inhalation sedation

Question 1

indications for inhalation sedation (6)

Answer 1

• Anxiety
  
  • Mild to moderate
• Needle phobia
• Gagging
• Traumatic procedures
• Medical conditions aggravated by stress
• Unaccompanied adults requiring sedation

Question 2

6 contraindications for inhalation sedation

Answer 2

• Common cold
• Tonsillar/adenoidal enlargement
• Severe COPD reduction in air to them
• First trimester of pregnancy no evidence, but just to avoid
• Fear of ‘mask’/claustrophobia
• Pts with limited ability to understand

Question 3

equipment for inhalation sedation

Answer 3

• Tanks (can have built into wall)
  
  • Blue N2O
  • Black with white topO2
• Pressure reducing valves
• Flow control meter
• Reservoir bag
• Gas delivery hoses
• Nasal hood
• Waste gas scavenging system

Question 4

components of dial on IS machine

Answer 4

Quantiflex Oxygen flow meter (not blue)

• Measures flow rates of up to 10 l/min.
• The reading is taken from equator(middle) of ball.
• Accuracy +/- 5%

Mixture control dial

• O2 : N2O
• Impossible to deliver less than 30% O2
  
  • Safety feature, only 21% in air
• If O2 runs out, machine switches off

Nitrous oxide flow is blue

Air entrainment valve - if gases fail, valve opens allows room air into circuit

Oxygen flush button

• flushes O2 35 l/min.
• For emergency use only!

Question 5

reservoir bag

Answer 5

• 2 or 3 litre bag – rubber or silicone
  
  • Smaller bag available for children
• The bag should move visibly with each inspiration and expiration
• Must not collapse
• Helps to monitor respiration
  
  • Can see if pt going into hyperventilation – doesn’t move much

Get them to breathe normally 12-16 breaths/min

Question 6

gas delivery hoses

Answer 6

• 2.5 cm diameter, corrugated hoses
• Universal joints to fit different machines
• One hose delivers fresh gases from machine
• One hose delivers waste gas to scavenging system
• Non return valve in expiratory limb prevents rebreathing expired gases
• Single use breathing circuits

Question 7

nasal mask/hood

Answer 7

• Various sizes
• Should form seal around pts nose
• Two connections to breathing circuit

Question 8

scavenging system

Answer 8

• Active scavenging of waste gases: small negative pressure
• Changing surgery air reduces nitrous oxide levels – 15 changes of room air per hour
• Watch for patient mouth breathing.
  
  • Check mask seal to reduce contamination
  • Get them to practice at home
  • Use of rubber dam will decrease likelihood of mouth breathing

Question 9

14 safety features of inhalation sedation equipment

Answer 9

• Colour coding
• Pin index system
  
  • prevents the wrong cylinder being attached on top of colour coding
• Diameter index system
  
  • prevents cross connection of piping
• Minimum oxygen delivery 30%
• Oxygen fail safe
  
  • operates when oxygen pressure < 40 psi
• Air entrainment valve
• Oxygen flush button
• Oxygen monitor
• Reservoir bag
• Scavenging system
• Oxygen and nitrous oxide pressure dials
  
  • 2 tanks on each side, have full spare one behind one in use
    
    • Always have a full unopened tank of O2 for each pt
• Pressure reducing valve
• One way expiratory valve
• Quick fit connection for positive pressure oxygen delivery

Question 10

10 safety features of inhalation sedation

Answer 10

• Rapid onset (2-3 mins)
• Rapid peak action (3-5 mins)
• Depth altered either way
• Flexible duration
• Rapid recovery
• No injection (for the sedation but LA still required depending on the procedure)
• Few side effects to patient
• Drug not metabolised (unlike IV drugs, quicker)
• Some analgesia (though better for ischaemic than inflammatory pain, can help with needle scratch)
• No amnesia
  
  • Good for aiding anxiety as good experience more likely to redo

Question 11

8 disadvantages of inhalation sedation

Answer 11

• Equipment expensive
• Gases expensive
• Space occupying equipment
• Not potent (only mild-moderate anxiety, need pt cooperation)
• Requires ability to breathe through nose
• Chronic exposure risk?
  
  • Scavenger system in place to minimise
• Staff addiction
• Difficulty to accurately determine actual dose
  
  • Leakage, movement etc

Question 12

10 pt signs of adequate sedation

Answer 12

• Patient relaxed/comfortable
  
  • Dreamy, floaty, daydreaming, heavy, tingling
• Patient awake
• Reduced blink rate
• Laryngeal reflexes unaffected
• Vital signs unaffected
• Gag reflex reduced
• Mouth open on request
• Decreased reaction to painful stimuli
• Decrease in spontaneous movements
• Verbal contact maintained

Question 13

10 symptoms of adequate sedation

Answer 13

• Mental and physical relaxation
• Lessened awareness of pain
• Paraesthesia – lips, fingers, toes, legs, tongue (tingling)
• Lethargy/”a few pints”, “why your mum is less grumpy after a glass of wine”
• Euphoria
• Detachment ‘floating feeling’
• Warmth
• Altered awareness of passage of time
• Dreaming
• Small controllable “fit of the giggles”

Question 14

9 signs/symptoms of oversedation

Answer 14

• Mouth closing – repeatedly
• Spontaneous mouth breathing
• Nausea/vomiting
• Irrational and sluggish responses
• Decreased cooperation
• Incoherent speech
• Uncontrolled laughter, tears
• Patient no longer enjoying the effects
• Loss of consciousness

Question 15

8 things to tell pt pre-op

Answer 15

• Have a light meal before appointment
• Take routine medicines as usual
• Children accompanied by a competent adult
• Adults accompanied at their first sedation appt. afterwards may then attend alone
• Do not drink alcohol on day of appointment
• Wear sensible clothing
• Arrange care of children during and after your appointment
• Plan to remain in clinic for up to 30 minutes after treatment

Question 16

Inhalation sedation procedure

Answer 16

• Set up the machine
• Select nasal hood (record size in notes)
• Connect to hoses
• Set mixture dial to 100% O₂
• Settle patient in dental chair
• Reinforce explanations of procedure
  
  • Stay nice and calm and breathe through nose at all times
• Set flow to 5-6l per minute
• Position hood on the patient’s nose
• Encourage nasal breathing
• Check reservoir bag movements on 100% O2
  
  • Should be small, regular movements – mimic lungs
  • Too small movements = check seal & look for mouth breathing +/- decrease the flow
  • movement too great = increase the flow rate
• Patient to be comfortable with hood before proceeding – about 1 minute
• Reduce O₂ by 10%
• Ask patient to signal when begin to feel different
  
  • Wait 1 minute and repeat
• After O₂ reaches 80%, reduce by 5% per minute
• Stop titration when patient ready for treatment

Question 17

what to do whilst carrying out tx under IS

Answer 17

• Constant reassurance & hypnotic suggestion
  
  • Visualise
    
    • Waves going in and out
    • a place that makes them feel calm – discuss before
• Monitor the patient during dental treatment nurse will too
  
  • If patient over-sedated increase O₂ in 5-10% increments until satisfactory sedation
  • If under-sedated decrease O₂ in 5% increments until satisfactory sedation

Question 18

recovery for inhalation sedation

Answer 18

• Gradually increase O₂ by 10-20% per minute until 100% or can turn straight to 100%
• Administer 100% O₂ for 2-3 minutes to prevent diffusion hypoxia
• Diffusion hypoxia can occur with the administration of inadequate amounts of oxygen during or immediately after N₂O anesthesia.
  
  • The Fink effect, also known as “diffusion anoxia,” “diffusion hypoxia,” or the “third gas effect,” is a factor that influences the partial pressure of oxygen (PO₂) within the alveolus- this is really a theoretical risk, it does not happen as our equipment always delivers enough O2
• Remove hood and turn gas flow off
• Return patient to upright slowly, give praise and reassurance
  
  • Make sure they feel completely alright and normal before standing

Question 19

after inhalation sedation tx

Answer 19

• Adult patients may leave unaccompanied at dentist’s discretion
• Child patients (<16 years) must be accompanied by a competent adult

Prior to discharge, ask how patient felt procedure went – and listen!

Patients may feel shivery after I.S- reassure patient that this is common and passes quickly