The effect of lung-protective permissive hypercapnia in intracerebral pressure in patients with subarachnoid haemorrhage and ARDS. A retrospective study.

Objective: Lung protective ventilation has a beneficial effect in treating patients with acute respiratory distress syndrome (ARDS). An effect of this ventilation modality is hypercapnia, which leads to increased cerebral blood flow. Since increased cerebral blood flow can induce brain oedema the question arises whether lung protective ventilation can be applied in patients with subarachnoid haemorrhage.

Methods: We retrospectively analysed 12 patients with subarachnoid haemorrhage who were ventilated with lung protective ventilation since they suffered of ARDS. Tidal volume was 5-8 ml/kg body weight, and positive end expiratory pressure was 10-15 cm H₂O. Intracerebral pressure was continuously measured by intracerebral probe.

Results: Despite of hypercapnia (pCO₂ 50-60 mmHg) there was no increase of the intracerebral pressure. Lung protective ventilation could be safely performed in patients with subarachnoid haemorrhage.

Conclusion: Patients with higher Hunt and Hess grades of subarachnoid haemorrhage who are predominantly intubated and ventilated and most of them suffer from ARDS can receive lung protective ventilation. In our small patient collective, the occurring hypercapnia did not influence (increase) the intracerebral pressure.