Efficacy of positive end-expiratory pressure titration after the alveolar recruitment manoeuvre in patients with acute respiratory distress syndrome

Abstract

Introduction: In acute respiratory distress syndrome (ARDS), adequate positive end-expiratory pressure (PEEP) may decrease ventilator-induced lung injury by minimising overinflation and cyclic recruitment-derecruitment of the lung. We evaluated whether setting the PEEP using decremental PEEP titration after an alveolar recruitment manoeuvre (ARM) affects the clinical outcome in patients with ARDS.

Methods: Fifty-seven patients with early ARDS were randomly assigned to a group given decremental PEEP titration following ARM or a table-based PEEP (control) group. PEEP and inspired fraction of oxygen (FiO2) in the control group were set according to the table-based combinations of FiO2 and PEEP of the ARDS network, by which we aimed to achieve a PEEP level compatible with an oxygenation target. In the decremental PEEP titration group, the oxygen saturation and static compliance were monitored as the patients performed the ARM along with the extended sigh method, which is designed to gradually apply and withdraw a high distending pressure over a prolonged period, and the decremental titration of PEEP.

Results: The baseline characteristics did not differ significantly between the control and decremental PEEP titration groups. Initial oxygenation improved more in the decremental PEEP titration group than in the control group. However, dynamic compliance, tidal volume and PEEP were similar in the two groups during the first week. The duration of use of paralysing or sedative agents, mechanical ventilation, stay in the intensive care unit and mortality at 28 days did not differ significantly between the decremental PEEP titration and control groups.

Conclusions: The daily decremental PEEP titration after ARM showed only initial oxygenation improvement compared with the table-based PEEP method. Respiratory mechanics and patient outcomes did not differ between the decremental PEEP titration and control groups.

Trial registration: ClinicalTrials.gov identifier: ISRCTN79027921.

Figure 1

Study groups of patients. Four patients who withdrew from the study were excluded from the analysis. ARDS = acute respiratory distress syndrome; PEEP = positive end-expiratory pressure.

Figure 2

Study protocol. (a) Table-based positive end-expiratory pressure (PEEP) setting (control) group. (b) Decremental PEEP titration group after alveolar recruitment manoeuvre (ARM). FiO₂ = inspired fracture of oxygen.

Figure 3

Respiratory values during the first week of treatment. The closed circles indicate the control group and the open circles denote the decremental positive end-expiratory pressure (PEEP) titration group. Values are expressed as the mean ± standard error of the mean (bars). *p < 0.05 between the control and decremental PEEP titration groups; ^†p < 0.05 compared with day 0 in the control group; ^‡p < 0.05 compared with day 0 in the decremental PEEP titration group.

Figure 4

Oxygenation changes and PaCO₂ levels during the first week of treatment. All patients showed improved oxygenation during treatment. The level of partial arterial pressure of carbon dioxide (PaCO₂) at day 1 was increased significantly in the decremental positive end-expiratory pressure (PEEP) titration group than the control group. The black bars indicate the control group and gray bars denote the decremental PEEP titration group. Values are expressed as the mean ± standard error of the mean (bars). *p < 0.05 between the control and decremental PEEP titration groups, ^†p < 0.05 compared with day 0 in the control group, ^‡p < 0.05 compared with day 0 in the decremental PEEP titration group.