complications key points

Question 1

issues leading to complications

Answer 1

reliance on flumazenil
bolus sedation still used
untrained sedationists
incorrect doses
 - labels, incorrect conc

Question 2

complications of IV cannulation

Answer 2

extravascular injection
venospasm
intraarterial injection
haematoma
fainting

Question 3

venospasm

Answer 3

disappearing vein syndrome - vein disappears as you put cannula in
veins collapse at attempted venepuncture
may be accompanied by burning
associated with poorly visible veins

Question 4

management of venospasm

Answer 4

time dilating vein - torniquet, tap vein
 - worse with repeated attempts
efficient technique
 - slow skin puncture makes worse
warm water/gloves in winter - dilates vessels

Question 5

extravascular injection

Answer 5

active drug placed into interstitial space (cannula not in)

Question 6

diagnosis of extravascular injection

Answer 6

pain

swelling

Question 7

extravascular injection potential problems

Answer 7

delayed absorption (will get absorbed at some time - oversedation?)

Question 8

preventing extravascular injection

Answer 8

good cannulation

test dose of saline - flush cannula

Question 9

tx of extravascular injection

Answer 9

remove cannula
apply pressure
reassure

Question 10

intra-arterial injection - where is it most likely?

Answer 10

rare
antecubital fossa (brachial artery)

Question 11

diagnosis of intra-arterial injection

Answer 11

pain on venepuncture (wall thicker)
red blood in cannula, bubbles
difficult to prevent leaks
pain radiating distally from cannulation site
loss of colour/warmth to limb/weakening pulse

Question 12

prevention of intra-arterial injection

Answer 12

avoid anatomically prone sites - ACF medial to biceps tendon
palpate before attack (if pulse not vein)
if have cannulated an artery - take out and apply pressure DON’T inject drug

Question 13

management of intra-arterial injection

Answer 13

monitor for loss of pulse (if artery irritated may constrict) - cold/discolouration
leave cannula in situ for 5mins post-drug
- no problems then remove
- symptomatic - leave and refer to hospital

Question 14

haematoma

Answer 14

bruise
extravasation of blood into STs
- due to damage to vein walls

Question 15

when can haematoma occur?

Answer 15

at venepuncture - poor technique
removal of cannula - failure to apply pressure
care w elderly

Question 16

prevention of haematoma

Answer 16

good cannulation technique - avoid multiple holes in vein wall
pressure post-op by operator until stops bleeding, then apply pressure and get pt to put pressure

Question 17

haematoma tx

Answer 17

time, rest, reassurance
if severe initial ice pack, moist heat 20mins in hour after 24hrs
consider heparin containing gel

Question 18

fainting during venepuncture

Answer 18

quite common
anxiety related
worse if starved
prevention
 - don't starve pt
 - topical skin anaesthesia
 - RA first (IHS 1st - more O2)
 - position of pt - put them part-reclined
tx - raise legs

Question 19

complications of drug administration

Answer 19

parodoxical reactions
hyper-responders
hypo-responders
sexual fantasy
allergic reactions
oversedation

Question 20

hyper-responders

Answer 20

deep sedation with minimal dose (1-2mg)
care with titration
 - 1mg increments
 - slow in elderly (sensitivity to midazolam increases) and 
   U16s
 - max 3.5mg for >60yrs

Question 21

hypo-responders

Answer 21

little sedative effect with large doses
check cannula in vein (re-flush)
due to tolerance?
 - BZD induced
 - cross-tolerance e.g. cocaine
 - idiopathic
threshold to abandon? - not over 10mg, BNF max 7.5mg

Question 22

parodoxical reactions

Answer 22

don't sedate how you expect
appear to sedate normally
react extremely to all stimuli
relax when stimuli removed
check for failure of LA
don't continue adding sedative
find other management techniques
watch immature teenagers (U16s)

Question 23

allergic reactions

Answer 23

rare to sedatives
- do not use flumazenil (also a BZD)
latex and elastoplast
manage as if not sedated - advantage of IV access

Question 24

oversedation

Answer 24

loss of responsiveness
resp depression
- sometimes just need to give O2 and tell pt to take deep breaths
loss of ability to maintain airway - collapses
respiratory arrest

Question 25

complications of IHS

Answer 25

pt panics

oversedation

Question 26

cause of oversedation in IHS

Answer 26

initially - misjudge dose
later
- traumatic procedure over
- mouthbreathing ceases e.g. if hood doesn’t fit well then fixed later so getting higher conc

Question 27

IHS pt panics

Answer 27

enough sedation?
reassurance
if cannot cope abort

Question 28

S+S of oversedation

Answer 28

irrational and sluggish responses
pt discomfort
fails to respond to verbal cues/mild stimuli
incoherent speech
LOC
lack of cooperation
mouth closing repeatedly
eyes closed, unable to open
nausea and vomiting
spontaneous mouth breathing
pt no longer enjoying effects
drop in O2 sats
pulsing head/temples
uncontrolled laughter/tears

Question 29

what are 2 signs you should stop IHS?

Answer 29

ears ringing

sore head

Question 30

tx of IHS overdose

Answer 30

reduce N2O conc by 5-10%
reassure
don’t remove nosepiece - diffusion hypoxia
- 3-5mins
- diffusion gradient N2O rushes out, stops O2 in