horizontal Line ◽  
Pulmonary Pressure ◽  
Volume Controlled

Figure: Waveforms for a patient undergoing mechanical ventilation with volume controlled mode. Tidal Volume of 500 ml, PEEP 15, Constant inspiratory flow of 45 l/min A: Airway pressure in cmH2O, B: Esophageal pressure in cmH2O, C: Trans-pulmonary pressure in cmH2O, D: Flow in l/min, E: Tidal volume in ml Red dashed horizontal line: values at end of expiratory occlusion maneuver, White solid horizontal line: values at end of inspiratory occlusion maneuver, Green dashed horizontal line: values during peak inspiratory pressure.

scholarly journals Positive end-expiratory pressure in COVID-19 acute respiratory distress syndrome: the heterogeneous effects

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Davide Chiumello ◽  
Matteo Bonifazi ◽  
Tommaso Pozzi ◽  
Paolo Formenti ◽  
Giuseppe Francesco Sferrazza Papa ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Respiratory System ◽  
Dead Space ◽  
Respiratory Mechanics ◽  
Peep Level ◽  
Lung Mechanics ◽  
Mechanical Power ◽  
Respiratory System Compliance ◽  
Lung Elastance ◽  
Lung Stress

Abstract Background We hypothesized that as CARDS may present different pathophysiological features than classic ARDS, the application of high levels of end-expiratory pressure is questionable. Our first aim was to investigate the effects of 5–15 cmH2O of PEEP on partitioned respiratory mechanics, gas exchange and dead space; secondly, we investigated whether respiratory system compliance and severity of hypoxemia could affect the response to PEEP on partitioned respiratory mechanics, gas exchange and dead space, dividing the population according to the median value of respiratory system compliance and oxygenation. Thirdly, we explored the effects of an additional PEEP selected according to the Empirical PEEP-FiO2 table of the EPVent-2 study on partitioned respiratory mechanics and gas exchange in a subgroup of patients. Methods Sixty-one paralyzed mechanically ventilated patients with a confirmed diagnosis of SARS-CoV-2 were enrolled (age 60 [54–67] years, PaO2/FiO2 113 [79–158] mmHg and PEEP 10 [10–10] cmH2O). Keeping constant tidal volume, respiratory rate and oxygen fraction, two PEEP levels (5 and 15 cmH2O) were selected. In a subgroup of patients an additional PEEP level was applied according to an Empirical PEEP-FiO2 table (empirical PEEP). At each PEEP level gas exchange, partitioned lung mechanics and hemodynamic were collected. Results At 15 cmH2O of PEEP the lung elastance, lung stress and mechanical power were higher compared to 5 cmH2O. The PaO2/FiO2, arterial carbon dioxide and ventilatory ratio increased at 15 cmH2O of PEEP. The arterial–venous oxygen difference and central venous saturation were higher at 15 cmH2O of PEEP. Both the mechanics and gas exchange variables significantly increased although with high heterogeneity. By increasing the PEEP from 5 to 15 cmH2O, the changes in partitioned respiratory mechanics and mechanical power were not related to hypoxemia or respiratory compliance. The empirical PEEP was 18 ± 1 cmH2O. The empirical PEEP significantly increased the PaO2/FiO2 but also driving pressure, lung elastance, lung stress and mechanical power compared to 15 cmH2O of PEEP. Conclusions In COVID-19 ARDS during the early phase the effects of raising PEEP are highly variable and cannot easily be predicted by respiratory system characteristics, because of the heterogeneity of the disease.

scholarly journals Comparing the Intellivent-ASV® Mode with Conventional Ventilation Modes during Weaning after Uncomplicated Cardiac Surgery

2021 ◽  
Vol 18 (3) ◽  
pp. 36-45
Author(s):  
А. А. Eremenko ◽  
R. D. Komnov ◽  
P. А. Titov ◽  
S. А. Gerasimenko ◽  
D. А. Chakal
Keyword(s):  
Mechanical Ventilation ◽  
Cardiac Surgery ◽  
Adverse Events ◽  
Tidal Volume ◽  
Driving Pressure ◽  
Conventional Ventilation ◽  
Respiratory Support ◽  
Control Group ◽  
Ventilation Modes ◽  
Ventilator Settings

The objective: to compare efficacy and safety of Intellivent-ASV® with conventional ventilation modes during weaning in the patients after cardiac surgery.Subjects and methods. In this randomized controlled trial, 40 adult patients were ventilated with conventional ventilation modes and 40 with Intellivent-ASV after uncomplicated cardiac surgery. Eight physicians were involved in the study.Care of both groups was standardized, except for the modes of postoperative ventilation.We compared:- The physician’s workload, through accounting number of manual ventilator settings and time they spent near the ventilator in every group,- Duration of tracheal intubation in ICU,- Evaluation of ventilation safety by considering driving pressure, mechanical power, positive end expiratory pressure, and tidal volume level,- The frequency of adverse events, postoperative complications, and lethality.Results. There were significant differences in the duration of respiratory support in ICU: 226 ± 31 min (Intellivent Group) vs 271 ± 78 min (Control Group) (p = 0.0013).In Intellivent Group, the number of manual ventilator settings and time spent by physicians near the ventilator before tracheal extubation were significantly lower: 0 vs 4 (2–6), and 35 (25–53) sec vs 164 ± 69 sec respectively (p < 0.001 in both cases).Intellivent-ASV provided significantly more protective ventilation through reduction in the driving pressure, tidal volume, FiO2 and PEEP levels but no difference was noted between paO2/FiO2 ratio. ∆P and Vt were significantly lower in Intellivent Group – ∆P on mechanical ventilation was 6 (5–7) cm H2O vs 7.25 (6.5–9.5) cm H2O (p < 0.001); Vt on mechanical ventilation was 6 (5.2–7) vs 7 (6–9.5) ml/kg/PBW (p = 0.000003). PEEP and FiO2 levels were also significantly lower in Intellivent Group, PEEP on mechanical ventilation was 5 (5–7.5) cm H2O vs 7 (5–11.5) cm H2O and FiO2 level was 26 (22–30) % vs 34 (30–40) %.There were no significant differences between the groups in frequency of adverse events and duration of ICU and hospital stay.Conclusion. Application of Intellivent-ASV mode after uncomplicated cardiac surgery provides more protective mechanical ventilation and reduces the physician’s workload without compromising the quality of respiratory support and safety of patients.

scholarly journals A Protective Tidal Volume Adapted To Lung Compliance and The PEEP Level With Lowest Transpulmonary Driving Pressure May Be Determined By a Rapid PEEP-Step Procedure

2021 ◽  
Author(s):  
Christina Grivans ◽  
Ola Stenqvist
Keyword(s):  
Body Weight ◽  
Tidal Volume ◽  
Peep Level ◽  
Ideal Body Weight ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Lung Compliance ◽  
Driving Pressure ◽  
Step Procedure ◽  
Ideal Body

Abstract Background: A protective ventilation strategy should be based on lung mechanics and transpulmonary pressure, as this is the pressure that directly “hits” the lung. Esophageal pressure has been used for this purpose but has not gained widespread clinical acceptance. Instead, respiratory system mechanics and airway driving pressure have been used as surrogate measures. We have shown that the lung pressure/volume (P/V) curve coincides with the line connecting the end-expiratory airway P/V points of a PEEP trial. Consequently, transpulmonary pressure increases as much as PEEP and lung compliance (CL) can be determined as ΔEELV/ΔPEEP and transpulmonary driving pressure (ΔPTP) as tidal volume divided by ΔEELV/ΔPEEP.Methods: In ten patients with acute respiratory failure, ΔEELV was measured during each 4 cmH2O PEEP-step from 0 to 16 cmH2O and CL for each PEEP interval calculated as ΔEELV/ΔPEEP giving a lung P/V curve for the whole PEEP trial. Similarily, a lung P/V curve was obtained also for the PEEP levels 8, 12, and 16 cmH2O only.Results: A two-step PEEP procedure starting from a clinical PEEP level of 8 cmH2O gave almost identical lung P/V curves as the four PEEP-step procedure. The lung P/V curves showed a marked individual variation with an over-all CL (CLoa ) 50-137 ml/cmH2O. ΔPTP of a tidal volume of 6-7 ml/kg ideal body weight divided by CLoa ranged from 8.6-2.8 cmH2O, while ΔPTP of tidal volume adapted to CLoa ranged from 3.3 in the patient with lowest to 4.3 cmH 2 O in the patient with highest CLoa . The ratio of airway driving pressure to transpulmonary driving pressure (ΔPTP/ΔPAW) varied between patients and changed with PEEP, reducing the value of ΔPAW as surrogate for ΔPTP in individual patients.Conclusion: Only a two PEEP-step procedure is required for obtaining a lung P/V curve from baseline clinical PEEP to end-inspiration at the highest PEEP level, i.e. without esophageal pressure measurements. The best-fit equation for the curve can be used to determine a tidal volume related to lung compliance instead of ideal body weight and the PEEP level where transpulmonary driving pressure is lowest and possibly least injurious for any given tidal volume.

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