The importance of preoperative assessment and evaluation to prepare the patient to surgical procedure is directly proportional with the degree of successful of any surgical procedure.
So, good preoperative assessment and evolution is necessary to avoid the morbidity and mortality that expected to the surgical procedures.
2. Reason for evaluation
īąAnesthesia and surgery are physiologically stressful.
īą Invasive interventions may exacerbate or uncover
underlying disease process.
īą most feared complications:
difficulty in oxygenation, ventilation,
myocardial infarction , and cerebrovascular accidents.
3. īą Allows the anesthesiologist, surgeon to
stratify and reduce risk for the patient.
īą Screen for and manage co-morbid disease.
īą Identify need for specialized technique.
īą Identify need for advanced post-op care.
5. Why is anesthesia risky?
īąDifficulty in obtaining an airway (adequately
oxygenate and ventilate). Injury during airway
management.
īąInduction: time of hemodynamic stress;
hypotension, hypertension, arrhythmias,
arrest.
īąMaintenances: differing degrees of
stimulation, fluid shifts, blood loss.
6. īąEmergence: physiologically stressful, secure
airway may be lost, hypothermia.
īąAnaphylactic reactions to medications.
īą positioning.
īą Spinal/epidural/regional carries risk ?!!
9. 3. Investigations.
4. Risk of anesthesia and suspected surgery.
5.Marking the site/side of operation.
6.Informed written consent.
10. The ASA Physical Status Classification
Example
Definition
ASA
Non-smoker
Normal healthy patient
1
Smoker, BMI 30-40,
pregnant, well
controlled HTN/DM
Mild systemic disease (no functional
limitations)
2
Poorly controlled
HTN/ DM
Sever systemic disease (some functional
limitation)
3
Recent MI, CVA,
sever CHF
Sever systemic disease that is a constant threat
to life
4
Ruptured AAA
Moribund patient who is not expected to
survive without the operation
5
Brain dead pat. whose organs are being
removed for donation
6
e.g. ASA 2E
Emergency
E
11. Airway Examination
ī§ Teeth and bite.
ī§ Mouth opening (inter-incisor distance).
ī§ Mallampati score.
ī§ Thyromental, Hyomental distances.
ī§ Length & thickness of neck.
ī§ Range of motion of head & neck.
16. Clinical Predictors of Increased
Perioperative Cardiovascular Risk
īąMINOR
ī§ Advanced age.
ī§ Abnormal ECG, Abnormal Rhythm.
ī§ Low functional capacity (e.g. inability to climb
one flight of stairs with a bag of groceries).
ī§ History of stroke.
ī§ Uncontrolled systemic hypertension.
17. Functional Capacity and Metabolic
Equivalent:
ī§ 1 MET: Can you take care of yourself? Eat,
dress, use the toilet? Walk a block or two on
level ground.
ī§ 4 METs : Do light work around the house like
dusting or washing the dishes? Climb a flight
of stairs.
ī§ >10 METs : Participate in sports like swimming
, tennis, football , basketball..?
20. īąMAJOR
ī§ Acute (<7day) or recent MI (<1month) with
evidence of ischemic risk.
ī§ Unstable or severe angina.
ī§ Decompensated heart failure.
ī§ Significant arrhythmias.
21. ī§ High-grade AV block.
ī§ Symptomatic ventricular arrhythmia.
ī§ SVT uncontrolled rate.
ī§ Severe valvular disease.
24. Intermediate risk (<5%):
ī§ Carotid.
ī§ Head and neck surgery.
ī§ Intraperitoneal and
intrathoracic procedures.
ī§ Orthopedic surgery.
ī§ Prostate surgery.
25. High risk (>5%):
ī§ Emergent major operations,
particularly in elderly.
ī§ Aortic and other major
vascular surgery.
ī§ Surgical procedures
associated with large
fluid shifts and/or blood loss.
26.
27. Evaluating Respiratory Disease
Risk Factors for Pulmonary Complications:
ī§ Urea > 40 mg/dL.
ī§ Age > 70.
ī§ COPD.
ī§ Neck, thoracic, upper abdominal, aortic or
neurological surgery.
29. URTI & anesthesia
ī§ Mild symptoms â can usually proceed.
ī§ Severe symptoms or underlying disease â
postpone.
ī§ Risk of increased bronchial reactivity and LRTI
â postpone.
ī§ Spinal ?! Epidural ?!
30. Diabetes Mellitus
ī§ FBS > 126mg/dl, HbAâc âĨ6.5%.
ī§ Should be well controlled prior to elective
surgery. ( 150 â 180mg/dl ?).
ī§ Surgical stress promotes hyperglycemia in the
diabetic patient.
ī§ Perioperative morbidity - end-organ damage.
31. ī§ â -ÂŊ of patients with type2 DM may unaware
of their condition till time of surgery.
ī§ Preoperative CXR in DM in more likely to
uncover cardiac enlargement , pulmonary
vascular congestion, pleural effusion, although
it is not routinely indicated.
32. ī§ ECG: Silent ischemia.
ī§ DM with HTN â 50% autonomic neuropathy.
ī§ DM > 10 years â CAD.
33. Problems of DM with Anesthesia
ī§ Autonomic neuropathy.
ī§ Delayed gastric emptying.
ī§ Renal impairment.
ī§ limited mobility of joints.
35. ī§ Nicotine half-life: 1-2 hrs.
ī§ Carbon monoxide (CO) half-life: 4hrs.
ī§ Bronchociliary function improves within 2-3days of
cessation.
36. ī§ Sputum volume decreases to normal levels
within 2 weeks.
ī§ Smoker with irritable air way, wheezy chest ?
Mask A ?, LMA ?, ETT ?
Smoking immediately before surgeryâĻ?!!
38. ī§ Other names: narghile, arghile, shesha.
ī§ No indication that water pipe tobacco
smoking (WTS) is less risky than cigarette
smoking.
ī§ Word wide icreasing among adolescents and
young adults, (30-40% of high school and
college students).
39. WTS Vs Cigarette
ī§ Studies shows that measurement of total puff
volume; WTS: 50 -80 L of smoke, in contrast
cigarette smokers inhale about 0.5 â 0.8
L/single cigarette, i.e. the ratio is 60 -160
cigarette.
ī§ 1.2 times of nicotine, 8 times of CO, 3 times of
nitric oxides, 4-15 times acrolien, 6-31 times
the formaldehyde, 3- 245 times the polycyclic
aromatic hydrocarbones (PAHs).
40. ī§ Should be carefully assessed preoperatively
with additional precautions and should be
treated in the same manner as a cigarette
smoker.
ī§ A high carboxyhemoglobin levels (15 â 28%)
suggest that patients require special attention.
NR: non smokers: up to 3%, smokers 2-5%,
heavy smokers 5-10%.
41. ī§ New generation oximeters are highly
advisable.
ī§ Blood sample on the day of the surgery for
measurement of carboxyhemoglobin... ?
43. Hold on day of surgery
ī§ Diuretics: unless thiazide for hypertension
unless severe heart failure.
ī§ Insulin & OHA ?!
ī§ ACEIâs or ARBâs (individual choice).
depends on procedure / risk of hypotension
44. e.g.
Time
NSAIDs
Stop 48 hours pre-op
Warfarin (bridging to
enoxaparin).
Stop 4 days pre-op
Clopidogrel
Stop 7 days pre-op
Stop 6 weeks prior to surgery.
Oral Contraceptive Pills
Aspirin 75 mg usually continued.
47. Minimum Fasting
period
Ingested Material
2 hours
Clear liquids: water, fruit juices without pulp,
carbonated beverages, tea and black coffee
(clear liquids should not include alcohol)
4 hours
Breast Milk
6 hours
Infant formula
6 hours
Non-human milk
6 hours
Light meal (typically consists of toast and clear
liquids)
8 hours
Full, heavy, fatty meal
48. Preoperative laboratory tests
ī§ No evidence supports the routine use of
laboratory tests.
ī§ Selected tests should based on patient's
preoperative history, physical examination and
proposed surgical procedures.
49. Unless there has been intervening
changes in patient's status:
âĸ
within 6 months of the
procedure
ECG & Chest X-
Ray
within one month are accepted
in the stable
conditions
Chemistries and hemoglobin/
HTC
not more than 1 week
Coagulation
studies
4 month
intervals
Virology screen
51. Antiplatelet
Aspirin and NSAID
ī§Either medication alone does not
increase risk.
ī§ Normal bleeding time does not indicate normal
homeostasis and vise versa.
ī§ Check for history of bruising, excessive bleeding,
female, old age.
53. Parenteral anticoagulant
Heparin:
ī§ Monitoring: aPTT.
ī§ To be stopped 4-6 hr.
LMW Heparin:
ī§ Half-life: 3-4 times more than Heparin.
ī§ prophylactic dose: wait 10 - 12 hr.
ī§ Therapeutic dose: delay 24 hr.
54. Anesthesia and Herbal Therapy
īąGarlic
ī§ Reduces blood pressure
, thrombus formation, and
serum lipid and cholesterol
levels.
ī§ Inhibits in vivo platelet aggregation is dose-
dependent.
ī§ Time to normal hemostasis after
discontinuation : 7 days.
55. īąGinkgo
ī§ Cognitive disorders, peripheral
vascular disease, vertigo, tinnitus,
and altitude sickness.
ī§ Inhibits platelet activating factor.
ī§ Time to normal hemostasis after
discontinuation :36 hrs.
56. īąGinseng
ī§ Protects against effects of stress.
ī§ May inhibit the coagulation cascade.
ī§ Time to normal hemostasis after
discontinuation â 24 hrs.
These represent no added risk for
spinal hematoma
57. Summery
ī§ Preoperative evaluation is mandatory.
ī§ The anesthetist is uniquely qualified to
evaluate the risk and he is responsible for
deciding fitness for anesthesia.
ī§ The risk is cumulative of: medical + surgical.
58. ī§ Preoperative investigation should be
requested according to its indications, routine
(blanket )preoperative investigations waste
resources & time.
ī§ Mendelsonâs syndrome may be fatal, there for
fasting time should be taken seriously.