Mod IX: Special Considerations for Posterior Fossa Craniotomies, Epilepsy Procedures & Intracranial Hemorrhage

Question 1

_{Special Considerations for Posterior Fossa Craniotomies}

•Position

Answer 1

Typically sitting, park bench, or prone

(Positions that allow for the posterior aspect of the head to be accessed)

Question 2

_{Special Considerations for Posterior Fossa Craniotomies}

Risk associated with the SITTING Position

Answer 2

VAE – 25-45%

Mid-cervical quadraplegia

Question 3

_{Special Considerations for Posterior Fossa Craniotomies}

Contraindications to the SITTING Position

Answer 3

Cardiac instability

Cervical spine disease

Others…

Question 4

_{Special Considerations for Posterior Fossa Craniotomies}

If SITTING Position must be used, Ensure:

Answer 4

Proper neck flexion

At least two finger breaths between chin and chest

Question 5

_{Special Considerations for Posterior Fossa Craniotomies}

PARK BENCH position is Similar to full lateral, but:

Answer 5

Down axilla is off the head of the bed

Question 6

_{Special Considerations for Posterior Fossa Craniotomies}

Describe the Posterior fossa and it’s constituent structures

Answer 6

Confined space comprised of the Medulla, Pons, and Cerebellum

This is where Motor & sensory pathways are

This is where Primary respiratory & cardiovascular centers are

Has Lower cranial nerve nuclei

Question 7

_{Special Considerations for Posterior Fossa Craniotomies}

Function of the Medulla

Answer 7

Autonomic control of respiration, BP, HR, reflex arcs and vomiting

Question 8

_{Special Considerations for Posterior Fossa Craniotomies}

Function of the Pons

Answer 8

Relays sensory info between cerebellum & cerebrum

Contains the pneumotaxic center that helps regulate respiration

Question 9

_{Special Considerations for Posterior Fossa Craniotomies}

Function of the Cerebellum

Answer 9

Multiple functions

Mainly to do with movement

Question 10

_{Special Considerations for Posterior Fossa Craniotomies}

Monitors

Answer 10

Standard monitors

2 large bore IVs

A-line positioned at highest point of skull

Multiorifice CVP catheter (b/c of high incidence of VAE)

Doppler (for VAE assessment)

Will probably be doing SSEPs, BAEPs, and MEPs

Question 11

_{Special Considerations for Posterior Fossa Craniotomies}

Why would doing SSEPs, BAEPs, and MEPs makes your case harder?

Answer 11

You cannot use NMBs

You must use low inhalation concentrations

etc.

Question 12

_{Special Considerations for Posterior Fossa Craniotomies}

Incidence of Venous air embolism of patients in sitting position is:

Answer 12

20 to 45%

Question 13

_{Special Considerations for Posterior Fossa Craniotomies}

What’s the Primary pathophysiologic event of VAE (Hemodynamic effect of VAE)?

Answer 13

Vasoconstriction of the pulmonary circulation

V/Q mismatch

Interstitial pulmonary edema

↓cardiac output

Question 14

_{Special Considerations for Posterior Fossa Craniotomies}

Which cardiac abnormality present in 20 to 30% population Lead to paradoxical air embolism?

Answer 14

Patent foramen ovale

Lead to paradoxical air embolism

Air to coronary or cerebral circulation

Question 15

_{Special Considerations for Posterior Fossa Craniotomies}

Measures to diagnose VAE include:

Answer 15

Measures to diagnose VAE

[Know what’s most sensitive and what’s easiest]

TEE is the most sensitive, but is considered to be invasive

Question 16

_{Special Considerations for Posterior Fossa Craniotomies}

Sensitivity ranking of monitors for detecting VAE

Answer 16

TEE>Doppler> PA catheter>Capno>Mass-Spec

Question 17

_{Special Considerations for Posterior Fossa Craniotomies}

Treatment of a VAE

Answer 17

Treatment of a VAE

Question 18

_{Special Considerations for Epilepsy Procedures}

Induction - Benzos typically withheld because

Answer 18

They lower the seizure threshold

Question 19

_{Special Considerations for Epilepsy Procedures}

You do Not want to provide a “Slack Brain”

Answer 19

Grids are placed superficially on brain tissue;

then evaluated once brain is full pool

If you provide a “Slack Brain”, then the grid placement moves

Check with surgeon on these cases prior to administering diuretics

Question 20

_{Special Considerations for Epilepsy Procedures}

What’s the of the grid system?

Answer 20

To map and detect the focal areas causing the seizure,

so that they can go in and remove that area of brain

Question 21

_{Special Considerations for Epilepsy Procedures}

What do you think may be compromised when the patient returns for the resection of the focal area?

Answer 21

…

Question 22

_{Special Considerations for Intracranial Hemorrhage}

Subarachnoid hemorrhage (SAH) - Incidence:

Answer 22

Estimated 27,000 Americans/yr

Question 23

_{Special Considerations for Intracranial Hemorrhage}

Subarachnoid hemorrhage (SAH) - Mortality & Morbidity rates

Answer 23

Morbidity rate 50%

Mortality rate 25%

Question 24

_{Special Considerations for Intracranial Hemorrhage}

Subarachnoid hemorrhage (SAH) - Age of Peak incidence

Answer 24

50 to 60 yrs old

Question 25

_{Special Considerations for Intracranial Hemorrhage} Subarachnoid hemorrhage (SAH) - Gender differences

Answer 25

Women \> men

Question 26

_{Special Considerations for Intracranial Hemorrhage} Pathophysiology of Subarachnoid hemorrhage (SAH)

Answer 26

Blood in subarachnoid space causes abrupt ↑ICP with is often associated with systemic HTN & dysrhythmias

Question 27

_{Special Considerations for Intracranial Hemorrhage} Clinical symptoms of Subarachnoid hemorrhage (SAH)

Answer 27

“Worst headache of my life,” stiff neck, photophobia, nausea & vomiting 50% have a warning leak

Question 28

_{Special Considerations for Intracranial Hemorrhage} What's the most common complications of Subarachnoid hemorrhage (SAH) in the 1st 24 hrs, and what's the tx for it?

Answer 28

**Rebleeding** Tx: Early aneurysm clipping is recommended in patients that were alert on admission

Question 29

_{Special Considerations for Intracranial Hemorrhage} What's the mechanism of Cerebral vasospasm a/w Subarachnoid hemorrhage (SAH)? when does it occur?

Answer 29

Mechanism unknown Occurs 30% of patients most often 4 to 12 days post bleed

Question 30

_{Special Considerations for Intracranial Hemorrhage} How is Cerebral vasospasm a/w Subarachnoid hemorrhage (SAH) treated? What's a risk of this therapy?

Answer 30

Treated with “Triple-H” therapy Hypervolemia, hypertension, and hemodilution Can worsen cerebral edema, ↑ICP, & cause hemorrhagic infarction However, Hypervolemia, hypertension, and hemodilution are needed to help perfuse the brain

Question 31

_{Special Considerations for Intracranial Hemorrhage} Which anesthetic technique is used when Cerebral vasospasm a/w Subarachnoid hemorrhage (SAH) is treated w/ Cerebral angioplasty? What risk are a/w Cerebral angioplasty?

Answer 31

Usually GETA Risks include rupture, intimal dissection, ischemia, & infarction

Question 32

_{Special Considerations for Intracranial Hemorrhage} Intracranial hypertension is present in most SAH. How is it treated?

Answer 32

May _not require treatment_ or may need **ventriculostomy** Abrupt lowering can lead to rebleed d/t disruption of tamponading

Question 33

_{Special Considerations for Intracranial Hemorrhage} How often does **Acute hydrocephalus** occur w/ SAH? How is it treated?

Answer 33

**Acute hydrocephalus** occurs in 20% of SAH Treated w/ **_Ventriculostomy_**

Question 34

_{Special Considerations for Intracranial Hemorrhage} Picture showing an aneurysm that has been surgically clipped

Answer 34

Picture showing an aneurysm that has been surgically clipped

Question 35

_{Special Considerations for Intracranial Hemorrhage} Anesthetic management - Goals are to:

Answer 35

Avoid rupture Maintain CPP and transmural pressure, and Provide a **“slack” brain** An ↑in MAP or fall in ICP will cause ↑transmural pressure and risk of rupture

Question 36

_{Special Considerations for Intracranial Hemorrhage} Anesthetic management - Monitors

Answer 36

Standard craniotomy monitors

Question 37

_{Special Considerations for Intracranial Hemorrhage} Anesthetic management - ICP management

Answer 37

Maintain normocarbia if ICP normal If ↑ICP, decrease PaCO2 to 30-35 mmHg This will give you a "slack" brain

Question 38

_{Special Considerations for Intracranial Hemorrhage} Anesthetic management - electrophysiology monitoring

Answer 38

May or may not do electrophysiology monitoring

Question 39

_{Special Considerations for Intracranial Hemorrhage} Anesthetic management - Deliberate hypotension technique

Answer 39

May request deliberate hypotension technique Make sure patient can tolerate Think about what chronic HTN does to the brain an to autoregulation

Question 40

_{Special Considerations for Intracranial Hemorrhage} Anesthetic management - Hypothermia

Answer 40

May be asked to provide Low grade hypothermia (32C to 34C) may be requested

Question 41

_{Special Considerations for Intracranial Hemorrhage} Anesthetic management - Intraoperative cerebral protection

Answer 41

Intraoperative cerebral protection with **thiopental** (or brevital) Provides burst suppression

Question 42

_{Special Considerations for Intracranial Hemorrhage} Anesthetic management - Extubation

Answer 42

If plan to extubate want a **smooth extubation**

Question 43

_{Special Considerations for Intracranial Hemorrhage} Anesthetic management - postop HTN and vasospasm

Answer 43

Treat postop HTN and vasospasm (“triple H”) The combination of **induced hypertension**, **hypervolemia**, and **hemodilution** (triple-H therapy) is often utilized to prevent and treat _cerebral vasospasm_ after aneurysmal subarachnoid hemorrhage (SAH).

Question 44

_{Neuro Anesthesia} Tangle of congenitally malformed blood vessels that form an abnormal communication between the arterial and venous system

Answer 44

Arteriovenous malformations (AVMs) Incidence Male \> females Age 10 to 40

Question 45

_{Arteriovenous malformations (AVMs)} Symptoms of Arteriovenous malformations (AVMs)

Answer 45

Parenchymal hemorrhage SAH Focal epilepsy Progressive focal neurologic sensory-motor deficits

Question 46

_{Arteriovenous malformations (AVMs)} Treatment of Arteriovenous malformations (AVMs) May be done by

Answer 46

**Craniotomy** or **Radiologic embolization**

Question 47

_{Arteriovenous malformations (AVMs)} Anesthetic management for Arteriovenous malformations (AVMs)

Answer 47

same as for craniotomy for aneurysm

Question 48

_{Arteriovenous malformations (AVMs)} Breakthrough cerebral edema may occur - why?

Answer 48

Blood flow diverted to vessels not accustomed to high blood flow

Question 49

_{Arteriovenous malformations (AVMs)} Complication from Arteriovenous malformations (AVMs) Embolization include

Answer 49

Embolic or ischemic **stroke**, and **hemorrhage**

Question 50

_{Special Considerations for OOR Neuro Cases} For procedures Done out of OR, what would you not have?

Answer 50

What you don't take with you “Take it with you or you won’t have it”

Question 51

_{Special Considerations for OOR Neuro Cases} Procedures done in OOR Neuro suites

Answer 51

Embolizations, angiography, coiling of cerebral aneurysms, balloon angioplasty of cerebrovascular disease or cerebral vasospasm, and therapeutic carotid occlusion for giant aneurysms and tumors

Question 52

_{Special Considerations for OOR Neuro Cases} MAC vs. GETA

Answer 52

A few cases under MAC Need for complete **immobilization** usually requires **GETA** with NMBs Patient moves they may die or worse ^{make sure they are relaxed!} May have drastic BP swings due to periods of no stimulation and then intense stimulation ^{have vasoactive gtts in line} Usually requires a-line (BP and ACT testing) and 2 IVs

Question 53

_{Special Considerations for OOR Neuro Cases} Drugs to take

Answer 53

Heparin, protamine, lots of NMBs, vasoactive gtts, and standard drugs for any procedure

Question 54

_{Neuro Anesthesia} Glue placed inside a Cerebral aneurysm

Answer 54

Glue placed inside a Cerebral aneurysm

Question 55

_{Neuro Anesthesia} Coil placed inside a Cerebral aneurysm

Answer 55

Coil placed inside a Cerebral aneurysm

Question 56

_{Special Considerations for Pituitary Tumors} A&P - Pituitary gland located ? - Divided into?

Answer 56

at base of skull in the **sella tircica** Divided into anterior (adenohypophysis) and posterior (neurohypophysis) lobes

Question 57

_{Special Considerations for Pituitary Tumors} Hormones produced by the anterior Pituitary

Answer 57

Hormones produced by the anterior Pituitary

Question 58

_{Special Considerations for Pituitary Tumors} Hormones produced by the posterior Pituitary

Answer 58

Hormones produced by the posterior Pituitary

Question 59

_{Special Considerations for Pituitary Tumors} Two categories of Pituitary tumors

Answer 59

Nonfunctioning Functioning

Question 60

_{Special Considerations for Pituitary Tumors} Nonfunctioning Pituitary Tumors - When diagnosed?

Answer 60

When large & producing mass effect Growth of tumors causes symptoms Headache, impaired vision, cranial nerve palsies, ↑ICP, & hypothyroidism

Question 61

_{Special Considerations for Pituitary Tumors} Nonfunctioning Pituitary Tumors - Sudden enlargement caused by spontaneous hemorrhage or infarction into the tumor produces a symptom complex known as

Answer 61

**Pituitary apoplexy** This is Life threatening Associated with Acute neurological deficits & rapid decline in pituitary function Treat with **_corticosteroids_** and _emergency decompression_

Question 62

_{Special Considerations for Pituitary Tumors} Functioning Pituitary Tumors - Why "functioning?" - when are they diagnosed?

Answer 62

Produce an excess of one or more of the anterior pituitary hormones Usually diagnosed when tumor is small

Question 63

_{Special Considerations for Pituitary Tumors} Which condition is a/w ↑corticotropin & cortisol?

Answer 63

**Cushing's disease** This ia an adrenocorticotropin secreting tumor (ACTH)) a/w Diabetes mellitus with insulin resistant hyperglycemia Hyperaldosteronism with hypokalemia & metabolic alkalosis HTN, mild CHF, and truncal edema (moon face, fat pads)

Question 64

_{Special Considerations for Pituitary Tumors} (GH producing tumor)

Answer 64

**Acromegaly** General overgrowth of skeletal, connective & soft tissues All major organs increase in size HTN, glucose intolerance, visual loss if tumor involves chiasm, hoarseness, dyspnea, cardiomyopathy, lumbar stenosis & cervical compression

Question 65

_{Special Considerations for Pituitary Tumors} Acromegaly (GH producing tumor) - Airway concerns

Answer 65

**Hypertrophy** Hypertrophy of mandible, nasal turbinates, soft palate, tonsils, epiglottis, arytenoids, tongue, lips, & nose **Narrowing** Glottis may be narrow (smaller tube than anticipated) Can have **vocal cord paralysis** May have difficult mask fit _Be ready for difficult airway_

Question 66

_{Special Considerations for Pituitary Tumors} Results from pressure effects of tumor on the pituitary gland

Answer 66

**Panhypopituitarism** These pts will be on Hormone replacement prior to surgery

Question 67

_{Special Considerations for Pituitary Tumors} Anesthetic considerations - All patients for pituitary surgery receive which drugs preop?

Answer 67

**Glucocorticoids**

Question 68

_{Special Considerations for Pituitary Tumors​} Most common surgical approach

Answer 68

**Transsphenoidal** Has Lower morbidity & mortality rates Associated with Less diabetes insipidus

Question 69

_{Special Considerations for Pituitary Tumors​} Anesthetic considerations - If sitting monitor for

Answer 69

**VAE** Have a doppler & CVP

Question 70

_{Special Considerations for Pituitary Tumors​} Anesthetic considerations - access

Answer 70

2 IVs and a-line

Question 71

_{Special Considerations for Pituitary Tumors​} Anesthetic considerations - What should you monitor if asked to administer 4% cocaine & lidocaine with epi

Answer 71

Can have HTN, dysrhythmias, & ischemia Purpose of 4% cocaine & lidocaine with epi is to dry out the nasal passages and keeps blood out of the surgical field

Question 72

_{Special Considerations for Pituitary Tumors​} Anesthetic considerations - Access limited to patient due to

Answer 72

Equipements around them C-arm, and other x-ray equipments that allow to see exactely where they are in the brain

Question 73

_{Special Considerations for Pituitary Tumors​} Anesthetic considerations - Do not let patient move - why?

Answer 73

Surgery is very close to the carotid and the brain Nasal packing is placed after surgery Avoid bucking on emergence but want patient awake to perform a neuro exam

Question 74

_{Special Considerations for Pituitary Tumors​} Diabetes insipidus can occur

Answer 74

pre, intra, or **postop** (most common) Can be temporary or permanent

Question 75

_{Special Considerations for Pituitary Tumors​} Signs and symptoms of Diabetes insipidus

Answer 75

Polyuria (3 to 15 L/day), polydipsia (drinks large amts), serum hyperosmolality (.320 mosmol/ml), dilute urine (sp gr 1.001 to 1.005)

Question 76

_{Special Considerations for Pituitary Tumors​} Administration of Salt containing solutions with Diabetes insipidus could lead to:

Answer 76

**Hypernatremia**

Question 77

_{Special Considerations for Pituitary Tumors​} Administration of Glucose containing solutions with Diabetes insipidus could lead to:

Answer 77

Hyperglycemia & Osmotic diuresis

Question 78

_{Special Considerations for Pituitary Tumors​} Drug therapy for Diabetes insipidus:

Answer 78

**DDAVP** Lysine vasopressin