Unit 3: Postural (orthostatic) Hypotension and Syncope
Postural Hypotension
Sudden drop in systolic blood pressure (20 mm Hg or more).
Caused by a change in body position, usually moving from a supine to a sitting position.
This change in position may cause the patient to lose consciousness after being repositioned.
Also referred to as orthostatic hypotension.
Postural Hypotension: Predisposing Factors
Some medications can cause individuals to suffer from orthostatic hypotension:
Antihypertensives
Diuretics
Calcium channel blockers
Parkinson’s medications
Vasodilators
Sedatives / tranquilizers
Other Predisposing Factors
Advanced age
Prolonged illness
Pregnancy
Exhaustion/starvation
Clinical Manifestations
Quick drop in blood pressure (20 mm Hg or more)
Loss of consciousness upon sitting upright or standing
Light-headed or blurred vision without loss of consciousness
Very low blood pressure (< 90/60)
Normal heart rate (60–100 beats per minute)
Why Does BP Drop Quickly?
When the patient moves from a supine to upright position, gravity’s effects on the cardiovascular system intensify.
Blood must now move upward against the force of gravity to supply blood to the brain.
The body cannot adapt adequately to gravity’s effects (the body has various mechanisms to do this, but in this case they are not all working).
This leads to a rapid drop in blood pressure.
What Do You Do for a Patient with Postural Hypotension?
Remain calm.
Management of Emergency
Assess consciousness
Call for help
Position patient – supine
Circulation
Airway
Breathing
Administer oxygen
Management of Emergency (continued)
Monitor vital signs – check BP before allowing them out of chair
(must be > 90/60)Slowly reposition patient so no recurrence
(be close by when they eventually get out of chair)Discharge with friend or family member
Prevention
Review and update patient’s medical history
Taking any medications?
History of dizzy spells or fainting?
Physical exam
Vital signs
History of low BP
Therapy or Appointment Adjustments
Do not allow patient to get up rapidly
Stand nearby patient as they get up
Slowly put chair in upright positioni
Vasodepressor Syncope
Syncope is also called vasovagal, neurocardiogenic, neurally mediated syncope, or the common term “faint.”
Sudden, transient loss of consciousness and postural tone with spontaneous recovery.
Most often caused by loss of cerebral oxygenation and perfusion referred to as cerebral ischemia.
In other words, a loss of consciousness caused because of decrease in blood flow to the brain.
Syncope: More Than “Just Fainting”
What is syncope?
Temporary loss of consciousness caused by decreased blood flow to the brain.
Always treat as potentially life-threatening.
Why it’s dangerous in the dental chair:
No response to stimuli
Loss of protective reflexes (swallowing)
Cannot maintain open airway
Look beyond the faint:
Syncope may indicate:
Cardiac abnormalities
Orthostatic hypotension
Hypoglycemia
Anxiety
Syncope: Occurrence
Most common life-threatening emergency (due to inability to maintain airway) in dental office.
Cause → stressful events, medication, or various illnesses.
“Fight or flight” – blood is sent to the muscles, but not moving in dental chair to return blood to the brain.
Affects patients of all ages.
Occurs after prolonged sitting or standing.
Be Prepared!
Initial steps in management regardless of cause:
Position – usually occurs when patient is upright; they will go down and out fast
Circulation
Airway
Breathing
Two big reasons for unconsciousness:
Low blood pressure
Low blood sugar
Predisposing Factors
Non-psychogenic: physical causes
Psychogenic: mental origin or cause other than physical
Psychogenic Factors
Fear, anxiety, stress
Pain / fear of pain
Blood, needles, “dental office smell”
Non-Psychogenic Factors
Poor physical condition
Hunger / missed meal / hypoglycemia
Exhaustion
Hot / crowded environment
Hyperventilation
Orthostatic hypotension
Acute illness
Presyncope (Precedes loss of consciousness)
Feeling of warmth
Pale, loss of color
Cold sweat
Decrease in BP
Increase heart rate (tachycardia)
Pupils dilated
Hyperpnea (increase depth of respiration)
Yawning
Coldness in hands and feet
Disturbed vision
Dizziness
Nausea
Goosebumps (piloerection)
Syncope (Actual loss of consciousness)
Breathing may become irregular, jerky and gasping, quiet, shallow, or cease entirely
Pupils dilated
Deathlike appearance / pale
Slight convulsive movements
Muscular twitching of hands, legs, or facial muscles
Bradycardia – slow heart rate, pulse
Hypotension – decreased BP
Post-Syncope (Return of consciousness)
Pale
Nausea
Weakness
Sweating
Short period of confusion or disorientation
Slow return of BP and pulse to normal
Embarrassment
Body is fatigued
Management of Syncope Emergency
Remain calm
Pre-syncope management:
Terminate treatment (remove items from patient’s mouth)
Place patient in semi-supine position
Remove offending stimuli
Administer oxygen
Supine and Trendelenburg Positions
Do NOT:
Position unconscious patient with head below heart → harder to breathe
Put pregnant patient too far back → fetus can put pressure on vena cava
(Position toward the left side)
Supine: head and heart at same level
Trendelenburg: head below heart / feet slightly elevated
Management of Syncope Emergency (continued)
Recovery is usually within 5 minutes.
If recovery isn’t fast, call EMS — could be more serious underlying problem.
What to Do Post-Syncope
Remove any predisposing stimuli (bloody gauze, needles)
Return chair to upright position slowly
Decide if treatment should be continued
Did vital signs return to baseline?
Do NOT leave patient unattended while they recover
(patient is fatigued and can faint again)Document episode in patient’s chart, including signs/symptoms and management
Patient should not be dismissed without accompaniment
Syncope Prevention
Position patient supine, especially during local anesthesia
Recognize anxiety and attempt to alleviate
Obtain thorough medical history
Therapy options:
Stress reduction
Premedication
Inhalation sedation (N₂O₂)
Intravenous sedation
Psychosedation