Introduction: The BrainIT database[1] comprises 200 patient’s data that includes minute by minute blood pressure (BP) and intracranial pressure (ICP), as well as clinical parameters such as body temperature and oxygen saturation. GOSe at 6 months is also recorded. In this analysis we study the association between the occurrence of ICP secondary insults and preceding blood pressure instability.

Methods: Using the ODIN browser program[2], episodes of raised ICP (ICP > 20 mmHg or ICP > 30 mmHg) were identified and the duration of each was obtained. Any arterial hypotension or hypertension that immediately preceded each ICP insult over a 30 minute period was noted, as well as pyrexia or drop in peripheral SaO2. GOSe at 6 months post primary insult was noted.

Results: Analysis of 148 patients from the database revealed 6452 secondary ICP insults (ICP>20mmHg), of which 6.1% were >30mmHg (Grade2/3). The median duration of raised ICP was 16 minutes. 69.8% of these had no preceding hypo- or hypertension in the preceding 30 minutes. Those over 65 years old were more likely to suffer Grade2/3 ICP insults (>30mmHg) compared to the under-65 age group (10.7% vs 6.0%; p<0.05). Blood pressure instability was more common in the over 65 year old age group than the under 65 (64.9% vs 28.8%; p<0.05), and was more likely to be hypertension than hypotension (72.7% vs 27.3%; p<0.05). Grade2/3 ICP insults, BP instability or pyrexia before an insult, and advancing age were associated with significantly poorer GOSe scores at 6 months.

Conclusions: In this dataset, Rosner’s hypothesis[3] that most periods of raised ICP are preceded by blood pressure instability, is supported in the over-65 year old age group. Grade2/3 ICP insults and increased occurrence of blood pressure instability in the over-65 age group were associated with increased rates of death and moderate-severe disability.

Patient Care: This research will improve our understanding of blood pressure instability prior to an ICP secondary insult. A significant association between secondary ICP insults and BP instability has been demonstrated, and this knowledge can be useful in predicting levels of disability 6 months post primary event.

Learning Objectives: By the conclusion of this session, participants should be able to: 1)Discuss the significance of blood pressure instability before an ICP secondary insult; 2)Discuss the significance of age in this relationship; 3)Discuss long-term outcomes in patients suffering from ICP secondary insults

References: [1] Piper I, Citerio G, Chambers I, Contant C, Enblad P, et al. The BrainIT group: concept and core dataset definition. Acta Neurochir 2003;145:615-629, [2] Howells T, Elf K, Jones PA, Ronne-Engström E, Piper I, Nilsson P, Andrews P, Enblad P. Pressure reactivity as a guide in the treatment of cerebral perfusion pressure in patients with brain trauma. J Neurosurg 2005;102:311–317, [3] Rosner MJ, Becker DP. Origin and evolution of plateau waves: Experimental observations and a theoretical model. J Neurosurg 1984 Feb;60:312-24