Background: Airway Pressure Release Ventilation (APRV) is an alternate mode of ventilation in acute respiratory failure (ARF), but there is inconsistent data to support its use over other modes of ventilation. Because of increased intrathoracic pressure for most of the respiratory cycle, a negative impact of APRV on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) has been hypothesized. We evaluated the effects of APRV ventilation, with particular attention to ICP, CPP and ICP-directed therapy, in a real-world cohort of neuro-ICU patients. Methods: Retrospective single-center analysis from January 2021 to December 2023 of neurosurgical ICU patients with ICP monitoring. APRV was used as a rescue mode at the physician's discretion when the Horovitz index (PaO2/FIO2 ratio) fell below 150 despite optimized conventional ventilation. Results: Between 2021 and 2023, APRV was utilized in 29 patients undergoing a total of 60 episodes. Forty patients (66.7%) were female, median age was 49.5 (Q1 34; Q3 61.25) years.
After transition to APRV, mean FiO2 decreased by 4.3% (t = 3.5, p < .001) and mean PaO2 increased by 22.7 mm Hg (t = 4.2, p < .001). The Horovitz index improved by 44.6 mm Hg (t = 4.9, p < .001). Mean compliance did not differ after transition to APRV (−1.5 ml/mbar, t = −0.9, p = .4).
During the APRV episode, mean ICP was 1.2 mm Hg lower (t = 2.6, p = .01), while mean CPP was 1.6 mm Hg higher (t = −0.9, p = .4) and the intensity of ICP-directed therapy (TIL) was significantly lower (X2 = 92.771, p < .001). Conclusion: APRV was hemodynamically tolerated in 29 out of 33 patients, and was safe with regard to ICP, CPP, and the intensity of ICP-directed therapy. Oxygenation was increased by APRV. 4 out of 33 patients would not tolerate APRV for hemodynamic reasons, APRV therefore was stopped immediately.
