Sedation Flashcards

1
Q

According to the 2009 Adult Dental Health Survey, what percentage of dentate adults are anxious about dental treatment?

A

48% of dentate adults are anxious about dental treatment.

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2
Q

What are the levels of dental anxiety found in the 2009 Adult Dental Health Survey?

A

36% of people experience moderate anxiety, while 12% have extreme fear.

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3
Q

What are some general aetiological factors contributing to dental anxiety?

A
  • General anxiety
    -age (younger people tend to be more anxious)
  • gender (women more anxious than men)
  • socio-economic status (lower = more anxious)
  • trauma
  • family/peer influence.
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4
Q

Which dental factors can contribute to dental anxiety?

A
  • Fear of needles
  • the sound of the drill
  • the dentist’s general manner
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5
Q

How does dental anxiety commonly present physiologically?

A
  • increased heart rate
  • hypertension
  • changes in respiratory rate
  • vasoconstriction
  • sweating
  • trembling
  • weakness/fatigue
  • sometimes aggression.
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6
Q

What are some psychological signs of dental anxiety?

A
  • impending danger
  • powerlessness
  • tension.
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7
Q

What are key management strategies for dental anxiety?

A

Management strategies include the ‘Tell Show Do’ technique
- modelling
- relaxation techniques
- changing perceptions (e.g., distraction)
- providing control (e.g., a stop signal)
- systematic desensitisation
- offering explanations
- providing reassurance
- showing empathy
- distraction methods
- time structuring

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8
Q

What are the two stages of gagging?

A

1 - Retching – an initial process of attempting to eliminate noxious substances from the stomach.
2 - Gagging – a protective reflex to stop material from entering the mouth and oropharynx.

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9
Q

What are the two classifications of gagging?

A

1 - Psychogenic – initiated by higher centres of brain, may occur without direct physical contact.
2 - Somatic – caused by direct contact that stimulates sensory nerves.

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10
Q

What is the severity of gagging at Stage 1?

A

Stage 1 is Normal – the gag reflex occurs naturally without interfering with dental procedures.

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11
Q

What characterises Stage 2 gagging severity?

A

Stage 2 is Mild – the patient usually regains control over the gag reflex.

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12
Q

Describe the characteristics of Stage 3 gagging severity.

A

Stage 3 is Moderate – gagging occurs regularly during dental procedures, the patient cannot regain control, and prevention measures that influence the treatment plan are necessary.

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13
Q

What is the severity of gagging at Stage 4?

A

Stage 4 is Severe – gagging occurs during all dental procedures and significantly impacts the treatment plan.

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14
Q

How is Stage 5 gagging defined?

A

Stage 5 is Very Severe – gagging occurs easily without any triggers, impacts attendance and behaviour, and greatly affects the treatment plan.

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15
Q

What types of special needs patients might experience gagging issues?

A

Patients with behavioural or medical conditions, such as cerebral palsy or Parkinson’s disease, may experience gagging issues.

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16
Q

What tool can be used to assess anxiety in gagging patients?

A

The Modified Dental Anxiety Scale can be used to assess anxiety in gagging patients.

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17
Q

What are the non-pharmacological management strategies for gagging patients?

A
  • behavioral management (with or without local anesthesia)
  • iatrosedation
  • hypnosis
  • cognitive-behavioral therapy (CBT)
  • time structuring (e.g., setting time limits like “I will drill for 10 seconds”).
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18
Q

What are some pharmacological methods for managing gagging?

A
  • Premedication with temazepam
  • Inhalation sedation
  • Intravenous sedation (midazolam)
  • Oral sedation
  • Transmucosal sedation
  • Intramuscular sedation
  • Rectal sedation
  • General anesthesia (GA)
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19
Q

What are the main indications for using general anaesthetic in dental treatment?

A
  • Very young patients
  • Uncooperative patients or those who failed conscious sedation
  • Patients requiring unpleasant or complex procedures
  • Patients with learning difficulties
  • ASA groups 3 and 4 needing specialist care in hospital
  • Patients with extreme anxiety
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20
Q

Why might general anaesthetic be chosen for very young patients?

A

GA is used when very young patients are uncooperative or cannot manage dental procedures with conscious sedation.

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21
Q

What ASA groups indicate a need for specialist care under general anaesthesia?

A

ASA groups 3 and 4, who have more significant medical risks, may require GA in a hospital setting for specialist care.

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22
Q

What are some disadvantages of general anaesthetic?

A
  • Greatest potential risk to patients
  • Most expensive method of treatment
  • Requires an accredited anaesthetist and a well-trained team
  • Requires high-standard equipment that is regularly serviced
  • GA facilities are subject to inspection and regulation
  • The team must have advanced life support skills
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23
Q

Why is general anaesthetic considered the most expensive method of dental treatment?

A

GA is the most expensive because it requires specialised staff (accredited anaesthetist), high-standard equipment, and strict regulatory oversight, all of which increase costs.

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24
Q

What is the definition of conscious sedation?

A

Conscious sedation is “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, but during which verbal contact is maintained throughout. The drugs and techniques used should carry a wide margin of safety to render loss of consciousness unlikely.”

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25
Q

What are key safety features of conscious sedation?

A
  • The patient remains conscious with communication maintained
  • The patient can spontaneously maintain their airway, and protective reflexes are intact
  • Minimal cardio-respiratory depression
  • It is reversible
  • Strict guidelines ensure patient safety
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26
Q

What are the main indications for conscious sedation?

A
  • Anxious patients
  • Patients with a gagging reflex
  • Persistent fainting
  • Medically compromised patients
  • Systemic diseases exacerbated by stress (e.g., ischemic heart disease, hypertension, asthma)
  • Movement disorders (e.g., Parkinson’s)
  • Mild/moderate mental or physical disabilities
  • For unpleasant or “nasty” procedures
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27
Q

Name some systemic diseases that might be exacerbated by stress and are indications for conscious sedation.

A

Systemic diseases include ischaemic heart disease (IHD), hypertension, and asthma.

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28
Q

What are some contraindications for conscious sedation?

A
  • Social issues (patient unwilling or uncooperative)
  • Severe or uncontrolled systemic disease
  • Severe psychiatric problems
  • Hepatic insufficiency
  • Pregnancy
  • Procedures that are too long or too traumatic
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29
Q

What qualities define the ideal sedative?

A
  • safe
  • simple
  • has a rapid onset and recovery
  • provides analgesia
  • possibly causes amnesia
  • Is acceptable to the patient
  • Compatible with other systemic drugs
  • Has no side effects
  • Is reversible
  • Low cost
  • Easy to titrate
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30
Q

Why is hepatic insufficiency a contraindication for conscious sedation?

A

Hepatic insufficiency may impair drug metabolism, making sedation unsafe or unpredictable.

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31
Q

What makes conscious sedation preferable in terms of airway and reflex maintenance?

A

During conscious sedation, the patient maintains their own airway and protective reflexes remain intact, making it a safer option compared to general anaesthesia.

32
Q

What are the main advantages of inhalation sedation?

A
  • Safe
  • Minimal effect on cough and swallow reflexes
  • Rapid onset
  • Easily titrated
  • Wide margin of safety
  • Large “window” of sedation
  • Fast, complete recovery (escort not needed)
  • Non-invasive
  • Analgesic and anxiolytic
  • Suitable for all age groups
  • Few contraindications
  • Creates a feeling of well-being and relaxation
33
Q

What are some disadvantages of inhalation sedation?

A
  • Expensive equipment
  • Need for scavenging
  • Technique sensitive (patient and dentist selection)
  • Patient perception of equipment
  • Intrusion of nasal mask on operating field (especially if labial flap needs raising for extraction/bone)
  • Bulky apparatus may hinder the operator
  • Risk of addiction
  • Chronic exposure risks
34
Q

What are the main indications for inhalation sedation?

A
  • Anxiety in adults and children
  • Gagging or retching
  • Needle phobia
  • Medical issues (benzodiazepine allergy, cardiovascular disease, respiratory disease, high BMI)
35
Q

Name some contraindications for inhalation sedation.

A
  • Poor patient cooperation or understanding
  • Pregnancy (Nitrous Oxide can damage the foetus)
  • Claustrophobia
  • Certain dental procedures (e.g., apicectomy)
  • Inability to breathe through the nose
  • Tuberculosis or acute pulmonary conditions
  • Psychiatric disease
36
Q

What are the key properties of oxygen used in inhalation sedation?

A

Oxygen is stored in a black cylinder, should be at 137 bar/2000 psi, and is colourless, odorless, non-flammable but supports combustion.

37
Q

What are the properties of nitrous oxide used in inhalation sedation?

A

Nitrous oxide is stored in a blue cylinder (reads 0 when empty), must be weighed to determine the amount of compressed liquid left, is colourless, sweet-smelling, non-irritant to pulmonary epithelium, non-allergenic, non-flammable but supports combustion, 1.5x denser than air, carried in physical solution, and does not enter metabolic pathways.

38
Q

What are the biochemical properties of nitrous oxide (N2O)?

A
  • Relatively insoluble in blood (rapid uptake and recovery)
  • Concentration effect: Higher concentration inhaled = rapid increase in arterial tension
  • Second gas effect: Rapid N2O intake leads to quicker uptake of other gases
  • Not very potent (wide margin of safety)
  • Central analgesic (requires 20% N2O for analgesic effect)
  • Enough for painless injection, but not strong enough for treatment without local anaesthesia
39
Q

Describe the pharmacodynamics of nitrous oxide.

A
  • Inhalation begins, increasing the partial pressure in the lungs
  • N2O diffuses across the alveolar membrane into the bloodstream (primary saturation complete within 3-5 minutes)
  • N2O is carried to the brain and gaseous exchange occurs with brain tissue
  • Clinical response occurs within 3-4 minutes
  • treatment carried out with LA
  • After treatment, 100% oxygen is delivered to reduce N2O partial pressure in the alveoli
  • N2O diffuses back into the lungs and is exhaled, (not metabolised but excreted unchanged through lungs)
40
Q

What are the signs and symptoms of Plane 1 (Moderate Sedation: 5-25%) in Guedel’s stages of anaesthetic?

A

Signs:
- Patient looks awake
- Responds clearly
- Retains open mouth
- Gag reflex slightly reduced

Symptoms:
- Feels relaxed
- Tingling in fingers, toes, cheeks, tongue
- Feeling of well-being

41
Q

What are the signs and symptoms of Plane 2 (Dissociation: 20-55%) in Guedel’s stages of anaesthetic?

A

Signs:
- Dreamy, faraway look
- Slow responses, slurred speech
- Reduced gag reflex
- Marked analgesia
- Mouth open
Symptoms:
- Feels light or heavy and warm
- Marked paraesthesia
- May giggle
- Very suggestible

42
Q

What are the signs and symptoms of Plane 3 (Total Analgesia: >55%) in Guedel’s stages of anaesthetic?

A

Signs:
- Verbal contact difficult
- Loss of mouth open
- Loss of cooperation

Symptoms:
- Feels disoriented, may experience nausea and headaches
- Total analgesia
- Feeling of doom and gloom
- Loss of consciousness may occur

43
Q

What are the cardiovascular (CVS) and respiratory effects of nitrous oxide (N2O)?

A

CVS: Minimal effects
Respiratory: Some changes, risk of diffusion hypoxia

44
Q

How does nitrous oxide (N2O) affect the nervous system and reproductive system?

A

Nervous System: Mild CNS depression, minimal effect on memory
Reproductive System: Increased miscarriage rate, decreased conception and fertility, N2O crosses the placenta

45
Q

What does N2O not effect

A

GIT / liver / kidney

46
Q

What is diffusion hypoxia and how can it be prevented?

A

Diffusion hypoxia occurs when N2O is ceased, there is rapid diffusion of large quantities of N2O from blood into alveoli which produces significant dilution of O2 present in alveolus
Symptoms: Headaches, nausea, lethargy
Prevention: Deliver 100% oxygen for at least 2 minutes at the start of recovery

47
Q

What safety features prevent incorrect gas attachment in nitrous oxide equipment?

A

Colour-coded system: N2O is blue, O2 is white
PIN index system: Pipes can only connect to the correct attachment
Oxygen fail-safe: N2O supply cuts off if O2 supply fails

48
Q

What is the purpose of the reservoir bag and one-way valve in nitrous oxide sedation equipment?

A

Reservoir bag: Patient inhales from the bag, ensuring gas availability
One-way valve: Prevents re-breathing of exhaled gases

49
Q

How can you check if the oxygen fail-safe mechanism in nitrous oxide equipment is functioning correctly?

A
  • Set the flow rate at 8L/min
  • Set N2O at 50%
  • Remove the oxygen tube: both silver balls should fall, indicating the system is working
50
Q

what are 4 other safety features

A
  • air entrainment valve
  • minimal oxygen delivery is 30% (impossible to give 100% N2O)
  • oxygen flush - high flow oxygen (30L/min) in event of emergency
  • automatic gas mixing
51
Q

What is scavenging and what are the two types of scavenging systems used in nitrous oxide sedation?

A

Scavenging – sucks waste gases from nasal mask so they do not pollute immediate atmosphere
Active: Removal of waste gases via pipes
Passive: Relies on the patient’s expiratory effort to expel gases

52
Q

what are complications of inhalation sedation?

A
  • undersedation
  • oversedation
  • diffusion hypoxia
  • chronic hypoxia
  • chronic exposure
  • recreational use
53
Q

What are the causes of undersedation during nitrous oxide sedation?

A
  • Nasal obstruction
  • Mouth breathing
  • Mask not sealed properly
  • Extreme anxiety
  • Patient talking during sedation
54
Q

What are the signs and symptoms of undersedation?

A
  • Patient not relaxed
  • Unable to start treatment due to lack of sedation effect
55
Q

What are the causes of oversedation during nitrous oxide sedation?

A

Oversedation is caused by administering too high a percentage of nitrous oxide (N2O).

56
Q

What are the signs and symptoms of oversedation during nitrous oxide sedation?

A
  • Nausea
  • Headache
  • Vomiting
  • Persistent mouth closing
  • Loss of consciousness
57
Q

How should oversedation during nitrous oxide sedation be managed?

A

Reduce N2O by 5-10%
Reassure the patient
Monitor the patient’s response

58
Q

What is diffusion hypoxia, and how can it be prevented during nitrous oxide sedation?

A

Diffusion hypoxia occurs when large quantities of N2O rapidly diffuse into the alveoli, diluting the oxygen.
Prevention: Administer 100% oxygen for 2 minutes or until the patient has fully recovered.

59
Q

What is the recommended Occupational Exposure Standard (OES) for nitrous oxide, and why is it important for staff?

A

The recommended OES for nitrous oxide is 100 ppm (parts per million) over an 8-hour time-weighted average (TWA). This limit is important to prevent chronic exposure risks for staff.

60
Q

What is a non-medical risk associated with nitrous oxide, and why is it concerning?

A

Recreational use of nitrous oxide is a concern due to potential health risks, including addiction and long-term neurological damage.

61
Q

What are the advantages of intravenous sedation?

A
  • Anxiolytic
  • Easily titrated
  • Fast onset (~45-minute working time)
  • Short-acting, with acceptable recovery within 1 hour
  • Amnesic
  • Reversible
  • Predictable
  • Anticonvulsant and muscle relaxant properties
  • Reduced gagging
62
Q

What are the disadvantages of intravenous sedation?

A
  • Respiratory depressant (risk of stopping breathing if administered too quickly)
  • Invasive (requires cannulation)
  • Cannulation may be difficult for needle-phobic patients
  • Requires escort after treatment
  • Not suitable for all ages
  • Amnesic effect
  • Does not cure anxiety
  • Requires specialist equipment and team
63
Q

What are the indications for using intravenous sedation?

A
  • Anxiety
  • Gagging
  • Unpleasant or traumatic procedures
  • Medical conditions, such as mild conditions aggravated by dental treatment stress or movement disorders
64
Q

What are the contraindications for intravenous sedation?

A
  • Benzodiazepine allergy or addiction
  • medical conditions: Significant cardiovascular pathology, Hepatic or renal disease
  • Gross obesity
  • Pregnancy
  • Myasthenia gravis
65
Q

What are the clinical effects of intravenous sedation?

A
  • Anxiolysis
  • Anticonvulsant
  • Slight sedation
  • Reduced attention
  • Amnesia
  • Intense sedation
  • Muscle relaxation
  • Anaesthesia
66
Q

What is the difference between pharmacodynamics and pharmacokinetics in IV sedation?

A

Pharmacodynamics: What the drug does to the body.
Pharmacokinetics: What the body does to the drug.

67
Q

Which form of injected drug is effective and ineffective in IV sedation?

A
  • Free and unionised = effective
  • Free but ionised = ineffective
  • Bound to plasma proteins = ineffective
68
Q

How do benzodiazepines like midazolam produce sedation?

A

Benzodiazepines bind to receptors close to GABA receptors, allowing more chloride ions into the cell, making the membrane hyperstable and less likely to fire, thus reducing sensory stimuli reaching the brain and producing sedation.

69
Q
A
70
Q
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71
Q

What factors affect the onset of IV sedation?

A
  • Total dose
  • Duration of injection
  • Cardiac output
  • Circulating blood volume
72
Q

What factors influence recovery from IV sedation?

A
  • Redistribution (unionised lipid soluble unbound ddrug passes into body tissues - mainly fat) → time taken for serum conc to fall by 50% = alpha half life
  • Metabolism
  • Excretion
73
Q

what is elimination

A
  • midazolam metabolised in liver and excreted by kidneys
  • time taken to remove half the drug completely = beta half life
74
Q

What are the side effects of IV sedation

A
  • respiratory depression →
    dose and rate related, peak onset at 3mins, persists for up to 2hrs, more pronounced in pts with pre-existing disease and elderly
  • increased heart rate → as vascular resistance decreases, BP increases →
    heart rate increases to compensate
  • sexual fantasy
75
Q

What is midazolam and its key properties in IV sedation?

A

Midazolam is a benzodiazepine:

  • Available mainly in 5mg/5ml, or 10mg/5ml, 10mg/2ml ampoules which are harder to titrate
  • Lipid-soluble at physiological pH (lipophilic)
  • Onset of action in 1 arm-brain circulation ~30 seconds
  • Elimination half-life: 1.7-2.3 hours
  • Hydroxylated in liver to active metabolites and excreted by kidney
  • 97% protein-bound
  • Clinical working time: ~45 minutes
76
Q

What is flumazenil and when is it used?

A

Flumazenil: A benzodiazepine antagonist (500mcg in 5ml ampoules) used in emergencies to reverse the effects of benzodiazepines.
Note: 3 ampoules should always be available in the surgery (2 for the patient, 1 as a backup).