Intensive Care Medicine, June, 2015, Vol.41(6), p.1067(10)
Byline: Fabian Guiza (1), Bart Depreitere (2), Ian Piper (3), Giuseppe Citerio (4), Iain Chambers (5), Patricia A. Jones (6), Tsz-Yan Milly Lo (7), Per Enblad (8), Pelle Nillson (8), Bart Feyen (9), Philippe Jorens (10), Andrew Maas (9), Martin U. Schuhmann (11), Rob Donald (12), Laura Moss (13), Greet Berghe (1), Geert Meyfroidt (1) Keywords: Traumatic brain injury; Adults; Children; Intracranial pressure; Cerebral perfusion pressure; Cerebrovascular autoregulation Abstract: Purpose To assess the impact of the duration and intensity of episodes of increased intracranial pressure on 6-month neurological outcome in adult and paediatric traumatic brain injury. Methods Analysis of prospectively collected minute-by-minute intracranial pressure and mean arterial blood pressure data of 261 adult and 99 paediatric traumatic brain injury patients from multiple European centres. The relationship of episodes of elevated intracranial pressure (defined as a pressure above a certain threshold during a certain time) with 6-month Glasgow Outcome Scale was visualized in a colour-coded plot. Results The colour-coded plot illustrates the intuitive concept that episodes of higher intracranial pressure can only be tolerated for shorter durations: the curve that delineates the duration and intensity of those intracranial pressure episodes associated with worse outcome is an approximately exponential decay curve. In children, the curve resembles that of adults, but the delineation between episodes associated with worse outcome occurs at lower intracranial pressure thresholds. Intracranial pressures above 20 mmHg lasting longer than 37 min in adults, and longer than 8 min in children, are associated with worse outcomes. In a multivariate model, together with known baseline risk factors for outcome in severe traumatic brain injury, the cumulative intracranial pressure--time burden is independently associated with mortality. When cerebrovascular autoregulation, assessed with the low-frequency autoregulation index, is impaired, the ability to tolerate elevated intracranial pressures is reduced. When the cerebral perfusion pressure is below 50 mmHg, all intracranial pressure insults, regardless of duration, are associated with worse outcome. Conclusions The intracranial pressure--time burden associated with worse outcome is visualised in a colour-coded plot. In children, secondary injury occurs at lower intracranial pressure thresholds as compared to adults. Impaired cerebrovascular autoregulation reduces the ability to tolerate intracranial pressure insults. Thus, 50 mmHg might be the lower acceptable threshold for cerebral perfusion pressure. Author Affiliation: (1) Department of Intensive Care Medicine, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium (2) Department of Neurosurgery, University Hospitals Leuven, Leuven, Belgium (3) Department of Clinical Physics, Southern General Hospital, Glasgow, UK (4) San Gerardo Hospital, Monza, Italy (5) James Cook University Hospital, Medical Physics, Middlesbroughnza, UK (6) Department of Paediatric Neurology, Royal Hospital for Sick Children, Edinburgh, UK (7) Department of Paediatric Intensive Care, Royal Hospital for Sick Children, Edinburgh, UK (8) Department of Neuroscience, Neurosurgery, Uppsala, Sweden (9) Department of Neurosurgery, Antwerp University Hospital, Edegem, Belgium (10) Department of Intensive Care Medicine, Antwerp University Hospital, Edegem, Belgium (11) Klinik fur Neurochirurgie, Universitatsklinikum Tubingen, Tubingen, Germany (12) School of Mathematics and Statistics, University of Glasgow, Glasgow, UK (13) Department of Clinical Physics and Bioengineering, NHS Greater Glasgow & Clyde, Glasgow, UK Article History: Registration Date: 06/04/2015 Received Date: 16/02/2015 Accepted Date: 05/04/2015 Online Date: 18/04/2015 Article note: F. Guiza and B. Depreitere contributed equally. Take-home message: In adult and paediatric patients suffering from severe traumatic brain injury, an approximately exponential curve describes the relationship between intensity and duration of episodes of increased intracranial pressure (ICP) and worse clinical outcomes. In children, compared to adults, this occurs at lower ICP thresholds of shorter duration. Electronic supplementary material The online version of this article (doi: 10.1007/s00134-015-3806-1) contains supplementary material, which is available to authorized users.
Intracranial Hypertension -- Research ; Brain Injuries -- Research ; Pediatric Injuries -- Research ; Medical Research
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