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Neurological and respiratory effects of lung protective ventilation in acute brain injury patients without lung injury: brain vent, a single centre randomized interventional study.
- Source :
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Critical care (London, England) [Crit Care] 2023 Mar 20; Vol. 27 (1), pp. 115. Date of Electronic Publication: 2023 Mar 20. - Publication Year :
- 2023
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Abstract
- Introduction: Lung protective ventilation (LPV) comprising low tidal volume (VT) and high positive end-expiratory pressure (PEEP) may compromise cerebral perfusion in acute brain injury (ABI). In patients with ABI, we investigated whether LPV is associated with increased intracranial pressure (ICP) and/or deranged cerebral autoregulation (CA), brain compensatory reserve and oxygenation.<br />Methods: In a prospective, crossover study, 30 intubated ABI patients with normal ICP and no lung injury were randomly assigned to receive low VT [6 ml/kg/predicted (pbw)]/at either low (5 cmH <subscript>2</subscript> O) or high PEEP (12 cmH <subscript>2</subscript> O). Between each intervention, baseline ventilation (VT 9 ml/kg/pbw and PEEP 5 cmH <subscript>2</subscript> O) were resumed. The safety limit for interruption of the intervention was ICP above 22 mmHg for more than 5 min. Airway and transpulmonary pressures were continuously monitored to assess respiratory mechanics. We recorded ICP by using external ventricular drainage or a parenchymal probe. CA and brain compensatory reserve were derived from ICP waveform analysis.<br />Results: We included 27 patients (intracerebral haemorrhage, traumatic brain injury, subarachnoid haemorrhage), of whom 6 reached the safety limit, which required interruption of at least one intervention. For those without intervention interruption, the ICP change from baseline to "low VT/low PEEP" and "low VT/high PEEP" were 2.2 mmHg and 2.3 mmHg, respectively, and considered clinically non-relevant. None of the interventions affected CA or oxygenation significantly. Interrupted events were associated with high baseline ICP (p < 0.001), low brain compensatory reserve (p < 0.01) and mechanical power (p < 0.05). The transpulmonary driving pressure was 5 ± 2 cmH <subscript>2</subscript> O in both interventions. Partial arterial pressure of carbon dioxide was kept in the range 34-36 mmHg by adjusting the respiratory rate, hence, changes in carbon dioxide were not associated with the increase in ICP.<br />Conclusions: The present study found that most patients did not experience any adverse effects of LPV, neither on ICP nor CA. However, in almost a quarter of patients, the ICP rose above the safety limit for interrupting the interventions. Baseline ICP, brain compensatory reserve, and mechanical power can predict a potentially deleterious effect of LPV and can be used to personalize ventilator settings. Trial registration NCT03278769 . Registered September 12, 2017.<br /> (© 2023. The Author(s).)
Details
- Language :
- English
- ISSN :
- 1466-609X
- Volume :
- 27
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Critical care (London, England)
- Publication Type :
- Academic Journal
- Accession number :
- 36941683
- Full Text :
- https://doi.org/10.1186/s13054-023-04383-z