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My BDS4 > Sedation - Intravenous > Flashcards

Sedation - Intravenous Flashcards

1
Q

Define conscious sedation

A

A technique in which the use of a drug or drugs produces a state of depression of the central nervous system enabling treatment to be carried out, but during which verbal contact with the patient is maintained throughout the period of sedation.
The drugs and techniques used to provide conscious sedation for dental treatment should carry a margin of safety wide enough to render unintended loss of consciousness
The level of sedation must be such that the patient remains conscious, retains protective reflexes, and is able to understand and respond to verbal commands. “Deep sedation” in which these criteria are not fulfilled must be regarded as general anaesthesia.
In the case of patients who are unable to respond to verbal contact even when fully conscious the normal method of communicating with them must be maintained

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2
Q

What are the medical indications for IV sedation? (8)

A
  1. Conditions aggravated by the stress of dental treatment:
    • Ischaemic heart disease
    • Hypertension
    • Asthma
    • Epilepsy
    • Psychosomatic illness (somatoform disorders)
    • Misc conditions that are made worse by stress- Ulcerative colitis, Crohn’s disease etc
  2. Conditions which affect cooperation – controversial (sedation doesn’t make a personal totally cooperative, can actually make them more uncooperative)
    • Mild to moderate movement or learning difficulties
    • Spasticity disorders = Parkinson’s disease
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3
Q

What are the psychosocial indications for IV sedation? (4)

A

• Phobias:
– Things in mouth
– Dental Procedures
– Needles
– Drills

• Gagging – more useful with inhalation sedation

• Persistent fainting
• Idiosyncrasy to LA (fainting)

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4
Q

What are the dental indications for (IV) sedation? (3)

A

• Difficult or unpleasant procedures
- Surgical extraction of wisdom teeth
- Orthodontic extractions/exposures
- Implants

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5
Q

What are the medical contraindications for IV sedation? (10)

A
  • Severe or uncontrolled systemic disease
  • Severe mental or physical disability = are unable to communicate and understand what is involved
  • Severe psychiatric problems = are unable to communicate and understand what is involved
  • Narcolepsy = if px fall asleep and cannot communicate with dentist that fails as part of the conscious sedation criteria
  • Hypothyroidism
  • myasthenia gravis (muscle wasting disorder) = don’t want to relax already weakened muscles as it can affect breathing further

• Intracranial pathology (don’t want to interfere with alertness as this is how you monitor IC pathology)

• COPD – (controversial) as well controlled px would be fit enough

• Hepatic insufficiency – unable to metabolise the drug

• Pregnancy and lactation – sedate the foetus or drug enters the breast milk

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6
Q

What are the social contraindications for IV sedation? (5)

A
  • Unwilling: become more uncooperative
  • Uncooperative: become more uncooperative
  • Unaccompanied: have to be observed closely after treatment whilst drug is metabolised (different for inhalation)
  • Children: IV cannot be used on those under 12
  • Very old: IV cannot be used on these px
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7
Q

What are the dental contraindications for IV sedation? (4)

A
  • Procedure too difficult and cannot be done with LA alone = long procedure, sedation wears off and px becomes uncooperative
  • Procedure too long (same as above)
  • Spreading infection = Airway threatening or Limits LA
  • Procedure too traumatic (see first)
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8
Q

What ASA class is IV sedation in the dental setting compatible with?

A

ASA I or II

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9
Q

What are the advantages of sedation? (4)

A

• Decrease dentist stress/staff
• Decrease patient stress
(nicer environment)
• Fewer Medical Incidents
• More productive appointments

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10
Q

What are the disadvantages of sedation? (3)

A

• Training required
• Equipment required
• Recovery time and after care (relevant to IV sedation)

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11
Q

What are the ideal properties of an IV sedation agent? (9)

A

• Anxiolytic
• Sedation (also a side effect)
• Ease of administration
• Non-irritant
• Quick onset
• Quick recovery
• No side effects
• Amnesia (side effect but useful)
• Low cost

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12
Q

How do benzodiazepines work? (3)

A

Acts on receptors in CNS to enhance effect of GABA (gamma-amino butyric acid) which is an inhibitory neurotransmitter.

Prolongs time for receptor repolarisation

Benzodiazepines mimics effects of glycine on receptors

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13
Q

Where does GABA act? (2)

A

the cerebral cortex and motor circuits

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14
Q

Where does glycine act? (2)

A

acts in the brainstem and spinal cord

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15
Q

Describe the respiratory depressive effects of benzodiazepines? (5)

A
  • CNS depression
  • muscle relaxation
  • Decreases cerebral response to increased CO2 (primary drive for breathing)
  • Synergistic relationship with other CNS depressants to enhance the effects
  • increases respiratory depression in already compromised patients
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16
Q

Describe the cardiovascular effects of benzodiazepines? (2)

A
  • decreases BP by causing muscle relaxation decreasing vascular resistance
  • increases HR due baroreceptor reflex compensating for BP fall
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17
Q

What are the side effects of benzodiazepines? (4)

A

• Drug Interactions;
- Any other CNS depressants
- Erythromycin
- Antihistamines

• Tolerance
- Apparent when px uses/abuses in daily life or for a long period of time
= cannot give enough sedative to overcome the tolerance

• Dependence
- Apparent when px use/abuse in daily life or for a long period of time

• Sexual Fantasies
- increased dose = increased chances of it happending

18
Q

What is the gold standard drug used for IV sedation?

A

Midazolam (hypnovel)

19
Q

What drug class is midazolam?

A

Water soluble imidazobenzodiazepine

20
Q

What are the advantages of midazolam in IV sedation? (5)

A
  • Painless on injection
  • Only one preparation required 5mg/5ml
  • more rapid onset than diazepam
  • 2-3x more potent than diazepam
  • Elimination half-life = 90 to 150mins (short)
  • cheap
  • reliable
21
Q

How is midazolam metabolised?

A

• In liver

• Small amounts of extra-heaptic metabolism occurs in bowel = less affected by liver disease patients

22
Q

What cannula do we use for IV sedation?

A

In-dwelling

23
Q

What are the advantages of using an indwelling cannula? (4)

A
  • More secure
  • Teflon (part in the hand)
  • Rarely blocks
  • Comes in a range of sizes
24
Q

Why do we not use butterfly cannulas nowadays? (3)

A
  • made of metal (part in the hand)
  • clots and obstructs
  • easily dislodged
25
Q

What areas can cannulas be placed for IV sedation?

A
  1. Dorsum of hand (common)
  2. Antecubital fossa
26
Q

What are the advantages of using the dorsum of the hand for cannula placement? (2)

A
  • Accessible since large amount of veins available
  • superficial and visible
27
Q

What are the disadvantages of using the dorsum of the hand for cannula placement? (2)

A
  • poorly tethered = move when cannulating
  • affected by peripheral vasoconstriction so may need to warm up hand
28
Q

What are the disadvantages of using the antecubital fossa for cannula placement? (2)

A
  • more risky as the brachial artery and the median nerve lie there (keep lateral in the area to avoid)
  • canula less stable during movement
29
Q

What is the first choice area for cannula placement for IV sedation?

A

Dorsum of Hand

30
Q

List the patient instructions provided before the IV sedation visit (14)

A
  • Have a light meal 1-2 hours before sedation
  • Wear loose clothing
  • Avoid nail varnish and false nails (allows pulse oximeter to be placed)
  • Continue routine meds as normal (unless advised otherwise)
  • Don’t drink alcohol or take recreational drugs for 48 hours before and after.
  • Inform dentist if you are/think you are pregnant
  • Don’t breastfeed for 12 hours after sedation
  • No children allowed on the visit
  • Bring responsible and able-bodied escort > 18 years old
  • Sedation effects can last for up to 12 hours
  • Rest for remainder of the day and be supervised by a responsible adult
  • Eat and drink when comfortable but avoid very hot/cold foods
  • Don’t make any important decisions that day
  • Don’t drive, use heavy machinery for the remainder of that day.
31
Q

What emergency precautions are present during IV sedation? (3)

A

Monitor vital signs throughout

Have emergency drugs on hand - Flumazenil

Have Means of ventilation

32
Q

Describe midazolam administration during IV sedation.

A

initially provide a 2mg bolus and watch for the patients reaction for 1 full minute

then provide 1mg every 60 seconds until a suitable level of sedation is achieved (maximum is 7.5mg)

33
Q

How do we know when enough sedation has been achieved? (6)

A
  • Slurring and slowing of speech
  • Relaxed
  • Slightly slow response to commands
  • Willingness to accept treatment
  • Verrill’s sign = ptosis (drooping eyelids)
  • Eve’s sign = loss of motor coordination (put hands out to the side and try to touch the nose with the finger = nose missed)
34
Q

How long are patients kept after their last dose of midazolam?

A

60 mins recovery

35
Q

What do we assess before patient is discharged after IV sedation? (1)

A
  • Ensure patient can walk unaided
36
Q

In an emergency situation, how do we manage respiratory depression? (7)

A

Indicated from pulsoximeter – drop in oxygen saturation;

• Talk, shake, assess response to pain
• Head tilt, chin lift, jaw thrust = allows more air in
Encourage them to take deep breathes (observe for chest rising and falling)
• Provide oxygen 2l/min via nasal canulae – allows treatment to continue
• Increase to oxygen 5l/min via Hudson mask
• If all of the above fails - Provide flumazenil to reverse (have other emergency equipment present)
• Use ambu bag
• Use airways

37
Q

What preparation of flumazenil is used in an emergency?

A

500mcg in 5ml

38
Q

What doses of flumazenil is used in an emergency?

A

200mcg given initially
100 mcg every 60 seconds until a response in seen

39
Q

What is the half-life of flumazenil?

A

50mins (shorter than midazolam)

40
Q

What is the risk of using flumazenil as an emergency reversal drug?

A

rebound sedation
- flumazenil has a shorter half life so midazolam may still act after the fluzamemil wears off.

My BDS4 (57 decks)

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