ABCs of Anaesthesia Boot Camp Flashcards
What are the components of the general anaesthetic assessment?
- Past Anaes Hx - issues previously? PONV? FHx of issues?
- PMHx/Systems
- Global function (METS)
- ET
- CVS (IHD, CCF, Valves, Rhythm, PVD, HTN)
- Resp (COPD, Asthma, OSA, URTI, Pneumonia, smoking)
- Other (Liver, Kidney, CNS, DM, Haem, Rheum, infection) - Meds/allergies
- Fasting/Aspiration risk
- last solids, liquids
- GORD or delayed gastric emptying - Exam
Height, weight, BMI, vitals, Cardio and resp
Airway assessment (+dental) - Ix
Additional considerations for obstetric assessment?
- Prev Obs Hx
- Pre eclampsia, HTN, DM etc - Gravidity / Parity
Weeks
Method of delivery and issues for each delivery - Ix
GH is valid with Ab
Obstetric US findings
plt for spinal
how to break down perioperative risk/benefit profile?
Perioperative risk
- ACS NSQIP risk calculator
Surgical risk
- chance of improvement
- chance of no improvement
- chance of harm
Risk of doing nothing
approach to anaesthetic consent
Common: pain, nausea/vomiting and a sore throat
There is a small chance of dental damage but this is unlikely
The risk of serious life threatening events is very unlikely
overall having this anaesthetic is probably safer than driving a car on the
road every year…
Would you like me to go through these risks or anything in more detail?’
In particularly high-risk patients you may want to mention that
• ‘Serious events include life-threatening complications with your heart and
lungs, brain, drug reactions, allergies and awareness’
What are the general legal requirements for obtaining consent?
- Consent must be given freely without coercion
- Withdrawal of consent must be a realistic option
- Consent may only be given by a person capable of doing so
- Consent must be informed – benefits, risks and alternatives
What are the possible surgical issues youd like to discuss with the surgeon?
- Position
- Duration
- Expected blood loss
- Antibiotics
- DVT prophylaxis
- Special requests (cell saver, avoiding muscle relaxant, tourniquet, NIM ETT, Airway preference, avoiding GA for local etc)
How can lungs be damaged during mechanical ventilation?
- Volutrauma (alveolar overdistention - causes APO/atelec)
- Barotrauma (high transpulm pressure- causes PTx/pneumomediastinum)
- atelectrauma (repeated open + closing of alveoli usually low volumes cause this)
- biotrauma (damage to lung and extrapulmonary organs caused by inflammatory response to mechanical ventilation)
- shear strain
- Oxygen toxicity (oxidative injury)
What is a normal FRC?
30mL/kg so around ~2L for a 70kg person
How many mL/min of O2 does an average person use?
3.5mL/kg/min so about 250mL/min for 70kg person
How many mins of apnoea do you have before running out of O2 if preoxygenated well
2L FRC, 80% O2 = 1600mL
3.5mL/kg O2 usage so 250mL/min
so 6 mins in ideal circumstances
FiO2 setting during maintenance of anaesthesia?
30-80%, usually 50%
avoid v low FiO2 incase of airway loss
avoid v high fiO2 to avoid masking progressive lung injury / O2 toxicity
what is the oesophageal sphincter pressure? why is this important?
15cmH2O (pressures above this with LMA could cause gastric insufflation)
What ventilator mode should be used for leaky circuits?
PCV
- VCV gives an uncertain volume to the lung (will say it was delivered, doesnt account for leak)
- Pressure is the limiting variable, therefore target a pressure. The pressure the vent measures as delivered is a true reading
- downside is high pressure can insufflate the stomach
What are the components of a basic anaesthetic plan?
- GA v Regional?
- Which components of the triad?
- ETT v LMA
- Monitors (art, CVC, Swan)
- Pain - meds, blocks, PCA/APS
- Post op HDU/ICU?
When might a case require paralysis?
Surgical
- Critically still - neuro
- Access - laparotomy, laparoscopy
Anaesthetic
- RSI/Intubation
Patient
- Significant lung disease
- obesity
When to use ETT v LMA
ETT - (PAVS)
- Paralyzed
- Airway protection
- need precise control of Vent (lung diseas, long case, neuro, unwell pt)
- Shared airway
LMA
- uncomplicated, fasted, well pt with no airway issues
AS reciepe?
GA, Art line, Gentle induction (GAG)
Spinal may give you less control over BP which is important for AS
Plan for 70M Laparotomy for bowel Ca, PHx severe restrictive resp disease, chronic back pain on 100mg oxycontin daily
- GA
- hypnosis, analgesia and Paralysis (surgical and severe lung disease)
- ETT
- Standard + Artline (gases for lung disease, elderly for bowel op)
- fent+/-morph, ketamine, regional block, APS, consider lignocaine/Mg
- ?HDU for pain
What do you have to consider when family members have ‘nearly died’ under anaesthesia?
- MH
- Sux Apnoea
- Anaphylaxis
- Congenital cardiac issues/arrhythmias
Framework to decide to proceed or postpone a case with a cardiac risk pt
EARLMC- Every Anaesthetist Really Loves Morning Coffee
Emergency - proceed (optimize, monitor) Active Cardiac condition - refer Risk - use RCRI risk calculator Low risk (0-1 risk factor) - proceed >4 METS - proceed will testing Change management - Yes(test) No (proceed)
can extrapolate this to more than just cardiac
What are active cardiac conditions as per the ACC/AHA guidelines which you would refer for
MADVA
- MI <60days
- Angina (unstable or severe)
- Decompensated HF (NYHA IV, Worsening, new)
- Valvular disease (severe, so AV area <1cm2 or mean pressure 40mmhg, or symptomatic MS)
- Arrhythmias (Slow: high grade AV block, Symptomatic brady, Fast: new VT, symptomatic ventricular arrhythmias, SVT with uncontrolled rate >100)
What is a MET?
- Metabolic equivalent
- ratio of WORK metabolic rate to REST metabolic rate
- 1 = 3.5mLO2/kg/min (250mL/min) in a 70kg Male sitting quietly
- scale is define by DASI - duke activity status index
- risk is increased if unable to meet a 4 MET demand in most daily activities
- correlates well with periop survival
Proceed or postpone?
68M w NSTEMI 2/52 prior, ongoing unstable angina, high speed MVA w FF in abdomen and surgeon wants theatre urgently
Emergency - yes, proceed
Optimize with artline, avoid tachy, potentially transfuse etc
Proceed or postpone?
78F #NOF, multicomorbid with unknown exercise tolerance, in pain with fluid overload
Emergency - yes (urgent), proceed
Have some time to refer and optimized (can postpone a bit)
Optimize: block, analgesia, diuresis, etc
Proceed or postpone?
70M w PR bleeding secondary to new Rectal Ca, Phx HTN, T2DM, Hchol, unknown ET
Emergency - yes, proceed
optimize as possible
Proceed or postpone?
60F Lap chole, in rAF, nil Sx
emergency - no
Active cardiac - yes, refer (postpone)
if biliary sepsis (cause for AF) - proceed, attempt to control rate
Proceed or postpone?
60F for Lap incisional hernia repair, PHx RA and hear a systolic murmur
Emergency - no
Active - potentially, refer (postpone, get TTE)
Proceed or postpone?
78F with recent TTE showing mod AS for cataract surgery, unable to walk up stairs due to arthritis
Emergency - no
Active - No (severe would be)
Risk - LOW - proceed
Proceed or postpone?
50M for inguinal hernia repair w trifasicular block and multiple fainting episodes
Emergency - no
Active - Yes, refer and postpone
Proceed or postpone?
60M lap chole, unkown ET secondary to back injury, nil PHx
Emergency - no
Active - no
Risk - Low
Proceed
Could argue unsure of METS and that testing might change mgmt? then - postpone for testing
Boss call
