Unconsciousness, Vasodepressor Syncope and Postural Hypotension

Cecille Mae Uy Deomano, DMD

UNCONSCIOUSNESS

Definition of Terms

• Unconsciousness – lack of response to sensory stimulation

• Syncope/ Faint- transient loss of consciousness caused by reversible disturbances in cerebral function (patient regains consciousness within 30 minutes)

• Anoxia – absence or lack of oxygen

• Hypoxia - low oxygen content

Possible Causes Cause Frequency

Vasodepressor syncope Most Common

Drug administration/ ingestion Common

Orthostatic Hypotension Less Common

Epilepsy Less Common

Hypoglycemic reaction Less Common

Acute adrenal insufficiency Rare

Acute allergic reaction Rare

Acute myocardial infarction Rare

Cerebrovascular accident Rare

Hyperglycemic reaction Rare

Hyperventilation Rare

Predisposing Factors

• Stress

• Impaired physical status

• Administration or ingestion of drugs (analgesics, anti-anxiety agents, antibiotics)

Clinical Manifestation

• Does not respond to sensory stimulation

• Has lost protective reflexes

• Inability to maintain patent airway

Pathophysiology Mechanism Clinical Example

Inadequate delivery of blood or oxygen to the brain

Acute adrenal insufficiency Hypotension Orthostatic hypotension Vasodepressor syncope

Systemic or local metabolic deficiencies

Acute allergic reaction Drug ingestion

Direct or reflex effects on nervous system

Cerebrovascular accident Convulsive episodes

Psychic mechanisms Emotional disturbance Hyperventilation Vasodepressor syncope

Inadequate Cerebral Circulation

• Dilation of peripheral arterioles

• Failure of normal peripheral vasoconstrictor activity

• Sharp drop in cardiac output

• Constriction of cerebral vessels (hyperventilation)

• Occlusion or narrowing of the internal carotid artery

• Life threatening ventricular dysrhythmias

Oxygen Deprivation

• Hypopharyngeal obstruction by the base of the relaxed tongue

• Complete or Partial airway obstruction

• Loss of Consciousness

Oxygen Consumption of the Brain

• Human brain uses approximately 20% of the total oxygen and 65% of the total glucose the body consumes

• 20% of the total blood circulation must reach the brain per minute

Prevention

• Pretreatment medical and dental evaluation of the patient

• Use of conscious sedation techniques

• Use supine position or slightly upright position in treating the patient

Management

• Recognition of the unconsciousness

– Shake the patient’s shoulder and shout loudly: “Are you alright?”

– Application of peripheral pain (pinch the suprascapular region)

• Terminate dental procedure

• Summon help

Management

• Position the victim

– Supine position with the brain at the same level as the heart and feet elevated slightly (10-15 deg)

– Trendelenburg position is discouraged

ABCs of Emergency Medicine

A- airway

B- breathing

C- Circulation

Assess and Open the Airway

• Head tilt- chin lift maneuver

Assess and Open the Airway

• Jaw-thrust technique

Assess airway patency and Breathing

• Look, listen and feel technique

Determination of Airway Patency and Breathing

Clinical signs Diagnosis Management

Feel Hear See

Airway patent; patient is breathing

Maintain airway

Feel Hear See

Airway patent; patient is breathing

Maintain airway

Feel Hear See (erratic and heaving)

Patient attempting to breathe but airway is still obstructed

Repeat head tilt, if necessary, use jaw thrust technique

Feel Hear See

Respiratory arrest Begin artificial ventilation

Artificial Ventilation

• Exhaled air ventilation

• Atmospheric air ventilation

• Oxygen rich ventilation

Exhaled Air Ventilation

Mouth to Mouth Mouth to Nose

First cycle: 2 full breaths In adults: 10-12 breaths per minute In children: 20 breaths per minute

Adequacy of ventilatory efforts

• Feeling the escape of air as the victim passively exhales

• Seeing the rise and fall of the victim’s chest

Atmospheric Air Ventilation

• Delivery of 21% oxygen

• Use of Bag-valve-mask

Airway Adjuncts

• relieve upper airway obstruction caused by the tongue by lifting the tongue from the back of the hypopharynx

Oxygen rich Ventilation

• Delivers greater than 21% of oxygen

• “E” cylinder of oxygen

Assess Circulation

• Monitoring heart rate and blood pressure

• Sites for heart rate monitoring:

– Brachial and radial arteries in the arm

– Carotid artery in the neck

Assess Circulation

• If a pulse is present, the rescuer should continue with steps 4-6 (maintaining postion, airway and breathing)

• If a palpable pulse is not present within 10 seconds, initial chest compressions must be done

Management of Unconsciousness

Recognition of the Problem

Discontinue Dental Treatment

Activate Office Emergency Team

P- Position the patient in supine position with feet elevated

A B C

Activate Emergency medical service if recovery is not immediate

D- Provide Definitive management as needed

VASODEPRESSOR SYNCOPE

Predisposing Factors

Psychogenic

• Fright

• Anxiety

• Emotional stress

• Receipt of unwelcome new

• Pain

• Sight of blood

Nonpsychogenic

• Erect sitting or standing posture

• Hunger from dieting

• Exhaustion

• Poor physical condition

• Hot, humid, crowded environment

• Male gender

• Age between 16 and 35 years

Prevention

• Proper positioning

– place patient in supine or semi-supine position

• Anxiety relief

– Do thorough patient evaluation to be able to modify treatment

– Psychosedation

Manifestations

• Presyncope

– Feeling of warmth

– Loss of color

– Heavy perspiration

– Reports of “feeling bad” or “faint”

– Nausea

– Slightly lower BP

– Tachycardia

Manifestations

• Syncope

– Differences in breathing pattern

– Dilation of pupil

– Convulsive movements and muscle twitching

– Bradycardia, HR less than 50 bpm

– Pulse is weak and thready

Manifestations

• Postsyncope

– Rapid recovery is expected after proper patient positioning

– Patient may exhibit pallor, nausea, weakness, and sweating

– Patient may also exhibit confusion and disorientation

– HR returns to baseline

Pathophysiology Stress

Release of catecholamines (epi and norepinephrine)

Increase blood flow to muscular tissues

Peripheral pooling of blood

Decrease in blood volume

Decrease in arterial blood pressure

Decrease in cerebral blood flow (<30ml/100g of brain tissues)

Syncope

Management

P – Position

A – Airway

B – Breathing

C – Circulation

D – Definitive measures

Definitive Care

• Administration of oxygen

• Monitoring of vital signs

• Additional procedures – Loosening of binding clothes

– Use of a respiratory stimulant (ammonia)

– Cold towel may be placed if patient is shivering

– If bradycardia persists, atropine may be administered

• Postpone further dental treatments

POSTURAL HYPOTENSION

Definition

• Disorder of the autonomic nervous system in which syncope occurs when the patient assumes an upright position

• Drop in the systolic pressure of 30mmHg or greater or a 10mmHg or greater fall in diastolic pressure

• Result of a failure of the baroreceptor reflex mediated increase in peripheral resistance

Predisposing Factors

• Administration and ingestion of drugs (antihypertensives, psychotherapeutics, opioids, histamine blockers, nitrous oxide, etc)

• Prolonged period of recumbency or convalescence

• Inadequate postural reflex

• Late- stage pregnancy

• Advanced age

• Venous defects in the legs

Prevention

• Thorough history taking

• Physical evaluation (BP, HR, RR)

• Dental therapy considerations

– Elevate the chair slowly

– Caution patient before standing up

– Stand nearby as the patient stands after treatment

Clinical Manifestations

• No prodromal signs and symptoms

• Patient may lose consciousness rapidly or may merely become light headed

• Patient may develop blurred vision

• Drop in BP but same HR

Normal Regulatory Mechanisms

Feet Head

120mmHg 120mmHg

12”

20”

30”

20”

Supine position: equal BP

Semiupright position: pressure decrease by 2mmHg/ in the individual remains above the heart level

Trendelenberg position: pressure increase by 2mmHg/in the individual remains below the heart level

Normal Regulatory Mechanisms

• Reflex arteriolar constriction and increase in HR through baroreceptors in the carotid sinus and aortic arch

• Reflex venous constriction mediated intrinsically and sympathetically

• Activation of venous pump

• Reflex increase in respiration

• Release of neurohormone substances

CV reaction to postural change

Change (at 60sec) after sudden elevation

Normal Postural Hypotension

Systolic BP Baseline or +/- 10mmHg

Decrease > 25mmHg

Diastolic BP Increase of 10-20mmHg

Decrease >10mmHg

Heart rate 5-20 beats per minute above baseline

Baseline or higher (>30 beats per minute)

Management

P – Position

A – Airway

B – Breathing

C – Circulation

D – Definitive measures

Definitive Care

• Administration of oxygen

• Monitoring of vital signs

• Subsequent management

– Change from supine to upright must be slowly with sufficient time for accommodation

– Help the patient rise from the chair

– Allow the patient to recover fully before leaving the office

THANK YOU!