Gas exchange and lung mechanics in patients with acute respiratory distress syndrome: comparison of three different strategies of positive end expiratory pressure selection.

The purpose of the study was to compare gas exchange and lung mechanics between different strategies to select positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS). In 20 consecutive ARDS patients, 3 PEEP selection strategies were evaluated. One strategy was based on oxygenation using the ARDS network PEEP/fraction of inspired oxygen (Fio2) table; and two were based on lung mechanics, either PEEP titrated to reach a plateau pressure of 28 to 30 cm H2O as in the ExPress trial or best respiratory compliance method during a derecruitment maneuver. Gas exchange, airway pressures, stress index (SI), and end-expiratory transpulmonary pressure (P(tpe)) and end-inspiratory transpulmonary pressure (P(tpi)) values were assessed. Data are expressed as median (interquartile range [IQR]). Lower total PEEP levels were observed with the use of the PEEP/Fio2 table (8.7 [6-10] cm H2O); intermediate PEEP levels, with the Best Compliance approach (13.0 [10.2-13.8] cm H2O); and higher PEEP levels, with the ExPress strategy (16.5 [15.0-18.5] cm H2O) (P < .01). Pao2/Fio2 ratio was lower with the PEEP/Fio2 table. Oxygenation with Best Compliance approach and ExPress strategy was not different with lower plateau pressure in the former (23 [20-25] vs 30 [29-30] cm H2O; P < .01). Paco2 was slightly higher with the ExPress method than the others 2 strategies. Negative P(tpe) was observed in 35% of the patients with the PEEP/Fio2 table, in 15% applying the Best Compliance, and in only 1 case with the ExPress method. Higher SI and P(tpi), with lower lung compliance, were obtained with ExPress strategy. Using a best respiratory compliance approach resulted in better oxygenation levels without risk of overdistension according to SI and P(tpi), achieving a mild risk of lung collapse according to P(tpe).

Valentini R ，Aquino-Esperanza J ，Bonelli I ，Maskin P ，Setten M ，Danze F ，Attie S ，Rodriguez PO ... -  《-》

Pulmonary acute respiratory distress syndrome: positive end-expiratory pressure titration needs stress index.

The heterogeneity of lung injury in pulmonary acute respiratory distress syndrome (ARDS) may have contributed to the greater response of hyperinflated area with positive end-expiratory pressure (PEEP). PEEP titrated by stress index can reduce the risk of alveolar hyperinflation in patients with pulmonary ARDS. The authors sought to investigate the effects of PEEP titrated by stress index on lung recruitment and protection after recruitment maneuver (RM) in pulmonary ARDS patients. Thirty patients with pulmonary ARDS were enrolled. After RM, PEEP was randomly set according to stress index, oxygenation, static pulmonary compliance (Cst), or lower inflection point (LIP) + 2 cmH2O strategies. Recruitment volume, gas exchange, respiratory mechanics, and hemodynamic parameters were collected. PEEP titrated by stress index (15.1 ± 1.8 cmH2O) was similar to the levels titrated by oxygenation (14.5 ± 2.9 cmH2O), higher than that titrated by Cst (11.3 ± 2.5 cmH2O) and LIP (12.9 ± 1.6 cmH2O) (P < 0.05). Compared with baseline, PaO2/FiO2 and recruitment volume were significantly improved after PEEP titration with the four strategies (P < 0.05). PaO2/FiO2 and recruitment volume were similar when using PEEP titrated by stress index and oxygenation but higher than that titrated by Cst and LIP. Compared with baseline, lung compliance increased significantly when PEEP determined by Cst, but there was no difference of Cst in these four strategies. There was no influence of PEEP titration with the four strategies on hemodynamic parameters. PEEP titration by stress index might be more beneficial for pulmonary ARDS patients after RM.

Huang Y ，Yang Y ，Chen Q ，Liu S ，Liu L ，Pan C ，Yang C ，Qiu H ... -  《-》

Lung Recruitment in Obese Patients with Acute Respiratory Distress Syndrome.

Fumagalli J ，Santiago RRS ，Teggia Droghi M ，Zhang C ，Fintelmann FJ ，Troschel FM ，Morais CCA ，Amato MBP ，Kacmarek RM ，Berra L ，Lung Rescue Team Investigators ... -  《-》

Positive end expiratory pressure titrated by transpulmonary pressure improved oxygenation and respiratory mechanics in acute respiratory distress syndrome patients with intra-abdominal hypertension.

Yang Y ，Li Y ，Liu SQ ，Liu L ，Huang YZ ，Guo FM ，Qiu HB ... -  《-》

Volume-controlled ventilation and pressure-controlled inverse ratio ventilation: a comparison of their effects in ARDS patients.

Mancebo J ，Vallverdú I ，Bak E ，Domínguez G ，Subirana M ，Benito S ，Net A ... -  《-》