Introduction: The BrainIT database 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, 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 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:  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,
 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,
 Rosner MJ, Becker DP. Origin and evolution of plateau waves: Experimental observations and a theoretical model. J Neurosurg 1984 Feb;60:312-24