Inhalation Sedation Flashcards
Define conscious sedation
A technique in which the use of a drug or drugs produces a state of depression of the CNS enabling treatment to be carried out.
Both verbal contact and protective reflexes are maintained in the patient throughout the period of sedation.
The drugs & techniques used to provide conscious sedation for dental treatment should carry a margin of safety wide enough to render loss of consciousness unlikely.
Why is sedation needed?
Fear
50% children moderately anxious, 10% extremely anxious
Deaths from GA
What are the sedation techniques?
Inhalation - nitrous oxide/oxygen, sevoflurane
Intravenous - midazolam, propofol
Transmucosal - midazolam (intranasal, buccal)
Oral - temazepam, diazepam, midazolam, katamine
Intramuscular - ketamine
Combo of above
Nitrous oxide features?
Recreational use
Deaths due to hypoxia
Properties of nitrous oxide?
Volatile
Denser than air - 1:1.5
Less potent - Min amount of gas to give 50% of population to not feel pain as has a MAC50 of 104
Often used in anaesthesia as carrier/induction gas
Poorly soluble - rapid onset/rapid recovery
Pharmacokinetics of nitrous oxide?
Inhaled into lungs with oxygen through nasal mask Travels down partial pressure gradient Alveolus to capillaries Hardly metabolised - 0.004% Excreted through lungs Elimination half life - 5 mins
Pharmacodynamics of nitrous oxide/oxygen sedation?
Analgesic
Anaesthetic
Hypnotic
Anxiolytic - GABA
What are the stages of anaesthesia?
- Analgesia
- Plane 1:
Moderate sedation and analgesia (5-25% N20)
- Plane 2:
Dissociation sedation and analgesia (20-55% N20)
- Plane 3:
Total analgesia (50-70% N20) - Excitement
- Surgical analgesia
- Respiratory paralysis
Signs that the sedation is adequate?
Awake Feels relaxed Suggestive state Giggling Verbal responses Maintaining mouth open Reduced blink rate Spontaneous respiration
Signs of over sedation?
Pt no longer enjoying effects Hysterical laughter, tears Decreased cooperation Nausea/vomiting Mouth closing - repeatedly Snoring Incoherent speech Irrational and sluggish responses Loss of consciousness
Indications for inhalation sedation?
Social
- Mild anxiety/needle phobias/gagging/fainting
- To enable cannulation
Medical
- Conditions aggravated by stress
- Conditions where continuous oxygen delivery is beneficial
- Conditions which affect co-operation
Dental
- Unpleasant procedures
- Avoid GA in medically compromised
Contraindications of inhalation sedation?
Social
- Severe anxiety/ claustrophobia/ no consent/lack of escort
- Lack of understanding
Medical
- Blocked nose/URTI/ unable to nose breathe
- Recent eye/ middle ear / sinus / intracranial surgery
- Bleomycin therapy (chemotherapy drug) / myaesthenia Gravis
- Pregnancy - 1st and 3rd trimesters
Dental
- Traumatic procedures /unsuitable for LA alone
- Tx on upper anterior teeth - lip trapped
Safety checks for inhalation sedation?
- Pin index = prevents oxygen and nitrous oxide mixing up
- Scavenging at 40L/minute = actively removes air at the level of the nose mask
- Nasal mask and tubing
- Oxygen failsafe = if O2 stops the N2O will also stop
- Max 70% N2O
- Oxygen flush = delivers 30L of oxygen in a second (only used in emergency)
- Air entrainment valve = allows pt to breathe air from atmosphere
- Reservoir bag
Nitrous oxide/oxygen pre-op instructions?
Light meal
Take routine medicines as usual
Children must be accompanied to and from their appt by a competent adult
Do not bring other children
Can cause dizziness /nausea/ headaches at higher doses
Steps of inhalation sedation?
Safety checks, consent, check escort
Introduce to child (happy gas)
Start O2 and turn up flow rate (5-6L/min)
Fit mask and encourage nose breathing
Titrate N20 - 10% per min to 30% and then 5% per min until sedation
Hypnotic suggestion, clinical monitoring
100% O2 minimum of 3 mins to recover
