RT Book, Section
A1 Rosengart, Axel J.
A1 Novakovic, Roberta L.
A1 Frank, Jeffrey I.
A2 Hall, Jesse B.
A2 Schmidt, Gregory A.
A2 Wood, Lawrence D.H.
SR Print(0)
ID 2293162
T1 Chapter 67. Coma, Persistent Vegetative State, and Brain Death
T2 Principles of Critical Care, 3e
YR 2005
FD 2005
PB The McGraw-Hill Companies
PP New York, NY
SN 9780071416405
LK accessmedicine.mhmedical.com/content.aspx?aid=2293162
RD 2022/08/07
AB The  neuroanatomy  of  coma  can  be  divided  into  three  major  categories:  diffuse  brain  dysfunction  or  bithalamic  injury,  primary  brain  stem  disorders,  and  secondary  brain  stem  compression  from  supratentorial  and  infratentorial  mass  lesions.Most  cases  of  coma  are  due  to  metabolic  disorders  or  exogenous  drug  intoxication.Patient  evaluation  must  follow  an  orderly  sequence,  beginning  with  vital  signs,  general  physical  examination,  and  neurologic  examination.The  most  important  single  sign  distinguishing  toxic-metabolic  coma  from  primary  brain  disease  is  the  presence  of  pupillary  light  responses.The  neurologic  examination  of  the  patient  in  coma  is  brief  and  focuses  on  (1)  level  of  consciousness,  (2)  pupils,  (3)  eye  movements,  (4)  motor  responses,  and  (5)  respiratory  pattern.Computed  tomographic  (CT)  scanning  of  the  brain  is  the  most  valuable  acute  test  to  rule  out  structural  causes  of  coma.Hypoxic-ischemic  encephalopathy  after  cardiopulmonary  arrest  or  shock  states  may  be  ameliorated  by  aggressive  measures  to  increase  cerebral  blood  flow  after  resuscitation.Serial  neurologic  examination  over  the  first  72  hours  is  most  helpful  to  determine  the  prognosis  for  patients  with  atraumatic  coma;  for  anoxic  brain  injury,  failure  to  recover  pupillary  responses  or  corneal  reflexes  in  the  first  24  hours  is  a  poor  prognostic  sign.As  therapies  aimed  at  cerebral  resuscitation  and  preservation  following  acute  injury  are  developed  and  proved  efficacious,  prior  guidelines  for  determining  prognosis  will  require  redefinition  and  reconfirmation.The  Uniform  Determination  of  Death  Act  states  that  “an  individual  who  has  sustained  either  (1)  irreversible  cessation  of  circulatory  and  respiratory  functions,  or  (2)  irreversible  cessation  of  all  functions  of  the  entire  brain,  including  the  brain  stem,  is  dead."The  determination  of  death  by  brain  criteria  is  based  on  clinical  examination,  and  in  most  cases  does  not  require  confirmatory  tests.  However,  the  cause  of  coma  must  be  known,  and  the  cause  must  be  sufficient  to  explain  irreversible  cessation  of  whole  brain  function.