Page 21 - CASA Bulletin of Anesthesiologisy 2022 9(6)-1 (3)

Vol. 9, No 6, 2022

medications and equipment that might not be immediately available for the more complex
patient or procedure and both types of locations might be unfamiliar surroundings in terms of
room layout “ ”
procedures expose both the patient and staff to high doses of radiation and it is important to
consider the possibility of pregnancy when appropriate and for staff to wear radiation protective
lead and increase their distance from the source of radiation as much as possible and particularly
during times of high usage as the dose of radiation is reduced to ¼ by doubling the distance away
from the source.

Mild allergic and other physiological reactions such as renal dysfunction to contrast media
are quite common. Predispositions to renal injury include age greater than 75 years, pre-existing
renal impairment, hypertension, diabetes mellitus (esp. with metformin use) and co-
ad ( A ’ ) . Careful attention
1
should be made to fluid management to maintain euvolemia and during longer duration
procedures it is important to consider that the interventionist may flush their catheters with 1-2
liters of crystalloid solution. Modern contrast media consist of non-ionized compounds that are
either iso or low osmolality and severe anaphylactoid reactions are very rare (1/2500) and
unrelated to shell fish or iodine allergy .
2
It is of the upmost importance that patients do not move during intracranial NIR procedures.
Using digital subtraction angiography the interventionist will create a roadmap of the intracranial
circulation and any movement of the patients head will cause the road map to be inaccurate.
Instrumentation and manipulation of the skull base arteries with catheters, wires and devices can
be uncomfortable and sufficiently stimulating to elicit reactions such as coughing and bucking
provoking imprecise deployment of coils, stents and embolic materials and complications such
as unwanted thrombosis, rupture or nonselective occlusion of vessels. For patient comfort and
safety most centers prefer patients to have general anesthesia for endovascular intracranial
interventions. For most elective procedures maintenance of physiological homeostasis is
acceptable but immobility is of paramount importance. In theory that latter should be achieved
with an adequate depth of anesthesia but the periods of intense stimulation can be unpredictable
and at our institution we have adopted a protocol of maintaining a profound neuromuscular
block. Most commonly the interventionist will access one of the femoral arteries and the side
“ ” monitoring and blood sampling.
An important consideration for interventions when larger diameter catheters are used is the need
for patients to lie relaxed and flat for up to six hours after the procedure to prevent hematoma
and possibly femoral artery pseudo aneurysm formation. This may necessitate the need for either
post procedural intubation or sedation in patients unable to do so. We have one proceduralist
whose preference is to use the radial artery which negates some of these concerns.

Specific procedure related considerations

Cerebral Aneurysms

Due to the risk of ischemic complications Endovascular interventions require the patient to
be heparinized typically with an initial bolus of heparin (50-70 mcg/kg) to achieve an ACT in the
range of 250-300s. Patients who are to be treated with either stent assisted coiling or flow
diverting stent are at even higher risk of ischemic complications due to in-stent thrombosis are
started on DAPT prior to treatment. Some patients have variable therapeutic responsiveness to

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