ANAESTHETIC IMPLICATIONS IN EPILEPSY SURGERIES

✔️If Awake Craniotomy/ wake up testing is planned, the procedure details should be explained to the patient, including what he/she is expected to hear and feel, inside the O.R.

✔️Get a brief description of the seizures and any prodromal symptoms 

✔️Continue anti epileptics through the morning of surgery

✔️Antiepileptics can reduce duration of action of NMBAs

✔️Usually a preoperative WADA test or fMRI would have been done, to check, whether the side of proposed surgery has any cerebral dominance or speech function 

✔️Abnormal LFTs can be expected with long term Valproate or Carbamazepine therapy

✔️WHAT THE COMMON AEDs DO?

✔️Phenytoin and Phenobarbitone: Reduce Hematocrit

Carbamazepine, Valproate,Ethosuximide and Primidone : Reduce platelet count

Carbamazepine and Primidone: Reduce WBC count

✔️If a difficult intubation is anticipated ( for e.g. After fixation of stereotactic frame ), an awake fibreoptic intubation can be considered 

✔️Moderate Sedation, if required can be achieved with Propofol 25-75 ug/kg/min plus Remifentanil 0.02-0.05 ug/kg/min OR Dexmedetomidine 1ug/kg/min over 10 minutes followed by 0.2-0.7 ug/kg/min

✔️Anticipated Surgical duration: 3 hours

✔️EBL: 250-500 ml ; blood transfusions are seldom needed

✔️Pain score 2-4

✔️If an Asleep-Awake-Asleep technique is used:

GA  continued for positioning, craniotomy and till the exposure of the surgical area. Then patient is allowed to awaken, to monitor neurological function during brain stimulation ( LMA removed OR  if ETT, it is removed over a tube exchanger). When seizure area, is fully delineated, GA is reinstituted.