1 - Complications of conscious sedation

Question 1

What are the complications of cannulation?

Answer 1

• venospasm
• extravascular injection
• intraarterial injection
• haematoma
• fainting

Question 2

What is venospasm?

Answer 2

• also known as disappearing vein syndrome
• veins collapse at attempts venepuncture
• may be accompanied with burning
• associate with poorly visible veins

Question 3

How do you manage venospasm?

Answer 3

• spend time dilating vein (tourniquet)
• efficient technique, slow puncture makes worse
• place hands in warm water or wear gloves prior

Question 4

What is extravascular injection?

Answer 4

• active drug placed into interstitial space (needle is in tissue)
• pain and swelling
• can cause delayed absorption or over sedation if more drug administered

Question 5

How do you manage extravascular injection?

Answer 5

• prevention with good cannulation and test dose of saline
• if tissued, remove cannula, apply pressure and reassure

Question 6

How do you test a cannula is in the vein?

Answer 6

• test dose of saline
• should not bubble or cause pain
• patient may feel cold up their arm

Question 7

How do you diagnose intraarterial injection?

Answer 7

• pain on puncture
• red blood in cannula
• cannula leaks bright red blood around needle
• pain radiating distally from site of cannulation
• loss of colour or warmth to limb with weakening pulse

Question 8

How do you manage an intraarterial injection?

Answer 8

• leave cannula in situ for 5 mins and monitor
• if there are no problems remove
• if symptomatic refer to hospital and leave in situ

Question 9

How do you prevent intraarterial injection?

Answer 9

• avoid anatomically prone sites (ie medial to bicep tendon)
• palpate before insertion (artery pulses)

Question 10

What is a haemtoma associated with cannulation?

Answer 10

• extravasation of blood into soft tissues due to damage to vein walls
• can occur at venepuncture or at removal of cannula if no pressure applied
• common in elderly

Question 11

How do you manage a haematoma?

Answer 11

• time, rest and reassurance
• if severe, ice then heat after 24 hours
• consider heparin containing gel

Question 12

How can you prevent fainting at cannulation?

Answer 12

• ensure patient has eaten
• topical skin anaesthesia
• risk assess

Question 13

How do you manage fainting at cannulation?

Answer 13

Lie patent flat with feet raised

Question 14

What are the complications of drug administration in IV sedation?

Answer 14

• hyper-responders
• hypo-responders
• paradoxical reactions
• oversedation
• allergic reaction

Question 15

What is a hyper-responder?

Answer 15

• deep sedation achieved with minimal dose (1-2mg midazolam)
• common in elderly

Question 16

What is the normal dose of midazolam for sedation?

Answer 16

5-6mg

Question 17

What is a hypo-responder?

Answer 17

• little sedative effect with large doses
• may be due to tolerance of previous drug use

Question 18

What is the threshold to abandon sedation?

Answer 18

10mg of midazolam

Question 19

What can cause tolerance to midazolam?

Answer 19

• benzos use
• cross tolerance of other drugs
• idiopathic
• methadone users

Question 20

What are paradoxical reaction?

Answer 20

• patient appears to sedate normally
• react extremely to all stimuli (becomes hyper)
• relaxes if stimuli removed
• requires reversal agent

Question 21

What are the signs of oversedation?

Answer 21

• loss of responsiveness
• respiratory depression
• loss of ability to maintain airway
• respiratory arrest

Question 22

How do you monitor respiratory depression?

Answer 22

Oxygen saturation

Question 23

How do you manage oversedation?

Answer 23

• stop procedure
• try to rouse patient
• use ABCs
• if no response, use reversal agent flumazenil

Question 24

What is the dosage of flumazenil?

Answer 24

• 200ug initial dose
• 100ug increments at minute intervals

Question 25

How do you manage respiratory depression?

Answer 25

• stimulate patient (encourage to take deep breaths)
• supplemental oxygen via nasal cannulae at 2l/min

Question 26

How do you manage an allergic reaction?

Answer 26

• rare to be allergic to sedative but do NOT use flumazenil as it is a benzodiazepine
• reaction is more likely to be to latex or Elastoplast
• manage as normal with IM adrenaline

Question 27

What are the complications of inhalation sedation?

Answer 27

• oversedation
• patient panics

Question 28

What is the maximum dose nitrous oxygen can be titrated with oxygen for sedation?

Answer 28

70%

Question 29

What is the average titration of nitrous oxygen that causes oversedation?

Answer 29

104%

Question 30

What are signs of nitrous oxide overdose?

Answer 30

• patient discomfort
• lack of cooperation
• mouth breathing
• giggling
• nausea and vomiting
• LOC

Question 31

How do you manage IS overdose?

Answer 31

• decrease nitrous oxide concentration by 5-10%
• reassure patient
• do not remove nose piece

Question 32

Why must you not remove the nose piece suddenly during IS?

Answer 32

Diffusion hypoxia

Question 33

How do you manage the patient panicking during IS?

Answer 33

• reassurance
• abort if patient cannot cope
• encourage the patient to breathe through their nose as the concentration of oxygen will then increase and room should stop spinning