Anesthesia for Surgery of the Carotid Artery - PowerPoint PPT Presentation

• Presented by R2 林至芃
• 2000.6.22

• Really helpful?!
• Symptomatic patients ( CAS >70%+ TIA, RIND, mild stroke within 6 months)

• Risk factors for peri-op complication:angiographic characters, Age >75.symptom status, severe HTN, before CABG, ICA thrombus, Hx of angina
• PAOD! => carotid duplex?
• Coexistent CAD! => major cause of M/M

• Internal CAS => impaired cerebrovascular reactivity + reduced ability to dilate intracerebral arterioles when CPP decline
• TCD for MCA blood flow velocity:a. predict cerebral ischemic riskb. identify asymptomatic patient

• Pre-op BP control, but how long?!
• Poorly controlled HTN :labile intra and post-op BP!
• BP reduction: gradually!! and stable!
• Diabetic patient: avoid hyperglycemia

• Goal:Risk factors modification for myocardial and cerebral ischemia.Maintain adequate CPP without stressing the heart!.Continual adjustment of CV parametersPrompt intervention

• No consensus!
• Xenon blood flow, TCD, cerebral oximetry, SEP, EEG, continual NE under RA
• processed EEG: not so sensitive!
• TCD: D/D hemodynamic and embolic eventair or particulate emboli?
• Cerebral oximetry: to be determined!

• Carotid shunt: not guarantee! emboli?
• BP control: as pre-op level, or higher potential myocardial risks=> TEE? Holter?
• BP fluctuation => deactivation (clamping) and re-activation (after declamping) of carotid sinus baroreceptor!=> local?! => increased intra and post-op hypertension

• Normocapnia!!
• Inverse steal?!Hyperventilation=>redistribute blood from intact cerebrovascular reactivity to CO2 to impaired area? Decreased cerebral blood flow?
• Hypercapnia=> intracerebral steal

• Normothermia!!
• JAMA 1997

• predict cerebral ischemia after ICA clamping!
• lower incidence of post-op hemodynamic liability?
• shorter post-op hospital stay?
• Rate of adverse cardiac outcome?
• Success of RA for CEA: gentle surgeon’s hands

• RA: superficial; deep cervical plexus block
• RA not ideal for: long OP time, difficult vascular anatomy, short neck.
• Even RA, anesthesiologist should be ready!
• Most anesthetic induction agents : no difference!(thiopental, etomidate)
• Isoflurane!

• Enhanced with moderate dose of narcoticsavoid dose compromise rapid emergenceRemifentanyl!!
• Beta-blocker:minimise surges in HR and BPperi-op beta blockade=> beneficial effect on cardiac outcome
• atropine for reflex bradycardia
• IVF+phylnephrine for hypotension

• Percutaneous angioplasty and stenting.
• Sedation for cannulation, patient awake during balloon inflation
• anti-cholinergics to attenuate baroreceptor response during balloon inflation or stenting
• hemodynamic control.

• 1/2~2/3 surgical etiology (ischemia during carotid clamping, postop thomboembolism)
• most common: emboli!
• 20% stroke => intraop hemodynamic origin

• Abrupt increase in blood flow with loss of autoregulation in surgically reperfused brain
• P’t with severe HTN
• Headache, signs of transient ischemia, seizure, cerebral edema, ICH
• MCA blood flow =>pressure dependent
• meticulous BP control!

• After CEA, carotid sinus sense sudden increase in BP => trigger baroreceptor mediated systemic hypotension!
• Anesthetise carotid sinus nerve, surgically induced carotid sinus nerve paresis.

• Recurrent laryngeal nerve dysfunction 5-6%
• Bilateral CEA=> loss of carotid body function => increase resting PaCO2
• unilateral CEA => impaired ventilatory response to mild hypoxemia.

• Upper airway obstruction after CEA: rare but potentially fetal!!
• Hematoma!!
• Tissue edema ,more common, secondary to venous and lymphatic congestion => edematous supraglottic mucosal fold => not responding to steroid! => difficult intubation and mask ventilation!!

• Phrenic nerve paresis (60-70%) after cervical plexus block (RA)
• little clinical consequence except mild increased PaCO2
• COPD!! Pre-existing contralateral diaphragmatic dysfunction!!

Thanks for your attention