Sedation Flashcards
9 principles of GDC?
- Put patient’s interests first
- Communicate effectively with patients
- Obtain valid consent
- Maintain and protect patient’s interests
- Clear and effective complaints procedure
- Work with colleagues in way that is in patients interest
- Maintain, develop and work within our professional knowledge and skill
- Raise concerns if pt at risk
- Ensure personal behaviour maintains confidence in us and dental profession
What is conscious sedation?
Technique which uses drugs to depress CNS but are able to maintain verbal contact with pt
Which medical conditions are aggravated by stress of dental treatment and therefore may be indications for sedation?
Ischaemic heart disease
Hypertension
Asthma
Epilepsy
UC
Crohn’s
Medical conditions which affect cooperation and therefore may be indications for sedation?
Movement/learning difficulties
Spasticity disorders
Parkinsons
Psychosocial issues which may be indication for sedation
Phobias
Gagging
Persistent fainting
Idiosyncrasy to LA
Causes of dental anxiety?
Trauma
Learned (parents,playground)
Fear of criticism
Lack of communication
Invasion of body orifice
Surgery appearance
Staff continuity
Age
Socioeconomic group
Dental procedures which may indicate sedations?
Surgical extraction of wisdom teeth
Ortho extractions
Implants
ASA Classification?
- Normal healthy pt
- Mild systemic disease
- Severe systemic disease
- Severe systemic disease that is a constant threat to life
- Moribund pt who is not expected to survive without operation
- Brain dead pt whose organs are being removed for donor purposes
Medical contraindications to IV sedation?
Intracranial pathology
COPD
Myasthenia gravis
Hepatic insufficiency
Pregnancy and lactation
Medical contraindications to inhalational sedation?
Blocked nasal airway
COPD
Pregnancy
Social contraindications to sedation?
Uncooperative
Unaccompanied
Children- for IV
Elderly
Dental contraindications to sedation?
- Procedure too difficult for LA alone
- Procedure too long/ traumatic
- Spreading infection: airway threatening, limits LA
Advantages of sedation?
Decrease dentist/staff/pt stress
Fewer medical incidents
More productive appointments
Disadvantages of sedation?
Training/equipment required
Recovery time and after care
Indications for Inhalation sedation(IS)?
Anxiety
Needle phobia
Gagging
traumatic procedure
Medical conditions aggravated by stress
Unaccompanied adults requiring sedation
Contraindications for IS?
Common cold
Tonsillar/adenoidal enlargement
Severe COPD
first trimester of pregnancy
Fear of mask/claustrophobia
Pt with limited ability to understand
Equipment required for IS?*
Gas cylinders
Pressure reducing valves
Flow control meter
Reservoir bag
Gas delivery hoses
Nasal hood
Waste gas scavenging system
Components of flow control meter?*
Emergency measures within it?
Quantiflex oxygen flow meter
Mixture control dial
Flow control knob
Nitrous oxide flow meter
Air entrapment valve
Oxygen flush button
Air entrapment valve- if gases fail, valve opens allows room air into circuit
Oxygen flush button- flushes 35l O2/min
What is a reservoir bag?*
2/3L bag
Moves with each inspiration/expiration
Helps monitor respiration
What are gas delivery hoses?*
1 hose delivers fresh gases from machine
1 hose delivers waste gas to scavenging system
Non return valve in expiratory limb prevents rebreathing expired gases
Advantages of IS?
Rapid onset(2-3mins)
Rapid peak action(3-5mins)
Depth altered either way
Flexible duration
Rapid recovery
No injection for sedation
Few side effects
Drug not metabolised
Some analgesia
No amnesia
Disadvantages of IS?
Equipment/gases expensive
Space occupying equipment
Not potent
Requires ability to breathe through nose
Staff addiction
Difficult to accurately determine actual dose
Signs of adequate IS?
Patient relaxed/awake
Reduced blink rate
Laryngeal reflexes/vital signs unaffected
Gag reflex obtunded
Mouth open on request
Decreased reaction to painful stimuli
Decrease in spontaneous movement
Verbal contact maintained
Symptoms of adequate IS?
Mental and physical relaxation
Decreased reaction to painful stimuli
Paraesthesia- lips,fingers,toes
Lethargic/euphoria
Detachment
Warmth
Altered awareness of passage of time
Dreaming
Giggles
Signs and symptoms of over sedation of IS?
Repeated mouth closing
Spontaneous mouth breathing
Nausea/vomiting
Irrational and sluggish responses
Decreased cooperation
Incoherent speech
Uncontrolled laughter,tears
Patients not enjoying effects
LOC
Preoperative instructions for IS?
Light meal before
Take routine medication
Children accompanied by competent adult
Adults accompanied at first sedation appointment then may come alone
No alcohol on day of appointment
Sensible clothing
Arrange care of children
Plan to remain in clinic for 30mins after appointment
IS technique?
Set up machine
Select nasal hood
Connect to hoses
Set mixture dial to 100% O2
Settle pt in dental chair
Reinforce explanations of procedure
Set flow to 5-6l per minute
Position hood on patient’s nose
Encourage nasal breathing
Check reservoir bag movements(small movements=decrease flow, large movements=increase flow)
Check pt comfortable with hood
Ask pt to signal when begins to feel different
Reduce o2 by 10%
Wait 1 min and repeat
After o2 reached 80% reduce by 5% per minute
Stop titration when pt ready for treatment
Constant reassurance and hypnotic suggestion
Monitor for signs and symptoms of adequate sedation- if pt over sedated increase o2 in 5-10% increments until satisfactory sedation- if pt under sedated decrease o2 in 5% increments until satisfactory sedation
For recovery gradually increase o2 by 10-20% per minute until 100%
Administer 100% o2 for 2-3 mins to prevent diffusion hypoxia
Remove hood and turn gas flow off
Return pt to upright slowly, giving praise/reassurance
What is diffusion hypoxia
May occur with administration of inadequate amounts of o2 during or immediately after n2O anaesthesia
Influences partial pressure of oxygen
Success rate for IS
50-90%
Difference due to: pt populations
Greater success for ortho extractions
Poorer in pt with pain
On completion of treatment under Is, what should be done?
Adult pt may leave unaccompanied at dentists discretion
Child pt must be accompanied by competent adult
Ask pt how they felt procedure went
Reassure pt that feeling shivery is normal
Describe the mechanics of breathing?
Diaphragm used for quiet breathing
Inspiratory muscles contract
Increased thoracic volume
Decreased thoracic pressure
Air pushed in along pressure gradient
Expiration is passive
Intercostal and accessory muscles used for more forceful breathing
Fill in names
How does pulmonary gas exchange take place?
Gas exchange occurs between alveolar air and pulmonary capillary blood
Gases move across alveolar wall by diffusion
Diffusion is determined by partial pressure gradients
How is gas transported in blood?
O2 and co2 are transported in blood
Erythrocytes play important role in transport of both
Haemoglobin important for o2
Nitrous oxide doesn’t bind to haemoglobin
Nitrous oxide is carried in simple solution in blood
Structure of haemoglobin?
Globular protein
MW= 68000
2 alpha and 2 beta protein chains
4 haem groups: porphyrin ring, Fe atom
Fe reversibly binds o2
200-300 Hb molecules/rbc
What do Bohr shifts in Hb-O2 dissociation curves show?
Shift to left= increased affinity for O2 caused by decreased temp, increased pH
Shift to right= decreased affinity for o2 caused by increased temp, decreased pH
How is breathing controlled?
Voluntary, automatic process.
Breathing rhythm generated by respiratory centres in brainstem
Basic rhythm modified by signals from various sensory receptors
Which sensory receptors send signals to respiratory centres for control of breathing?
Peripheral chemoreceptors
Central chemoreceptors
Joint and muscle receptors
Lung stretch receptors
What is hypoxic hypoxia?
Decreased o2 reaching alveoli
Decreased o2 diffusion into blood
What is anaemic hypoxia
Decreased o2 transport into blood
What is stagnant (ischaemic) hypoxia?
Decreased o2 transport in blood
What is cytotoxic hypoxia?
Decreased o2 utilisation by cells
What is cyanosis?
Blue colouration of skin, mucous membranes
Due to >5gm deoxygenated Hg/deoxyhaemoglobin of blood (1/3rd of normal)
2 main forms: central and peripheral
What is central cyanosis?
Generally due to decreased o2 delivery to blood, hypoxic hpoxia:
- low atmosphere po2
- decreased airflow in airways
- decreased o2 diffusion into blood
- decreased pulmonary blood flow
- shunting
What is pulmonary cyanosis?
Due to decreased o2, delivery to localised and peripheral part of body.
Often due to decreased blood flow to tissues- stagnant hypoxia
How to manage patients with involuntary movements?
Assessment: mental and physical status, anxiety, pain experience
How to manage patients with learning difficulties?
Assessment:
Will behaviour management be possible?
Is pharmacological management needed?
Sedation or GA or both?
What are some conscious sedation techniques?
Inhalational
IV
Oral
Transmucosal- rectal
What can be used for IV sedation?
Midazolam
Propofol
Advantages of oral/transmucosal sedation?
Avoid cannulation
Can make induction more pleasant
Better cooperation/ future behavior
Disadvantages of oral/transmucosal sedation?
Baseline reading
Bitter taste
Lag time
Untitrateable
Difficulty in monitoring level of sedation
Behaviour in recovery
How to decide between GA and sedation?
Safety (controlled airway with GA/ difficult intubation)
Cooperation
Waiting lists and access to services
Pain
PMH
Still a need for a GA
Describe remimazolam?
Benzodiazepine ring and methyl ester molecule
Rapid breakdown and onset
Distribution half life 0.5 to 2 min
Terminal elimination half life 7 to 11 mins
Differences between midazolam and remimazolam?
M vs R- Distribution half life(4-18mins vs 0.5-2mins) Elimination half life(1.5-2hrs vs 7-11mins)
Complications of cannulation in IV sedation?
Venospasm
Extravascular injection
Intraarterial injection
Haematoma
Fainting
What is venospasm?
Disappearing vein syndrome
How to manage venospasm?
Time dilating vein- worse with repeated attempts
Warm water/ gloves in winter
What is an extravascular injection?
Active drug placed into interstitial space
How to manage extravascular injection?
Prevention: good cannulation, test dose of saline
Treatment: remove cannula, apply pressure, reassure
How to manage intra arterial injection?
Prevention: avoid anatomically prone sites- ACF Medial to biceps tendon.
Palpate before attack
Management:
-Monitor for loss of pulse(cold,discolouration)
- leave cannula in situ for 5mins post drug
- remove if no problems
- symptomatic leave and refer to hospital (procaine 1%)
What is a haematoma?
Extravasation of blood into soft tissues due to damage to vein walls
Prevention of haematoma?
Good cannulation technique
Pressure post operatively
Care with elderly
Treatment of haematoma?
Time
Rest
Reassurance
If severe: - initial ice pack- moist heat 20 mins after 24 hours- consider heparin containing gel
What to do if pt faint?
Lift legs over head
Complications of IV drug administration?
Hyper/hypo responders
Paradoxical reactions
Oversedation
Allergic reactions
Reasons for hyporesponders?
May be due to tolerance: BZD induced, cross tolerance, ideopathic
What are paradoxical reactions?
Appear to sedate normally
React extremely to all stimuli
Relax when stimuli removed
Check for failure of LA
Do not go on adding sedatives
Watch immature teenagers
How to manage oversedation
Stop procedure
Try to rouse pt
ABC
If no response to stimulation and support reverse with flumazenil 200micrograms then 100micrograms increments at minute intervals- watch for 1-4 hours
Management of respiratory depression?
Check oximeter
Stimulate pt- ask to breathe
Supplemental oxygen- nasal cannulae 2 litres per minute
Reverse with flumazenil
How to manage loss of airway control and/or respiratory arrest?
Stimulate pt/assess consciousness
Maintain/clear airway
Ventilate pt
Reverse sedation
Consider other medical incident
Complications of IS
Oversedation
Pt panics
Order of assessment for IV sedation?*
PMH, DH, SH
EO, IO, Vital signs
Treatment Plan
Consent
Information for pt and escort
Questions to ask during DH for IV sedation?*
Referral source
Previous bad experience
Previous sedation/GA
Symptoms
Discuss Proposed procedure
What should there be special emphasis on during MH for IV sedation?
Drug history
Drug allergy
Previous sedation/GA
Recreational drug use
Which drugs increase sedative effects of midazolam?
Alcohol
Opiods
Erythromycin
Antidepressants, antihistamine, antipsychotic
Recreational drugs
How would u ASA classify a pt who is a current smoker, pregnant, well controlled epilepsy, well controlled asthma, NIDDM, BP=140-159/90-94, Obesity (30-<40)?
ASA 2
How would u ASA classify a pt with IDDM, >6/12 post MI, >6/12 post CVA, stable angina, COPD, BP=160-199/95-114, BMI>40?
ASA 3
How would u ASA classify pt with unstable angina, <3/12 post MI, <3/12 post CVA, severe COPD, BP>200/115?
ASA 4
Where should an ASA1 pt be treated?
May be treated in primary care
Where should an ASA 2 pt be treated?
May be treated in primary care
Where should an ASA 3 pt be treated?
Should be secondary care
Where should an ASA 4 pt be treated?
Must be secondary care
What conditions do sedatives affect?
Almost all sedative agents cause respiratory depression
Psychiatric disease- sedatives may trigger neurosis/ psychosis
Theoretical risks to pregnancy
What is a term used to describe interactions between drugs which have similar or antagonistic pharmacological effects when given IV sedative?
Pharmacodynamic interactions-
Examples:
Antidepressants + BDZ’s
Antihypertensive + BDZ’s
What are pharmacokinetic interactions?
1 drug alters absorption, distribution, metabolism or excretion of another, thereby increasing or reducing amount of drug available to produce its pharmacological effects
What vitals signs are assessed prior to IV Sedation?
HR
BP
Oxygen saturation
BMI
What measurements are underweight, healthy, overweight and obese for BMI?
<18.5= underweight
18.5-24.9= healthy weight
25-29.9= overweight
>30= obese
What is the BMI cut off for sedation and fir the chair in terms of weight?
BMI 35 and 28 stones
What are the ideal properties of an IV sedation agent?
Anxiolysis
Sedation
Ease of administration
Non- irritant
Quick onset/ recovery
No side effects
Low cost
What are the actions of Benzodiazepines?
Acts on receptors in CNS to enhance effect of GABA( gamma amino butyric acid)- prolongs time for receptor repolarisation
Mimics effects of glycine on receptors
*GABA- cerebral cortex and motor circuits
GABA- inhibitory CNS neurotransmitter
Glycine- brainstem and spinal cord
How do benzodiazepines cause respiratory depression?*
CNS depression and muscle relaxation
Decreases cerebral response to increased CO2
Synergistic relationship with other CNS depressants
Increased respiratory depression in already compromised patients
What affect do benzodiazepines have on CV?*
Decreased BP by muscle relaxation decreasing vascular resistance
Increased HR due baroreceptor reflex compensating for BP fall
Side effects/ effects of benzodiazepines?
Drug interactions(erythromycin, antihistamines)
Tolerance
Dependence
Sexual fantasies
Increased respiratory depression
Decreased BP
Increased HR
Properties of diazepam?*
Elimination half life= 43+/-13 hours
Redistribution half life=40 mins
Metabolites
Risk of rebound sedation
Dose= 0.1-0.2mg/kg
Long recovery
Unpredictable
Properties of midazolam?
One preparation is 5mg/5ml
PH= 3.5
Elimination half life=90-150 mins
Metabolised in liver
Extra hepatic metabolism in bowel so less affected by liver disease
Benefits of midazolam vs diazepam?
Painless
Quicker onset/ recovery
2-3 times more potent
More reliable
Water soluble vs insoluble(not written in benefits- just something to mention)
Who is part of sedation team?
Operator- sedationist
Dental nurse
Runner
Receptionist
All must have appropriate sedation training- must be able to manage sedation related emergencies- annual ILS training and sedation scenario training
Why is a butterfly cannula not recommended?
Metal
Clots and obstructs
Easily dislodged
Where are the sites of cannulation?
Dorsum of hand: accessible, superficial and visible, poorly tethered, affected by peripheral vasoconstriction so may need to warm hand
Antecubital fossa: brachial artery and median nerve, keep lateral, second choice, less stable
Describe procedure for IV sedation?
Pre-op pulse and BP
Escort must stay in building
Consent
Cannulation
High volume aspiration
Pulse oximeter
NIBP monitoring every 5-10mins
Drug administration- midazolam- 2mg bolus- 1mg increments every 60 seconds- max 7.5 mg generally
Emergency- flumazenil, means of ventilation
How do u know that u are at end point of IV sedation?
Slurring/slowing of speech
Relaxed
Delayed responses to commands
Willingness to accept treatment
Verrill’s sign-ptosis
Eve’s sign loss of motor coordination
What is the procedure for recovery after IV sedation?
Escort can be with pt during recovery
60 mins after last increment
Cannula needs to be removed before leaving
Ensure pt can walk unaided
Escort given post op instructions
Treatment for respiratory depression?
Talk, shake, hurt
Head tilt, chin lift, jaw thrust
O2 (2l/min via nasal cannulae)
02 (5l/min via hudson mask)
Flumazenil
Ambu bag
Airways
Properties of flumazenil?
Preparation 500mcg in 5ml
Dose-200mcg then 100mcg increments every 60s until response seen
Shorter half life than midazolam-50 mins
Risk of resedation
What are the key points for a pt under conscious sedation?
Remains conscious
Retains protective reflexes
Understands and responds to verbal commands
What are the stages of the paediatric pt assessment?
History
Pt factors
Goals
Treatment plan
What takes place in paeds history for sedation?
Pain
Nature of anxiety
DH
MH
What is included in the pt factors assessment for paeds sedation?
Understanding
Coping style
Cooperation
What anxiety assessment tools are there for paeds sedation?
Adapted Faces version of Modified Child Dental Anxiety Scale (MCDASf)
Score 9-45 (9=no dental anxiety, >31=extreme dental fear)
Whose goals are included in the paeds sedation assesssment?
Pt
Parent
Clinician
What is used for the management of pain and anxiety in the treatment plan for paeds sedation?
NPBM
LA
GA
Sedation
How can LA be given to children?
Some will use Wand STA system
Examples of non pharmacological behaviour management?
Hypnosis
CBPT
What gases are used in IS for children?
Nitrous oxide and oxygen
IS indications for paeds?
Age
Anxiety level
Management of gag reflex
Medical considerations
PDH
dental needs
IS contraindications
Age
Anxiety level
Medical considerations
PDH
Dental needs
Pt choice
What must u do during IS treatment of child?
Keep talking to pt- continue behaviour management
Ensure child avoids mouth breathing
Monitor- max dose when child feels tingling or starts giggling- stop if ears ringing or sore head
Postoperative instructions
What is common after IV sedation in children?
Amnesia
IV indications in paeds?
Age
Anxiety levels
Medical considerations
PDH
Dental needs
IV Contraindications in paeds?
Age
Anxiety levels
Medical considerations
Dental needs
What is TCI Propofol in paeds?
Target controlled infusion sedation- useful for very long and very short procedures- mean rapid onset and recovery
What is an alternative form of sedation for paeds?
Oral and transmucosal sedation- midazolam- less controlled- cannulation
What is CBT?
Provides psychoeducation and uses behavioural modification techniques and cognitive restructuring skills to challenge unhelpful behaviours and beliefs- effective in helping people with dental anxiety, depression, PTSD
