Effects of pressure support ventilation on ventilator-induced lung injury in mild acute respiratory distress syndrome depend on level of positive end-expiratory pressure: A randomised animal study.
Eur J Anaesthesiol
; 35(4): 298-306, 2018 04.
Article
em En
| MEDLINE
| ID: mdl-29324568
ABSTRACT
BACKGROUND:
Harmful effects of spontaneous breathing have been shown in experimental severe acute respiratory distress syndrome (ARDS). However, in the clinical setting, spontaneous respiration has been indicated only in mild ARDS. To date, no study has compared the effects of spontaneous assisted breathing with those of fully controlled mechanical ventilation at different levels of positive end-expiratory pressure (PEEP) on lung injury in ARDS.OBJECTIVE:
To compare the effects of assisted pressure support ventilation (PSV) with pressure-controlled ventilation (PCV) on lung function, histology and biological markers at two different PEEP levels in mild ARDS in rats.DESIGN:
Randomised controlled experimental study.SETTING:
Basic science laboratory.PARTICIPANTS:
Thirty-five Wistar rats (weightâ±âSD, 310â±â19)âg received Escherichia coli lipopolysaccharide (LPS) intratracheally. After 24âh, the animals were anaesthetised and randomly allocated to either PCV (n=14) or PSV (n=14) groups. Each group was further assigned to PEEPâ=â2âcmH2O or PEEPâ=â5âcmH2O. Tidal volume was kept constant (≈6âmlâkg). Additional nonventilated animals (n=7) were used as a control for postmortem analysis. MAIN OUTCOMEMEASURES:
Ventilatory and mechanical parameters, arterial blood gases, diffuse alveolar damage score, epithelial integrity measured by E-cadherin tissue expression, and biological markers associated with inflammation (IL-6 and cytokine-induced neutrophil chemoattractant, CINC-1) and type II epithelial cell damage (surfactant protein-B) were evaluated.RESULTS:
In both PCV and PSV, peak transpulmonary pressure was lower, whereas E-cadherin tissue expression, which is related to epithelial integrity, was higher at PEEPâ=â5âcmH2O than at PEEPâ=â2âcmH2O. In PSV, PEEPâ=â5âcmH2O compared with PEEPâ=â2âcmH2O was associated with significantly reduced diffuse alveolar damage score [median (interquartile range), 11 (8.5 to 13.5) vs. 23 (19 to 26), Pâ=â0.005] and expressions of IL-6 and CINC-1 (Pâ=â0.02 for both), whereas surfactant protein-B mRNA expression increased (Pâ=â0.03). These changes suggested less type II epithelial cell damage at a PEEP of 5âcmH2O. Peak transpulmonary pressure correlated positively with IL-6 [Spearman's rho (ρ)â=â0.62, Pâ=â0.0007] and CINC-1 expressions (ρâ=â0.50, Pâ=â0.01) and negatively with E-cadherin expression (ρâ=â-0.67, Pâ=â0.0002).CONCLUSION:
During PSV, PEEP of 5âcmH2O, but not a PEEP of 2âcmH2O, reduced lung damage and inflammatory markers while maintaining epithelial cell integrity.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Síndrome do Desconforto Respiratório
/
Respiração com Pressão Positiva
/
Lesão Pulmonar Induzida por Ventilação Mecânica
Limite:
Animals
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article