Bedside assessment of the effects of positive end-expiratory pressure on lung inflation and recruitment by the helium dilution technique and electrical impedance tomography.
Intensive Care Med
; 42(10): 1576-1587, 2016 Oct.
Article
em En
| MEDLINE
| ID: mdl-27518321
ABSTRACT
PURPOSE:
Higher positive end-expiratory pressure might induce lung inflation and recruitment, yielding enhanced regional lung protection. We measured positive end-expiratory pressure-related lung volume changes by electrical impedance tomography and by the helium dilution technique. We also used electrical impedance tomography to assess the effects of positive end-expiratory pressure on regional determinants of ventilator-induced lung injury.METHODS:
A prospective randomized crossover study was performed on 20 intubated adult patients 12 with acute hypoxemic respiratory failure and 8 with acute respiratory distress syndrome. Each patient underwent protective controlled ventilation at lower (7 [7, 8] cmH2O) and higher (12 [12, 13] cmH2O) positive end-expiratory pressures. At the end of each phase, we collected ventilation, helium dilution, and electrical impedance tomography data.RESULTS:
Positive end-expiratory pressure-induced changes in lung inflation and recruitment measured by electrical impedance tomography and helium dilution showed close correlations (R (2) = 0.78, p < 0.001 and R (2) = 0.68, p < 0.001, respectively) but with relatively variable limits of agreement. At higher positive end-expiratory pressure, recruitment was evident in all lung regions (p < 0.01) and heterogeneity of tidal ventilation distribution was reduced by increased tidal volume distending the dependent lung (p < 0.001); in the non-dependent lung, on the other hand, compliance decreased (p < 0.001) and tidal hyperinflation significantly increased (p < 0.001). In the subgroup of ARDS patients (but not in the whole study population) tidal hyperinflation in the dependent lung regions decreased at higher positive end-expiratory pressure (p = 0.05), probably indicating higher potential for recruitment.CONCLUSIONS:
Close correlations exist between bedside assessment of positive end-expiratory pressure-induced changes in lung inflation and recruitment by the helium dilution and electrical impedance tomography techniques. Higher positive end-expiratory pressure exerts mixed effects on the regional determinants of ventilator-induced lung injury; these merit close monitoring.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tomografia
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Respiração com Pressão Positiva
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Impedância Elétrica
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Testes Imediatos
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Hélio
Tipo de estudo:
Clinical_trials
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Diagnostic_studies
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Etiology_studies
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Observational_studies
Limite:
Adult
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Aged
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Aged80
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Female
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Humans
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Male
/
Middle aged
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article