Inhalation Sedation 1 Flashcards
What is conscious sedation?
A technique using a drug/s to produce state of depression of the CNS enabling treatment to be carried out
If have conscious sedation what is maintained?
Protective reflex e.g swallow and verbal contact
Types of sedation techniques?
Inhalation IVS Transmucosal Oral Intramuscular
What drug is given for inhalation sedation?
Nitrous oxide/ oxygen - combination
What drug is given for IV sedation?
Midazolam
What can be used for transmural sedation?
Midazolam
What drugs can be used orally for sedation?
Temazepam, diazepam, midazolam
When is oral sedation useful?
Premedication
What is used for IM sedation?
Ketamine
What are some properties of nitrous oxide?
Volatile
Denser than air
Least potent anaesthetic gas
Poorly soluble - rapid onset and recovery
What is MAC
Minimal alveolar concentrate
Minimum [] to provide surgical anaesthesia for 50% population
What is MAC nitrous oxide?
104
Means can’t be provided alone to prevent feeling surgery
How does nitrous oxide work?
Inhaled into lungs via nasal mask
Travel down pressure gradient from alveolus into blood
Hardly metabolised as exhaled quicker
Excreted through lungs
Propertiies of nitrous oxide?
Analgesic
Mild anaesthetic
Hypnotic
Anxiolytic
How is nitrous oxide an anxiolytic?
Acts on central nervous system through interaction GABA
What are 4 stages anaesthesia?
- Analgesia
- Excitement
- Surgical analgesia
- Respiratory paralysis
What % of nitrous oxide to reach moderate sedation?
5-25% nitrous oxide
What % nitrous oxide produces dissociation sedation and alangesia?
20-55%
What happens in dissociation analgesia?
Susceptibel to suggestion
What % needs of nitrous oxide to provide total analgesia?
50-70%
What risk of providing high levels nitrous oxide?
Loss consciousness
What signs suggest adequate sedation?
Awake and relaxed In suggestive state Giggling Verbal response Maintain open mouth Reduced blink rate Spontaneous respiration
What signs suggest over sedation?
Hysterical laughter, tears Decreased co-operation Nausea Mouth closing Snoring Irrational response LOC
What are social indications of sedation?
Mild anxiety, needle phobia, gagging, fainting
Why is IHS good for people who faint?
Continuous oxygen flow prevent faint
Medical indications for sedation?
Conditions aggravated by stress
Continuous oxygen delivery beneficial - asthma
Conditions affecting co-operation
Benefit IHS?
Avoid GA
Social contraindications of IHS?
Severe anxiety
Claustrophobia
No consent or escort
Medical contraindications iHS?
Blocked nose URTI Unable nose-breah Recent eye/ middle ear/ sinus surgery Pregnancy - even if only escorting child myasthenia gravis
What medical conditions are contraindication to IHS?
Myasthenia gravis
Bleomycin therapy
What dental procedures are contraindicated to IHS?
Tx upper anterior teeth - lip become trapped
Name safety features on IHS?
Pin index - can't plug wrong gas canisters Scavenging Nasal mask and tubing Oxygen failsafe Max 70% nitrous oxide Oxygen flush Reservoir
Purpose of scavenging?
Important HCP don’t inhale gas, this is provided through nasal mask
What is oxygen fail safe?
If cuts off nitrous oxide also cut so never give 100% nitrous oxide
What is max amount nitrous oxide can be given via safety features?
70%
When is oxygen flush used?
High rate oxygen delivered to bring pt out of sedation - not pleasant
What does reservoir bag do?
Monitor pt breathing
What are pre-op instructions for IHS?
Have light meal
Take routine medications
Child must be accompanied
Aware may cause dizziness/ nausea/ headache
How long must oxygen be left after IHS?
3 mins to prevent diffusion hypoxia
What happens if turned off w/o oxygen?
Nitrous oxide moves through pressure gradient quicker oxygen- lungs flooded with nitrous oxide and could become hypoxic (theoretical)
What does COSHH recommend to reducing exposure?
Active scavenging - 45L/min
Passive scavenging - floor level
Supplementary high vol aspiration
Other ways to reduce risk of exposure?
Rubber dam
Well-fitting mask
Good technique
What are categories of occupational hazards?
Reproductive
Haematological
Neurological
What are reproductive occupations hazards?
Risk miscarriage
Reduced fertility
Poss risk teratogenesis
What are haematological risks?
Impair DNA synthesis
Oxidisation B12
Pernicious anaemia
Neurological risks of iHS?
Peripheral neuropathy