Anesthesia for Carotid Anesthesia for Carotid SurgerySurgery

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Patient ProfilePatient Profile

Name: Name: 陳阿檜 陳阿檜 Sex: female Sex: female

Age: 49y/oAge: 49y/o

Admission date: 93/12/03 Admission date: 93/12/03

C.C: Paroxysmal right side limbs shaking fC.C: Paroxysmal right side limbs shaking followed by right-sided transient weakness ollowed by right-sided transient weakness since 4 weeks ago since 4 weeks ago

Present IllnessPresent IllnessThis 59 y/o female has a history of H/T anThis 59 y/o female has a history of H/T and DM under regular medication for several d DM under regular medication for several years.years.

Baseline BP: 140/80 mmHgBaseline BP: 140/80 mmHg

She had TIA in 92/06 and recovered compShe had TIA in 92/06 and recovered completely. letely.

4 weeks ago, she started to had paroxysm4 weeks ago, she started to had paroxysmal right-sided shaking limbs followed by rigal right-sided shaking limbs followed by right-sided transient weakness, dysarthria anht-sided transient weakness, dysarthria and dysphagia which would recover in a few d dysphagia which would recover in a few seconds were notedseconds were noted

Admitted to NTUH on 12/03.Admitted to NTUH on 12/03.

Image Study: pre-opImage Study: pre-op

Long segmental general narrowing & dimiLong segmental general narrowing & diminished flow are noted at the distal right ICnished flow are noted at the distal right ICA.A.

Diffuse narrowing with poor perfusion is noDiffuse narrowing with poor perfusion is noted at the bilateral ACAs and MCAs, more ted at the bilateral ACAs and MCAs, more severe at the right side.severe at the right side.

Diagnosis & TreatmentDiagnosis & Treatment

Moyamoya disease with PC-AC and PC-MMoyamoya disease with PC-AC and PC-MC collateral; bilateral ICA narrowingC collateral; bilateral ICA narrowing

Scheduled EC-IC bypass (L’t STA and MCScheduled EC-IC bypass (L’t STA and MCA branch anastomosis) on 12-08A branch anastomosis) on 12-08

Fentanyl 4 ml

Pentothol 250 mg

Esmeron 40 mg

Isoflurane

IVF: Normal saline

MAP: 60 +/- mmHg

12/09

post-op D1

MAP 100 +/- mmHg

Image Study: post-opImage Study: post-op

Anastomosis between left superficial tempAnastomosis between left superficial temporal artery and left MCA posterior frontal broral artery and left MCA posterior frontal branch as compared with prior ECA study.anch as compared with prior ECA study.

Anesthesia of carotid surgeryAnesthesia of carotid surgery

Preoperative Concerns

Anesthetic Technique

Cerebral Monitoring and protection

Postoperative Concerns

Pre-operative evaluation and management

Central nervous system: Pre-operative neurological deficits

Cardiovascular system:

1. CAD is present in about 20±40% of patients undergoing CEA

2. silent CAD: most influenced factor of long-term prognosis

3. CEA: intermediate cardiac risk procedure

Best Pract Res Clin Anaesthesiol (14) 2000

BP control: avoid BP control: avoid hypotension

CPP = MAP - ICP

Continued: β-blocker / calcium channel blocker ( heart protection)

Discontinued: ACEI (lead to hypotension in combination with anesthesia agents)

Peri-op Anaesthesia Care

Goal: the protection of cerebral function

prevent cerebral ischemia

minimize risk for myocardial infarct

Anesthetic Modalities

Blood pressure

Anesthetics managementAnesthetics management

General anesthesia (General anesthesia (Balanced anesthesiaBalanced anesthesia))

Barbiturate: Barbiturate: PentotholPentothol (most common), (most common), Etomidate, PropofolEtomidate, Propofol

OpioidOpioid

Muscle relaxant: no direct effect Muscle relaxant: no direct effect

Volatile agent: Volatile agent: IsofluraneIsoflurane (greatest brain (greatest brain protection)protection)

Regional anesthesia: cervical plexus blockRegional anesthesia: cervical plexus block

Regional AnesthesiaRegional Anesthesia

the need for benzodiazepines and/or opioids to make the patient comfortable

airway management

lack of the possibility to achieve cerebral protection

Blood PressureBlood Pressure

During ischemia, autoregulation is impaired and CBF become exquisitely dependent on perfusion pressure.Increasing perfusion should open collateral vessels, effecting an increase in flow to the area of ischemia.Maintain normal to high mean arterial pressure in most situations(10% to 20% above normal)

Approximately 1/3 of perioperative strokes are hemodynamic in nature

No demonstrable advantage of a specific general anesthetic technique

Cerebral monitoringCerebral monitoring

no single method to achieve the goalASA standard monitorsASA standard monitorsA-line: close observation of the haemodynamic parametersEEG: manage burst suppressiontranscranial Doppler ultrasound (TCD):

detect a significant decrease of velocity in the MCA during cross-clamping of the ICA (the velocities decreased)

detecting embolization during and after CEA (sharp spikes)Awake Patient

Cerebral ProtectionCerebral Protection

HypothermiaHypothermia

NormocapniaNormocapnia

Avoid hyperglycemiaAvoid hyperglycemia

Normal to high mean arterial pressure

Hemodilution

HypothermiaHypothermia

Mild hypothermia (33-34ºC) has benefit upon cerebral ischemia But, many patients may suffer from shivering in the recovery phase if mild hypothermia is employed Consequent increase in myocardial oxygen consumption Routine employment of mild hypothermia is not recommended Endovascular cooling and rewarming devices.Hyperthermia should be avoided.

NormocapniaNormocapnia

Available data do not support reduction of PaCO2 as a routine intervention to reduce cerebral injury

Normocapnia seems to be most appropriate during CEA in most situations.

ASA Refresher Courses (29) 2001ASA Refresher Courses (29) 2001

ASA Annu Rev (54) ASA Annu Rev (54)

Post-op periodPost-op period

Goal: smooth and prompt emergenceGoal: smooth and prompt emergence

optimal systemic and cerebral hemooptimal systemic and cerebral hemodynamicsdynamics

Post-op hyperperfusion syndromePost-op hyperperfusion syndrome

HypertensionHypertension

Myocardial Infarction

Cranial Nerve Injury

Postoperative Hyperperfusion Syndrome

Abrupt increase in blood flow Loss of autoregulation in surgically reperfused brainHigh risk: high grade carotid artery stenosis

severe hypertension after CEAFinding: headache, signs of transient cerebral ischemia, seizures, brain edema and even intracerebral hemorrhageNormotension should be maintained in patients at risk for the hyperperfusion state

Post-op HypertensionPost-op Hypertension

Worsen neurologic outcome

Exacerbating the hyperperfusion syndrome

Resultant intracerebral hemorrhage.

ββ-blocker, Trandate, and Nitrates -blocker, Trandate, and Nitrates

What about our patient?What about our patient?

Induction and maintenance agentsInduction and maintenance agents

Mean arterial blood pressureMean arterial blood pressure

Peri-op: 60 +/- mmHgPeri-op: 60 +/- mmHg

Post-op: 100 +/- mmHgPost-op: 100 +/- mmHg

BT: 35 → 36℃BT: 35 → 36℃eTCOeTCO22: 30 +/-: 30 +/-

Thanks for Your AttentionThanks for Your Attention

Have a nice dayHave a nice day