Hysteresis and Lung Recruitment in Acute Respiratory Distress Syndrome Patients: A CT Scan Study.
Crit Care Med
; 48(10): 1494-1502, 2020 10.
Article
em En
| MEDLINE
| ID: mdl-32897667
ABSTRACT
OBJECTIVES:
Hysteresis of the respiratory system pressure-volume curve is related to alveolar surface forces, lung stress relaxation, and tidal reexpansion/collapse. Hysteresis has been suggested as a means of assessing lung recruitment. The objective of this study was to determine the relationship between hysteresis, mechanical characteristics of the respiratory system, and lung recruitment assessed by a CT scan in mechanically ventilated acute respiratory distress syndrome patients.DESIGN:
Prospective observational study.SETTING:
General ICU of a university hospital. PATIENTS Twenty-five consecutive sedated and paralyzed patients with acute respiratory distress syndrome (age 64 ± 15 yr, body mass index 26 ± 6 kg/m, PaO2/FIO2 147 ± 42, and positive end-expiratory pressure 9.3 ± 1.4 cm H2O) were enrolled.INTERVENTIONS:
A low-flow inflation and deflation pressure-volume curve (5-45 cm H2O) and a sustained inflation recruitment maneuver (45 cm H2O for 30 s) were performed. A lung CT scan was performed during breath-holding pressure at 5 cm H2O and during the recruitment maneuver at 45 cm H2O. MEASUREMENTS AND MAINRESULTS:
Lung recruitment was computed as the difference in noninflated tissue and in gas volume measured at 5 and at 45 cm H2O. Hysteresis was calculated as the ratio of the area enclosed by the pressure-volume curve and expressed as the hysteresis ratio. Hysteresis was correlated with respiratory system compliance computed at 5 cm H2O and the lung gas volume entering the lung during inflation of the pressure-volume curve (R = 0.749, p < 0.001 and R = 0.851, p < 0.001). The hysteresis ratio was related to both lung tissue and gas recruitment (R = 0.266, p = 0.008, R = 0.357, p = 0.002, respectively). Receiver operating characteristic analysis showed that the optimal cutoff value to predict lung tissue recruitment for the hysteresis ratio was 28% (area under the receiver operating characteristic curve, 0.80; 95% CI, 0.62-0.98), with sensitivity and specificity of 0.75 and 0.77, respectively.CONCLUSIONS:
Hysteresis of the respiratory system computed by low-flow pressure-volume curve is related to the anatomical lung characteristics and has an acceptable accuracy to predict lung recruitment.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Síndrome do Desconforto Respiratório
/
Mecânica Respiratória
/
Pulmão
Tipo de estudo:
Observational_studies
/
Prognostic_studies
Limite:
Aged
/
Aged80
/
Humans
/
Middle aged
Idioma:
En
Revista:
Crit Care Med
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Itália