Susan L. Smith, MN, PhD


March 28, 2003

The Clinical Neurologic Examination

The clinical neurologic examination is the standard method for the determination of brain death. This examination can proceed only if: (1) complicated medical conditions that may confound the clinical assessment, particularly severe electrolyte, acid-base, or endocrine disturbances, have been ruled out; (2) severe hypothermia, defined as a core body temperature ≤ 32°C, is absent; (3) the patient is not hypotensive; and (4) there is no evidence of drug intoxication, poisoning, or presence of neuromuscular blocking agents in the patient's system.[5] The clinical neurologic examination for the determination of brain death is discussed in detail in a Medscape Clinical Update, Donation and Transplantation: Into the New Millennium.[5]

Neurologic examination criteria for determining brain death include coma and an absence of[8]:


  • Motor response to painful stimuli; spinal cord reflexes may still be present

  • Pupillary reflex (response to light and pupils at midposition with respect to dilation)

  • Corneal reflexes

  • Oculovestibular reflex

  • Gag reflex

  • Coughing in response to tracheal suctioning

  • Respiratory drive at a PaCO2 of 60 mm Hg or 20 mm Hg above baseline level

  • Sucking and rooting reflex (in infant).


More than 1 consecutive neurologic examination may be necessary to determine brain death. Depending on the patient's age, the time intervals between neurologic examinations are as follows[8]:


  • 48 hours for newborn term infant to 2 months

  • 24 hours for > 2 months to 1 year,

  • 12 hours for > 1 year to < 18 years

  • Optional for ≥ 18 years.


In some cases, confirmatory tests such as cerebral angiography, electroencephalogram, transcranial Doppler ultrasonography, or cerebral scintigraphy may be necessary to make the determination of brain death. Guidelines for the use of confirmatory tests to declare brain death are also based on the patient's age[9]:


  • 2 confirmatory tests are necessary for newborn term infant to 2 months

  • 1 confirmatory test is necessary for > 2 months to 1 year

  • Use of confirmatory tests is optional for > 1 year to < 18 years

  • Use of confirmatory tests is optional for ≥ 18 years.


When brain death is imminent, the patient is considered to be a potential organ donor until determined otherwise, usually by the medical director of an OPO or a transplant physician or surgeon.


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