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Anesthesia for Surgery of the Carotid Artery

Anesthesia for Surgery of the Carotid Artery. Presented by R2 林至芃 2000.6.22. Indications for CEA. Really helpful?! Symptomatic patients ( CAS >70%+ TIA, RIND, mild stroke within 6 months). Preoperative Considerations.

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Anesthesia for Surgery of the Carotid Artery

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  1. Anesthesia for Surgery of the Carotid Artery • Presented by R2 林至芃 • 2000.6.22

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

  3. Preoperative Considerations • 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

  4. Preoperative Considerations • 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

  5. Preoperative Considerations • 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

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

  7. Cerebral Monitoring • 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!

  8. Cerebral protection • 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

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

  10. Temperature management • Normothermia!! • JAMA 1997

  11. Choice of anesthesia • 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

  12. Choice of anesthesia • 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!

  13. Hemodynamic Stability • 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

  14. Minimally invasive carotid artery surgery • 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.

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

  16. Post-op hyperperfusion syndrome • 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!

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

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

  19. Airway and ventilation problems • 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!!

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

  21. Thanks for your attention

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