gms | German Medical Science

Objective: Cerebral vasospasm is one of the major complications in patients with subarachnoid hemorrhage (SAH). In these cases, there has been a debate about the degree of neuroprotection related to magnesium. Thus, we investigated the influence of early intravenous administration of magnesium sulfate (MgSO4) on local cerebral microcirculation during real-time vascular neuromonitoring.

Methods: Fourteen patients (11 female, 3 male, median age 56.5±9.7) with aneurysmatic SAH Hunt and Hess grades 2 to 5 due to an aneurysm of the anterior circulation were examined. We used a non-invasive combined laser-Doppler spectrophotometry system to measure capillary venous oxygenation (SO2), post-capillary venous filling pressures (rHb), blood cell velocity (velo) and blood flow (flow) in 7 mm tissue depth. During microsurgical clipping of the aneurysm, a fiberoptic probe was placed onto the cortex next to the site of preparation to measure local microcirculation. Data samples of 60 seconds were recorded as baseline immediately before and 10 minutes after intraoperative application of a loading dose of 50mg/kg body weight MgSO4 sulfate 10%.

Results: All of the fourteen aneurysms (ACA: 2, AcoA: 5, MCA: 7) were clipped successfully. Compared to baseline values, we observed an increase in median flow of 27% (9-67%), velo of 4% (1-45%) and SO2 of 11% (2-39%) with no changes in rHb. Postoperative vasospasm was detected in 8 patients by transcranial ultrasound, however, only 2 patients had a related neurological deficit.

Conclusion: These prelimary results indicate that early intraoperative administration of MgSO4 induced an increase of local cerebral microcirculation as detected during real-time measurement by non-invasive laser-Doppler spectrophotometry. To determine and verify this observation, further studies on clinical outcome and the exact dosage of MgSO4 are needed.