Complications of Sedation

Question 1

What were the adverse findings of the Rapid Response report?

Answer 1

Bolus sedation still used

Untrained seditionists

Incorrect doses given- incorrect labels/concentration

Reliance on flumazenil

Question 2

What is the bolus technique?

Answer 2

this is where the drug is put in at one time rather than slowly and gradually by titration while checking regularly

Question 3

What is the only concentration of midazolam used?

Answer 3

1mg/1ml

Question 4

When should flumazenil be used?

Answer 4

Used in an emergency to reverse effect of midazolam only
 Should not be used to speed up recovery
 Should not be relied on with practitioners wrongly choosing to over-sedate patient on purpose

Question 5

What is the ultimate complication of sedation?

Answer 5

Death
 Extremely rare
 Would be due abuse or excessive levels/incorrect doses of drug given

Question 6

What are the complications of cannulation in IV sedation?

Answer 6

Venospasm

Extravascular injection

Intra-arterial injection

Haematoma

Fainting

Question 7

What is venospasm? (disappearing vein syndrome)

Answer 7

Veins collapse at attempted venepuncture (Associated with poorly visible veins)
-> May be accompanied by burning

Question 8

How is venospasm prevented?

Answer 8

Using tourniquet/vein tapping to help dilate vein

Gravity

Warm water/gloves

Quicker puncture

Question 9

What occurs in an extra-vascular injection?

Answer 9

Active drug placed into interstitial space
-> Pain/swelling
-> can result in delayed absorption

Question 10

How is EVI prevented?

Answer 10

Good cannulation

Test dose of saline (flush)

Question 11

How is EVI treated?

Answer 11

Remove cannula

Apply pressure

Reassure

Question 12

Which artery is most commonly affected by intra-arterial injection?

Answer 12

Brachial artery

Question 13

What are the signs of an IA injection?

Answer 13

Pain on venepuncture

Red blood in cannula

Difficult to prevent leaks

Pain radiating distally from site of cannulation

Loss of colour or warmth to limb / weakening pulse (as artery could constrict and blood supply could be stopped)

Question 14

How can IA injections be prevented?

Answer 14

 Always stay superficial
 Artery walls are thicker- puncture is thicker
 Prevent by going lateral to bicep tendon
 Palpate to check if vessel has pulse (if positive it is not a vein)

Question 15

How is an IA injection treated?

Answer 15

Monitor for loss of pulse- Cold/Discolouration

Leave cannula in situ for 5 mins post drug

No problems – remove

Symptomatic- leave and refer to hospital (procaine 1%)

Question 16

What can happen if diazepam is giving intra-arterially?

Answer 16

Necrosis

Question 17

What is a haematoma?

Answer 17

Extravasation of blood into soft tissues (bruising)
-> Due to damage to vein walls

Question 18

How are haematomas prevented?

Answer 18

Good cannulation technique- Avoid multiple holes in vein wall

Pressure on removal of cannula/post operatively
(Operator not patient)

Care with the elderly

Question 19

How are haematomas treated?

Answer 19

Time, Rest, Reassurance
-> If severe- ice pack (initially), moist heat (20mins at a time)
-> Consider heparin containing gel

Question 20

What are the main causes of fainting during venipuncture?

Answer 20

Being starved

Anxiety toward needles

Question 21

How is fainting prevented?

Answer 21

Don’t starve patients

Topical skin anaesthesia

IS First- to relax patient

Position of patient- supine (allows legs to be raised)

Question 22

What are the complications of drug administration in IV sedation?

Answer 22

Hyper-responders

Hypo-responders

Parodoxical reactions

Oversedation

Allergic reactions

Question 23

What are the features of hyper-responders?

Answer 23

Deep sedation with minimal dose
-> 1-2mg midazolam

Question 24

How can effect in hyper-responders be managed?

Answer 24

Care with titration
-> 1mg increments
-> Slow titration in elderly

Question 25

What is the cause of hyporesponse to IV sedation?

Answer 25

 Cannula in incorrect place- flush it again?  Patient may have cocaine/benzo habits (cross tolerance)

Question 26

What is the max dose given to hypo-responder?

Answer 26

10mg then stop if not working

Question 27

What are paradoxical reactions?

Answer 27

Patient does not sedate as expected:  Patient becomes more hyper instead of more sedate  Large reactions (screams) to stimuli such as high speed- check it is numbed properly -> more common in immature teenagers

Question 28

What should never be done in event of paradoxical reaction to IV sedation?

Answer 28

Add more sedative -> find another management technique instead

Question 29

What is over-sedation and its features?

Answer 29

 Lose responsiveness  Respiratory depression- give oxygen and take deep breaths (usually)  Loss of ability to maintain airway  Respiratory arrest- BVM

Question 30

How is over sedation managed?

Answer 30

Stop procedure Shake patient/Shout A B C If no response to stimulation and support -> Reverse with flumazenil 200mcg then 100mcg increments at minute intervals (Watch for 1- 4 hours)

Question 31

How is respiratory depression managed?

Answer 31

Check the oximeter -> If low 90s: Stimulate patient- Ask to breathe deeply -> If below 90- Supplemental oxygen via Nasal cannulae (2 litres per minute) ->Reverse with flumazenil

Question 32

How is loss of airway control/respiratory arrest managed?

Answer 32

Stimulate the patient / assess consciousness Maintain / clear airway Ventilate the patient Reverse sedation Consider other medical incident

Question 33

What is done if there is an allergic reaction in IV sedation?

Answer 33

More likely to be to latex/elastoplast than sedative -> do not use flumazenil to reverse (doubling up on benzos which patient may have allergy to) -> manage as if patient not sedated- IM adrenaline and ABC

Question 34

How are dentists/patients protected from sexual fantasy disclosure in IV sedation?

Answer 34

Having a chaperone present at all times

Question 35

What are the complications of IS sedation?

Answer 35

Oversedation Patient panics

Question 36

What is the feature of IS machines which prevent hypoxia in the patient?

Answer 36

Max percentage of NO in mix is 70%

Question 37

What are the causes of over sedation in IS

Answer 37

Misjudging dose Traumatic part of procedure finished- patient relaxes but dose is not reduced Mouth breathing- patient receives no effect due to this, then starts to breathe properly through nose and becomes overstated

Question 38

What are the signs and symptoms of Nitrous Oxide overdose?

Answer 38

Patient discomfort Lack of co-operation Mouthbreathing Giggling Nausea Vomiting Loss of consciousness

Question 39

How is over sedation in IS treated?

Answer 39

Decrease N2O concentration by 5-10% Reassure Don’t remove nosepiece (Diffusion hypoxia)- change to 100% oxygen

Question 40

What is diffusion hypoxia and how is it prevented?

Answer 40

Diffusion Hypoxia- NO in lungs and bloodstream wants to rush out lungs and tissues into atmosphere (much smaller concentration than what patient is breathing) -> When turning off keep oxygen on for 3-5mins

Question 41

Why may a patient panic during IS?

Answer 41

Only light sedation- may not be enough for their anxiety level -> reassure and remind them to keep breathing (if they cannot cope-abort)

Question 42

What are the complications of oral and transmucosal sedation?

Answer 42

Same as IV -> manage in the same way -> if under-sedated top up with IV