anesthesia interventional neuroradiology sherif 2008

In the Name of Allah Most Merciful Most Compassionate

Sherif M El Hadi MDAnaesthesia Department

Faculty of Medicine

Alexandria

Anaesthesia for Interventional Neuroradiology

Development of Interventional Neuroradiology (INR)

New imaging

technology

Catheter systems

Detachable balloons,

coils

Vascular embolic

agents

Method

Digital road map is created Vascular system is imaged by

angiographic dye Projected onto a live fluoroscopy image Bone and soft tissue has been

subtracted (DSA) Accessed typically through the femoral

system

Method

Systemic heparinization Catheter system is advanced under

direct visualization into the cerebrovascular system

Superselective catheter advanced into the vessels to be treated

Indications of INR

Selective occlusion Aneurysm ablation-GDC coiling Endovascular embolization of AVM Sclerotherapy of venous angiomas

Indications of INR

Selective increase in blood flow Balloon angioplasty Thrombolysis of acute stroke Carotid angioplasty with stent

Arterial delivery: Chemotherapy or embolic in tumor

Preoperative Assessment

Allergies Contrast media reaction

5%-8% incidence of untoward systemic reactions

Allergies to Iodine and shellfish Protamine

Preoperative Assessment

Medications Anticoagulation Antihypertensive Anticonvulsants Blood sugar control

Preoperative Assessment

Cardiovascular and pulmonary history

Neurological history Physical exam

Impaired consciousness favors General Anaesthesia

Transportation

Guiding the medical management of critical patients during transport to and from the

radiology suites

Transport of Patient

Emergency Room

Intensive Care Unit

Operating Theatre

Radiology Suite

Anesthetic Objectives (1)

Maintenance of patient immobility and physiologic stability

Manipulating systemic or regional blood flow ..

Anesthetic Objectives (2)

Managing anticoagulation Treating and managing sudden

unexpected complications during the procedure

Rapid recovery from anesthesia to facilitate neurological evaluation..

Radiation exposure

Exposure decreases proportionally to the square of the distance from the source of the radiation

Digital subtraction angiography (DSA) delivers more radiation than fluoroscopy

Optimal protection-apron, thyroid shield, communication ..

Anaesthetic Technique

Intravenous Sedation Goals are to alleviate

Pain (introduction of contrast/prolonged immobilization, distention or traction on cerebral arteries)

Anxiety (if high risk of bad outcome) Discomfort (prolonged immobility)

Anaesthetic Technique

Intravenous Sedation (continued) Patient immobilty Rapid recovery to allow neurologic

examination Be prepared to secure the airway Various techniques, propofol

infusion ..

Mild Sedation Moderate Deep Sedation

Increasing sedative dose

DANGER

Dangers of IV sedation

Poor control of the airway, potential: •Hypoxia •Hypercapnia•Stertorous breathing and aspiration

Side effects of IV sedatives•Dysphoria•Prolonged somnolence•Extrapyramidal symptoms

Benefits of IV sedation

Techniques needing cooperation of patient

The Wada test before occlusion of a vessel

Wada test

It judges which hemisphere is dominant for specific function.

e.g. If speech arrest or other language impairment (dysphasia, paraphasia) were observed immediately following drug injection into one hemisphere, then the injected side was judged to be dominant for language.

Wada test using propofol For the Wada test, a solution of

propofol dispensed at a concentration of 1mg/ml in 10 mL of saline.

The dose of propofol ranges from 10- 17 mg/ bolus enough for producing transient contralateral hemiplegia and aphasia

General Anaesthesia

Rationale for general anesthesia

Improved images Airway control in the supine position Induced hypotension facilitated Improved control of elevated ICP Augmentation of blood pressure with

occlusive disease Facilitating rescue operations

Propofol

No accumulation with prolonged useTIVA – rapid BP control

Antiemetic (short-lived) Inhibition of airway reflexes Permits SSEP and MEP monitoring.

Zone of ischaemia

CBFPropofol

Propofol + hypocapnia

Opioids

Decreased CMRO2 (Max. 35%)

Decreased CBF with higher doses

(Max. 50%)

Depressed airway reflexes

Autonomic tolerance to noxious

stimuli.

Problems

Muscle RigidityHypotension Increased ICP???

Nitrous oxide:

Vacuolation of mitochondria and cytoplasmic reticulum of posterior cingulated gyri of rats after nitrous oxide.Jetovic-Todorovic. Nature 1998.

Nitrous oxide:

Thiopentone, isoflurane increase survival time in mice if given before exposure to ischaemia

Nitrous oxide eliminates this protective effect

N2O alone decreases survival time.

Nitrous oxide:

Protein synthesis: Cytoskeletal proteins damage ↑ Pro-apoptotic proteins when used

with isoflurane, midazolam and ketamine.

Halothane

CMRO2

Concentration

1 MAC 2 MAC 3 MAC

Min. metabolic rate to

maintain membrane

integrity

Sevoflurane and Desflurane

Speedier recovery than isoflurane Low solubility in blood and tissues

rapid recovery Desflurane increases BP and HR on

induction

Sevoflurane and Desflurane

Effect on ICP Desflurane > isoflurane > sevoflurane

BUT

Differences disappear with hyperventilation

Holmstrom A. J Neurosurg Anesthesiol. 2004

Intracranial aneurysm ablation

Intracranial aneurysm ablation

Intracranial aneurysm ablation

Intracranial aneurysm ablation

Complications Distal thromboembolism Rupture Recurrence and hemorrhage

(incomplete obliteration) No guarantee the aneurysm is

removed from the circulation. BP control essential

Seven coils to obliterate aneurysm

Vasospasm

Larger arteries: balloon angioplasty, Small arteries:

Intraarterial vasodilators Papaverine: hypotension, ↑ ICP,

worsened vasospasm, seizures Nimodipine (Biondi 2004) Nicardipine (Badjatia, 2004)

Effect of angioplasty on spastic segment

AV malformation

Before surgical resection or solely treated by embolization

Factors leading to rupture: High feeding artery pressure Draining stenosis

Potential risk of cerebral edema after embolization of AVM Steroid pretreatment and fluid

restriction

Carotid artery stenting

Bradycardia and hypotension: 7% (Mlekusch, 2004) Anticholinergic agents Prophylactic transvenous pacemaker

inserted Thromboembolism, dissection, TIA,

stroke

Thank You