Preoperative assessment Flashcards
How do we consider a surgery as an emergency surgery?
if its life, limb, or organ saving
OPTIMAL TIMING <6hrs
When should an urgent surgery be preformed?
if there is any condition that threatens life, limb, or organ
OPTIMAL TIMING 6-24hrs
If a patient is stable, but requires intervention within the next couple of days or weeks, how do we categorize this surgery?
time-sensitive surgery
What are the surgeries that can take up to 1 year to preform?
elective surgeries
What are the systems that should be reviewed before anesthesia?
CNS
- GCS = 8 intubation has to be preformed to preserve airway but wait until it gets higher to take to OR
(GCS decreases 2 after patient wakes up)
CVS
- all anesthesia drugs weaken the heart so patient with a weak heart may develop MI
- if heart is transplanted
- use regional anesthesia is heart is diseased
Liver Stat
- drug metabolism
- clotting factors
Lung Stat
- use regional anesthesia if lungs are diseases
Kidney
- drug clearance
Stomach
- when was the last meal
- gerd
What are the most important things to take from a patient’s history before anesthesia?
- if patient had previous anesthesia and malignant hyperthermia
- allergies
- medications
- difficult intubation
- previous experience
- delayed emergence/recovery
What are the drugs that may interfere with anesthesia?
HEART BRAIN
-heart failure - anticonvulsants
-antihypertensives - psychiatric medications
- antiarrhythmic
BLOOD
- anticoagulants
LUNG - antiplatelets
- bronchodilators
ENDROCRINE
- steroids
- insulin
What drugs should be stopped before surgery?
ANTICOAGULANTS
which drugs will be continued throughout surgery?
antihypertensives
Which drugs require a dose modification pre-op?
steroids need a stress dose to compensate body need during surgery
Which drugs should be changed?
Warfarin should be changed to heparin then stopped 4 hours pre-op
What physical examination should be preformed for the brain pre-op?
- level of consciousness
- any neurological deficit
- paresthesia
- paraplegia
- peripheral nerve injury
- position on operating table or surgical complication
- GCS
What are the airway examination tests that should be preformed pre-op?
- Mallampati’s test
- Thyromental and sternomental distance (normal is
- 5cm)
- less than 6cm is difficult
- 5cm)
- head extension (35 degrees or more is normal)
- mouth opening
- less than 4cm or 3 fingers is difficult - Cormack and Lehane view
- Grade I: vocal cords visible
- Grade II: only posterior commissure or arytenoids
visible
-Grade III: only epiglottis visible
- Grade IV: no glottic structure visible - X-ray, CT, or MRI for lower airway if abnormality is suspected
- Flexible nasendoscopy if there’s a suspected abnormality above vocal cords
What should be done in case of difficult intubation?
- awake intubation
- awake percutaneous tracheostomy under local anesthesia
- postpone surgery
- refer to a higher center
What symptoms could be found in case of heart problem during physical examination?
raised JVP
pitting edema
How do we assess the preioperative cardiac risk?
Metabolic equivalent task (MET): measure of functional capacity which estimates energy requirement for daily activities
How many METS are required for surgery?
MINIMUM 4 METS
1 MET is 3.5mL/kg/min = resting oxygen uptake
What are the blood tests required pre-op?
- Haemoglobin (13 - 18 in males & 11.5 - 16.5 in females)
- HCT (0.4 - 0.52)
- Platelets (150-400)
- WBCs (4-11)
- Group and screen/crossmatch
- ABO (10mins)
- cross matching (45mins)
What tests of coagulation should be made pre-op?
- INR to monitor Warfarin therapy
- APTT to monitor unfractioned heparin
- TT to diagnose hypo/dysfibrinogenaemia
- assess liver function
- assess coagulopathy
Why is the ECG used?
To assess cardiac rhythm and identify any pathology that may cause surgical risk
- Q-wave = previous infarction
- arrhythmia = conduction defects
- bundle branch block = heart ischemia
- strain patterns = hypertrophy of heart chambers (uncontrolled blood pressure)
What is the most important lead to check pre-op?
LEAD II (measures the same direction of conduction) most accurate
What is the indication of an ECHO?
structural and functional assessment of heart and great vessels
STRUCTURE
- size of chambers
- wall motion
- valves
FUNCTION
- ejection fraction
- pulmonary artery
- aorta
- valves
What is the purpose of preoperative evaluation?
- to identify patients whose conditions are too poor so surgery will only hasten their death
- can lead anesthesiologist to change their anesthetic plan
- to provide patient wit anesthetic risk
- to provide psychological support
- to obtain informed consent for the anesthetic plan
Which classification is based ONLY on the patients medical disease NOT the surgical procedure?
American Society of Anesthesiologist’s classification ASA
1 normal
2 controlled systemic disease
3 uncontrolled systemic disease
4 severe systemic disease that is a constant threat to life
5 moribund patient who is not expected to survive without the surgery
6 brain dead patient whose organs are being removed for donor purposes
what are the pre-operative fasting guidelines?
- Clear liquids - 2 hours
- breast milk - 4 hours
- normal milk - 6 hours
- light meal - 6 hours
- heavy meal - 8 hours
- medications - depends on their excretion
Why should a proper preoperative evaluation always be done?
It will guide the anesthetic plan if it was inadequate it will lead to - avoidable delays - cancellations - complications - costs
