Mod11: Interventional Neuroradiology - Anesthesia Technique Flashcards
Anesthesia for Radiology & Radiation Therapy - Interventional Neuroradiology
Which anesthetic technique can be used here?
Conscious sedation
General anesthesia
Sleep-awake-sleep” technique
Interventional Neuroradiology - Anesthetic Technique
Which variations of conscious sedation could be used here?
Midazolam/Fentanyl combination
(could be done by RN)
Propofol infusion
(Anesthesia required - Keep pt comfortable and Not obstructing)
Interventional Neuroradiology - Anesthetic Technique
General anesthesia is more commonly requested by neuroradiologists. Which airway devices could be used? What are the most commonly used induction agents
ET intubation and PPV most common
LMA suitable alternative
STP/Propofol most commonly used induction agents
(Caution with Propofol: be able to titrate it to where the pt is asleep an not obstructing)
Interventional Neuroradiology - Anesthetic Technique
What is the “Sleep-awake-sleep” technique?
Keep the patient asleep until catheter is in the right position
Pt is awaken for neurologic testing
Pt put back to sleep for the procedure to be completed
Interventional Neuroradiology - Anesthetic Technique
Which intra-procedure neuro exam is possible with the “Sleep-awake-sleep” technique? What are the benefits of performing that exam?
SAFE: Superselective Anesthesia Functional Exam
Performed prior to embolization to determine if catheter is positioned in a vessel that supplies an eloquent area of the brain or spinal cord (speech/language areas)
Interventional Neuroradiology - Anesthetic Technique
Infusions commonly used for “Sleep-awake-sleep” technique
Propofol/Remifentanil or
Propofol/Alfentanil
Interventional Neuroradiology - Anesthetic Technique
True or False: invasive monitoring is less used in interventional neuroradiology than in neurosurgical procedures
True
Interventional Neuroradiology - Anesthetic Technique
Benefits of Arterial line in Interventional Neuroradiology procedures:
Continuous BP monitoring
BP manipulation as requested by neuroradiologist
Interventional Neuroradiology - Anesthetic Technique
What are the benefits of “controlled hypotension”? Which drugs are used to acheive it?
Facilitate embolization AVM
Esmolol, labetalol, metoprolol, hydralazine commonly used
Interventional Neuroradiology - Anesthetic Technique
Benefits of Moderate hypertension and drug of choice
Reduction of cerebral ischemia and cerebral vasospasm
Phenylephrine is the drug of choice
Anesthetic for Radiology & Radiation Therapy - CT & MRI
Pain considerations with CT & MRI: are these painful? If not, why is pain a concern? why is anesthesia needed at times?
Relatively painless
There is an absolute requirement for motionless patient
Anesthetic for Radiology & Radiation Therapy - CT & MRI
Why would anesthesia be required for these otherwise non-invasive procedures?
Patient must remain motionless
Anesthetic for Radiology & Radiation Therapy - CT & MRI
What are anesthetic requirements for adults and children in these areas?
Sedation/general anesthesia
(For children & Adults with _neurologic disorder_s)
No sedation
(For most adults)
Anesthetic for Radiology & Radiation Therapy - CT & MRI
Why must acute trauma patients be stabilized before transported to radiology department?
They may otherwise develop:
Cardiac arrest - Raised ICP - LOC - Hemorrhagic shock
Anesthetic for Radiology & Radiation Therapy - CT Scan
What’s the purpose and the characteristics of Stereotactic-guided surgery?
For biopsy or aspiration of intracranial mass
Performed using CT scanning to minimize injury to adjacent structures
Radiolucent frame placed around head and held in place by inserting pins into skull → PAINFULL
(Deep Brain stimulator is an example of Stereotactic-guided surgery include and is helpful in Parkinson’s Dz)
Anesthetic for Radiology & Radiation Therapy - CT Scan
What are Anesthetic Considerations for Stereotactic-guided surgery?
Deep sedation or General with LA
Proceed with caution while sedating those with intracranial HTN
Anesthetic for Radiology & Radiation Therapy - CT Scan
What is the most stimulating and most Painfull part of Stereotactic-guided surgery?
Radiolucent frame placement
Frame placed around head and held in place by inserting pins into skull
Done in CT or MRI - Propofol used
Open Craniotomy done in the OR with the patient awake
Anesthetic for Radiology & Radiation Therapy - CT Scan
Why should we Proceed with caution while sedating those with intracranial HTN during Stereotactic-guided surgery?
….
Anesthetic for Radiology & Radiation Therapy - CT Scan
Which complication is associated with Frame during Stereotactic-guided surgery? How shoould it be managed?
Airway Oclusion by Frame!!!
Be prepared for rapid airway control should need arise
LMA - FOI - Removal of frame
Anesthetic for Radiology & Radiation Therapy
What’s the science behind Magnetic Resonance Imaging (MRI)?
Uses Radiofrequency waves and
a Strong magnetic field rather than x-rays
Anesthetic for Radiology & Radiation Therapy - MRI
How long does it take to establish Magnetic field?
Several days
Anesthetic for Radiology & Radiation Therapy - MRI
True or False: The Magnetic field is CONSTANTLY present
True
Anesthetic for Radiology & Radiation Therapy - MRI
Which delineates the peripheral field around the MRI magnet, and inside which equipment malfunction is a common risk?
“Gauss lines”
Anesthetic for Radiology & Radiation Therapy - MRI
What is measured at “Gauss lines”?
Strength of magnetism
(↓ with ↑ distance from center magnet)
Anesthetic for Radiology & Radiation Therapy - MRI
What are adverse effects of MRI due to human exposure to the magnetic field?
None has been described!!!
Anesthetic for Radiology & Radiation Therapy - MRI
Why must a Rigorous checklist be completed by the patient & staff before entering the MRI?
Serious risk of injury or even DEATH!!!
with presence of ferrometallic foreign bodies
(cerebral aneurysm clips/pacemakers/AICD’s)
Anesthetic for Radiology & Radiation Therapy - MRI
Why MUST we CHECK TO DETERMINE IF ANY PIECE OF EQUIPMENT IS MRI COMPATIBILE BEFORE TAKING it INTO SCANNING ROOM?
Anesthesia machine, equipment, monitors, infusion pumps, laryngoscopes, gas cylinders all can become LETHAL PROJECTILES if brought within the 50 gauss line
Anesthetic for Radiology & Radiation Therapy - MRI
Why should a Nonferrous or fiberoptically cabled pulse oximeters be used instead of a Standard pulse?
Burns!!!
Standard pulse ox work, but may produce burns
Anesthetic for Radiology & Radiation Therapy - MRI
Why do we have lots of EKG artifacts in MRI
EKG sensitive to changes in magnetic signal
Anesthetic for Radiology & Radiation Therapy - MRI
Why should EKG Electrodes be placed close together & insulated from skin?
To prevent thermal injury
Anesthetic for Radiology & Radiation Therapy - MRI
Most infusion pumps can be used in MRI, but how far must they be placed?
Outside 30 gauss line
(extension tubing available - Plan for more IV anesthetic agents to fill the extension tubing)
Anesthetic for Radiology & Radiation Therapy - MRI
Which takes longer? MRI or CT scan?
MRI takes up to 30”
May take much longer if anesthesia envolved
(vs. 5” with CT scan)
Anesthetic for Radiology & Radiation Therapy - MRI
Why should magnetic coils be avoided?
Magnetic coils emit heat adding to discomfort
Anesthetic for Radiology & Radiation Therapy - MRI
Why should Both patient and anesthesia provider wear hearing protection?
The MRI room is loud
Emits up to 90dB
Anesthetic for Radiology & Radiation Therapy - MRI
Once scan starts, no one can leave or enter room. What do you do in case of emergency?
Stop scan
Remove pt from scanner
Resuscitation attempts to occur outside
(unless MRI compatible)
Anesthetic for Radiology & Radiation Therapy - CT & MRI
What percent of adults require sedation to tolerate CT & MRI*?
14%
MRI>CT d/t length
Most of the sedation given by non-anesthesia providers
Could be oral or IV sedation
Anesthesia providers called in for more complicated cases
Anesthetic for Radiology & Radiation Therapy - CT & MRI
Which pediatric population will require sedation or GA? How is sedation provided?
Children under 5 years of age
Oral sedation (usually higher ASA) or IV sedation used
Anesthetic for Radiology & Radiation Therapy - CT & MRI
What percentage of pediatric pts will have some type of adverse event?
22%
(e.g., a drop in pulse ox, Nausea)
Anesthetic for Radiology & Radiation Therapy - CT & MRI
What are anesthetics options for pediatric pts during CT & MRI?
Deep sedation with propofol infusion with or w/o midazolam also successful
General anesthesia a/w low incidence of adverse effects
LMA very common unless contraindicated
