Effects of PEEP in intracranial pressure in patients with acute brain injury: An observational, prospective and multicenter study

Abstract

Abstract Background The communication pathway between the brain and the lung is called the brain-lung crosstalk. The effects of positive end-expiratory pressure (PEEP) in intracranial pressure (ICP) are variable. We prospectively analyzed the impact of PEEP changes in ICP dynamics in patients with acute brain injury (ABI). Methods Observational, prospective and multicenter study (PEEP-PIC study) including neurocritically ill patients who underwent invasive neuromonitorization from November, 2017 to June, 2018. Baseline ventilatory, hemodynamic and neuromonitoring variables were collected immediately before PEEP changes and during the following 30 minutes. Ethics Committee approval for the study was initially obtained (Hospital Universitario 12 de Octubre, Madrid: CEI: 17/221). Written informed consent was obtained from patients’ closest relatives. Results One-hundred and nine patients were included. Mean age was 52.68 (15.34) years, male 71 (65.13%). Traumatic brain injury was the cause of ABI in 54 (49.54%) patients. Length of mechanical ventilation was 16.52 (9.23) days. In-hospital mortality was 21.1%. Moderate PEEP increases (mean 6.24 to 9.10 cmH2O) resulted in ICP increase from 10.4 to 11.39 mmHg, p < 0.001, without changes in cerebral perfusion pressure (CPP) (p = 0.548). Moderate PEEP decreases (mean 8.96 to 6.53 cmH2O) resulted in ICP decrease from 10.5 to 9.62 mmHg (p = 0.052), without changes in CPP (p = 0.762). Significant correlations were established between the increase of ICP and the delta PEEP (R = 0.28, p < 0.001), delta driving pressure (R = 0.15, p = 0.038) and delta compliance (R=-0.14, p = 0.052). ICP increment was higher in patients with lower baseline ICP. Conclusions Moderate PEEP changes were not associated with clinically relevant modifications in ICP values in patients with ABI. The magnitude of the change in ICP after PEEP increase was correlated with the delta of PEEP, the delta driving pressure and the delta compliance. Patients who had lower baseline ICP had a higher percentage of increase in ICP values.