Acute treatment Strategies of Comatose
Patients and Stages of Coma
Consciousness is the state
of full awareness of the self
and one’s relationship to the
Normal Brain Anatomy
Anatomy of Consciousness
Ascending reticular activating system (RAS)
is a system of fibers which arises
from the reticular formation of the
brainstem and projects to the
Neurons in the reticular formation
receive collaterals from the
ascending spinothalamic pathways
and then projects diffusely to the
entire cerebral cortex .
Thus sensory stimuli are involved not only with
sensory perception but also play role in the
maintenance of consciousness through their
connections with the RAS.
Stimulation of RAS produces arousal and destruction
of RAS produces coma. Hypothalamus is also
important for consciousness, stimulation of posterior
hypothalamic region cause arousal.
The degree of alteration in consciousness is roughly
proportional to the volume of brain tissue involved in
Consciousness is divided in to two main components
The physiology of arousal is
dependent on the reticular
activating system (RAS).
The RAS is a poorly
localized network of cells
in the brainstem with
projections to the thalamus,
hypothalamus and cortex.
Awareness is mediated by the
cerebral cortex in widely distributed
neuronal networks. Awareness is
the product of cortical function that
resides within both hemispheres
and then projects down to the
thalamus and then out, for either
motor or sensory functions.
Terms used to describe altered states of
Clouding of Consciousness:
Mild form of altered mental status.
Patient has reduced wakefulness or awareness.
Include hyperexcitibility or irritability alternating with
More profound deficit including disorientation and
difficulty in following commands due to focal deficit of
Patient has a lessened interest in the
environment, slowed responses to stimulation, and
tends to sleep more than normal with drowsiness in
between sleep states .
Only vigorous and repeated stimuli will arouse the
individual, and when left undisturbed, the patient will
immediately lapse back to the unresponsive state .
State of unresponsiveness , patient cannot be
aroused by stimuli even with vigorous stimulation.
Locked in Syndrome:
Ventral brainstem destruction sparing the RAS. Patient
is mute and quadriplegic but not comatose, with
variable preservation of consciousness. Patient is
awake but speechless & motionless with little response
to stimuli and Sustained eye opening along with
aphonia or hypophonia.
Persistant Vegetative state:
Vegetative describes an organic body capable of
growth and development but devoid of sensation and
thought. Patient have massive bilateral hemisphere
damage with intact brainstem. In PVS, patient is awake
but unaware of environment.
Minimally Conscious state:
Patients shows limited but clear evidence of awareness
of themselves or their environment by atleast following
simple commands, gestural or verbal yes/no response.
Further improvement is more likely than patients in a
Sub category of minimally conscious state in which
patient neither tend to move nor speak, lack motor
functions such as speech, facial expression, gestures
but demonstrate alertness. They can move their eyes
in response to auditory stimulus or move after repeated
Causes of COMA
Structural Non- Structural
(Focal) (Diffuse or
Sites and Causes of Coma
Diffuse hemisphere , eg; Trauma, ischaemia,
eg ; supra or infra
Two major classes of Structural brain injuries
Compressive lesions Destructive lesions
Indirectly by compressing the directly by destructing or
RAS from outside, this process injury to the RAS
is due to herniation, whereby a itself. Eg ; brainstem
mass lesion or swelling causes stroke or haemorrhage.
displacement of cerebral structures
ultimately compressing the
midbrain and brainstem
Sites and Representative causes of Structural
lesions that can cause Coma
Supratentorial Mass Lesions Ischaemia
hematomas Subarachoid haemorrhage
tumor other mass lesions
Infratentorial Mass Lesions
Non Structural (Diffuse, Metabolic or Multifocal
causes of Coma)
A. Deprivation of oxygen, substrate or metabolic
4. Cofactor deficiency (thiamine, niacin, pyridoxine)
B. Toxicity of Endogenous products
1. Due to organ failure (hepatic coma, uremic coma)
2. Due to hyper or hypofunction of endocrine organs
C. Toxicity of Exogenous poisoning
1. Sedative drugs
2. Acid poisons/ poisons with acid breakdown
3. Psychotropic drugs
D. Abnormalities of ionic or acid base environment of
E. Endocrine disturbances
F. Infections or inflammation of CNS
Mnemonic for Causes of Coma:"SPITE ME NOT”
S – Space occupying lesion M - Metabolic
P – Psychiatric E - Epileptic
I - infectious/inflammatory
T - trauma
E - Endocrine
N - Neoplastic
O - oxygen
T - toxic
Assessment and Examination of Comatose
Examination must be thorough , but brief.
Begin by informally assessing the patient level of
Examiner addresses the patient verbally
If, no response
Examiner speak more loudly & shake the patient
If, no response
Formal coma evaluation should begin
Coma Evaluation Scales
Glasgow Coma Scale
Graham and Bryan, Neurosurgery professors
developed this scale in 1974 at the University of
15 point scale - Initially used to assess the level of
GCS is used to test best motor response (6), best
verbal response (5) and best eye response (4).
Score ranges from 3 (deep coma or death) to 15 (fully
According to Glasgow Coma Scale
(GCS) (HICKEY 2003)
MILD Head injury or
Admitted to Non ICU
Moderate Head injury
than 9 Deep
Motor Response (total score = 6)
Score 6 – Obeys commands:
o Highest level of motor response
o Accurate response to instruction (twice)
eg: raise eyebrows, stick out tongue.
Score 5 - Localising pain:
o Response to pain stimulus –
movement of limb as to
attempt to remove
1. Sternal rub
2.Supra orbital pressure
3. Trapezius squeeze
4. Nail bed pressure
Score 4 - Withdrawal from Pain:
o Normal flexion in response to central pain
stimuli, but failing to locate source of pain.
o Pulls limb away from painful stimulus.
Score 3 - Flexion to Pain:
o Decorticate posturing: due to a block in motor
pathway between cerebral cortex and brain
o Slower response
o Flexing upper arm & rotating of wrist & thumb
through fingers and extension of lower limb
Score 2 - Extension to Pain:
o Decerebrate posturing:
occurs due to
o Straightening of elbow
& internal rotation of
shoulder and wrist; leg
Score 1- No Motor Response:
oBrain incapable of processing any sensory input
& motor activity
oRigid to all pain stimuli
Verbal Response (total score = 5)
Score 5 – Oriented
oAwareness of the self and the environment.
( Who, Where, When, Why )
Score 4 – Disoriented
oResponses to questions with presence of confusion
Score 3 – Inappropriate words
oSpeech in a random way.
oNo conversational exchange
Score 2- Incomprehensible sounds
oMoaning and Groaning
Score 1- No verbal response
oNo response to any deep or vigorous stimuli
Eye Response (total score = 4)
Score 4 – Spontaneous
oIndicates activity of brainstem arousal
mechanisms, but not necessary patient is attentive.
Score 3 – To Speech
Tested by any verbal approach (spoken or shouted),
Not necessary the command to open the eyes.
Score 2 – To pain
Tested by a stimulus in the limbs.
o (supra- ortibal pressure may cause grimacing)
Score 1 – No Eye response
oNo response to speech or pain
Rapid Assessment Scales for Coma - 2
Is the patient Is the patient
Alert and oriented? Alert and oriented?
Responding to voice? Confused?
Responding to pain? Drowsy?
Grady Coma Scale
Grade State of awareness
I Confused, drowsy, lethargic, un co-operative.
Does not lapse in to sleep when left undisturbed
II Stuporous, un co-operative, disoriented to time,
place, person, lapse in to sleep if not disturbed.
III Deep Stupor, Requires strong pain to evoke
IV Exhibits decorticate or decerebrate posturing
to deep pain stimulation.
V Does not respond to any stimuli.
Rancho los Amigos Scale (RLA)
It is used as the patient improves or stabilise.
There are 8 levels in this scale
Level I - No response to any stimuli - indicates coma
Level II - Generalized response, i.e. patient reacts
inconsistently and nonpurposefully to stimuli, Responses are
limited such gross body movement - indicates coma
Level III - Localized response, i.e. patient reacts specifically but
inconsistently to stimuli, such as turning head toward a sound
and following simple commands in an inconsistent, delayed
manner - not considered coma, but stimulation techniques
appropriate through Levels III.
Level IV - Confused-Agitated, i.e. patient is in a state of
severely decreased ability to process information. Does not
discriminate among persons or objects. Behavior is often
bizarre and un co operative.
Level V - Confused-Inappropriate, Non-Agitated, i.e. patient
appears alert and is able to respond to simple commands fairly
consistently, but responds to more complex commands in a
Level VI - Confused-Appropriate, i.e. the patient shows goal-
directed behavior, but is dependent on external input for
direction. Responses may be incorrect due to memory
problems, but they are appropriate to the situation.
Level VII - Automatic-Appropriate, i.e. the patient appears
oriented, goes through daily routines automatically, patient
shows minimal to no confusion and shallow recall of
activities, and requires at least minimal supervision for learning
and safety purposes. Judgment and other higher level cognitive
abilities remain compromised.
Level VIII - Purposeful and Appropriate, i.e. the patient is alert
and oriented able to recall and integrate past and recent
events, is aware of and responsive to the environment, and
needs no supervision once learning has occurred.
The FOUR ( Full outline of
New Coma Scale is devised in 2005, due to the
shortcomings of GCS such as:
oFailure to assess verbal score in intubated patients.
oInability to test brainstem reflexes.
o(Eye, Motor, Brainstem, Respiration)
Each component has maximum of score of Four.
Wijdicks E, Bamlet WR et al. Validation of New Coma Scale: The Four Scale. Ann Neurol 2005; 58:
585 – 593.
Eye response ( Score – 4)
4 - eyelids open , tracking, or blinking to command
3 - eyelids open but not tracking
2 - eyelids closed but open to loud voice
1 - eyelids closed but open to pain
0 - eyelids remain closed with pain
Motor response (Score – 4)
4 - thumbs-up, fist, or peace sign
3 - localizing to pain
2 - flexion response to pain
1 - extension response to pain
0 - no response to pain
Brainstem reflexes ( Score – 4)
4 - pupil and corneal reflexes present
3 - one pupil wide and fixed
2 - pupil or corneal reflexes absent
1 - pupil and corneal reflexes both absent
0 - absent pupil, corneal, and cough reflex
Respiration (Score – 4)
4 - not intubated, regular breathing pattern
3 - not intubated, Cheyne–Stokes breathing pattern
2 - not intubated, irregular breathing
1 - breathes above ventilator rate
0 - breathes at ventilator rate or apnea
(from relatives, friends, emergency medical personnel)
Onset (abrupt, gradual)
Recent complaints (headache, depression, focal
Previous medical illness (diabetes, renal failure, heart
disease), History of headache of recent onset suggests
compressive lesion, depression or psychiatric disease
suggests drug intoxication.
General Physical Examination
Elevated temperature infection/serious intracranial disease
Elevated blood pressure hypertensive encephalopathy/
ABC (Airway, Breathing, Circulation)
Evidence of trauma (search for signs of head trauma such as
bruises, lacerations, fractures & other signs of injury)
Examine the neck, if possibility of trauma, neck should be
Resistance to Neck flexion suggests meningeal irritation.
Evidence of drug ingestion (needle marks, alcohol on breath)
pupil only on the
pupil of opposite
Changes in Pupils with lesions at different levels
of brain that can cause Coma
Occulo- cephalic response or Doll’s eye
Turning the head in one direction causes the eye to turn in
opposite direction. This response indicates that brainstem is
intact & pathways connecting the vestibular nuclei (medulla) to
extraocular nuclei (pons and midrain) are functioning. No
response or asymmetry indicates brainstem dysfunction.
Cold Caloric testing
If doll’s eye movements are absent proceed to caloric. Ice cold
water applied to the tympanic membrane normally elicits a slow
conjugate deviation to the irrigated side. Absence indicates
brain stem diysfunction. Caloric testing is more sensitive than
the oculocephalic response. Check the tympanic membrane is
intact before testing.
Examination of Eye movements
Hold the eyelids gently in an open position to observe eye
position and movements in a comatose patient.
Small flashlight held about 50 cm from the face and shined
toward the eyes of the patient & should reflect of the same point
in the cornea of each eye if the gaze is conjugate.
Patients with impaired consciousness demonstrate a slight
Observe for a few moments for spontaneous eye movements.
Slowly roving eye movements are typical of metabolic
If conjugate, it imply an intact ocular motor system.
Corneal reflex testing
Test is performed by lightly touching the cornea with a cotton
swab. The normal response is that the patient should blink
both eyes. Testing must be performed bilaterally to evaluate
both afferent components of the fifth cranial nerve.
Abnormal Respiratory patterns in coma
Cheynes - Stokes
Cheyne – Stokes Respiration
Periods of hyperpnea alternate with periods of hypopnea.
Respirations increase in depth and volume up to a peak, then
decline until a period of apnea, after which cycle repeats.
Cheyne stokes respiration may be due to bilateral hemisphere
lesions, and increased intracranial pressure.
Pattern of breathing is irregular, with erratic shallow and deep
respiratory movements. Ataxic breathing occurs with dysfunction
of the medullary respiratory centers.
Central Neurogenic hyperventilation
Central neurogenic hyperventilation refers to
sustained, rapid, and regular hyperpnea. It is primarily
associated with disease affecting the reticular formation in the
low midbrain and upper pons, but it may also occur with lesions
in other brainstem locations.
Prolonged inspiratory phase, and occurs in pontine lesions just
rostral to the trigeminal motor nuclei, or cervicomedullary
Motor examination in disorders of consciousness
requires skilled observation and difficult to recognise
the presence of hemiplegia in comatose patient.
If both arms are lifted, affected extremity falls more
rapidly and in flail like manner, while normal arm drops
slowly and same for lower extremity.
If lower extremities are passively flexed with heels
resting on the bed and then released, paretic limb
rapidly falls to an extended position with hip in external
rotation, while affected extremity gradually returns to its
Patients with forebrain or diencephalic lesions often have a
hemiparesis but can generally make purposeful movements
with the opposite side.
Upper Midbrain damage
Lesions involving the junction of the diencephalon and the
midbrain may show decorticate posturing, including flexion of
the upper extremities and extension of the lower extremities.
Upper Pontine damage
Lesions involving upper pontine may progress to decerebrate
posturing, including extension of both upper and lower
Depending on the level of coma, the patient may not
perceive even the most painful stimulus, or may
respond to painful stimuli by wincing or withdrawing
the part of the body stimulated.
Examination must be comparing responses to
painful stimulation on the two sides of the body.
Extensor plantar response may occur with either
structural or metabolic coma.
Frontal release signs (forced grasping, palmomental
responses etc) and paratonic rigidity may be present
with altered mental status of either structural or
Stages of Coma
Grade I - Individuals who respond with recognition
when their name is called and do not lapse into sleep
when left undisturbed.
Grade II - If the alteration in level of consciousness
is more severe, so that the person lapses into sleep
when undisturbed and is arouse only when a pin is
tapped gently over the chest wall.
Grade III - Patient who winces in response to deep
pain stimulus. Deep pain stimulus may result in
abnormal postural reflexes either unilateral or bilateral.
Grade IV – Deep pain stimulus may result in decorticate
and decerebrate posturing.
Grade V - The patient who maintains a state
of flaccid unresponsiveness despite deep pain
Consciousness level Diagnostic Criteria
No behavioral signs of awareness
Loss of brain functions (brainstem reflexes)
No behavioral signs of awareness
Impaired spontaneous breathing
Impaired brainstem reflexes
Arousal/stpontaneous or stimulus-induced eye
No behavioral signs of awareness
Preserved spontaneous breathing
Preserved brainstem reflexes
> 1 month: persistent vegetative
grimaces to pain, localization to sounds
visual fixation, response to threat, inappropriate
Consciousness level Diagnostic Criteria
Fluctuating behavioral signs of awareness
Response to verbal order
Object localization and manipulation
Sustained visual fixation
Intentional but unreliable communication
Locked in Syndrome
Preserved cognitive functions
Communication with eye gaze
Acute treatment Strategies
Initial Management of Coma
Even before detailed history & examination, it is important to
direct towards emergency measures such as correction of
possible deficiencies in glucose, oxygenation and blood
After determination of vital signs, attention should be towards
ensuring an adequate airway, oxygenation and intravenous
Immediately after obtaining blood samples, 50 cc of 50%
glucose followed by 100 mg of thiamine should be given.
Naloxone and flumazenil are often given in case there has
been an opiate or benzodiazepine overdose.
A “Coma cocktail” consisting of
dextrose, flumazenil, naloxone and thiamine is sometimes
used in the management of the comatose patient.
Preparation of intubation, respiratory support, and use of
pressor agents should become necessary.
Always assume a cervical spine injury may be present, and
immobilise the neck until a fracture can be ruled out.
Patients in Coma experience sensory deprivation because
their ability to respond to internal and external stimuli is altered.
Threshold of activation of Reticular activating system may
increase in coma patients.
Practical implication of Sensory deprivation is that controlled
stimulation (sufficient frequency, intensity, duration) should be
given to meet the higher threshold of reticular neurons and
increase cortical activity.
Undamaged axons send out collateral connections that is
called collateral spouting which assist in re organizing the brain’s
On the basis of an Animal model, sensory stimulation of
sufficient, intensity and duration was given to arouse the brain
and improve neuronal organization, increased dendritic
branching which in turn stimulate the RAS and increase the
level of cognitive function.
Maximum recovery can occur within first few weeks. Delayed
intervention may predispose to various complications such as
pressure ulcers, muscle wasting.
So, Early Intervention to enhance consciousness recovery is
mandatory to minimize these complications
It is hypothesized that frequent sensory stimulation could
facilitate dendritic growth, neuronal reorganization, and
synaptic re innervation and improve the rate of recovery from
Coma Stimulation / Arousal Therapy
May stimulate the RAS and increase arousal and attention to the
level necessary to perceive incoming stimuli.
Prevent sensory deprivation, which has been shown to retard
recovery and the development of central nervous function and
further depress impaired brain functioning.
Allows for frequent monitoring of patient's responsiveness.
May improve the quantity and quality of responses toward
Principles of Coma Stimulation
Before starting any stimulation, check resting vital signs (heart
rate, blood pressure, and respiratory rate).
Avoid or minimize stimulation programs with comatose patients
that have a ventriculostomy when increased intracranial pressure
(ICP) and/or cerebral perfusion pressure (CPP) are still issues.
The environment should be simple and undisturbed, with a
limited number of people around the patient, and with the TV off
and the door closed during treatment.
Allow extra time for the patient to respond (because of slow
information processing). 1 or 2 minutes between the
administration of different stimuli is useful as an initial guide until
the length of response delay is established.
Keep sessions relatively brief - patients can usually tolerate
up to 15-30 minutes.
Conduct sessions frequently, allowing patients to respond
several times daily.
Select meaningful stimuli, such as voice of family and
friends, favorite music etc. Stimuli that have emotional
significance to the patient are usually more likely to elicit
Avoid overstimulation, indicated by
perspiration, agitation, eye closing, sudden decrease in arousal
level, increase in muscle tone, and prolonged increase in
respiration rate, by alternating periods of stimulation with
periods of rest.
Techniques of Coma Arousal Therapy
Each movement was done 2 times, allowing 1 min to respond.
Lying on bed
A. Movement of arms – patient's arm was supported at the elbow
and hand. And then arm was slowly moved above the head as far
as it go. Then it was held for 3 sec then arm was
lowered, keeping the elbow as straight as possible.
B. Movement of legs – Patient's leg was supported at the knee
and ankle, and was slowly bent toward the chest as far as
possible, held for 3 sec and then lowered down, attempting to
straighten the knee.
C. Movement of head – Head was turned side to side, stretching
as far as it could go.
D. Patient's knees were flexed, placing the feet flat on the bed
and then laterally rotated keeping the knees together, held for
3 sec in each position.
Stimulus was presented for 5 sec, twice, with a 3 sec break
between each stimulus. It was repeated to right and then, left
upper extremities; then right and left lower extremities. Materials
used were brush, various cloth textures, sandpapers, cotton
Different stimuli were used in sequence. Each stimulus was
presented for 5–10 sec, twice, with a 3 sec break, on right
side and then on left side. Materials used are ring bell, familiar
voices, and religious chants using ear pieces of ipod.
Stimulus was presented for 5 sec, twice, with a 3 sec break
between each stimulus in front outer, inner upper and lower
quadrant/field of vision. Materials used are, brightly colored
block, familiar photo, functional object.