what is brain death and how the diagnosis will be done?

 

Brain death

What is brain death? I think you may know about it. In this blog I’m just briefing about what is it? And what is the diagnosis?

Brain death is an irreversible one. Once you get your brain dead then you will be dead slowly by terminating each part of your body. If you have a loss of function of entire cerebrum and brain stem then you will be in coma. Then you will have no spontaneous reaction and loss of reflexes.

Diagnosis:

The patient will be diagnosed by

·       serial determination of clinical criteria

·       Apnea testing

·       Sometimes EEG, brain vascular imaging

If you are declaring brain death structural and metabolically cause of brain damage must be present.

If the patient has suspected an epileptics then EEG should be done.

You should observe the patient and do examinations on the patient.

Examination includes:

·       Assessment of pupil reactivity

·       Assessment of occulovestibular, occulocephalic, and cornea reflexes

·       Apnea testing

 

For examination we need the equipment Reflex hammer, flashlight, cotton-tipped swab, tongue depressor, 60ml syringe, kidney basin, ice cold water, towel roll, arterial blood gas, oxygen source, T-piece, Suction catheter.

If we need to know the person is in brain dead we need to do the examination of patient:

If patient is in coma check the diagnosis:

To examine the patient we need to check the stimulus or automatic response for the body like if we keep pen in between toes press against the toe in the abnormal condition the foot will not remove but in normal condition you will remove the foot.

Pain full nail beds response if the patient is in normal by applying pressure to any of the nail beds then you will remove the hand but in the abnormal condition you will not remove the hand by applying the pressure. And also you need to check the pupilary response to the stimulus.

Interrogate brainstem

Check the pupillary response: in normal condition you will observe that the constriction in response to the flashlight but in the abnormal there will be no any constriction of pupil

                                      a.                                                                                     b.

But in certain conditions is difficult in assessing pupillary response like:

1.   Pre-existing pupillary abnormalities – Coloboma

2.   By administrating of certain medications to the eye –Atropine or phenylephrine

3.   Trauma to the eye

Corneal reflex: by taking cotton-tipped swab touch the cornea if your eye blinks then the patient is in normal condition if not then the patient is in abnormal condition.

Oculocephalic maneuvers: observe the patient eye can maintain mid line position when the head turned and should never perform this test in patients with known or suspected cervical spine injury. But in this case if he/she is not maintaining same position then the patient is in abnormal condition.

Oculovestibular reflexes: To do this test you need to put head of the bed in 30 degrees so you can have semicircular canals orthogonal to gravity. Since it is a good idea that we are about put water in to bed and put towel to out of the basin. The fill the basin with cold water. Then we would take into syringe 50cc’s of cold water. Before going further you need to check there is no wax in the ear and no pathology that we would prevent the test. Then hold back the eye lids. Then place the basin beside the ear insert the syringe tube(attach any IV tube to the syringe). And as rapidly install 50ml of ice water into the otic canal and observe the eye stimulus if the eye is moving more towards cold water stimulus and less towards opposite then the patient is in normal condition. If the patient eye is moving only towards the cold water then the patient is having brainstem response but no cortical response. If the patient eye is not responding then he/she having neither brainstem response nor cortical response.

Note: after installing cold water into the ear you may need to wait 90-120seconds. To observe the response before concluding that there is no response.

Difficult in evaluating oculovestibular reflex:

1.   Cerumen ( in otic canal) will prevent the cold water reaching from the typhanic membrane

Oropharyngeal response: we can this by any tongue blade or any cotton swab by keeping deep in to the mouth and you will observe elevation of palatal but in the abnormal patient you will see no response from the musculature in retropharyngeal area.

Apnea test: to observe this apnea test first we need to give oxygen to the patient by the ventilator through the T-piece, and disconnect from ventilator and ensure that the oxygen level >85% and B.P remain 5 percentile to the age. And observe for a period of 5-10 min so that PaCO₂ would raise at least 20mm of mercury

·       Note: if the O₂ level fall below 85% or BP fall below the limit then the test discontinue.

·       Before reconnecting to the ventilator draw arterial blood gas

·       If ABG demonstrates PaCO₂ > 60mmHg then the apnea test is positive. Then appear for second clinical exam

If you have not seen the breathing for 5-10 min the connect to the ventilator before it draw the arterial blood gas and wait for ABG test

If the test shows increase at least 20mmHg of PaCO₂ and the level is greater than 60mmHg: the child haven’t breathed to that stimulus.

Note: if the PaCO₂ level is < 60 do not diagnose brain death

Some experts told that the threshold should rise higher than a PaCO₂ level of 60mmHg

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