Anesthesia Interventional Neuroradiology Sherif 2008

In the Name of Allah Most Merciful Most Compassionate

Anaesthesia for Interventional Neuroradiology

Sherif M El Hadi MD

Anaesthesia Department

Faculty of Medicine

Alexandria

Development of Interventional Neuroradiology (INR) n

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New imaging technology Catheter systems Detachable balloons, coils Vascular embolic agents

Method n

Digital road map is created Vascular system is imaged by angiographic dye n Projected onto a live fluoroscopy image n Bone and soft tissue has been subtracted (DSA) n Accessed typically through the femoral system n

Method Systemic heparinization n Catheter system is advanced under direct visualization into the cerebrovascular system n Superselective catheter advanced into the vessels to be treated n

Indications of INR n

Selective occlusion n Aneurysm

ablation-GDC coiling n Endovascular embolization of AVM n Sclerotherapy of venous angiomas

Indications of INR n

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

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Arterial delivery: n

Chemotherapy or embolic in tumor

Preoperative Assessment n

Allergies Contrast media reaction 5%-8% incidence of untoward systemic reactions n Allergies to Iodine and shellfish n Protamine n

Preoperative Assessment n

Medications Anticoagulation n Antihypertensive n Anticonvulsants n Blood sugar control n

Preoperative Assessment n

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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

Radiology Suite

Intensive Care Unit

Operating Theatre

Anesthetic Objectives (1) n

Maintenance of patient immobility and physiologic stability

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Manipulating systemic or regional blood flow ..

Anesthetic Objectives (2) n n

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Managing anticoagulation Treating and managing sudden unexpected complications during the procedure Rapid recovery from anesthesia to facilitate neurological evaluation..

Radiation exposure n

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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 n Goals are to alleviate Pain (introduction of contrast/prolonged immobilization, distention or traction on cerebral arteries) n Anxiety (if high risk of bad outcome) n Discomfort (prolonged immobility) n

Anaesthetic Technique Intravenous Sedation (continued) n Patient immobilty n Rapid recovery to allow neurologic examination n Be prepared to secure the airway n Various techniques, propofol infusion ..

Mild Sedation

Moderate

Deep Sedation

DANGER

Increasing sedative dose

Dangers of IV sedation n

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

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

Benefits of IV sedation n

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Techniques needing cooperation of patient The Wada test before occlusion of a vessel

General Anaesthesia

Rationale for general anesthesia n n n n n

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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 n

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No accumulation with prolonged use TIVA – rapid BP control Antiemetic (short-lived) Inhibition of airway reflexes Permits SSEP and MEP monitoring.

CBF

Propofol Propofol + hypocapnia Zone of ischaemia

Opioids n

Decreased CMRO2 (Max. 35%)

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Decreased CBF with higher doses (Max. 50%)

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Depressed airway reflexes

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Autonomic tolerance to noxious stimuli.

Problems n Muscle

Rigidity n Hypotension n 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: n

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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: n Cytoskeletal proteins damage n ↑ Pro-apoptotic proteins when used with isoflurane, midazolam and ketamine.

Halothane

CMRO2

Min. metabolic rate to maintain membrane integrity

1 MAC

2 MAC Concentration

3 MAC

Sevoflurane and Desflurane n n

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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 n

Complications Distal thromboembolism n Rupture n Recurrence and hemorrhage (incomplete obliteration) n

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No guarantee the aneurysm is removed from the circulation. BP control essential

Seven coils to obliterate aneurysm

Vasospasm n n

Larger arteries: balloon angioplasty, Small arteries: Intraarterial vasodilators Papaverine: hypotension, ↑ ICP, worsened vasospasm, seizures n Nimodipine (Biondi 2004) n Nicardipine (Badjatia, 2004) n

Effect of angioplasty on spastic segment

AV malformation n

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Before surgical resection or solely treated by embolization Factors leading to rupture: High feeding artery pressure n Draining stenosis n

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Potential risk of cerebral edema after embolization of AVM n

Steroid pretreatment and fluid restriction

Carotid artery stenting n

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

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Thromboembolism, dissection, TIA, stroke

Interventions Deliberate Hypotension n Indications Test cerebrovascular reserve in patients undergoing carotid occlusion n To slow flow in a feeding artery of brain AVMs before cyanoacrylate injection n

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Choice of agent at discretion of attending Determined by experience, patients medical condition

Interventions Deliberate Hypertension n Indications Arterial occlusion n Vasospasm n

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Augmentation of the collateral perfusion pressure by increasing the systemic blood pressure

Crisis Management

Crisis Management n

Potentially rapid and life threatening

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Require effective communication between anesthesia and radiology teams required n

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headache, nausea, vomiting, localized vascular pain, sudden LOC, seizures in awake patients sudden bradycardia, extravasation of contrast in GA

Crisis Management n

ABC Secure the airway if required n Determine if the problem is: n

-Hemorrhagic (immediate cessation of anticoagulation, reversal with protamine or platelets) -Occlusive (increase distal perfusion by increasing blood pressure with or without direct thrombolysis

Postoperative Management n

Immediate postoperative period in PACU or ICU Watch for signs of neurologic or hemodynamic instability n Blood pressure control may require continuation n Occasional requirement for CT scan n Rarely a need for emergency craniotomy n

Thank You