Article
TCD and SEP together might indicate threatening cerebral metabolic conditions in patients with subarachnoid haemorrhage and vasospasms
TCD und evozierte Potentiale können gemeinsam zerebrale metabolische Risikosituationen bei Patienten mit Subarachnoidalblutung und Vasospasmen abschätzen
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Authors
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Zafer Cinibulak
- Kliniken der Stadt Köln, Neurochirurgie, Köln, Deutschland
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Alexander Erich Hartmann
- Kliniken der Stadt Köln gGmbH, Neurochirurgie, Köln, Deutschland
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Paiman Shalchian-Tehrsan
- Kliniken der Stadt Köln gGmbH, Neurochirurgie, Köln, Deutschland
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Joachim Spreer
- Kliniken der Stadt Köln, Radiologie und Neuroradiologie, Köln, Deutschland
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Samir Sakka
- Kliniken der Stadt Köln, Anästhesiologie und operative Intensivmedizin, Köln, Deutschland
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Makoto Nakamura
- Kliniken der Stadt Köln gGmbH, Neurochirurgie, Köln, Deutschland
| Published: | May 8, 2019 |
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Outline
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Guidelines mention increase of perfusion pressure (PP) and intraarterial spasmolysis for the treatment of delayed vasospasms (VS) following subarachnoid hemorrhage. The suggestion of the existence of VS in unconscious patients bases on the measurement of blood flow velocity (BFV) using transcranial Doppler sonography (TCD). The reliability for therapeutic decisions is debated. Decrease of cerebral blood flow might cause tissue hypoxia and alteration of electric de- and repolarization resulting in prolonged latency (LAT) of sensory evoked potentials (SEP).
Aim: To correlate repeated measurements BFV by TCD and SEP LAT of the median and tibial nerves in patients (pts.) with acute SAH. Hypothesis: SEP might indicate decrease of oxygen metabolism in pts. in whom lack of BFV adaptation does not sufficiently prevent hypoxia.
Methods: Prospective monocenter evaluation of 20 SAH pts (HH 3–5). Repeated TCD and SEP measurements over several days. TCD recording of the MCA (M1/M2, maximal mean flow (MM); cm/s). SEP LAT of N20 of the median nerve and SEP LAT of P40 of the tibial nerve.
Results: For the group of all 20 pts. there were no correlations between all N20 or all P40 values and the corresponding MM except a nonsignificant trend of LAT N20 increase of the left median nerve during increase of the MM of the right MCA: at MM above 105 cm/s there was an mean increase of LAT with values above 26 ms (max normal 21±1,6). With respect to the side of initial hemorrhage all ipsilateral N20 and P40 values were not different from the LAT-N20/-P40 of the other side. In 4 pts. with development of VS proven by i.a. angiography, LAT of N20 was increased up to 29.4 ms corresponding to low MM (below 40 cm/s). In 3 pts. N20- and P40-LAT were not increased during increased MM above 110 cm/s.
Conclusion: In pts. with SAH LAT of both SEP (N20/P40) do not correlate to BFV. LAT of N20/P40 might remain normal at increased BFV indicating a protective mechanism of flow regulation, due to sufficient high PP and preserved autoregulation. If in few cases BFV decreased below 40 cm/s, LAT N20/P40 showed a tendency to increase. This might indicate impairment of blood flow regulation, particularly in distal VS with increase of vascular resistance. It is suggested that significant decrease of BFV should be prevented by improvement of perfusion pressure and that solely documented increase of BFV is not sufficient to assess a critical metabolic situation.
