greenbook

Appearance

Neuroanesthesia ​

Neuro Attendings: Claudia Clavijo MD, Julio Montejano MD, Tony Oliva MD/PhD, Ben Scott MD, Colby Simmons DO, Scott Vogel DO

The neuroanesthesia rotation may be familiar to you by the time that you begin your actual rotation. It is common to provide anesthesia for patients undergoing craniotomies, spines or emergent IR stroke cases while on call or general OR days. This rotation allows you to see a wide variety of procedures and the considerations that come with each of them.

Before starting your rotation, you will receive an orientation email from the neuroanesthesia team. Below is an education schedule from the orientation email if you want to get a head start:

  • Week 1: CNS Anatomy, Physiology and Pharmacology
  • Week 2: Neurosurgical Anesthesia
  • Week 3: CNS Monitoring
  • Week 4: Head trauma, Supratentorial tumors, Posterior fossa
  • Week 5: Intracranial aneurysms, Cerebral ischemia, Neuroendocrine tumors
  • Week 6: Cerebral protection, Epilepsy and epilepsy surgery, Interventional neuroradiology

EVD ​

In anesthesia, we often do not manage EVDs daily, however many of our patients coming to the operating room for NSGY procedures will have EVDs that we will need to know how to manage upon transport as well as in the operating room.

WARNING

DO NOT ATTACH A PRESSURE BAG TO AN EVD. A PRESSURE BAG IS NOT NECESSARY AND CAN CAUSE HARM

If you don't feel comfortable setting up an EVD or have questions, call a neuroanesthesia attending, contact a neurosurgery resident or call the neuro ICU charge for help.

Neuro ICU Charge: x83590

EVD protocol can be found under the neuroanesthesia protocols under “EVD Management.”

Instructions above written by Dr. Clavijo.

Case Types ​

Intracranial Procedures ​

Perform your preoperative evaluation like you would for a general case.

Look through the notes to find out if the patient shows any sign of increased ICP. If there are any neurologic deficits at baseline or any other concerning factors, document those changes in the pre-op evaluation. Do your own basic neurological exam as part of your pre-operative evaluation the day of surgery.

Include imaging description as part of your evaluation. It is useful view the imaging yourself to know the size/location of a tumor and the surrounding structures that may be at risk.

Most patients will simply need 0.5-1.0 MAC of gas and narcotic/propofol mix unless there is evidence of increased ICP on imaging/symptoms, PONV considerations, or neuromonitoring (NM) is requested.

It is necessary to know the NM techniques that will be used for the particular case since your anesthetic technique of choice may need to be changed or modified based on the NM test performed.

Inhalational agents and neuromuscular blockers can’t be used if motor evoked potentials (MEPs) are included in the NM.

Neuromuscular blockers can’t be used if EMG monitoring is selected as part of the NM technique.

On the other hand, both inhalational agents and neuromuscular blockade can be used if ABRs are the only NM technique selected.

Open the pdf attachment in the scheduling email that is sent the day before, titled “OR Daily Schedule”. If you scroll to your patient, you will find important information regarding whether neuromonitoring will be used, whether the procedure be awake vs asleep, whether MRI will be done prior to the procedure, etc. This will help to prepare your anesthetic plan prior to calling your attending. (I am not sure the PDF now is as useful for some of this info)

Some patients undergoing MRI prior to the procedure will require intubation after having a frame placed under local anesthetic preoperatively by the neurosurgeon. This will require an awake intubation, which can be discussed with your attending. Ideally you will see the patient in pre-op before they go down to MRI, but do not delay their transport to MRI to complete the consent.

Neurosurgical patients will be turned either 90 or 180 degrees from induction position in most instances. All lines need to be organized in a way that they are secured and not at risk of being pulled while turning and positioning. This includes having extensions on your circuit and CO2 lines when needed.

Lastly, make sure you grab a neuro box for EVERY case. The neuro box contains most of the medications needed for neuro cases: (mannitol (with filter), Keppra, labetalol, nicardipine, adenosine, fluorescein, IC green, and Albumin when not on shortage). Also grab any blood pressure infusions you may need (uppers and downers) as these patients often have very narrow blood pressure ranges and having things in the room and ready to spike is always in your best interest. You will also need plenty of pumps for the different infusions. Generally, two brains are needed.

The surgeon will tell you the doses and of which meds they want for the procedure during time out. Always repeat dosing and clarify timing of medications with them.

A bolus of propofol or opioid is commonly given before head pinning to prevent excessive increases in blood pressure. You should have enough left from induction to bolus or have a second syringe ready before pinning. –Also, antihypertensive medications (esmolol, labetalol, nicardipine) are useful during this time. You have to have them ready. Feel free to let the NSGY resident/fellow know when the patient is “ready” for pinning from an anesthetic/amnestic/analgesic perspective.

When waking up, be prepared for hemodynamic swings as the anesthesia wears off, though your goal will be to stay within the already designated BP range designated by the NSGY team; Have a plan with your attending regarding which poppers (again, uppers AND downers) in which concentrations (because you will likely make them yourself) you should have ready.

Awake craniotomies have a few extra items to prepare in advance.

If the procedure will be done awake, have an iGel LMA available in the event of urgent airway management during the procedure as the head frame makes mask ventilation and intubation practically impossible.

Surgeons usually defer the sedation plan to us but check with them to see if any considerations need made. Propofol and remifentanil is a common combination used for sedation for arterial line and bladder catheter placement as well as frame placement if it wasn’t done in preop. While Precedex can be used, it often is not. (This surgeon is no longer at UCH) Your attending will know the most common sedation technique for the particular case. The surgeons are typically good at providing decent pain relief with local anesthetic for accessing the cranial vault and meninges, but I would have some propofol in line just in case.

Seizures may occur during awake craniotomies, so have a plan A, B, C, D for how to break a seizure if it were to happen (midazolam vs. propofol vs cold water infiltration by the surgeon, etc.). Some of these decisions need to be carefully planned as they may impact the rest of the case (i.e., if you give midazolam, that patient may not be as aware as the surgeon needs to proceed).

Pituitary Tumors and Other Sellar Pathologies ​

Patient might be scheduled for a microscopic or endoscopic endonasal transsphenoidal approach. Both procedures require endotracheal intubation.

Please tape the ETT to the left angle of the mouth to avoid interference with the surgical field. The operating table will be moved 90 or 180 from the original induction position. If planning on using an oral RAE ETT please be mindful of your patient’s height and size up appropriately.

The head of the bed is removed, and the patient is placed in pins for the microscopic approach but remains in place for the endoscopic approach.

DO NOT GIVE STEROIDS without consulting with the neurosurgeon.  In most cases, such as pituitary tumors, steroids are not given since they interfere with the post-operative endocrinology evaluation.  In other cases, steroids are given after tumor sample has been sent to pathology and pathology has confirmed an adequate sample, or not given at all due to the risk of infection.

Patients should be extubated when they are fully protecting their airway. Positive pressure ventilation to rescue the airway should be AVOIDED due to the risk of creating/producing pneumocephalus. Have an LMA easily accessible in the event the patient requires PPV.

Hemodynamic goals are similar to other intracranial procedures with SBP <140 mmHg. An arterial line is not required for the procedure, but patient and tumor characteristics may warrant placement.

Spines ​

Most of you will have done plenty of spines prior to starting this rotation. You know that flipping can be challenging, especially if the case is anterior and posterior. Work on line management and finding a strategy that works best for you to make flipping the patient smooth.

Some other general considerations:
Sedline monitoring is commonly used in spine cases. Secure it well with tegaderms, steri-strips, tape, etc, otherwise it will detach when patient is in prone.

Have a prone view available unless Mayfield frame will be used.

Tape, tegaderm, and check that the connections on your ETT are tight not once, twice but THREE times prior to flipping. It is a sad day when the ETT comes out on a prone patient.

If this were to happen, alert the surgical team, call your attending ASAP, and decide how stable the patient is (and where you are in the procedure) if you should flip back on to the stretcher vs place an LMA as a temporizing measure.

Esophageal temperature probe is preferable since nasopharyngeal probe can easily come out in prone position.

Know what type of neuromonitoring will be involved and plan appropriately.

Soft bite blocks are needed for most spine surgeries. TWO are mandatory if motor evoked potentials are going to be performed.

Many patients have chronic pain. Have a plan in place to provide adequate pain control as these can be very painful procedures. Consider alerting APS ahead of time if the patient is on numerous pain medications at home and is at high risk for significant and prolonged post-operative pain.

Be prepared for possible but significant blood loss – multi level fusions and osteotomies can result in significant blood loss. Make sure you have the access, blood products and resources (arterial line, level 1, Belmont etc.) available that you may need.

Know baseline neurologic deficits and document these deficits in the pre-op evaluation.

Take a peek at the neuromonitoring and ask questions. This might help solidify concepts that are typically tested.

dotphrases ​

.neuroplan

general neuroplan

.craniwithnm

crani w/ neuromonitorying

.craninmbplan

crani w/o neuromonitorying

.craniawake

awake crani

Resources ​

Other options: Barash, Newfield, Faust

Library e-books link to find these books if the above links are broken: https://library.cuanschutz.edu/ebooks (this link is broken)

Neuro Protocols

  • OneDrive
  • Epic >> Preop >> Manuals & FAQ Tab >> Neuroanesthesia Protocols

REQUIRED READING

  • Week 1: CNS Anatomy, Physiology and Pharmacology
    • Faust’s Anesthesiology Review, Fourth Ed., Ch 55-57, 131, 132
    • Clinical Anesthesiology, Barash et al, Seventh Ed, Pg 996-1000
    • Miller’s Anesthesia, Miller et al, Eighth Ed, Pages 387-419
  • Week 2: Neurosurgical Anesthesia
    • Faust’s Anesthesiology Review, Fourth Ed., Ch 133-140
    • Clinical Anesthesiology, Barash et al, Seventh Ed, Pg 1009-24
    • Miller’s Anesthesia, Miller et al, Eighth Ed, Pg 2158-2196
  • Week 3: CNS Monitoring
    • Clinical Anesthesiology, Barash et al, Seventh Ed, Pages 1000-1009
    • Miller’s Anesthesia, Miller et al, Eighth Ed, Pg 1487-1521
  • Week 4: Controversies in Neuroanesthesia
    • Processed EEG
    • BP management
    • TIVA vs IA - Stroke Alert GA vs MAC - Consent in AMS patient