inhalation sedation

Question 1

why do we need sedation

Answer 1

• 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

Question 2

define conscious sedation

Answer 2

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

Question 3

give some properties of a sedative agent

Answer 3

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

Question 4

what agent do we use for inhalation sedation

Answer 4

nitrous oxide

Question 5

what are the properties of nitrous oxide

Answer 5

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

Question 6

what are the clinical effects of nitrous oxide

Answer 6

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

Question 7

what effect does nitrous oxide have on the CVD i

Answer 7

it depresses the cardiovascular system and acts as a vasodilation

Question 8

what system does nitrous oxide effect

Answer 8

respiratory
CV system

Question 9

what is the mechanism of nitrous oxide

Answer 9

→ 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

Question 10

what effects does nitrous oxide have

Answer 10

analgesic effect
anxiolytic effect

Question 11

what is diffusion hypoxia

Answer 11

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

Question 12

how do we treat diffusion hypoxia

Answer 12

100% oxygen for 3 minutes

Question 13

what issues does long term use of No cause

Answer 13

Haematological effects
Neurological
Malignancy
Reproductive
Liver and kidney

Question 14

how do we limit exposure of nitrous oxide to staff

Answer 14

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

Question 15

what are the indications of inhalation sedation

Answer 15

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

Question 16

what are the contraindications of inhalation sedation

Answer 16

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

Question 17

what are the contraindications of inhalation sedation

Answer 17

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

Question 18

why are there adverse effects of long term nitrous oxide use

Answer 18

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

Question 19

why is inhalation sedation contraindicated in methotrexate

Answer 19

can effect folate metabolism

Question 20

why is bleomycin contraindicated

Answer 20

respiratory failure risk if given oxygen at 25%

Question 21

what are the advantages of inhalation sedation

Answer 21

→ 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

Question 22

what are the disadvantages of inhalation sedation

Answer 22

→ 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

Question 23

what are the safety features of nitrous oxide canisters

Answer 23

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

Question 24

what patient preparation do we need to carry out

Answer 24

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

Question 25

what is the pre sedation assessment

Answer 25

→ 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

Question 26

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

Answer 26

→ 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

Question 27

how do we administer inhalation sedation

Answer 27

→ 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

Question 28

what are signs of adequate sedation

Answer 28

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

Question 29

how do we monitor the patient

Answer 29

· 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

Question 30

what are some reasons we have ineffective technique for inhalation sedation

Answer 30

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

Question 31

what are some signs of over sedation

Answer 31

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

Question 32

how do we recover the patient

Answer 32

· 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

Question 33

what do we need to record in the sedation record

Answer 33

· 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