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General Anesthesia in Status Epilepticus

General Anesthesia in Status Epilepticus. Presented by R2 簡維宏 / VS 黃謙琳. Status Epilepticus. continuous and rapidly repeating seizures medical emergency 102,000 to 152,000 cases per year in US and roughly 55,000 deaths associated with status epilepticus annually.

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General Anesthesia in Status Epilepticus

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  1. General Anesthesia in Status Epilepticus Presented by R2 簡維宏 / VS 黃謙琳

  2. Status Epilepticus • continuous and rapidly repeating seizures • medical emergency • 102,000 to 152,000 cases per year in US and roughly 55,000 deaths associated with status epilepticus annually ~NEJM 1998; 338(14):970-976

  3. Definition (I) • In 1962, Marseilles conference described status epilepticus as “enduring epileptic state”

  4. Definition (II) • In 1981, the International League against Epilepsy defined status epilepticus as a seizure that “persists for a sufficient length of time or is repeated frequently enough that recovery between attacks does not occur” ~Epilepsia 1981;22:489-501

  5. Definition (III) • Status epilepticus as seizures that persist for 20 to 30 minutes, which is an estimate of the duration necessary to cause injury to central nervous system ~JAMA 1993;270:854-9

  6. Definition (IV) • Either continuous seizures lasting at least five minutes or two or more discrete seizures between which there is incomplete recovery of consciousness ~NEJM 1998; 338(14):970-976

  7. Clinical features (I) • Loss of consciousness • Clinically obvious seizures • Duration • Differential diagnosis with rigor due to sepsis, myoclonic jerking, generalized dystonia, and pseudostatus epilepticus ~NEJM 1998; 338(14):970-976

  8. Clinical features (II) • Clinical manifestation often become subtle with time • Electrographic status epilepticus: no observable, repetitive motor activity, and the detection of ongoing seizures requires electroencephalography • Still at risk for CNS injury and require prompt treatment ~NEJM 1998; 338(14):970-976

  9. Etiology (I) • Acute process 1. Electrolyte imbalance 2. Cerebrovascular accident 3. Cerebral trauma 4. Drug toxicity 5. Cerebral anoxic/hypoxic damage 6. CNS infection 7. Renal failure 8. Sepsis syndrome ~Anaestthesia 2001;56: 648-659

  10. Etiology (II) • Chronic process 1. Pre-existing epilepsy 2. Poor anticonvulsant drug compliance or change of anticonvulsant therapy 3. Chronic alcoholism 4. Cerebral tumors or other space- occupying lesion ~Anaestthesia 2001;56: 648-659

  11. Pathophysiology (I) • Failure of mechanism that normally abort an isolated seizure • Arise from abnormally persistent, excessive excitation or ineffective recruitment of inhibition • ??? ~NEJM 1998; 338(14):970-976

  12. Pathophysiology (II) • Status epilepticus lasting for 30-45 minutes can cause cerebral damage • Glutamate-mediated excitotoxicity • Superimposition of systemic stress exacerbating the degree of neuronal injury e.g. hyperthermia, hypotension, hypoxia ~Arch Neurol 1973; 29: 82-7

  13. Management (I) • Initial care includes standard measures applicable to any acute medical emergency • See Figure1. ~NEJM 1998; 338(14):970-976

  14. Management (II) • Treatment should proceed of four fronts 1. Termination of status epilepticus 2. Prevention of recurrence 3. Management of potential precipitating causes 4. Management of complications and underlying conditions ~Epilepsia 1999; 40(suppl.1): s59-63

  15. Principles of Drug Treatment (I) • Drug of choice: Lorazepam (0.1mg/kg) • Other drugs: 1. Phenobarbital (15mg/kg) 2. Diazepam (0.15mg/kg) and Phenytoin (18mg/kg) 3. Phenytoin (18mg/kg) only ~NEJM 1998; 339(12): 792-798

  16. Principles of Drug Treatment (II) Successful rate: ~NEJM 1998; 339(12): 792-798

  17. Principles of Drug Treatment (III) • Patients who did not respond to first-line agents 1. Response rate to second-line agents: 7% 2. Response rate to third-line agents: 2.3% • Status epilepticus that does not respond to a benzodiazepine, phenytoin, or Phenobarbital is considered refractory and required more aggressive treatment

  18. Treatment of Refractory Status Epilepticus (I) • Continuous intravenous infusions with anesthetic doses of midazolam, propofol, or barbiturates • Inhalation anesthetic gases ~Anaesthesia, 2001; 56: 648-659

  19. Treatment of Refractory Status Epilepticus (II) • Continuous EEG monitor should be available • Electrophysiological end-point 1. burst suppression 2. isoelectric patterns ~Quarterly Journal of Medicine 1996;89:913-920

  20. Treatment of Refractory Status Epilepticus (III) • Long acting anti-epileptic drug therapy should be maintained at the upper limit of the normal range • Anesthetized duration 1. 24 to 96 hours 2. Gradually tapering and if seizure recur, then re-anesthetized ~current treatment options in neurology 1999;1:359-69

  21. IV General anesthesia (I) • Propofol 1-2mg/kg bolus followed 2-10mg/kg/hr • Barbiturate-like and benzodiazepine-like effect at the GABA receptor and a potent anticonvulsant action at clinical dose • Rapid clearance • Metabolic acidosis and lipidemia • Avoid rapid discontinuation ~Anaesthesia, 2001; 56: 648-659

  22. IV General Anesthesia (II) • Midazolam 0.2mg/kg bolus followed 0.75-10 µg/kg/min • Rapid clearance and less hypotensive effect than barbiturates • Tachyphylaxis ~Anaesthesia, 2001; 56: 648-659

  23. IV General Anesthesia (III) • Barbiturates (Thiopental) 3-5mg/kg bolus followed 3-5mg/kg/hr • Potential cerebral protective effects • Accumulates in lipoid tissues during prolong infusions, resulting in delay recovery • Severe hypotension requiring vasopressor therapy • Potently immunosuppressive and prolonged use increase the risk of nosocomial infection ~Anaesthesia, 2001; 56: 648-659

  24. Inhalation Anesthetic Gases • Drugs of choice : Isoflurane • N2O: single use can’t achieve enough anesthetic level and long term use causing bone marrow suppression • Enflurane: lowering seizure activity • Halothane: High anesthetic gas concentration is need and resulting in hemodynamic unstable and potential organ toxicity

  25. Isoflurane (I) • An effective, rapidly titratable anticonvulsant • Invasive monitors such as: A-line, CVP • Usually necessitates hemodynamic support with fluids and/or vasopressors ~Anesthesiology, 1989; 71(5): 653-659

  26. Isoflurane (II) • A clinical series result (nine patient) • Isoflurane administrated for 1-55 hours • 8 of 11 occasions, seizures resumed upon discontinuation of isoflurane • 6 of 9 patients died ~Anesthesiology, 1989; 71(5): 653-659

  27. Isoflurane (III) • Effects on pathogenetic process 1. Can isoflurane “control” seizures permanently or alter a seizure focus? 2. Temporarily attenuate activity of epileptic neural generators 3. No evidence that adverse neuropathologic processes were stopped ~Anesthesiology 1989; 71(5): 653-659 ~Anesthesiology 1987; 67: A390

  28. Isoflurane (IV) • Earlier use of isoflurane, within 60 minutes “therapeutic window” proposed by Delgado-Esceuta et al. • Early role of isoflurane • Advantage: Titratablility and reversibility • Lack of prospective study ~NEJM 1982; 306: 1337-1340

  29. Outcomes (I) • Overall mortality: approximately 20~25% • Higher mortality rate group: 1.age over 60 year-old 2.patient with ECG change 3.more severe underlying brain damage and underlying disease ~Epilepsia 1992; 33 (suppl.4):s15-25

  30. Outcome (II) • 90% of patients with status epilepticus secondary to anti-epileptic drug withdrawal, alcohol or trauma have good outcomes • 33% 0f patients with status epilepticus secondary to stoke or hypoxia have good outcome

  31. Outcome (III) • Uncontrolled status epilepticus lasting more than 1 hour  mortality rate 34.8% • Seizures were terminated within 30 minutes  mortality rate 3.7% • It is not clear whether the success of treatment was the cause or the effect of the better prognosis, or a combination of both ~Epilepsia 1992; 33 (suppl.4):s15-25

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