Recovery from anaesthesia Flashcards
when is the greatest risk of anaesthetic death?
Within 3 hours of recovery
What are the risk factors for anaesthetic death?
Risk of death increased in:
- ASA III-V
- Cats (even ASA I-II)
* potential causes: hypothermia, cardiovascular problems, respiratory problems, small-size drug overdose, poor monitoring in recovery, intubation (laryngeal oedema)
- Brachycephalic breeds (airway obstruction)
Give some of questions to include in a post-op check list
Describe the sequence of events at the end of a surgical procedure
- procedure ends
- wounds cleaned & dressed
- Any monitoring equipment no longer required is removed
- vaporiser switched off
(if using nitrous oxide, switch off & increase oxygen to deliver adequate fresh gas flow & minimise diffusion hypoxia) - Dump reservoir bag on breathing system & will with fresh gas
- Leave patient on oxygen for few min if possible
- Disconnect patient from breathing system
- switch off oxygen
- Move patient to recovery area
- Extubate
- Have a recovery monitoring chart (start with TPR every 5 min and then every 10min as recovery progresses)
Describe extubation in dogs
Wait until gag-reflex returns
- Indicated by swallowing & tongue flicking (same in most species)
Don’t deflate cuff to early
- Esp. following dentals & patients who are at risk of regurgitation (Brachycephalics)
- wait to deflate cuff until just before extubation
Extubate on inspiration where possible
- Naturally abduct arytenoid cartilages during inspiration so less likely to cause damage
Describe extubation in Brachycephalics
High risk of compromised airway
Minimising stress is vital
Be prepared to sedate on
Describe extubation in cats
Timing is precise
- ideally 15sec before swallowing
- late extubation can lead to laryngeal spasm (which obstructs airway)
Keep tube cuffed until ready to extubate
Look for increased jaw tone, palpebral reflex, tongue movement & ear flick
Re-intubation difficult
IV access required to allow for emergency anaesthesia & resuscitation drugs to be given
What is laryngeal oedema in cats?
Can result from rough/difficult intubation
Can result in airway obstruction during recovery
Be gentle & patient during cat intubation
(of all anaesthetic deaths: 63% of intubated cats died in recovery)
In what position should you keep animals post extubation?
Head & neck should be extended
Tongue gently pulled forward to maintain patent airway
What is emergence delirium?
Dissociated state of consciousness
Thrashing, paddling & vocalisation post extubation
Can be difficult to differentiate between ED, pain & dysphoria (one can cause the other)
Make sure patient has enough analgesia & discuss plan for bad recovery before it happens
Risk of harm to both patient & staff so handle with care (muzzle if possible, put patient on floor & mild sedation may be required)
- always have induction agent available just in case (e.g. Propofol/Alfaxalone)
What are some important considerations of a recovery area
Ideally there should be dedicated recovery area
considerations:
- staff always present
- consider logistics
- species separated to reduce stress
- good ventilation to eliminate exhaled gases
- open fronted kennels
- warming equipment/blankets
- protective clothing/gloves
- emergency equipment
What are examples of emergency equipment
Anaesthetic machine
Breathing system
Anaesthetic induction drugs & analgesics
Equipment for IVFT
Endotracheal tubes & laryngoscope
Suction apparatus
Monitoring equipment
Emergency drugs (crash box)
Defribilator
*staff should be trained in good recovery techniques
What should be monitored during recovery?
Level of consciousness, activity & recovery of physiological reflexes
Body temp
Oxygenation (pulse oximeters very useful)
ventilation & airway patency!
Circulation
- HR, pule quality, MMC, CRT
Postoperative analgesia
- waking up in pain = poor recovery
Describe the effects of hypothermia on recovery
Predisposes to prolonged recovery times
Prevention better than cure
- blankets, heat pads, warm fluids
Shivering can increase oxygen demand so may need O2 supplementation until shivering stops
Painful
How long should you monitor a patient for?
Monitor until:
- alert, lifting head & swallowing
- normal ocular reflexes
- jaw tone indicates good muscle strength
- not shivering & body temp above 35C
- MM pink while breathing room air
- breathing well without ETT in place
- No signs of upper airway obstruction
- Effective analgesia has been provided & is likely to last until next assessment is due
What are some common causes of upper airway obstruction?
Loss of pharyngeal muscle tone
Regurgitation or vomiting
Laryngospasm or laryngeal oedema
- esp. cats
Traumatic intubation
Brachycephalics
What are some signs of airway obstruction?
Increased resp noise & effort
- won’t hear anything in patients that are completely obstructed so important to monitor closely
Abdominal effort & nares flaring
‘Air hunger’ posture (head & neck extended)
Cyanosis (late sign)
Restlessness & agitation
Agonal breathing (terminal sign)
