SEDATION Flashcards
What is conscious sedation?
This is sedation where the patient is still concious, retains protective reflexes and is able to understand and respond to verbal commands during treatment.
List some medical indications for sedation.
- Medical conditions that are worsened by stress:
- Ischaemic heart disease
- Hypertension
- Asthma
- Epilepsy
- Psychosomatic illness
- Medical conditions that affect co-operation
- Mild/moderate movement or learning difficulties
- Spasticity disorders
- Parkinsons
- Psychosocial
- Phobias (Dentist/drills/needles/Gagging)
List some dental indications for sedation.
Difficult or unpleasant procedures
Surgical extraction of wisdom teeth
Orthodontic extractions
Implants.
List some contraindications for sedation
- Severe or uncontrolled systemic disease
- Severe mental or physical disability (unable to communicate or understand)
- Severe psychiatric problems
- Respiratory depression.
- Narcolepsy- condition where you suddenly fall asleep (loss of communication under sedation)
- Myasthenia gravis- Weak muscles so greater danger of airway collaspe under sedation.
List some contraindications of IV sedation.
Intracranial pathology- You need to monitor how alert the patient is and sedation interferes with this.
Myasthenia gravis.
Hepatic insufficency- inabililty to metabolise the drug.
Pregnancy and lactation- drug will pass to the baby.
List some contraindications of inhalational sedation.
Blocked nose
COPD
Pregnancy
Enlarged tonsils or adenoids- they will be natural mouth breathers.
List some dental contraindications of sedation:
- Spreading infection.
- Procedure too long (sedation will wear off)
- Procedure too traumatic.
What is ASA 1 classification .
Normal Healthy patient (non smoker/minimal alcohol)
What is ASA 2 classification .
Mild systemic disease or well controlled (e.g. current smoker/well controlled epilepsy)
What is ASA 3 classification .
Severe systemic disease which limits activity but is not incapacitating.
SWhat is ASA 4 classification .
Severe systemic disease that is a constant threat to life.
What ASA classifications can be treated with sedation without an aesthetist.
ASA 1 and 2
What social history are we assessing before Sedation/ GA
- Occupation- are they able to work the day after sedation.
- Responsibilities- are there other people they are responsible for
- Escort-Who can accompany them to the appointment
- Transport- how will they get to and from the appointment
- Alcohol intake- don’t want them drinking when they come in for sedation.
- Smoking- do they smoke?
- Fears- phobia/anxiety/
How do most drugs affect medazolam?
They increase the sedative effect.
What is a pharmacodynamic interaction and which drugs do this?
Interactions between drugs which have similar or antagonist pharmacological effects or side effects
Antidepressants and benzodiazepines.
Antihypertensives and benzodiazepines.
What is a pharmacokinetic interaction ?
When one drug alters the absorption/distribution/metabolism/excretion of another.
Why is it vital to know about any of the patient’s respiratory problems .
As sedation can cause respiratory depression.
What vital signs do we check when assessing a patient for Sedation?
- HR
- BP
- O2 Saturation
- BMI
What is the BMI cutoff for sedation?
35
What is an underweight BMI?
<18.5
What BMI means the patient is a healthy weight.
18.5-24.9
What BMI means the patient is obese?
>30
What BMI means the patient is overweight.
25-29.9
Why do we avoid overcomplicated treatments for sedation treatment plans?
As the sedation will only last 45 minutes.
How do Benzodiazepines work?
Acts on receptors in CNS to enhance the effect of GABA. This prolongs the time for receptor repolarisation of the cerebral cortex and motor circuits.
i.e. the longer to repolarise- so takes longer to register the pain.
Describe the effects of benzodiazepines on respiration.
Respiratory depression:
- CNS depression and muscle relaxation.
- Decrease in cerebral response to increased O2 (Primary driver for breathing)
- Synergistic relationship with other CNS depressants.
- Increased respiratory depression in already compromised patients.
Describe the effects of benzodiazepines on Cardiovascular.
Muscle relaxation decreases vascular resistance which decreases the BP.
Baroreceptor reflex compensates for the BP fall by increasing the HR.
What drugs do benzodiazepines interact with?
CNS depressants.
Erythromycin
Antihistamines
Antihypertensive
Antidepressants.
What can we use for IV sedation and why?
Midazolam-
- A water soluble drug which makes it painless on injection.
- It has rapid onsent (2-3 times more potent than diazepam)
- Short elimination half life (less working time but safer as patients are sedated for less time)
- Metabolised in the liver.
Porphylol
How many people are needed to sedate a patient?
2 trained people in the room at all times and a 3rd person who acts as a runner.
How do we adminster IV sedation
We use an indwelling canula (as it need sto stay in while we carry out the treatmenent- this might be needed for emergency treatment)
What are the two most used sites for canulation?
Dorsum of the hand
Cubital fossa.
Discuss the advantages & disadvantages of the Dorsum of the hand for cannulation.
Adv
- good access
- No nearby arteries
- No nearby nerves
- No joints .
Disadv-
- Smaller veins
- Suceptible to cold and anxiety
- Veins are mobile
- Veins are more painful.
Discuss the advantages & disadvantages of the cubital fossa for cannulation.
Adv-
big well tethered veins
less painful
Less venoconstruction
Disadv-
More difficult access
Risk of nerve damage or potential intraarterial injection.
What are the pre-operative instructions for sedation:
Light meal & hydrate(don’t eat or drink 2 hours before hand)
Don’t use recreational drugs or drink alcohol 48 hours before.
Don’t smoke for 24 hours prior.
Avoid any tablets that make you sleepy (sleeping tablets/hayfever)
Must be accompanied by a responsible adult who will stay in the building while treatment happens.
Do not drive to appointment.
All nail varnish and false nails needs removed (interferes with montitoring equipment)
Remove any facial piercings
EMLA cream- can recommend this to the patient.
What is EMLA cream?
This is a numbing cream we prescribe to patients who are wary of recieving Canulation and they should apply it on the dorsum of each hand 60 minutes before cannulation.
How do we monitor a patient during IV sedation.
Use a pulse oximeter to monitor changes in O2 Saturation
BP measurement every 5-10 minutes/
Describe the procedure for IV sedation
- Pulse oximeter and BP monitor on.
- Complete pre-operative measurements
- Cannulate the patient
- Adminster drug
- 2mg bolus and watch for 1 minute to see how the patient responds.
- 1mg increments every 60s
- 7.5mg is considered the maximum safe dosage.
What are the signs that we have achieved sedation?
Speech becomes slurred & slower.
Relaxed
Delayed response to commands
Willingness to accept treatment
Verrilli’s sign ptsosis -Eyes drooping.
Eve’s sign- loss of motor co-ordination (get the pt to close their eyes and try and touch their nose with their finger.
What are the post operative instructions for IV sedation
Don’t go to work the next day.
Don’t make any important descisions
Escort should take patient straight home
Avoid public transport
Patient should not go out alone
Do not be in charge of any dependents for 24hours
Don’t drink or smoke.
If a nursing mother- don’t breast feed for 24hours after treatment.
Don’t do anything strenous for 24 hours
What drug can be used to reverse sedation.
How do we use it
And what is there risk of?
Flumazenil
A 500microgram in 5ml preparation is used.
Providing 200 micrograms then 100 increments every 60 seconds until a response is seen.
Risk of rebound sedation- as it has a shorter half life than midazolam
What should we check before discharging a patient after iv sedation?
- Should be 60 minutes since their last increment
- Canula is removed
- Can the patient walk unaided.
- Has the escort been given the post-operative instructions.
What is contained in a blue tank?
Nitrous oxide .
What is contained in the black tank with the white top?
Oxygen
What is this and what does it do?
Flow control meter- this measures flow rates and allows you to control the mixture.
What is this and what is it’s function?
2-3L bag which is used to monitor respiration.
It should visibily move when the patient is breathing in and out.
What is this and what is it used for?
These are the gas delivery hoses.
1 hose delivers fresh gas from the machine and 1 hose delivers waste gas to the scavenging system.
What is the scavenging system?
This is the active scavenging of waste gases (small negative pressure) which ensures the gases are sucked away.
List some signs of adequate sedation.
- Feeling relaxed
- Patient awake
- Reduced blink rate
- Laryngeal reflexes unaffected
- Vital signs unaffected
- Gag reflex obtunded
- Mouth opens on request
- Decreased reaction to painful stimuli
- Decrease in spontaneous movements
- Verbal contact maintained.
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List some symptoms of adequate sedation.
- Mental and physical relaxation.
- Lessened awareness of pain
- Paraesthesia (lips/fingers/toes/legs/tongue)
- Lethargy (“feeling after a few drinks”)
- Euphoria
- Detachment ‘floaty feeling’
- Warmth
- Altered awareness of passage of time
- Dreaming
- Small controllable ‘fit of the giggles’
What are the pre-operative instructions for inhalation sedation?
- Light meal.
- Take routine medicines as normal.
- Adults need to be accompanied for the first appointment (afterwards can attend alone)
- Children should be accompanied by a competent adult
- Do not drink on day of appointment
- Alcohol should not be drunk on the day.
- Children should be cared for during and after appointment.
- Plan to remain in clinic for 30 minutes after treatment.
- We need to be told if you previously had a blocked nose.
Describe the technique for inhalation sedation.
- Set up the machine
- select size of nasal hood (and record size in notes)
- Connect to the noses
- Set the mixture dial to 100% O2
- Settle the patient into the dental chair
- Reinforce the explanations of the procedure.
- Set flow to 5-6L per minute
- Position the hood on the patient’s nose.
- Encourage nasal breathing and check reservoir bag movements:
- It should be mimicking lung movement
- If movements are small (check seal/look for mouth breathing/decrease flow)
- Movements too big - increase the flow rate.
- Let the patient get comfortable with the hood by getting them to breathe in and out for a minute.
- Ask the patient to signal when they feel different
- Reduce O2 by 10% (10% nitrous oxide and 90% oxygen)
- Wait 1 minute and repeat.
- When it reaches 80% oxygen reduce by 5% per minute.
Explain what semi-hypnotic suggestion is .
You are suggesting that the patient feels comfortable and their legs are heavy/ they are feeling relaxed/ their limbs feel heavy and loose.
How do you treat Inhalation sedation overdose.
Increase the percentage of oxygen in 5-10% increments until satisfactory sedation.
How do you deal with an inhalation sedation patient that is undersedated.
Decrease oxygen in 5% increments until sedation is satisfactory.
How do we recover the patient after inhalation sedation?
Gradually increase O2 by 10-20%` per minute until 100% or can turn it straight to 100%.
Administer 100% O2 for 2-3 minutes to prevent diffusion hypoxia.
Remove hood and turn gas off.
What are the post-operative instructions for Inhalation sedation?
Adults can leave unaccompanied
Child patients < age 16 will be accompanied by a competent adult.
The patient may feel shivery (Reassure the pateint that this is common and will quickly pass)
Discuss the advantages and disadvantages of inhalational sedation?
Adv- Rapid recovery and flexible duration
Disadv- Keeps nasal hood in place. Less muscle relaxation. Requires coordination of nasal breathing when the mouth is open.
Discuss the advantages and disadvantages of IV sedation.
Adv- Good sedation achieved. There is less co-operation needed.
Disadv- need to take baseline reading . IV cannulation is required. Assessing sedation level. Behaviour during recovery. Efficacy swallowing.
How does oral sedation work?
This is when we drink midazolam.
How does intranasal sedation work?
A concentrated solution of midazolam is squirted up the nose.
What is the negative of providing sedation orally or transmucosally?
This is more unpredictable- so you still need to canulate the patient once they have been sedated incase the patient over sedates and needs reversed.
What is the most widely used sedation type in paeds?
Inhalation sedation.
What are some paeds terms we can use when describing inhalation sedation?
Nose bobble- mask.
Floaty air- nitrous oxide
What do you tell the patient is going to happen when providing them with inhalation sedation?
They are going to breathe in air that will make them feel floaty and relaxed.
They will be back to normal within 5/10 minutes.
They will still need LA to go ahead with the procedure.
What should be done if the child describes having ringing ears or a sore head?
Increase the oxygen level.
At what age can we give IV sedation?
Aged 12 and above.
What drug do we use for IV sedation in children?
Propofol.
What do you tell a paediatric patient to describe IV sedation?
You will have a canula in the back of your hand (a floaty drip )
You will not remember what happens.
List some complications of cannulation.
- Venospasm
- Extravascular injection
- Intra-arterial injection
- Haematoma
- Fainting
What is a venospasm
How do we diagnose this?
and how do we avoid this complication of cannulation?
This is when we put in the canula and the vein collapses.
Burning feeling.
Avoided by:
- Make sure the vein is dilated beforehand (turniquet and tapping the vein)
- Avoid slow skin puncture
- Put the patient’s hand in hot water to help dilate the vessels.
What is extravacular injection?
How do we diagnose it?
How do we prevent it?
How do we treat it?
This is when we think the canula is in the correct position but it isn’t. This results in the drug being injected into the interstitial space.
Diagnosed- pain and swelling,
Prevention-flush of saline.
Treatment- Remove canula, apply pressure and reassure.
What is an intraarterial injection?
How do we diagnose this?
How do we prevent this?
How do we manage this?
This is when we put the canula in the brachial artery by accident when applying a canula to the cubital fossa.
Diagnosis-
- Bright red blood (as it is oxygenated)
- Blood under high pressure- causing it to bubble out of the canula
- Pain radiating distally from the site of canulation.
- Loss of colour/warmth to limb/ weakening pulse.
Prevention- place canula medial to bicep tendon of the antecubital fossa.
Palpate the vein before attack (it is a vein if it has a pulse)
Management -
- Monitor for loss of pulse (Cold/discolouration)
- Leave canula in situ for 5 minutes post drug.
- If symptomatic we leave it and refer.
What is a haematoma?
How do we treat a haematoma?
Extravasation of blood into soft tissues due to damage to the vein walls.
Treatment- time/ rest/ reassurance.
If severe- initial ice pack and then moist heat 20 minutes an hour after 24hours.
List some complications of giving the patient the IV sedation drug?
- Oversedation
- Hyporesponse
- Hyperesponse
- Allergy
- Paradoxical reaction
What is a hyperresponse and how do we avoid it?
This is when the patient shows a greater response to a smaller dose of the sedative agent.
We start with 1-2mg of midazolam and increase the dose in 1mg increments.
What age group do we need to be more careful with incase of hyperresponse and how?
Elderly people
Give them Midazolam in 0.5mg increments
Discuss a Hyporesponse to IV sedation.
This is when the patient shows little effect from the sedative agent with large doses.
What can cause a hyporesponse to IV sedation?
- If the canula is not in the right place.
- Previous Benzodiazepine use
- Cross tolerance- a coccaine addiction could make them hyper-respondent.
Discuss a paradoxical reaction to IV sedation.
When the reaction is not what we expected.
e.g. they appear to be sedated normally but may react extremely to some stimuli.
What happens when a patient is oversedated with IV sedation.
Oversedation Causes
- Loss of responsiveness
- Respiratory depression
- Unable to maintain airway
- Respiratory arrest.
How do we manage oversedation?
- Stop
- Try and rouse the patient (ABC)
- If no response to stimulation and support
- Reverse with flumazenil 200mg then 100mg increments at minute intervals
- Watch for 1-4hours
Patient is under sedation and their oxygen saturation is falling. How do you respond ?
- Check they are not playing with the pulse oximeter
- Ask patient to take a deep breath
- Adjust the patient’s airway (head tilt chin lift)
- Nasal cannulate (2l per minute- helps you carry on with treatment)
- If oxygen level is still falling- reverse with Flumazenil.
The patient has had an allergic reaction how do we treat them?
DO not use flumazenil (it is a benzodaizapine- so if the allergen is the drug it will make it worse)
Give IM adrenaline with ABCs
What are the signs and symptoms of oversedation of inhalation sedation ?
- Mouthclosing
- Spontaneous mouth breathing
- Nausea/ vomitinig
- Irrational and sluggish responses
- Decreased co-operation
- Incoherent speech
- Uncontrolled laugher/tears
- Patient no longer enjoying the effects
- Loss of conciousness.
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How do we treat inhalation sedation overdose?
