Coma

Question 1

Delirium definition

Answer 1

fluctuating confusion, inattention, misperceptions (illusions or hallucinations).

Question 2

Stupor definition

Answer 2

a sleep-like state from which the patient can be aroused only by vigorous stimuli.

Question 3

Coma definition

Answer 3

a sleep-like state where the patient is unresponsive to external stimuli, and there are no sleep-wake cycles. Usually lasts no more than 4 weeks. GCS 8 or less.

Question 4

Glasgow Coma Scale

Answer 4

• Motor
  
  • 1 = no response
  • 2 = extension (decerebrate)
  • 3 = flexion (decort)
  • 4 = normal flexion/withdrawal
  • 5 = localizes pain
  • 6 = obeys command
• Verbalization
  
  • 1 = no response
  • 2 = incomprehensible sounds
  • 3 = innapropriate words
  • 4 = confused
  • 5 = oriented
• Eye opening
  
  • 1 = no eye opening
  • 2 = opens to pain
  • 3 = opens to voice
  • 4 = spontaneous eye opening

Question 5

Types of abnormal postures

Answer 5

• Decorticate (flexion) – upper extremity flexion with lower extremity extension (suggests lesion at hemispheres)
• Decerebrate (extension)– upper extremity extension with lower extremity extension (suggests lesion at upper brainstem)
• Prognosis of decerebrate is worse than decorticate

Question 6

“Determination of Death”

Answer 6

• Pt. has sustained irreversible cessation of circulatory and respiratory functions; or
• Pt. has sustained irreversible cessation of all functions of the entire brain, including the brainstem.

Question 7

Criteria of brain death

Answer 7

• unresponsiveness
  
  • deep coma; GCS = 3
• absent motor responses during application of painful stimulus
  
  • spinal reflexes may be present
  • seizures or flex/extend posturing are not
• brainstem reflexes are absent
  
  • pupils, corneals, oculocephalic, oculovestibular, cough, gag, respirations
  • apnea test is positive
• specific vitals
  
  • core body temp 32.2 C (90 F)
  • no toxic explanation for low neuro state
  • adequate BP & pulse (SBP 90, P>50)

Question 8

Corneal reflex test

Answer 8

• Touch cornea with tissue ==> (normal) blink response
• Tests CNs V and VII
• @ brain death: no blink response in either ey

Question 9

Cold Caloric Test

Answer 9

• “oculovestibular reflex”
• Test: Flush each external auditory canal with 20 ml ice water x 2 and observe
  
  • normal response: eyes turn toward theipsilateral ear, with horizontal nystagmus to the contralateral ear.
• Tests CNs VIII, III, IV and VI
• @ brain death: no eye movements

Question 10

Cough reflex test

Answer 10

• Test: Suction the trachea at the carina.
  
  • normal response: cough
• Tests CN X
• @ brain death: no cough response

Question 11

Gag reflex test

Answer 11

• Test: touch the oropharynx with Q-tip ==> (normal) gag
• Tests CNs IX and X
• @ brain death: no movement of the oral structures.

Question 12

Situations in which organ donation occurs

Answer 12

1. Donation after Brain Death
2. Donation after Cardiac Death

• **patient must be declared dead prior to organ harvesting

Question 13

Characteristics of consciousness

Answer 13

• product of biological events occurring within brainstem and thalamus
• derives from the activation of the intralaminar nuclei of the thalamus by the reticular activating system which project from the reticular formation of the brainstem

Question 14

Apnea test procedure

Answer 14

1. Deliver 100% O2 for 10 minutes.
2. pCO2 is around 40 mmHg on ABG.
3. Maintain adequate blood pressure (~90) and pulse (>50).
4. Determine if pt has tripped the vent recently.
5. Disconnect vent from ET tube and begin timing
6. Deliver O2 at 6L/min by t-piece, thus oxygen is being delivered.
7. Observe and feel for respiratory effort (if breathing is observed, stop test and reconnect ventilator)
8. After 8 minutes, draw blood gas and reconnect ventillator.

• **If no respiratory effort was observed and pCO2 is more than 20 mmHg higher than baseline, the apnea test is positive, consistent with brain death.

Question 15

Confirmatory tests for brain death

Answer 15

• Cerebral angiogram → 4 vessel, in brain death no flow above neck.
• EEG → flat line almost, not entirely flat b/c of artifacts from vent and moving patient
• Evoked responses → BAER, VER, Somatosensory ER
• Radionucleotide scan → cerebral blood flow
• CT angiogram → contrast media and CT immediately. Most conclusive.
• Transcranial doppler blood flow study → Last choice. Difficult.

Question 16

Conditions under which physician performs confirmatory tests for brain death

Answer 16

• If BP/Pulse cannot be stabilized
• Anatomy doesn’t allow examination
• Patient is a young child (always if <1 yo)

Question 17

Considerations in organ donation after brain death

Answer 17

• Pt must be dead before harvesting
• The surgeon harvesting may not be involved in determination and death
• In donation after cardiac death, families should be warned that the patient may not die after withdrawal of life support, will be returned to ICU
• Proper documentation of cardiac and brain death