Placing intracerebral probes to optimise detection of delayed cerebral ischemia and allow for the prediction of patient outcome in aneurysmal subarachnoid haemorrhage.

Cerebral microdialysis could be useful to detect delayed cerebral ischemia in aneurysmal subarachnoid haemorrhage patients. The optimal location of the probes, however, remains controversial. Here, we determined the vascular territories with the highest infarct risk in relation to aneurysm location to define probe implantation guidelines. These guidelines were retrospectively validated by studying the likelihood of probe to fall in a secondary infarct area, and by analysing their influence to predict patient outcome. The vascular territories with highest risk of infarction were the anterior cerebral arteries for anterior communicating artery aneurysms and the ipsilateral middle cerebral artery for internal carotid artery, posterior communicating artery and middle cerebral artery aneurysms. When cerebral microdialysis probes had been implanted in these territories, 79% were located within an infarcted area versus 54% when they were implanted in other territories. Delayed cerebral ischemia was detected only when the probe was located within a brain area later affected by secondary infarction, which could justify the use of implantation guidelines. Moreover, individual patient outcomes could be predicted when probes were placed in the brain territories as suggested by this study. Thus, a precise probe placement algorithm can improve delayed cerebral ischemia detection sensitivity and allow for a better prediction concerning patient outcome.

Outcome of poor-grade subarachnoid hemorrhage as determined by biomarkers of glucose cerebral metabolism.

PURPOSE: The aim of this study was to determine if the measurement of blood biomarkers of glucose cerebral metabolism, performed with retrograde jugular catheter, could predict the outcome of poor-grade aneurysmal subarachnoid hemorrhage (aSAH) patients. METHODS: This study was conducted in 68 poor-grade aSAH patients. A total of 4,024 blood samples obtained from jugular and radial catheters were analyzed for glucose, lactate, and oxygen content every 8 h for 10 ± 0.5 days. Metabolic ratio (MR) and lactate-oxygen index (LOI) were obtained by ratios using arterio-jugular differences. Functional outcome was evaluated at 12 months with the Glasgow Outcome Scale. RESULTS: Outcome was unfavorable in 40 patients. In this group of patients, the MR was significantly lower (p < 0.0001) and the LOI was significantly higher (p = 0.0001) than in the group with favorable outcome. The MR cutoff value, below which the patients are likely to have an unfavorable outcome, was determined to be 3.35. More interestingly, the data obtained in this study demonstrated that the patients achieving an unfavorable outcome were distinguished from those with a favorable outcome by having at least three events of MR inferior to 3.35 (sensitivity = 90 %, specificity = 82.1 %). Moreover, in patients who developed cerebral vasospasm, we observed a significant decrease in the MR. CONCLUSION: Our data provide additional support to the view that the MR is a reliable marker for predicting the outcome of poor-grade aSAH patients. Prospective studies are needed to confirm its value in multimodal monitoring.