Good Morning 10 June 2002

Perioperative Stroke Prevention R 2 林子富

Anaesthesia 1997;52:879-83

 Incidence  0.02 to 0.7%  In the postoperative period (the majority events)  The average time : 7 days after surgery Anaesthesia 1997;52:  Significance  High mortality  Assisted care for living  Large impact and cost

Risk Factors  Perioperative period itself  Type of surgery  Coexisting conditions  Cardiac disease  Age  Others  hypotension, dehydration, hypercoagulable state and emergency surgery Anesthesiology 2000;92:425-32

Pathophysiology  Intraoperative hypotension  Thrombotic or embolic events – more important  Hypercoagulable state after surgery  Others  Extended bad rest  Thrombogenic devices  Dehydration Stroke 1982;13:766-73

Prevention  Identifying patients at risk (ex. CVA)  Altering risk factors (ex. delay surgery for 4-6 wk)  Carotid endarterectomy for carotid stenosis?  Consumption of aspirin?  Control of hypertension  Good anesthetic technique  Effect of anesthetic agents on postoperative hypercoagulability (ex. propofol) Anaesth Intensive Care 2000;28:227-28

Cerebral Protection Techniques To increase the supply of oxygen to the injured tissue To reduce the metabolic demands To affect specific pathways in the ischemic cascade to reduce the production of unwanted metabolites

Cerebral Protection I. Physiological  BP maintained within 20% of normal range  Maintain CPP greater than 70 mm Hg  Hemodilution  Maintain normocarbia  Mild hypothermia  Treat fever aggressively  Avoid hyperglycemia

Cerebral Protection II. Anesthetic Agents  Barbiturates  Isoflurane  Propofol  Lidocaine Anesthesiology 1999;90: Anesthesiology 2000;93:858-75

Cerebral Protection III. Other Pharmacological Agents  Calcium antagonist  Magnesium Other agents under investigation Prostanoids Free radical scavengers Lipid membrane peroxidation inhibitors NMDA receptor antagonists Stroke 1992;23:3-8

Summary  Uncommon but devastating  Knowledge of important risk factors  Measures to prevent ischemic cerebral events  Current and experimental pharmaceutical agents

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