SYRINGOMYELIA- ANESTHESIA IMPLICATIONS "SAB"

# sensitive to muscle relaxants

# autonomic hyperreflexia , avoid suxamethonium

# bulbar palsy

ATROPINE ; A VERY FAMILIAR ?STRANGER!

ATROPINE ; A VERY FAMILIAR ?STRANGER!

💧Atropine produces complete vagal block at a dose of 3 mg; 

💧should be avoided in pyrexial children, as it inhibits sweating ; 

💧delirium is another side-effect ; 

💧patients with Downs syndrome may show resistance to atropine; 

💧parenteral atropine wont cause significant pupillary dilatation and so is not contraindicated in glaucoma.

An approach in dealing with accidental Aretynoid dislocation after endotracheal intubation

Follow up the patient:

If voice is not improving: (Better to call the ENT Surgeon to do this-) Do a laryngoscopy and using any instrument, just give a mild pressure on aretynoid; usually it will fall back to correct  position.

If speech is improving,  advice VOCAL CORD ADDUCTION EXERCISES

🉐 Standing position.. Take a deep inspiration 

   and stop..and hold the breath.. this closes glottis..now strongly fall over and push against a wall...keep it for a few seconds.. Repeat this a few times.. This can force the aretynoid back to normal position by a stretching force... Usually voice is regained by this after 2 days.. 

🉐Or lift heavy weights after deep inspiration (not for CAD patients) 

🉐Plus continue Speech Therapy

Problem occurs, when Aretynoid dislocates, and nobody attempts to relocate it, and it get fixed in that position..

Intracranial Electro Corticogram(ECOG) and Anesthetic agents

Intracranial Electro Corticogram(ECOG) is an invasive EEG monitoring using subdural grids/strips or depth electrodes. Depth electrodes are an excellent modality designed to study electrical discharges from deep grey matter.

Placement of these electrodes needs general anaesthesia. Once the electrodes are inserted, the patient can have a further period of telemetry. 

With this information, the seizure focus can be defined with greater accuracy and it is also possible to undertake functional mapping of the cortical areas studied.

During resective epilepsy surgery intraoperative ECOG helps to guide the resection.

☀️Propofol is the commonly used induction agent

☀️nitrous oxide :  controversial (?decreases the spike activity significantly in some studies)

☀️remifentanil infusion enhances spike activity in the epileptogenic zone. So it can be used during ECOG monitoring

☀️Sevoflurane has greater neuro excitatory properties than isoflurane, however, the wide spread irritative response to sevoflurane is not useful in localizing the epileptogenic area. Therefore it may not be suitable for ECOG monitoring during surgery.

☀️Patients who are on long term treatment with phenytoin and carbamazepine may have increased fentanyl requirements and may be resistant to non- depolarising relaxants.

NALOXONE DOSAGE

DOSAGE: IV: For  reversal  of  post-operative  respiratory  depression  and  coma:    20-40mcg  IV  PRN 

For  opioid  overdose:    40-400mcg  IV  PRN 

Infusion:    If  an  infusion  is  required,  commence  the  infusion  with  an  hourly  infusion  rate calculated  as  2/3rd  of  the  total  bolus  dose  given  to  achieve  the  desired  opioid  reversal effect 

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:   Dose  as  in  normal  renal  function    

 DOSAGE  IN  PAEDIATRICS: IV: For  post-operative  respiratory  depression  or  over-sedation,  give  0.002mg/kg/dose  (i.e. dilute  0.4mg  to  20ml  and  then  give  0.1ml/kg/dose).    Repeat  every  2  minutes  x4  if required,  then  commence  infusion  by  adding  0.3mg/kg  to  30ml  5%  dextrose  and running  at  0-1ml/hr  (0.01mg/kg/hr).   For  opiate  overdose,  give  0.01mg/kg  (max  0.4mg)  (i.e.  dilute  0.4mg  to  10ml  and  give 0.25ml/kg/dose).    Repeat  every  2  minutes  x4  if  required,  then  commence  infusion  by adding  0.3mg/kg  to  30ml  5%  dextrose  and  running  at  0-1ml/hr  (0.01mg/kg/hr

ANESTHESIA IMPLICATIONS IN MYESTHENIA GRAVIS

 

No priming/ precurarization with NMBA

Can cause airway obstruction during induction

Less efficacy of neostigmine as patient is on long term pyridostigmine

High risk of phase 2 block with succinyl choline

Sevoflurane better to use <1 mac; >1 MAC can produce significant NMB

In fact, we can avoid nmba fully with sevoflurane

Better to monitor tof even with sevo alone

Steroids reduce dose requirement of nmba

If pulmonary reserve is poor ...consider plasmapheresis

Whether to continue anticholinesterase, d/w neurologist

Regional anesthesia is better

PAIN CAN PRECIPITATE MYASTHENIC CRISIS: So give good postoperative analgesia