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Critical Care

, 9:P102 | Cite as

Temporal effect of applied pressures on observed alveolar recruitment

  • J DiRocco
  • D Carney
  • L Gatto
  • S Landas
  • G Nieman
Poster presentation
  • 685 Downloads

Keywords

Continuous Positive Airway Pressure Acute Respiratory Distress Syndrome Ventilatory Strategy Lavage Lung Alveolar Level 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Introduction

Lung recruitment has been hypothesized to be an important component of protective ventilatory strategy in acute respiratory distress syndrome. Determination of optimal recruitment strategies is limited by uncertainty regarding the relationship between time, pressure, and recruitment at the alveolar level. In this study, we assessed the temporal characteristics of alveolar recruitment.

Methods

Rats were subjected to saline lavage lung injury. In vivo microscopy identified five separate alveolar sacs for which individual recruitment pressures (RP) were determined by increasing the continuous positive airway pressure (CPAP). The time to recruitment was recorded upon application of three pressures for a maximum of 120 s: RP, RP – 1 cmH2O, and RP – 2 cmH2O. Volume history was normalized before each pressure application.

Results

No recruitment was observed in the 2-min time period with a pressure of RP – 2 cmH2O. The time to recruitment was significantly shorter with application of RP vs RP – 1 cmH2O (Fig. 1). Significance was determined by a one-tailed, paired t test, P < 0.03.
Figure 1

(abstract P102)

Conclusions

We were able to directly observe recruitment behavior that exhibited sensitivity around a critical opening pressure with marked changes in time to recruitment with small changes in pressure. This suggests that very small differences in the airway pressures (as small as 1 cmH2O in this study) may have dramatic alterations in lung recruitment.

Copyright information

© BioMed Central Ltd 2005

Authors and Affiliations

  • J DiRocco
    • 1
  • D Carney
    • 1
  • L Gatto
    • 2
  • S Landas
    • 1
  • G Nieman
    • 1
  1. 1.Upstate Medical UniversitySyracuseUSA
  2. 2.SUNY – CortlandUSA

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