Open lung strategies in patients with intracranial lesions and acute lung injury

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Objective

For patients with acute lung injury, a recent randomized controlled trial showed the superiority of a ventilator strategy with low tidal volumes and elevated PEEP levels after performing recruiting maneuvers (together termed the `open lung approach') compared to a conventional approach with tidal volumes of 12 ml/kg body weight [1]. However, patients with intracranial lesions were excluded from this and other ARDS studies due to the potential risk of exacerbation of intracranial pressure.

Methods

We present the clinical course of eight patients with known intracranial pathology and concomitant acute lung injury, which was treated according to the open lung concept. Primary diagnosis was either traumatic brain injury (n=3), subarachnoid hemorrhage (n=2), cerebellar hemorrhage (n=1), cerebellar infarction (n=1) or frontal meningeoma (n=1). ICP monitoring was present in all patients, brain tissue oxygen (p_tiO₂) monitoring in two of them. Data was collected with multimodal monitoring devices with a sampling rate of 1 per min.

Results

Ventilation according to the open lung approach improved the mean oxygenation index (p_aO₂/F_iO₂) significantly from 130± 104 before to 344± 63 measured 24 h after first recruiting (P<0.001). Mean PEEP after the first recruitment maneuver was 14.9± 2.7 mmHg. ICP values during the first 24 h rose slightly (not significant) in seven of the eight patients, requiring standard treatment with immediate response in two of them. In one patient, the ICP decreased from 33 mmHg to 25 mmHg after the first recruitment maneuver. Relevant change of p_tiO₂ values was not noticed, as the F_iO₂ was consequently lowered, according to provide an arterial p_aO₂ around 100 mmHg, and with respect of a p_tiO₂ above 20 mmHg.

Conclusion

Although this study was done as a feasibility analysis and lacks a control group, our results encourage us to propose open lung strategies, which had been restricted up to now, for neurosurgical patients with acute lung injury. The potential risk of intracranial deterioration due to critical ICP values seems far lower than the achievable benefit and decrease of mortality due to improved oxygenation.