inhalation sedation Flashcards by Yusra Khan

why do we need sedation

Due to dental anxiety
- Linked to poor oral health and quality of life, poor dental attendance, poor compliance with prevention
  This anxiety can be passed onto children

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define conscious sedation

a technique in where a drug or drugs produces a state of CNS depression allowing tx to be carried out but verbal contact is maintained

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give some properties of a sedative agent

Safe - wide margin of safety, no adverse reactions
Simple - easy to admin
Rapid action - rapid onset and recovery
Anxiolytic
Analgesic
Acceptability
Compatibility - minimum interaction with other drugs
Cost - inexpensive

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what agent do we use for inhalation sedation

nitrous oxide

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what are the properties of nitrous oxide

Colourless
Slightly sweet odour
Stored as a liquid
1.5x density of room air - the NO will fall at ground level
Non flammable
Non irritant
Insoluble in blood

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what are the clinical effects of nitrous oxide

Depresses the CNS
- Relaxation
- Paraesthesia
- Sedation
- Analgesia
  Euphoria

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what effect does nitrous oxide have on the CVD i

it depresses the cardiovascular system and acts as a vasodilation

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what system does nitrous oxide effect

respiratory
CV system

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what is the mechanism of nitrous oxide

→ Inhalation of N2O
→ Raised partial pressure of N20 in lungs
→ Forced into blood stream across alveolar membrane
→ Carried to brain
Gas exchange within the brain

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what effects does nitrous oxide have

analgesic effect
anxiolytic effect

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what is diffusion hypoxia

Rapid elimination of NO from the blood
Value volumes of NO enter the lungs
Can displace O2 from the alveoli causing diffusion hypoxia

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how do we treat diffusion hypoxia

100% oxygen for 3 minutes

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what issues does long term use of No cause

Haematological effects
Neurological
Malignancy
Reproductive
Liver and kidney

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how do we limit exposure of nitrous oxide to staff

active scavenging
Exposure limit of 100ppm for an average 8 hour period

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what are the indications of inhalation sedation

mild to moderate dental anxiety
gag reflex
traumatic procedures
medically compromised patients
prior to IV sedation

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what are the contraindications of inhalation sedation

URTI
blocked nose
chronic respiratory infections
pregnancy
pre cooperative children
ocular surgery
methroeate and bleomycin

what are the contraindications of inhalation sedation

URTI
blocked nose
chronic respiratory infections
pregnancy
pre cooperative children
ocular surgery
methrotrexate and bleomycin

why are there adverse effects of long term nitrous oxide use

due to oxidation of the vitamin B12 which reduces the activity of methionine synthetase which impairs DNA synthesis

why is inhalation sedation contraindicated in methotrexate

can effect folate metabolism

why is bleomycin contraindicated

respiratory failure risk if given oxygen at 25%

what are the advantages of inhalation sedation

→ Simple, non invasive
→ Fast onset and recovery
→ Can regulate depth of sedation - in A&E Entonox is 50% NO and 50% O2 and cannot be titrated
→ Minimal effect on cardio- respiratory system
→ Minimal interaction with other drugs
Easily reversed with 100% o2

what are the disadvantages of inhalation sedation

→ Nasal mask not always accepted - difficult when treating the central incisors in place
→ Nasal hood can interfere with tx
→ Degree of patient compliance is required
→ Need continuous NO delivery
→ Cost of equipment
NO pollution

what are the safety features of nitrous oxide canisters

pin index system- connected system and stand alone system
minimum oxygen level- is 30%
oxygen flush- delivers 100% of oxygen in an emergency
oxygen fail safe- ensures that 100% Nitrous oxide cannot be delivered
reservoir bag- monitors the patients breathing
air entrapment valve- allows atmospheric air in the system if the gasses run out
air scavenging

what patient preparation do we need to carry out

atient selection is essential
→ Show them nasal mask
→ Consent prior to appointment and the parent can give consent for the child
For both the dental treatment and the sedation procedure
Written information given in advance

what is the pre sedation assessment

→ Full medical history → Prescribed and non prescribed drugs → Known allergies → BMI → ASA status → Dental history → Anxiety assessment → Sedation and GA history → Social history - escort, dependants, pregnancy → Nasal and airway patency → Dental treatment plan including radiographs → The selection conscious sedation technique and justification → Patient requirements

what are pre operative instructions that we should give to the patient

→ Light meal 2 hours before appointment → No alcohol 24 hours before → Children to be accompanied with a responsible adult → Transport home in car/taxi → Avoid bikes, trampolines, machinery Children supervised by adult - an adult does not need an escort unless indications such as mobility issues

how do we administer inhalation sedation

→ Fitting the appropriate size mask → Start off in a supine/semi supine positioning · Start with 100% oxygen and adjust flow rate of 4-6L/minute · Reservoir bag should expand with every breath · After a few minutes titrate N2O in 10% increments per minute · Above 30% N2O then give in 5% increments · Semi hypnotic suggestion, distraction and reassurance throughout · Encourage breathing through nose and minimise talking One happy with sedation, commence treatment

what are signs of adequate sedation

· Relaxed · Warm feeling · Tingling in hands and feet · Lethargic · Dreamy · Reduced gag reflex · Response to questions Vital signs and reflexes intact

how do we monitor the patient

· Level of consciousness · Airway patency · Respiration · Skin colour It is not required for blood pressure and pulse oximetry to be taken, but it can be advised in patients who have cardiovascular disease

what are some reasons we have ineffective technique for inhalation sedation

· Nasal obstruction · Mouth breathing · Ineffective seal around nasal mask · Patient resisting effects- due to anxiety Faulty equipment

what are some signs of over sedation

Complain of headache or nausea Squinting eyes Manage this by Reducing N2O by 5-10% Reassure patient Monitor If recover we can continue If not then postpone tx

how do we recover the patient

· Reduce n2o to 0 · Give 100% oxygen and breathe for more than 3 minutes - to avoid the risk of diffusion hypoxia · Remove nasal mask · Sit upright · Ask if they are dizzy or nauseous · Check they can walk And post op instructions for the tx as well as sedation

what do we need to record in the sedation record

· Dose · Route · Time of admin of n2o · Details of clinical monitoring · Personnel present · Dental tx provided · Patient reaction, sedation score(hoops score? 0-6)and success of sedation Time of discharge