Abstract
BackgroundManagement of delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH) is difficult and still carries controversies. In this study, the effect of therapeutic hypervolemia, hemodilution, and hypertension (HHH-therapy) on cerebral blood flow (CBF) was assessed by xenon-enhanced computerized tomography (XeCT) hypothesizing an increase in CBF in poorly perfused regions.Methods Bedside XeCT measurements of regional CBF in mechanically ventilated SAH patients were routinely scheduled for day 0–3, 4–7, and 8–12. At clinical suspicion of DCI, patients received 5-day HHH-therapy. For inclusion, XeCT was required at 0–48 h before start of HHH (baseline) and during therapy. Data from corresponding time-windows were also collected for non-DCI patients.ResultsTwenty patients who later developed DCI were included, and twenty-eight patients without DCI were identified for comparison. During HHH, there was a slight nonsignificant increase in systolic blood pressure (SBP) and a significant reduction in hematocrit. Median global cortical CBF for the DCI group increased from 29.5 (IQR 24.6–33.9) to 38.4 (IQR 27.0–41.2) ml/100 g/min (P = 0.001). There was a concomitant increase in regional CBF of the worst vascular territories, and the proportion of area with blood flow below 20 ml/100 g/min was significantly reduced. Non-DCI patients showed higher CBF at baseline, and no significant change over time.ConclusionsHHH-therapy appeared to increase global and regional CBF in DCI patients. The increase in SBP was small, while the decrease in hematocrit was more pronounced, which may suggest that intravascular volume status and rheological effects are of importance. XeCT may be potentially helpful in managing poor-grade SAH patients.
Highlights
The complex mechanisms leading to secondary brain injury and the sometimes devastating course of delayed cerebral ischemia (DCI) [1] after aneurysmal subarachnoid hemorrhage (SAH) are still not well understood [2]
The increase in systolic blood pressure (SBP) was small, while the decrease in hematocrit was more pronounced, which may suggest that intravascular volume status and rheological effects are of importance
20 patients with clinical suspicion of DCI were identified where xenon-enhanced computerized tomography (XeCT) measurements of cerebral blood flow (CBF) had been taken within 0–48 h before the initiation of HHH-therapy, and during the 5-day HHH-therapy (Fig. 2)
Summary
The complex mechanisms leading to secondary brain injury and the sometimes devastating course of delayed cerebral ischemia (DCI) [1] after aneurysmal subarachnoid hemorrhage (SAH) are still not well understood [2]. Improved techniques for early surgical or endovascular interventions and general improvement of the neurointensive care (NIC) have reduced mortality and morbidity in these patients during the last decades [3]. In modern NIC, clinical surveillance combined with multimodal systemic and cerebral monitoring is used to aid the early detection of avoidable factors and DCI [5]. Management of delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH) is difficult and still carries controversies. The effect of therapeutic hypervolemia, hemodilution, and hypertension (HHH-therapy) on cerebral blood flow (CBF) was assessed by xenon-enhanced computerized tomography (XeCT) hypothesizing an increase in CBF in poorly perfused regions
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