Limits...
Do spontaneous and mechanical breathing have similar effects on average transpulmonary and alveolar pressure? A clinical crossover study.

Bellani G, Grasselli G, Teggia-Droghi M, Mauri T, Coppadoro A, Brochard L, Pesenti A - Crit Care (2016)

Bottom Line: Overall, ΔPL was similar between CMV and PSV, but only loosely correlated.By contrast, the Palv profile was very different between CMV and SB; SB led to progressively more negative Palv during inspiration, and Palv became lower than the set positive end-expiratory pressure in nine of ten patients at low PSV.Under similar conditions of flow and volume, transpulmonary pressure change is similar between CMV and PSV.

View Article: PubMed Central - PubMed

Affiliation: Department of Health Science, University of Milan-Bicocca, Via Cadore, 48 20900, Monza, Italy. giacomo.bellani1@unimib.it.

ABSTRACT

Background: Preservation of spontaneous breathing (SB) is sometimes debated because it has potentially both negative and positive effects on lung injury in comparison with fully controlled mechanical ventilation (CMV). We wanted (1) to verify in mechanically ventilated patients if the change in transpulmonary pressure was similar between pressure support ventilation (PSV) and CMV for a similar tidal volume, (2) to estimate the influence of SB on alveolar pressure (Palv), and (3) to determine whether a reliable plateau pressure could be measured during pressure support ventilation (PSV).

Methods: We studied ten patients equipped with esophageal catheters undergoing three levels of PSV followed by a phase of CMV. For each condition, we calculated the maximal and mean transpulmonary (ΔPL) swings and Palv.

Results: Overall, ΔPL was similar between CMV and PSV, but only loosely correlated. The differences in ΔPL between CMV and PSV were explained largely by different inspiratory flows, indicating that the resistive pressure drop caused this difference. By contrast, the Palv profile was very different between CMV and SB; SB led to progressively more negative Palv during inspiration, and Palv became lower than the set positive end-expiratory pressure in nine of ten patients at low PSV. Finally, inspiratory occlusion holds performed during PSV led to plateau and Δ PL pressures comparable with those measured during CMV.

Conclusions: Under similar conditions of flow and volume, transpulmonary pressure change is similar between CMV and PSV. SB during mechanical ventilation can cause remarkably negative swings in Palv, a mechanism by which SB might potentially induce lung injury.

No MeSH data available.


Related in: MedlinePlus

a Pressures (transpulmonary pressure swings [ΔPL] on the left, shown as bars and standard deviation), versus the level of support (high, medium, or low). It shows that, by contrast with airway pressure, ΔPL swings during inspiration were similar and not statistically different between controlled mechanical ventilation (CMV) and any of the support levels. Closed symbols represent mean values during inspiration, and open symbols show maximum values during inspiration. The correlation between the value recorded during CMV and pressure support ventilation (PSV), albeit significant, was poor (b). The difference between the measurement of ΔPL obtained during CMV and PSV was explained largely by the corresponding difference in the inspiratory flow (c), as shown by the highly significant correlation. Indeed, when the analysis was restricted to the breaths with similar inspiratory flows (i.e., with an absolute difference less than 0.1 L/minute) (d), the correlation of ΔPL obtained during CMV and PSV became very tight
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4862136&req=5

Fig2: a Pressures (transpulmonary pressure swings [ΔPL] on the left, shown as bars and standard deviation), versus the level of support (high, medium, or low). It shows that, by contrast with airway pressure, ΔPL swings during inspiration were similar and not statistically different between controlled mechanical ventilation (CMV) and any of the support levels. Closed symbols represent mean values during inspiration, and open symbols show maximum values during inspiration. The correlation between the value recorded during CMV and pressure support ventilation (PSV), albeit significant, was poor (b). The difference between the measurement of ΔPL obtained during CMV and PSV was explained largely by the corresponding difference in the inspiratory flow (c), as shown by the highly significant correlation. Indeed, when the analysis was restricted to the breaths with similar inspiratory flows (i.e., with an absolute difference less than 0.1 L/minute) (d), the correlation of ΔPL obtained during CMV and PSV became very tight

Mentions: As expected (Fig. 2a), switching from CMV to decreasing levels of PSV led to a significant reduction in airway pressure (p < 0.001 by ANOVA). Simultaneously, Pmus was almost zero during CMV, and application of decreasing levels of PSV led to a progressive increase of Pmus (p < 0.001 by ANOVA) (Table 2).Fig. 2


Do spontaneous and mechanical breathing have similar effects on average transpulmonary and alveolar pressure? A clinical crossover study.

Bellani G, Grasselli G, Teggia-Droghi M, Mauri T, Coppadoro A, Brochard L, Pesenti A - Crit Care (2016)

a Pressures (transpulmonary pressure swings [ΔPL] on the left, shown as bars and standard deviation), versus the level of support (high, medium, or low). It shows that, by contrast with airway pressure, ΔPL swings during inspiration were similar and not statistically different between controlled mechanical ventilation (CMV) and any of the support levels. Closed symbols represent mean values during inspiration, and open symbols show maximum values during inspiration. The correlation between the value recorded during CMV and pressure support ventilation (PSV), albeit significant, was poor (b). The difference between the measurement of ΔPL obtained during CMV and PSV was explained largely by the corresponding difference in the inspiratory flow (c), as shown by the highly significant correlation. Indeed, when the analysis was restricted to the breaths with similar inspiratory flows (i.e., with an absolute difference less than 0.1 L/minute) (d), the correlation of ΔPL obtained during CMV and PSV became very tight
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4862136&req=5

Fig2: a Pressures (transpulmonary pressure swings [ΔPL] on the left, shown as bars and standard deviation), versus the level of support (high, medium, or low). It shows that, by contrast with airway pressure, ΔPL swings during inspiration were similar and not statistically different between controlled mechanical ventilation (CMV) and any of the support levels. Closed symbols represent mean values during inspiration, and open symbols show maximum values during inspiration. The correlation between the value recorded during CMV and pressure support ventilation (PSV), albeit significant, was poor (b). The difference between the measurement of ΔPL obtained during CMV and PSV was explained largely by the corresponding difference in the inspiratory flow (c), as shown by the highly significant correlation. Indeed, when the analysis was restricted to the breaths with similar inspiratory flows (i.e., with an absolute difference less than 0.1 L/minute) (d), the correlation of ΔPL obtained during CMV and PSV became very tight
Mentions: As expected (Fig. 2a), switching from CMV to decreasing levels of PSV led to a significant reduction in airway pressure (p < 0.001 by ANOVA). Simultaneously, Pmus was almost zero during CMV, and application of decreasing levels of PSV led to a progressive increase of Pmus (p < 0.001 by ANOVA) (Table 2).Fig. 2

Bottom Line: Overall, ΔPL was similar between CMV and PSV, but only loosely correlated.By contrast, the Palv profile was very different between CMV and SB; SB led to progressively more negative Palv during inspiration, and Palv became lower than the set positive end-expiratory pressure in nine of ten patients at low PSV.Under similar conditions of flow and volume, transpulmonary pressure change is similar between CMV and PSV.

View Article: PubMed Central - PubMed

Affiliation: Department of Health Science, University of Milan-Bicocca, Via Cadore, 48 20900, Monza, Italy. giacomo.bellani1@unimib.it.

ABSTRACT

Background: Preservation of spontaneous breathing (SB) is sometimes debated because it has potentially both negative and positive effects on lung injury in comparison with fully controlled mechanical ventilation (CMV). We wanted (1) to verify in mechanically ventilated patients if the change in transpulmonary pressure was similar between pressure support ventilation (PSV) and CMV for a similar tidal volume, (2) to estimate the influence of SB on alveolar pressure (Palv), and (3) to determine whether a reliable plateau pressure could be measured during pressure support ventilation (PSV).

Methods: We studied ten patients equipped with esophageal catheters undergoing three levels of PSV followed by a phase of CMV. For each condition, we calculated the maximal and mean transpulmonary (ΔPL) swings and Palv.

Results: Overall, ΔPL was similar between CMV and PSV, but only loosely correlated. The differences in ΔPL between CMV and PSV were explained largely by different inspiratory flows, indicating that the resistive pressure drop caused this difference. By contrast, the Palv profile was very different between CMV and SB; SB led to progressively more negative Palv during inspiration, and Palv became lower than the set positive end-expiratory pressure in nine of ten patients at low PSV. Finally, inspiratory occlusion holds performed during PSV led to plateau and Δ PL pressures comparable with those measured during CMV.

Conclusions: Under similar conditions of flow and volume, transpulmonary pressure change is similar between CMV and PSV. SB during mechanical ventilation can cause remarkably negative swings in Palv, a mechanism by which SB might potentially induce lung injury.

No MeSH data available.


Related in: MedlinePlus