scholarly journals Driving pressure is not associated with mortality in mechanically ventilated patients without ARDS

Critical Care ◽  
2019 ◽  
Vol 23 (1) ◽  
Author(s):  
Michael J. Lanspa ◽  
Ithan D. Peltan ◽  
Jason R. Jacobs ◽  
Jeffrey S. Sorensen ◽  
Lori Carpenter ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Language Processing ◽  
Respiratory System ◽  
Linear Models ◽  
Cohort Analysis ◽  
Driving Pressure ◽  
Respiratory System Compliance ◽  
Mechanically Ventilated ◽  
Volume Ventilation ◽  
Comorbidity Index

Abstract Background In patients with acute respiratory distress syndrome (ARDS), low tidal volume ventilation has been associated with reduced mortality. Driving pressure (tidal volume normalized to respiratory system compliance) may be an even stronger predictor of ARDS survival than tidal volume. We sought to study whether these associations hold true in acute respiratory failure patients without ARDS. Methods This is a retrospectively cohort analysis of mechanically ventilated adult patients admitted to ICUs from 12 hospitals over 2 years. We used natural language processing of chest radiograph reports and data from the electronic medical record to identify patients who had ARDS. We used multivariable logistic regression and generalized linear models to estimate associations between tidal volume, driving pressure, and respiratory system compliance with adjusted 30-day mortality using covariates of Acute Physiology Score (APS), Charlson Comorbidity Index (CCI), age, and PaO2/FiO2 ratio. Results We studied 2641 patients; 48% had ARDS (n = 1273). Patients with ARDS had higher mean APS (25 vs. 23, p < .001) but similar CCI (4 vs. 3, p = 0.6) scores. For non-ARDS patients, tidal volume was associated with increased adjusted mortality (OR 1.18 per 1 mL/kg PBW increase in tidal volume, CI 1.04 to 1.35, p = 0.010). We observed no association between driving pressure or respiratory compliance and mortality in patients without ARDS. In ARDS patients, both ΔP (OR1.1, CI 1.06–1.14, p < 0.001) and tidal volume (OR 1.17, CI 1.04–1.31, p = 0.007) were associated with mortality. Conclusions In a large retrospective analysis of critically ill non-ARDS patients receiving mechanical ventilation, we found that tidal volume was associated with 30-day mortality, while driving pressure was not.

scholarly journals Management of hypercapnia in critically ill mechanically ventilated patients—A narrative review of literature

2020 ◽  
Vol 21 (4) ◽  
pp. 327-333
Author(s):  
Ravindranath Tiruvoipati ◽  
Sachin Gupta ◽  
David Pilcher ◽  
Michael Bailey
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Dead Space ◽  
Hypercapnic Acidosis ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Low Tidal Volume ◽  
Volume Ventilation ◽  
Low Volume ◽  
Ventilated Patients

The use of lower tidal volume ventilation was shown to improve survival in mechanically ventilated patients with acute lung injury. In some patients this strategy may cause hypercapnic acidosis. A significant body of recent clinical data suggest that hypercapnic acidosis is associated with adverse clinical outcomes including increased hospital mortality. We aimed to review the available treatment options that may be used to manage acute hypercapnic acidosis that may be seen with low tidal volume ventilation. The databases of MEDLINE and EMBASE were searched. Studies including animals or tissues were excluded. We also searched bibliographic references of relevant studies, irrespective of study design with the intention of finding relevant studies to be included in this review. The possible options to treat hypercapnia included optimising the use of low tidal volume mechanical ventilation to enhance carbon dioxide elimination. These include techniques to reduce dead space ventilation, and physiological dead space, use of buffers, airway pressure release ventilation and prone positon ventilation. In patients where hypercapnic acidosis could not be managed with lung protective mechanical ventilation, extracorporeal techniques may be used. Newer, minimally invasive low volume venovenous extracorporeal devices are currently being investigated for managing hypercapnia associated with low and ultra-low volume mechanical ventilation.

scholarly journals Driving Pressure Is Associated with Outcome during Assisted Ventilation in Acute Respiratory Distress Syndrome

2019 ◽  
Vol 131 (3) ◽  
pp. 594-604 ◽  
Author(s):  
Giacomo Bellani ◽  
Alice Grassi ◽  
Simone Sosio ◽  
Stefano Gatti ◽  
Brian P. Kavanagh ◽  
...  
Keyword(s):  
Respiratory System ◽  
Odds Ratio ◽  
Pressure Support ◽  
Distress Syndrome ◽  
Peak Pressure ◽  
Plateau Pressure ◽  
Assisted Ventilation ◽  
Driving Pressure ◽  
Respiratory System Compliance ◽  
Controlled Mechanical Ventilation

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Driving pressure, the difference between plateau pressure and positive end-expiratory pressure (PEEP), is closely associated with increased mortality in patients with acute respiratory distress syndrome (ARDS). Although this relationship has been demonstrated during controlled mechanical ventilation, plateau pressure is often not measured during spontaneous breathing because of concerns about validity. The objective of the present study is to verify whether driving pressure and respiratory system compliance are independently associated with increased mortality during assisted ventilation (i.e., pressure support ventilation). Methods This is a retrospective cohort study conducted on 154 patients with ARDS in whom plateau pressure during the first three days of assisted ventilation was available. Associations between driving pressure, respiratory system compliance, and survival were assessed by univariable and multivariable analysis. In patients who underwent a computed tomography scan (n = 23) during the stage of assisted ventilation, the quantity of aerated lung was compared with respiratory system compliance measured on the same date. Results In contrast to controlled mechanical ventilation, plateau pressure during assisted ventilation was higher than the sum of PEEP and pressure support (peak pressure). Driving pressure was higher (11 [9–14] vs. 10 [8–11] cm H2O; P = 0.004); compliance was lower (40 [30–50] vs. 51 [42–61] ml · cm H2O-1; P &lt; 0.001); and peak pressure was similar, in nonsurvivors versus survivors. Lower respiratory system compliance (odds ratio, 0.92 [0.88–0.96]) and higher driving pressure (odds ratio, 1.34 [1.12–1.61]) were each independently associated with increased risk of death. Respiratory system compliance was correlated with the aerated lung volume (n = 23, r = 0.69, P &lt; 0.0001). Conclusions In patients with ARDS, plateau pressure, driving pressure, and respiratory system compliance can be measured during assisted ventilation, and both higher driving pressure and lower compliance are associated with increased mortality.

Effect of changes in lung volume on respiratory system compliance in newborn infants

1989 ◽  
Vol 67 (3) ◽  
pp. 1192-1197 ◽  
Author(s):  
F. Ratjen ◽  
R. Zinman ◽  
A. R. Stark ◽  
L. E. Leszczynski ◽  
M. E. Wohl
Keyword(s):  
Tidal Volume ◽  
Respiratory System ◽  
Lung Volume ◽  
Newborn Infants ◽  
Face Mask ◽  
Flow Volume ◽  
Respiratory System Compliance ◽  
Tidal Breathing ◽  
Volume Changes ◽  
Passive Flow

Total respiratory system compliance (Crs) at volumes above the tidal volume (VT) was studied by use of the expiratory volume clamping (EVC) technique in 10 healthy sleeping unsedated newborn infants. Flow was measured with a pneumotachograph attached to a face mask and integrated to yield volume. Volume changes were confirmed by respiratory inductance plethysmography. Crs measured by EVC was compared with Crs during tidal breathing determined by the passive flow-volume (PFV) technique. Volume increases of approximately 75% VT were achieved with three to eight inspiratory efforts during expiratory occlusions. Crs above VT was consistently greater than during tidal breathing (P less than 0.0005). This increase in Crs likely reflects recruitment of lung units that are closed or atelectatic in the VT range. Within the VT range, Crs measured by PFV was compared with that obtained by the multiple-occlusion method (MO). PFV yielded greater values of Crs than MO (P less than 0.01). This may be due to braking of expiratory airflow after the release of an occlusion or nonlinearity of Crs. Thus both volume recruitment and airflow retardation may affect the measurement of Crs in unsedated newborn infants.

scholarly journals Pneumomediastinum secondary to invasive and non-invasive mechanical ventilation

2019 ◽  
Vol 7 (27) ◽  
pp. 36-42 ◽  
Author(s):  
Sara Mousa ◽  
Hawa Edriss
Keyword(s):  
Mechanical Ventilation ◽  
Tidal Volume ◽  
Distress Syndrome ◽  
Invasive Mechanical Ventilation ◽  
X Rays ◽  
Mechanically Ventilated ◽  
Non Invasive ◽  
Low Tidal Volume ◽  
Volume Ventilation ◽  
High Frequency Oscillatory

Pneumomediastinum (PM) is defined as the presence of abnormal gas in the mediastinum.It is a known complication of invasive mechanical ventilation and has been reported withnon-invasive ventilation. Recent studies have reported that the incidence of barotrauma islowest in post-operative patients and is highest in mechanically ventilated patients with acuterespiratory distress syndrome. The incidence has dropped with the low tidal volume ventilationtechnique. Chest x-rays can miss up to 25% of small PMs detected by computed tomographyscans of the chest. Pneumomediastinum is managed with low tidal volume ventilation withplateau pressures <30 cm H2O and treatment of the underlying lung disease. Novel ways ofventilation, such as high frequency oscillatory ventilation and asynchronous independent lungventilation, may improve ventilation in some patients.

scholarly journals Tidal volume dependency of gas exchange in bronchoconstricted pig lungs

2007 ◽  
Vol 103 (1) ◽  
pp. 148-155 ◽  
Author(s):  
Axel Kleinsasser ◽  
I. Mark Olfert ◽  
Alex Loeckinger ◽  
G. Kim Prisk ◽  
Susan R. Hopkins ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Dynamic Compliance ◽  
Inert Gas ◽  
High Tidal Volume ◽  
Pulmonary Resistance ◽  
Mechanically Ventilated ◽  
High Tidal Volume Ventilation ◽  
Volume Ventilation ◽  
Closed Airway

Independent of airway pressure, pulmonary resistance is known to fall with increasing tidal volumes, traditionally thought to result from radial traction on the airways. R. C. Anafi and T. A. Wilson ( J Appl Physiol 91: 1185–1192, 2001) recently presented a model of a single terminal airway that explains the tidal volume-associated fall in resistance with an additional mechanism pertinent to narrow airways: a stable, nearly closed airway that is challenged with an increase in tidal volume “pops open” to become a stable, well-opened airway, and thus resistance drops suddenly. To test this model in vivo, the effects of high (24 ml/kg) and low (9 ml/kg) tidal volume in bronchoconstricted lungs were assessed using 1) the multiple inert gas elimination technique (MIGET) and 2) a 15-breath multiple breath inert gas washout (MBW) technique in anesthetized pigs. With high tidal volume, ventilation/perfusion (V̇a/Q̇) mismatch was reduced (log SD Q̇ from 1.30 ± 0.11 to 1.09 ± 0.12, P < 0.05), and blood flow to lung units with V̇a/Q̇ ratios < 0.1 was significantly reduced (37 ± 4% of cardiac output to 7 ± 4%, P < 0.05). Dynamic compliance was twice as high during high-tidal-volume ventilation ( P = 0.002). MBW analysis revealed that, while heterogeneity of ventilation during bronchoconstriction was not significantly different between either low or high tidal volume (log SD V̇mbw = 1.39 ± 0.09 and 1.34 ± 0.02, respectively), preinspiratory lung volume (PILV) decreased by 42% with low-tidal-volume ventilation ( P < 0.05), whereas it did not change with high-tidal-volume ventilation. The higher PILV during high tidal volume is also consistent with Anafi and Wilson's model. In summary, the outcomes from MIGET, and to some extent the MBW, in our anesthetized and mechanically ventilated pigs are consistent with a bistable terminal airway model as proposed by Anafi and Wilson. However, our data do not allow exclusion of other mechanisms that may lead to improved ventilatory distribution when tidal volume is increased.

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