IHS key points Flashcards
indications
mild/mod anxiety needle phobia hyper gag reflex multiple quadrant tx in young kids traumatic procedures medical conditions aggravated by stress - asthma unaccompanied adults requiring sedation age (can understand) ASA1 preventively for traumatic procedures or ortho ext - esp if no tx experience
contraindications
may not match their coping style (monitor) common cold mouthbreather extreme anxiety tonsillar/adenoidal enlargement severe COPD 1st trimester pregnancy? fear of "mask"/claustrophobia pts with limited ability to understand unsuccessuful prev attempt NM disease e.g. myesthenia gravis, MS
age cut off
no absolute, generally 7yrs and over prev experience maturity understanding pt prep by parent
equipment
gas cylinders - blue N2O - black with white top O2 - may be piped gases in hospital pressure reducing valves flow control meter reservoir bag gas delivery hoses nasal hood waste gas scavenging system
quantiflex O2 flow meter
measures flow rates of up to 10l/min
readings taken from equator of ball
accuracy +/- 5%
white meter
air entrainment valve
if gases fail valve opens - allows room air into circuit
they can continue to breathe if machine switches off
mixture control dial
tells you % O2 - can’t turn it lower than 30% (safety)
flow control knob
how many l/min
nitrous oxide flow meter
blue
measure flow rates of up to 10l/min
read centre of ball
accuracy +/- 5%
O2 flush button
flushes O2 35l/min
v fast O2 delivery
emergency use only
reservoir bag
2/3l bag, rubber or silicone
- smaller available for children
full of air and O2
bag should move visibly with each inspiration and expiration
helps to monitor respiration - emulates pts lungs
- helps you know what flow rate to give them
- must not collapse - need to increase flow rate
- if stuffed - reduce flow rate
want 12-16 breaths/min
gas delivery hoses
2.5cm diameter, corrugated
universal joints
one hose delivers fresh gases from machine
one hose delivers waste gas to scavenging system
non-return valve in expiratory limb prevents rebreathing expired gases
single use breathing circuits - tubing and mask
nasal mask/hood
various sizes
should form a seal around nose (gases shouldn’t escape)
2 connections to breathing circuit
pin index system
prevents wrong cylinder being attached
can’t attach wrong gas
diameter index system
prevents cross-contamination of piping
minimum O2 delivery
30%
O2 fail safe
operates when O2 pressure <40psi
if O2 runs out machine switches off
scavenging system
external to the quantiflex machine or piped gas system
active scavenging of waste gases - small negative pressure (so they get sucked away)
changing surgery air reduces N2O levels - 15 changes of room air per hour
watch for pt mouth breathing
- expelling waste gas into atmosphere not system
check mask seal to reduce contmination
use dam - reduce mouth breathing, reduce some of waste gas expelling
safety features of quantiflex
air entrainment valve O2 flush button O2 monitor - see what they are receiving reservoir bag - emulate pt lungs colour coding - pin index system scavenging system O2 and N2O pressure dials pressure reducing valves one way expiratory valve quick fit connection for positive pressure O2 delivery 2 tanks esp for O2 - back tank is a reserve - so you always have enough O2 minimum O2 delivery 30% O2 fail safe - if runs out machine switches off
advantages
rapid onset 2-3mins
rapid peak action 3-5mins
depth altered either way - can turn sedation up and down
flexible duration
rapid recovery when N2O turned off
no injection (but may need LA)
few SEs, safe
drug not metabolised
some analgesia (better for ischaemic than inflammatory)
- fingers and toes a bit tingly/numb
no amnesia - in future may be happy to do without sedation
disadvantages
£ equipment £ gases space occupying equipment not potent, need cooperation - just helps them cope a bit - won't disarm a pt who isn't wanting tx requires ability to breathe through nose chronic exposure risk? staff addiction difficult to accurately determine actual dose - accuracy not great +/- 5% - if pt speaks to you they are breathing through mouth - leakage if nasal hood not fitting less muscle relaxation
signs of adequate sedation
pt relaxed/comfortable - feeling like just before you fall asleep pt awake low blink rate laryngeal reflexes unaffected vital signs unaffected gag reflex reduced mouth open on request decreased reaction to painful stimuli (LA easier) decrease in spontaneous movements verbal contact maintained
symptoms of adequate sedation
mental and physical relaxation lessened awareness of pain paraesthesia - lips, fingers, toes, legs, tongue - tingly lethargy euphoria detachment 'floating feeling' warmth (take jackets off first) altered awareness of passage of time dreaming (daydream) small controllable "fit of the giggles"
if have anxious parent what can you get them to do?
watch the bag
