Complications of Conscious Sedation in Dentistry Flashcards
Historically what factors contributed to complications of conscious sedation in dentistry?
- bolus sedation used
- untrained seditionists
- incorrect doses given
- mixed up labels
- incorrect concentration
- reliance on flumazenil
What are the possible complications of cannulation?
- venospasm
- extravascular injection
- intraarterial injection
- haematoma
- fainting
What is venospasm?
- disappearing vein syndrome
- increased with poor technique
- must ensure good dilation
- quick insertion
- increased with poor technique
- vein collapse at attempted venipuncture
- on insertion of cannula
- may be accompanied by burning
- associated with poorly visible veins
How is venospasm managed?
- dilating vein
- should be well dilated
- worse with repeated attempts
- efficient technique
- slow puncture makes worse
- warm water/gloves
- better vasodilation
What is extravascular injection?
- active drug placed into interstitial space
- cannula not inserted into vein
- symptoms
- pain
- swelling
- liquid bubbles up in tissue
- delayed absorption
- delayed sedation
- 20-30 minutes
- drug still absorbed so treatment must be delayed
- delayed sedation
How is extravascular injection managed?
- prevention
- good cannulation
- test dose of saline
- ensures in vein
- treatment
- remove cannula
- apply pressure
- reassure
- midazolam is non-irritant
What is intra-arterial injection?
- cannulation of artery
- often brachial artery if antecubital fossa
- must cannulate lateral to bicep tendon
- high blood pressure can push cannula out
- often brachial artery if antecubital fossa
- symptoms
- pain on venepuncture
- thicker artery wall
- radiates distal to cannulation site
- red blood in cannula
- difficult to prevent leaks
- loss of colour or warmth to limb
- visible or weakened pulse
- pain on venepuncture
How are intra-arterial injections managed?
- prevention
-insert lateral to bicep tendon
- if antecubital fossa cannulation- palpate before insertion
- management
- monitor for loss of pulse
- cold
- discolouration
- leave cannula in situ for 5 minutes post drug
- if no problems, remove
- if symptomatic leave
- refer to hospital
- administer procaine 1%
- monitor for loss of pulse
What is a haematoma and how does it occur because of cannulation?
- extravasation of blood into soft tissues
- damage to vein walls
- can occur at venipuncture
- poor technique
- puncture both side of vein
- blood pooling
- can occur at removal of cannula
- failure to apply pressure
- particularly common in elderly patients
How can haematoma be prevented?
- good cannulation technique
- avoid multiple holes in vein wall
- pressure post-operatively
- operator should apply, not patient
- 2-3 minutes afterwards
- take care with elderly
How can haematoma be treated?
- time
- rest
- reassurance
- in severe cases
- initially apply ice pack
- moist heat for 20 minutes
- after 24 hours
- consider heparin gel
Why can fainting occur during venepuncture?
- anxiety related to venepuncture
- low blood sugar
- anxious patients may not eat
- increased chance of fainting
- accompanied by shaking or tremoring
- urinary incontinence is possible
- bowel incontinence is not a faint
How can fainting during venepuncture be managed?
- prevention
- encourage patients to eat
- topical anaesthesia
- management
- lie patient down
- raise legs
What are the possible complications of drug administration during intravenous sedation?
- hyper-response
- hypo-response
- paradoxical reactions
- over sedation
- allergic reactions
What is considered a hyper-response to intravenous sedation and how is it managed?
- deep sedation with minimal dose
- 1-2mg midazolam
- care with titration
- reason for 1mg increments
- even slower with elderly
- very sensitive
What is considered a hypo-response to intravenous sedation and how is it managed?
- little sedative effect with large doses
- check cannula is in vein
- may be due to tolerance
- benzodiazepine induced
- BDZ, drug users/addicts, methadone
- cross tolerance
- idiopathic
- benzodiazepine induced
- maximum doses
- 15mg in hospital settings
- 7.5mg in general practice
What are paradoxical reactions to intravenous sedations and how are they managed?
- patients appear to sedate normally
- react extremely to all stimuli
- relax when stimuli removed
- check for failure of LA
- do not give further sedative
- find alternative management technique
- consider flumazenil
- special care for immature teenagers
What is oversedation?
- loss of responsiveness
- unable to tell patient to take deep breaths
- respiratory depression
- respiratory centres acted on by drug
- pulse oximeter used at all times
- below 90% give oxygen
- loss of ability to maintain airway
- respiratory arrest
- patient stops breathing
How is over sedation managed?
- stop procedure
- try to rouse patient
- continually assess ABC
- if no response to stimulation
- reverse with flumazenil
- 200ug initially
- 100ug increments every minute
- watch for 1-4 hours
- aware of re-sedation risk
- reverse with flumazenil
- be more careful next time
How can respiratory depression be managed?
- check pulse oximeter
- stimulate patient
- ask to take deep breaths
- supplemental oxygen
- nasal cannulae
- 2l per minute
- reverse with flumazenil
What allergic reactions can occur in response to sedation and how should they be managed?
- very rare to have allergy to sedative
- if benzodiazepine allergy:
- do not give flumazenil
- also benzodiazepine
- do not give flumazenil
- consider latex and Elastoplast allergies
- deliver adrenaline
- IM injection to thigh
How might sedation result in sexual fantasy?
- sedation can feel like being drunk
- aetiology and incidence unknown
- documented but uncommon
- no way to prevent
- aetiology and incidence unknown
- all patients must be chaperoned at all times
What is the elimination half-life of midazolam and how long does it remain in the body?
- elimination half life
- 1-2 hours
- in body
- 12 hours
What are the distribution half life, recovery period and working period of midazolam?
- distribution half life
- 15 minutes
- recovery period
- 1 hour
- working time
- 45 minutes
