Anaesthesia lectures Flashcards
WHO surgical checklist
A pre-operative assessment performs multiple functions:
anaesthetic chart components
All types of anaesthesia alter normal body physiology to some degree
This may cause several common effects:
Think about which co-morbidities or acute pathology will cause each of these effects to be much worse. For example:
A – Airway obstruction:Obese, large tonsils, snore regularly, already obstructing e.g. intoxicated
B – Hypoventilation & hypoxia:Pre existing lung disease, current asthma exacerbation, pneumonia
C – Hypotension:Heart failure, hypovolaemic, septic
D – Post operative nausea and vomiting (PONV):Previous history of PONV, female, non smoker
E – Heat loss and hypothermia: low body mass, hypothyroid
G – Loss of airway reflexes and reflux risk: not fasted, pre existing reflux
How does pre-op assessment differ elective vs acute surgeries?
core categories from the pre-operative assessment
anaesthetic history
pre-op presenting complaint questions
pre-op PMH: important things to ask
**renal and liver disease **will affect drug handling
Cardio – as in depth as you need. If you find someone has angina, you want to explore this further. What brings it on, what resolves it, how long, has it been getting worse? Unstable angina and recent myocardial infarction (especially in last 3 months) will significantly increase the risk of an anaesthetic PND – paroxysmal nocturnal dyspnoea
Resp – current respiratory illness, especially in children, puts patients at increased risk of worsening infection/pneumonia and airway complications e.g. bronchospasm, laryngospasm. Recent COVID (< 7 weeks) has been shown to increase postoperative complications
Exercise tolerance – anaesthesia and surgery puts additional stress on the body. Can the body respond appropriately? Quantifying how much a person can do for themselves (e.g. independently can wash/dress/cook/clean) is helpful. Can they manage a flight of stairs? Two flights? How far can they walk on the flat or up a hill? What makes them stop – chest pain? SOB? Joint pain?
pre-op DH: key questions
pre-op SH: key things to ask
how does alcohol affect anaesthesia?
Alcohol – will cause increased metabolism of certain drugs, unless progressed to hepatic impairment. Will affect doses, effect and duration
pre-op fasting rules
2 hours – clear fluids (not fizzy or with sediment)
4 hours – breastmilk
6 hours – solid food
Tablets – take with a small sip of water (preferably < 30 ml) at any time
paediatric fasting rules
Paediatrics – fluids up to 1 hour before
factors to consider that will delay gastric emptying in pre-op period
Trauma / pain will delay gastric emptying: Take the fasting time from the time of injury.
Reflux:if significant reflux, when asleep this could cause an aspiration risk. Questions around timing (e.g. when lying down at night) and whether medication helps can help judge severity
pre-op assessement: examination
Examination
* General appearance
* Brief cardiovascular / respiratory: sensible to check pulse (to rule out new arrhythmias) and brief hydration status assessment. Any cardiac history – would benefit from listening to the heart for valve pathology and lungs for evidence of fluid overload or effusion
* Airway / dental
Observations
* HR, BP, RR, SpO2, Temp, Capillary glucose (if diabetic)
* Weight & height
pre op assessemnt: airway assessement key things to consider
- mouth opening: sclerosis, TMJ, fractured mandible
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dental: Loose teeth can become dislodged and enter the lungs, causing obstruction and collapse.
Patients may also have very expensive dental work that they will be very upset if gets damaged e.g. caps and crowns - neck: If patients are unable to extend their neck (due to arthritis, damage, muscle tension) then this can make any airway manipulation very difficult
what is mallampati score?
Mallampati score. Simple score which is easy to perform. how hard it is to intubate someone
* Class I – can see hard, soft palate, uvula and tonsillar pillars.
* Class II – pillars disappear.
* Class III – cannot see the whole of the uvula and only a tiny portion of the soft palate.
* Class IV – only hard palate visible.
* Class III and IV associated with difficult laryngoscopy and intubation, however poor positive predictor value.
what is an ASA grade and what are its components?
pre-op investigations
table of investigations for elective surgeries: minor, intermediate and major surgery investigations against their ASA grade
Minor surgery: skin lesion excision, draining abscess
Intermediate surgery: tonsillectomy, knee arthroscopy, inguinal hernia repair
Major surgery: total joint replacements, abdominal hysterectomy, prostatectomy
If at risk refers to
AKI risk: pre existing CKD, diabetes, intraperitoneal surgery, heart failure, > 65 years old, on nephrotoxic medications such as ACEi or ibuprofen, liver disease)
pre-op assessment: optimise for elective surgery
pre op medicine management: essential medications to continue and important medications to continue if able
aspirin rule pre op
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