A comparison of two alveolar recruitment maneuver approaches in patients with acute respiratory distress syndrome and hemorrhagic stroke with Glasgow Coma Scale ≤ 8

Background and objectives

Alveolar recruitment maneuvers (ARM) are generally not used in acute respiratory distress syndrome (ARDS) patients in an acute phase of brain injury, aiming to avoid increasing the intracranial pressure (ICP).

Methods

Sixteen patients with ARDS and hemorrhagic stroke were evaluated. Criteria for admission were: acute onset, bilateral chest radiographic infiltrates, pulmonary-capillary wedge pressure ≤ 18 mmHg, PaO₂/FiO₂ ratio <200 and Glasgow Coma Scale ≤ 8 with ICP monitorization. Patients were randomized into two similar groups. One group received ARM with CPAP of 35 cmH₂O for 40 s, and the other group received pressure control ventilation (PCV) with a positive end expiratory pressure (PEEP) of 15 cmH₂O and pressure control above a PEEP of 35 cmH₂O for 2 min (tidal recruitment). The ICP, cerebral perfusion pressure (CPP) and oxygen pulse saturation (SpO₂) were similar in both groups before the randomization. Thefraction of inspired oxygen (FiO₂) was kept to 1.0 during the study. The ICP, CPP and SpO₂ were measured before and after ARM and were compared by Student's t test. Mortality was compared by Fisher's test.

Results

Initial values of the ICP, CPP and SpO₂ were, respectively: 13.38 ± 4.53 mmHg (CPAP group) vs 13.25 ± 3.45 (tidal recruitment group), P = 0.95; 82.75 ± 10.37 (CPAP group) vs 84.25 ± 10.37 mmHg (tidal recruitment group), P = 0.73; and 95.75 ± 1.04 (CPAP group) vs 95.0 ± 1.51% (tidal recruitment group), P = 0.26. After ARM, the ICP was higher in the CPAP group (20.50 ± 4.75 mmHg vs 13.13 ± 3.56 mmHg; P = 0.003), the CPP was lower in the CPAP group (62.38 ± 9.81 vs 79.60 ± 6.80 mmHg; P = 0.001) and the SpO₂ was lower in the CPAP group (96.58 ± 1.50 vs 98.25 ± 1.83%; P = 0.045). Mortality was lower in the tidal recruitment group, but was not statistically different (37.5% vs 50%; P = 0.50)

Conclusion

Tidal recruitment with a PEEP of 15 cmH₂O and pressure controlabove a PEEP of 35 cmH₂O did not affect the ICP and decreased the CPP, but at safe levels, besides improving oxygenation, it can be done safely in patients with ARDS and brain injury. On the other hand, ARM with a CPAP of 35 cmH₂O for 40 s can worsen the ICP and CPP, and should be avoided in these patients.