Article
The influence of hemoglobin levels on cerebral perfusion in patients with aneurysmal subarachnoid hemorrhage
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Authors
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Lina Igel
- Klinik für Neurochirurgie, Heinrich-Heine-Universität Düsseldorf, Medizinische Fakultät, Düsseldorf, Deutschland
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Daniel Hänggi
- Klinik für Neurochirurgie, Heinrich-Heine-Universität Düsseldorf, Medizinische Fakultät, Düsseldorf, Deutschland
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Kerim Beseoglu
- Klinik für Neurochirurgie, Heinrich-Heine-Universität Düsseldorf, Medizinische Fakultät, Düsseldorf, Deutschland
| Published: | June 2, 2015 |
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Outline
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Objective: Maintaining an adequate cerebral perfusion after aneurysmal subarachnoid hemorrhage (aSAH) is of major importance, thus strict control of haemoglobin levels (Hgb) are recommended to guarantee sufficient oxygen delivery. However, evidence for optimum Hgb in the presence of altered cerebral perfusion as well as thresholds for red blood cell transfusion is scarce. In this retrospective analysis we identified the relationship of Hgb and cerebral perfusion as measured by perfusion computer tomography (PCT) at different times after aSAH.
Method: Retrospectively, Hgb levels and PCT data of 191 patients with confirmed aSAH were analyzed. Hgb was assessed at least three times per day and the mean, minimum and maximum value was recorded until discharge from intensive care unit. PCT was performed immediately after admission, on day 2, day 4 and between day 9 and 11. Mean transit time (MTT) and cerebral blood flow (CBF) were included into this analysis as known relevant parameter focusing on cerebral perfusion in the presence of delayed cerebral ischemia (DCI). Correlation analysis and group comparison was performed to identify the relationship of Hgb and PCT values.
Results: Correlation analysis identified a significant relation (p=0.011, r= -0.201) between low Hgb levels and increased MTT on days 3 to 5 after the incident. The Kruskal-Wallis test confirmed a significant difference (p=0.018) for MTT depending on Hgb level within the first two days after aSAH. At day 3 to 5 the significant difference in MTT (p=0.034) as well as CBF (p=0.001) depending on Hgb level continues.
Conclusions: Lower Hgb level after aSAH significantly impair cerebral perfusion e.g. MTT and CBF as measured by PCT. This effect increases after day three and might therefore contribute to the risk for delayed cerebral ischemia (DCI) and ultimately cerebral infarction. Thus, prospective analysis is warranted in order to evaluate the relevance for the incidence of DCI and the overall outcome as well as to define thresholds for optimum Hgb level.
