Monitoring for vasospasm following SAH

By Alex Yartsev - Jul 01, 2015

A discussion of these techniques was expected from the candidates in Question 2 from the second paper of 2013, Question 5 from the first paper of 2013 and Question 8 from the first paper of 2008. Generally speaking, the college wants the candidates to discuss the advantages and disadvantages of the various techniques.

Techniques used to monitor for vasospasm
Technique	Advantages	Disadvantages
Clinical examination	Cheap Available at the bedside Easily sequentialised	Inaccurate Operator-dependent Many episodes of vasospasm are not associated with physical signs
DSA	Gold standard Offers a means of treating the vasospasm	May overtreat by picking up narrowing which is not associated with a decreased flow Radiation exposure Contrast exposure Need for transport Need for skilled personnel invasive 1% risk of stroke or dissection
CTA	Reasonable sensitivity and specificity Non-invasive	Radiation exposure Contrast exposure Need for transport Need for skilled personnel Frustrated by the presence of coils and clips (artifact is generated)
Transcranial Doppler	High (100%) specificity; non invasive Easily sequentialised	Operator-dependent Mediocre sensitivity
EEG	Highly sensitive and specific Can pick up features of ischaemia and vasospasm earlier than the development of obvious signs or radiological features Non invasive	Requires skilled operator and interpreter; may not be available Ideally, EEG monitoring should be continuous.
SPECT	potentially very useful in detecting ischaemia and cerebral hypoperfusion	Not validated, and mainly a tool of research

References

Oh's Intensive Care manual

Chapter 51 (pp. 568) Acute cerebrovascular complications by Bernard Riley and Thearina de Beer

Marshall, Scott A., Paul Nyquist, and Wendy C. Ziai. "The role of transcranial Doppler ultrasonography in the diagnosis and management of vasospasm after aneurysmal subarachnoid hemorrhage." Neurosurgery Clinics of North America21.2 (2010): 291-303.

Greenberg, E. D., et al. "Diagnostic accuracy of CT angiography and CT perfusion for cerebral vasospasm: a meta-analysis." American Journal of Neuroradiology 31.10 (2010): 1853-1860.

Sloan, M. A., et al. "Sensitivity and specificity of transcranial Doppler ultrasonography in the diagnosis of vasospasm following subarachnoid hemorrhage." Neurology 39.11 (1989): 1514-1514.

Rivierez, M., et al. "Value of electroencephalogram in prediction and diagnosis of vasospasm after intracranial aneurysm rupture." Acta neurochirurgica 110.1-2 (1991): 17-23.

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