Interventional Neuroradiology Flashcards
What are the Hunt & Hess Classifications of Subarachnoid Haemorrhage?
Uses clinical features to predict prognosis/outcome
What is the classic World Federation of Neurosurgeons (WFNS) Clinical Grading System for S.A.H?
Developed 1988.
The scale reflects that the biggest determinant of mortality is conscious state, whilst the predictor of morbidity is the presence of hemiparesis or aphasia
What is the modified WFNS Scale for S.A.H? Why was it developed
Developed 2016. Aka Modified Rankin Scale. It was proposed to address inter-rater variability in determining what signs and symptoms constitute a focal neurological deficit and was shown to have better outcome prediction
What is the Fisher Scale in grading S.A.H?
Described in 1980. Its primary use was in predicting the occurrence & severity of cerebral vasospasm (highest in Grade 3)
What is the Modified Fisher Scale in grading S.A.H?
Method for grading SAH secondary to intracranial aneurysm rupture. Made in 2006 to account for patients with thick cisternal blood and concomitantintraventricular hemorrhage. When using the modified Fisher scale, the risk of developingvasospasmprogressively increases with each grade; in the original Fisher scale, the risk counterintuitively peaked at grade 3 and decreased for grade 4.
What is an AVM?
Arteriovenous Malformation
- is a congenital abnormality which commonly consists of a complex or bundle of abnormally large and complex vessels, often containing fistulae with multiple arterial and venous supplies
- they shunt blood from the arterial to the venous systems and because you don’t have the usual capillary bed acting as pressure stop cocks, high pressure is transmitted directly to the fragile low pressure veins with subsequent risk of rebleeding.
What is a stroke?
WHO definition:
- A rapidly developing clinical sign of focal or global disturbance of neurological (WHO says cerebral) function, lasting more than 24 hours (unless death) with no apparent cause other than one of vascular origin
What are the anaesthetic goals for interventional neuroradiology procedures?
HNMICAE - Helping Neurosurgeons Make Important Contributions Allday Everyday
- Haemodynamic stability (induction, maintenance, extubation, post-op)
- Neuroprotection (O2, CO2, BSL, temp) and avoidance of secondary insults
- Maintenance of adequate CPP
- patient Immobility
- rapid management of Complications
- timely Administration of medications to assist proceduralist (e.g. management of anticoagulation)
- smooth and rapid Emergence
What is a seizure?
a sudden change in consciousness, behaviour or bodily movements caused by electrical hyper-synchronisation of neuronal networks in the cerebral cortex. Tends to be transient
What is epilepsy?
a disease characterised by a predisposition to generate epileptic seizures
What are SSEPs?
Somatosensory evoked potentials
SSEPs involve a peripheral electrical stimulus typically applied over the tibial and median/ulnar nerves. Analysis of the resulting depolarization at the spinal cord and cerebral cortex (typically averaged over 2-3 mins) is used to demonstrate and monitor intact neural transmission
-Low amplitude potentials measured at the somatosensory cortex in response to peripheral nerve stimulation
- assesses the ascending dorsal column tracts (supplied by the posterior spinal artery)
What are MEPs?
Motor evoked potentials
Application of a transcranial electrical stimulus to the motor cortex with action potentials measured at the skeletal muscle level (via needle electrodes)
- high amplitude
- tests integrity of the descending corticospinal tracts supplied by anterior spinal artery
What is Autonomic Hyperreflexia/Dysreflexia?
Why is it a concern?
Phenomenon that occurs after spinal cord injury at a level of T6 or above - where their BP increases 20mmHg above baseline.
It can manifest as a hypertensive crisis with severe complications (ICH, APO)
