Complications

Question 1

complications of cannulation

Answer 1

venospasm
extravascular injection
intraarterial injection
haematoma
fainting

Question 2

what is venospasm

Answer 2

disappearing vein syndrome
veins collapse at attempted venepuncture
may be accompanied by burning
associated with poorly visible veins

Question 3

management of venospasm

Answer 3

1. time dilating vein - worse with repeated attempts
2. efficient technique - slow skin puncture makes it worse
3. warm water / gloves

Question 4

what is extravascular injection

Answer 4

active drug place into interstitial space
seen as pain / swelling
issue is then delayed absorption

Question 5

management of extravascular injection

Answer 5

prevention = good cannulation & test dose of saline
tx = remove cannula, apply pressure & reassure

Question 6

what is an intra arterial injection

Answer 6

cannulate artery and not the vein i.e. into brachial artery in arm
increased pressure as artery walls much thicker so pain on venepuncture
red blood in cannula
difficult to prevent leaks
pain radiates distally from site of cannulation
loss of colour / warmth to limb or weakening pulse

Question 7

prevention of intra arterial injection

Answer 7

avoid anatomically prone sites i.e. ACF medial / lateral to bicep tendon
palpate before

Question 8

management of intra arterial injection

Answer 8

monitor for loss of pulse
leave cannula in situ for 5 mins post drug
if no problems then remove
if symptomatic then leave & refer to hospital

Question 9

haematoma

Answer 9

extravasation of blood into soft tissues due to damage to vein walls
1. at venepuncture due to poor technique
2. on removal of cannula due to failure to apply pressure
take care with elderly pt

Question 10

tx of haematoma

Answer 10

time
rest
reassurance
if severe initial ice pack then moist heat for 20mins in hr after
consider heparin containing gel

Question 11

fainting during venepuncture

Answer 11

anxiety, worse if starved
feet up then reassure when they come around
if this doesn’t work then DRS ABC
can lose control of bladder if they faint but if they lose control of bowels this is not a faint

Question 12

complications of drug administration

Answer 12

hyper responders
hypo responders
paradoxical reactions
over sedation
allergic reaction

Question 13

av dose of midazolam with IV sedation

Answer 13

5-6mg

Question 14

hyper responder

Answer 14

deep sedation with minimal dose i.e. 1-2mg midazolam
care with titration so give 1mg increments & slow titration in elderly

Question 15

hypo responders

Answer 15

little sedative effect with large doses
check cannula is in vein
may be due to tolerance i.e. benzo diazepam users, cross tolerance or idiopathic
threshold is 15mg in hospital dental setting or 10mg in GDP setting

Question 16

paradoxical reactions

Answer 16

appear to sedate normally
react extremely to all stimuli
relax when stimuli removed
check for failure of LA
do not go on adding sedative - reverse it
find other management technique
quite rare but more likely in immature teens

Question 17

oversedation

Answer 17

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

Question 18

management of over sedation

Answer 18

stop procedure
rouse pt
ABC
if no response then reverse with flumazenil 200 microg then 100 microg increments at minute intervals
watch for 1-4hrs
be careful next time

Question 19

management of respiratory depression

Answer 19

check oximeter
stimulate pt - ask them to breathe
supplemental O2 - nasal cannulae 2L / min
reverse with flumazenil

Question 20

allergic reactions

Answer 20

rare
do not use flumazenil

Question 21

elimination & distribution 1/2 life of midazolam

Answer 21

elimination 1/2 life = 1-2hrs but is in system for up to 12hrs

distribution 1/2 life = 15mins i.e. this is how long it takes to distribute around the body

Question 22

complications of IS

Answer 22

1. over sedation
2. patient panics

Question 23

signs and symptoms of N2O overdose

Answer 23

pt discomfort
lack of cooperation
mouthbreathing
giggling
nausea
vomiting
loss of consciousness

Question 24

tx of N2O overdose

Answer 24

decrease N2O conc by 5-10%
reassure
don’t remove nosepiece as can lead to diffusion hypoxia