W11 - Sedation/GA in Kids - Mistry Flashcards
4 Sedation techniques available for dental treatment
- Nitrous oxide
- GA
- Oral sedation
- IV sedation
- Combo
What is RA?
Relative analgesia
Ex. Nitrous oxide
- Partial analgesic affect
Features of NO (3)
- Conscious sedation
- Pt can breathe on their own
- Anxiolytic and analgesic
Features of Stage 1 Plane 1 - NO (6)
Moderate sedation and analgesia
- Increased pain threshold
- Normal vitals
- Reflexes unaffected
- Feeling relaxed and less scared
- Paraesthesia (tingling in fingers, lips)
- Can communicate and cooperate
Features of Stage 1 Plane 2 - NO (feeling, reflexes) (7)
Dissociation sedation and analgesia
- like plane 1 but further relaxation
- Reduced blink rate
- Pharyngeal reflex is reduced
- Laryngeal reflex intact
- “floating” euphoric sensation
- Can maintain open mouth
- Possibility of amnesia and time warp
How do stage 1 plane 1 and 2 differ from each other in terms of reflex?
Both planes will remain with laryngeal reflex
- Pharyngeal reflex is reduced in plane 2
What clinical tips can be done to help monitor pts dosage of Nitrous oxide?
No glasses - assess their eyes and blink rate
No bite block - ask if they can keep their mouth open (if not, has gone beyond plane 2)
Features of Stage 1: Plane 3 - NO
Total analgesia (not advised for dental practice)
No longer relative analgesia
- Pt may not be able to open mouth
- May be sleepy/sweaty/nauseous
- May not respond to words or pain
- Reduced pharyngeal and laryngeal reflexes
Features of stage 2 - NO (6)
Excitement or Delerium
- Not advised for dental surgery
- Excitement or struggling
- Pharyngeal and laryngeal reflexes significantly reduced
- Increased vitals (BP, HR, Resp)
- Dilated pupils
- Could have loss of consciousness
Features of stage 3 and stage 4 (NO)
Stage 3 - surgical anesthesia (GA)
Stage 4 - respiratory paralysis → death
Properties of N2O gas
- Non irritating
- Non flammable
- Colourless
- Sweet smelling
What makes N2O have quick onset and recovery (2)
Gas is relatively insoluble in blood
Primary saturation of blood and brain takes 3-5 min (induction)
How does the body metabolise N2O
It doesnt
- No biotransformation in body
- Excreted unchanged via the lungs (99%) at a similar rate to absorption
Effects of N2O on CNS (2)
- Acts directly on opioid receptors
- Acts of RAS - controls emotions
Produces:
- Analagesia
- Euphoria
- Amnesia
- Anxiolytic
Physiological effect of N2O on the CVS (3)
- No clinically significant difference to heart rate at therapeutic doses
- Reduced heart rate of first stage could be due to peripheral vasodilation or anxiolytic effect
- Peripheral vasodilation - flushing
Effects of N2O on resp
No direct effect
Non irritating
Caution with emphysema / COPD
Conditions to be mindful of with N2O
Emphysema
COPD
GIT (N2O can cause nausea)
Is N2O safe for pregnancy?
Yes generally
BUT
Passes readily through placenta
Avoid in first trimester (but not contraindicated)
Indications for N2O (3)
- Mild to mod anxiety (not severe)
- Sensitive to gag reflex
- Intolerance to long appointments
Contra-indications for N2O (7)
Airway blockage (cold, obstructive passage)
Precooperative child (<3 yo)
Uncooperative / severe behavioural problems
Intellectually disabled
Psychiatric disorders
Conditions with trapped gas
Significant medically compromised patients
What are some significant medically compromised scenarios where N2O is contraindicated?
Bleomycin chemotherapy - Lungs are fibrosed (contraindicated)
MTHFR Deficiency - metabolic disease assoc w/ hemocystinuria
Caution:
Complex cardiac conditions
Myasthenia gracis
MS
COPD
Severe asthma
What pts are at risk for N2O induced bone marrow suppression, neurotoxicity or increased homocysteine levels
- History of B12 or folate deficiency
- Vegetarians
- Pts on proton pump inhibitors or H2 blockers
- MTHFR deficiency
Not contraindicated (except MTHFR) - just take caution
Maximum percentage dose of N2O
50%
Though Mistry only goes up to 40%
Safety Features of N2O equipment
- Min oxygen flow of 3L/min and max flow of 10L/min N2O
or minimum of 30% oxygen
- Capacity for administration of 100% oxygen (“O2 Flush”)
- Automatic environemental air intake in event of gas flow supply failure
- Serviced / checked routinely
- Scavenging system for expired gases (that way not everyone in the room gets high)
- One way valve (prevent rebreathing)
Requirements for N2O administration (6)
- Credentialed dentists
- Administrator must be present at all times
- Always have a chaperone
- Advanced life support skills
- Informed consent
- Record details
N2O Technique steps (7)
Nasal mask placed
Adjust flow rate
Start with 100% oxygen
Reservoir bag partially inflated but not full
Titrate
Constant monitoring
Rubber dam and HVS
What is diffusion hypoxia and how can it be overcome
N2O diffuses out of blood and into alveoli rapidly
- This dilutes availble oxygen in the lungs
Restore via the administration of 100% O2 for 3-5 minutes after N2O termination
- Give post op instructions and discharge
When do complications arise for N2O (3)
- Over sedation
- Lack of monitoring
- Interaction with other meds (CNS depressants)
Adverse reactions of N2O (6)
- Nausea / vomiting
- Dizziness
- Hypoxia
- Oversedation
- Volume/pressure on trapped gas filled cavities
- Bone marrow depression from chronic use (>24h)
Occupational hazards of N2O
Prolonged exposure can lead to:
Interference with V B12 synthesis
Resulting in haematopoietic and myeloneuropathic disturbances
Ex. impaired RBC production and subsequent anemia, neurological disorders (paraesthesia, ataxia)
Teratogenicity
Reduced fertility
Spontaneous abortions
Advantages of N2O (6)
Non invasive
Mild analgesic
Anxiolytic/sedative
Minimal impact on reflexes
Easily titrated
Rapid onset/recovery
Disadvantages of N2O (6)
Requires coop with mask
Mask interferes with procedure
Needs continuous administration
Occupational hazard
Lack of potency
Cost for practice
If pt is super anxious or stressed, will N2O work?
No - recommend GA
Describe the effectiveness of N2O paediatric dentistry
In anxious children, the use of N2O for the first few sessions leads to significantly reduced anxiety in following sessions, even without N2O
what is oral and IV sedation
- Form of conscious sedation
- Minimally depressed level of consciousness (can still maintain airway and respond to touch and verbal command)
Contraindications of oral sedation
- Pts who are unable to take medication orally
- Medical issues and interactions
- Use precautions with kids <6
Indications for IV sedation (2)
Anxious
Invasive procedures of short duration
Children 12+
Contraindications of IV sedation
Inability to tolerate IV access
Medical issues and interactions
Children <6
Sedative agents (5)
Benzos (midazolam, diazepam/valium)
Antihistamines
Opioids
Ketamine
Barbituates
What is GA? Features? (3)
Induced state of unconsciousness
- Accompanied by partial or complete loss of reflexes
- Inability to maintain airway
- Unresponsive to physical stimulation and verbal command
Objectives of GA (5)
- Reduce movement and reaction to treatment
- Eliminate anxiety
- Provide safe, efficient, effective care
- Aid in tx of mentally, physically, medically compromised pt
- Eliminate pain response
Indications for GA (6)
Very anxious
Moderately-extremely uncoop
Uncoop due to medical, physical, psycho disability
Extensive surgery
When prompt tx of acute condition is required (ex abscess threatening airway)
Not responsive to behaviour management
Contraindications for GA
where medical issue risks outweigh the benefits
How should you manage pt if theyre going under GA?
What is required?
Effort should be made to ensure that only one session is required
- Need comprehensive workup (radiographs)
- Comprehensive tx planning
- Definitive tx (no GICs, should last)
Indications and contraindications of Oral sedation (3 and 3)
Indications:
- To be used when parenteral routes are not preferred or not possible
- Anxious
- Coop needed for procedures of long duration
Contraindications:
- Unable to take meds orally
- Medical issues and interactions
- Careful with kids <6
