RT Book, Section
A1 Butterworth IV, John F.
A1 Mackey, David C.
A1 Wasnick, John D.
SR Print(0)
ID 1190607370
T1 Anesthesia for Patients with Neuromuscular Disease
T2 Morgan & Mikhail’s Clinical Anesthesiology, 7e
YR 2022
FD 2022
PB McGraw-Hill Education
PP New York, NY
SN 9781260473797
LK accessanesthesiology.mhmedical.com/content.aspx?aid=1190607370
RD 2024/04/19
AB KEY  CONCEPTS  Weakness  associated  with  myasthenia  gravis  is  due  to  autoimmune  destruction  or  inactivation  of  postsynaptic  acetylcholine  receptors  at  the  neuromuscular  junction,  leading  to  reduced  numbers  of  receptors  and  degradation  of  their  function  and  to  complement-mediated  damage  to  the  postsynaptic  membrane.  Patients  who  have  myasthenia  gravis  with  respiratory  muscle  or  bulbar  involvement  are  at  increased  risk  for  pulmonary  aspiration  and  pneumonia.  Many  patients  with  myasthenia  gravis  are  exquisitely  sensitive  to  nondepolarizing  neuromuscular  blockers  (NMBs).  Patients  who  have  myasthenia  gravis  are  at  risk  for  postoperative  respiratory  failure.  Disease  duration  of  more  than  6  years,  concomitant  pulmonary  disease,  a  peak  inspiratory  pressure  of  less  than  –25  cm  H2O  (eg,  –20  cm  H2O),  a  vital  capacity  less  than  4  mL/kg,  and  a  pyridostigmine  dose  greater  than  750  mg/d  are  predictive  of  the  need  for  postoperative  ventilation  following  thymectomy.  Patients  with  Lambert–Eaton  myasthenic  syndrome  and  other  paraneoplastic  neuromuscular  syndromes  are  very  sensitive  to  both  depolarizing  and  nondepolarizing  NMBs.  Respiratory  muscle  degeneration  in  patients  with  muscular  dystrophy  interferes  with  an  effective  cough  mechanism  and  leads  to  retention  of  secretions  and  frequent  pulmonary  infections.  Degeneration  of  cardiac  muscle  in  patients  with  muscular  dystrophy  is  common  but  results  in  dilated  or  hypertrophic  cardiomyopathy  in  only  10%  of  patients.  Succinylcholine  should  be  avoided  in  patients  with  Duchenne  or  Becker  muscular  dystrophies  because  of  unpredictable  response  and  the  risk  of  inducing  severe  hyperkalemia  or  triggering  malignant  hyperthermia.  Anesthetic  management  in  patients  with  periodic  paralysis  is  directed  toward  preventing  attacks.  Perioperative  management  must  include  frequent  determinations  of  plasma  potassium  concentration  and  correction  of  abnormal  values,  with  careful  electrocardiographic  monitoring  to  detect  arrhythmias.  In  patients  with  periodic  paralysis,  the  response  to  NMBs  is  unpredictable,  and  neuromuscular  function  should  be  carefully  monitored  during  their  use.  Increased  sensitivity  to  nondepolarizing  NMBs  is  likely  to  be  encountered  in  patients  with  hypokalemic  periodic  paralysis.