Management of arterial partial pressure of carbon dioxide in the first week after traumatic brain injury: results from the CENTER-TBI study.

PURPOSE

To describe the management of arterial partial pressure of carbon dioxide (PaCO) in severe traumatic brain-injured (TBI) patients, and the optimal target of PaCO in patients with high intracranial pressure (ICP).

METHODS

Secondary analysis of CENTER-TBI, a multicentre, prospective, observational, cohort study. The primary aim was to describe current practice in PaCO management during the first week of intensive care unit (ICU) after TBI, focusing on the lowest PaCO values. We also assessed PaCO management in patients with and without ICP monitoring (ICP), and with and without intracranial hypertension. We evaluated the effect of profound hyperventilation (defined as PaCO < 30 mmHg) on long-term outcome.

RESULTS

We included 1100 patients, with a total of 11,791 measurements of PaCO (5931 lowest and 5860 highest daily values). The mean (± SD) PaCO was 38.9 (± 5.2) mmHg, and the mean minimum PaCO was 35.2 (± 5.3) mmHg. Mean daily minimum PaCO values were significantly lower in the ICP group (34.5 vs 36.7 mmHg, p < 0.001). Daily PaCO nadir was lower in patients with intracranial hypertension (33.8 vs 35.7 mmHg, p < 0.001). Considerable heterogeneity was observed between centers. Management in a centre using profound hyperventilation (HV) more frequently was not associated with increased 6 months mortality (OR = 1.06, 95% CI = 0.77-1.45, p value = 0.7166), or unfavourable neurological outcome (OR 1.12, 95% CI = 0.90-1.38, p value = 0.3138).

CONCLUSIONS

Ventilation is manipulated differently among centers and in response to intracranial dynamics. PaCO tends to be lower in patients with ICP monitoring, especially if ICP is increased. Being in a centre which more frequently uses profound hyperventilation does not affect patient outcomes.