PURPOSE: To describe the management of arterial partial pressure of carbon dioxide (PaCO2) in severe traumatic brain-injured (TBI) patients, and the optimal target of PaCO2 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 PaCO2 management during the first week of intensive care unit (ICU) after TBI, focusing on the lowest PaCO2 values. We also assessed PaCO2 management in patients with and without ICP monitoring (ICPm), and with and without intracranial hypertension. We evaluated the effect of profound hyperventilation (defined as PaCO2 < 30 mmHg) on long-term outcome.
RESULTS: We included 1100 patients, with a total of 11,791 measurements of PaCO2 (5931 lowest and 5860 highest daily values). The mean (± SD) PaCO2 was 38.9 (± 5.2) mmHg, and the mean minimum PaCO2 was 35.2 (± 5.3) mmHg. Mean daily minimum PaCO2 values were significantly lower in the ICPm group (34.5 vs 36.7 mmHg, p < 0.001). Daily PaCO2 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. PaCO2 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.
Bibliographical noteFunding information: Open access funding provided by Università degli Studi di Milano - Bicocca within the CRUI-CARE Agreement. The Collaborative European NeuroTrauma Efectiveness Research in Traumatic Brain Injury (CENTER-TBI study, registered at clinicaltrials.gov NCT02210221) was funded by the FW7 program of the European Union (602150). Additional funding was obtained from the Hannelore Kohl Stiftung (Germany), from OneMind (USA) and Integra LifeSciences Corporation (USA). The funder had no role in the design of the study, the collection, analysis, and interpretation of data, or in writing the manuscript.
- carbon dioxide
- intracranial pressure
- traumatic brain injury