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The role of spontaneous effort during mechanical ventilation: normal lung versus injured lung.

Yoshida T, Uchiyama A, Fujino Y - J Intensive Care (2015)

Bottom Line: Thus, increased transpulmonary pressure provides various benefits for gas exchange, ventilation pattern, and lung aeration.Thus, during the early stages of severe ARDS, the strict control of transpulmonary pressure and prevention of Pendelluft should be achieved with the short-term use of muscle paralysis.When there is preserved spontaneous effort in ARDS, spontaneous effort should be maintained at a modest level, as the transpulmonary pressure and the effect size of Pendelluft depend on the intensity of the spontaneous effort.

View Article: PubMed Central - PubMed

Affiliation: Intensive Care Unit, Osaka University Hospital, 2-15 Yamadaoka, Suita, Osaka 565-0871 Japan.

ABSTRACT
The role of preserving spontaneous effort during mechanical ventilation and its interaction with mechanical ventilation have been actively investigated for several decades. Inspiratory muscle activities can lower the pleural components surrounding the lung, leading to an increase in transpulmonary pressure when spontaneous breathing effort is preserved during mechanical ventilation. Thus, increased transpulmonary pressure provides various benefits for gas exchange, ventilation pattern, and lung aeration. However, it is important to note that these beneficial effects of preserved spontaneous effort have been demonstrated only when spontaneous effort is modest and lung injury is less severe. Recent studies have revealed the 'dark side' of spontaneous effort during mechanical ventilation, especially in severe lung injury. The 'dark side' refers to uncontrollable transpulmonary pressure due to combined high inspiratory pressure with excessive spontaneous effort and the injurious lung inflation pattern of Pendelluft (i.e., the translocation of air from nondependent lung regions to dependent lung regions). Thus, during the early stages of severe ARDS, the strict control of transpulmonary pressure and prevention of Pendelluft should be achieved with the short-term use of muscle paralysis. When there is preserved spontaneous effort in ARDS, spontaneous effort should be maintained at a modest level, as the transpulmonary pressure and the effect size of Pendelluft depend on the intensity of the spontaneous effort.

No MeSH data available.


Related in: MedlinePlus

EIT waveforms in experimental lung injury—spontaneous versus mechanical breaths. Note that the early inflation in the dependent region (Zones 3 and 4) was accompanied by concomitant deflation of nondependent region (Zones 1 and 2), indicating movement of air from nondependent to dependent lung (i.e. Pendelluft). Note that under the same tidal volume, spontaneous breathing during mechanical ventilation unsuspectedly increased dependent lung inflation (Zones 3 and 4) due to Pendelluft. Adapted with permission of the American Thoracic Society Copyright © 2014 American Thoracic Society (Ref. [12]).
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Fig4: EIT waveforms in experimental lung injury—spontaneous versus mechanical breaths. Note that the early inflation in the dependent region (Zones 3 and 4) was accompanied by concomitant deflation of nondependent region (Zones 1 and 2), indicating movement of air from nondependent to dependent lung (i.e. Pendelluft). Note that under the same tidal volume, spontaneous breathing during mechanical ventilation unsuspectedly increased dependent lung inflation (Zones 3 and 4) due to Pendelluft. Adapted with permission of the American Thoracic Society Copyright © 2014 American Thoracic Society (Ref. [12]).

Mentions: In contrast to the fluid-like behavior that is observed in normal lungs, the change in Ppl generated by inspiratory muscle contractions in injured lungs is not uniformly transmitted across the lung surface, but rather is concentrated in dependent lung regions [12] (Figure 3). This locally elevated change in PL causes unsuspected local overstretch in dependent lung regions, accompanying an alveolar air shift from nondependent (fluid-like, more recruited regions) to dependent (solid-like, less recruited regions) parts of the lung (i.e., Pendelluft) (Figure 4) [12].Figure 4


The role of spontaneous effort during mechanical ventilation: normal lung versus injured lung.

Yoshida T, Uchiyama A, Fujino Y - J Intensive Care (2015)

EIT waveforms in experimental lung injury—spontaneous versus mechanical breaths. Note that the early inflation in the dependent region (Zones 3 and 4) was accompanied by concomitant deflation of nondependent region (Zones 1 and 2), indicating movement of air from nondependent to dependent lung (i.e. Pendelluft). Note that under the same tidal volume, spontaneous breathing during mechanical ventilation unsuspectedly increased dependent lung inflation (Zones 3 and 4) due to Pendelluft. Adapted with permission of the American Thoracic Society Copyright © 2014 American Thoracic Society (Ref. [12]).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4940771&req=5

Fig4: EIT waveforms in experimental lung injury—spontaneous versus mechanical breaths. Note that the early inflation in the dependent region (Zones 3 and 4) was accompanied by concomitant deflation of nondependent region (Zones 1 and 2), indicating movement of air from nondependent to dependent lung (i.e. Pendelluft). Note that under the same tidal volume, spontaneous breathing during mechanical ventilation unsuspectedly increased dependent lung inflation (Zones 3 and 4) due to Pendelluft. Adapted with permission of the American Thoracic Society Copyright © 2014 American Thoracic Society (Ref. [12]).
Mentions: In contrast to the fluid-like behavior that is observed in normal lungs, the change in Ppl generated by inspiratory muscle contractions in injured lungs is not uniformly transmitted across the lung surface, but rather is concentrated in dependent lung regions [12] (Figure 3). This locally elevated change in PL causes unsuspected local overstretch in dependent lung regions, accompanying an alveolar air shift from nondependent (fluid-like, more recruited regions) to dependent (solid-like, less recruited regions) parts of the lung (i.e., Pendelluft) (Figure 4) [12].Figure 4

Bottom Line: Thus, increased transpulmonary pressure provides various benefits for gas exchange, ventilation pattern, and lung aeration.Thus, during the early stages of severe ARDS, the strict control of transpulmonary pressure and prevention of Pendelluft should be achieved with the short-term use of muscle paralysis.When there is preserved spontaneous effort in ARDS, spontaneous effort should be maintained at a modest level, as the transpulmonary pressure and the effect size of Pendelluft depend on the intensity of the spontaneous effort.

View Article: PubMed Central - PubMed

Affiliation: Intensive Care Unit, Osaka University Hospital, 2-15 Yamadaoka, Suita, Osaka 565-0871 Japan.

ABSTRACT
The role of preserving spontaneous effort during mechanical ventilation and its interaction with mechanical ventilation have been actively investigated for several decades. Inspiratory muscle activities can lower the pleural components surrounding the lung, leading to an increase in transpulmonary pressure when spontaneous breathing effort is preserved during mechanical ventilation. Thus, increased transpulmonary pressure provides various benefits for gas exchange, ventilation pattern, and lung aeration. However, it is important to note that these beneficial effects of preserved spontaneous effort have been demonstrated only when spontaneous effort is modest and lung injury is less severe. Recent studies have revealed the 'dark side' of spontaneous effort during mechanical ventilation, especially in severe lung injury. The 'dark side' refers to uncontrollable transpulmonary pressure due to combined high inspiratory pressure with excessive spontaneous effort and the injurious lung inflation pattern of Pendelluft (i.e., the translocation of air from nondependent lung regions to dependent lung regions). Thus, during the early stages of severe ARDS, the strict control of transpulmonary pressure and prevention of Pendelluft should be achieved with the short-term use of muscle paralysis. When there is preserved spontaneous effort in ARDS, spontaneous effort should be maintained at a modest level, as the transpulmonary pressure and the effect size of Pendelluft depend on the intensity of the spontaneous effort.

No MeSH data available.


Related in: MedlinePlus