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.

1. Principles of Preoperative
evaluation
and preparation
Mahmood Hasan Taha
H.D Anesthesia
Head of Anesthesia Dep.
Zakho Emergency H.
April 2018

2. Reason for evaluation
Anesthesia and surgery are physiologically stressful.
 Invasive interventions may exacerbate or uncover
underlying disease process.
 most feared complications:
difficulty in oxygenation, ventilation,
myocardial infarction , and cerebrovascular accidents.

3.  Allows the anesthesiologist, surgeon to
stratify and reduce risk for the patient.
 Screen for and manage co-morbid disease.
 Identify need for specialized technique.
 Identify need for advanced post-op care.

4. Avoid unnecessary delays/cancellations.
Motivate patients to improve pre-op.
outcome.
 Obtain informed consent.

5. Why is anesthesia risky?
Difficulty in obtaining an airway (adequately
oxygenate and ventilate). Injury during airway
management.
Induction: time of hemodynamic stress;
hypotension, hypertension, arrhythmias,
arrest.
Maintenances: differing degrees of
stimulation, fluid shifts, blood loss.

6. Emergence: physiologically stressful, secure
airway may be lost, hypothermia.
Anaphylactic reactions to medications.
 positioning.
 Spinal/epidural/regional carries risk ?!!

7. Evaluation Steps

8. 1. History:
present illness, PMH, PS/AH, Social H.,
drugs., Exercise and METs.
2. Examination:
Airway, CVS, Resp., Musculoskeletal,
Neurological, Peripheral vasculature, BMI.

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
 Teeth and bite.
 Mouth opening (inter-incisor distance).
 Mallampati score.
 Thyromental, Hyomental distances.
 Length & thickness of neck.
 Range of motion of head & neck.

12. Mallampati Classification
(pharyngeal view)

13. Mallampati Class ?

14. Mallampati Class ?

15. Thyromental distance

16. Clinical Predictors of Increased
Perioperative Cardiovascular Risk
MINOR
 Advanced age.
 Abnormal ECG, Abnormal Rhythm.
 Low functional capacity (e.g. inability to climb
one flight of stairs with a bag of groceries).
 History of stroke.
 Uncontrolled systemic hypertension.

17. Functional Capacity and Metabolic
Equivalent:
 1 MET: Can you take care of yourself? Eat,
dress, use the toilet? Walk a block or two on
level ground.
 4 METs : Do light work around the house like
dusting or washing the dishes? Climb a flight
of stairs.
 >10 METs : Participate in sports like swimming
, tennis, football , basketball..?

18. Perioperative cardiac
and long-term risks
are elevated in
patients unable to
obtain 4-MET Demand .

19.  INTERMEDIATE
 Mild angina pectoris.
 Previous MI (>1month).
 Compensated heart failure.
 Diabetes mellitus (particularly insulin type).
 Renal insufficiency (creatinine >2.0).

20. MAJOR
 Acute (<7day) or recent MI (<1month) with
evidence of ischemic risk.
 Unstable or severe angina.
 Decompensated heart failure.
 Significant arrhythmias.

21.  High-grade AV block.
 Symptomatic ventricular arrhythmia.
 SVT uncontrolled rate.
 Severe valvular disease.

22. Surgery-specific risk
.

23. Low risk (<1%):
Endoscopic procedures.
Superficial procedures.
Cataract surgery.
Breast surgery.

24. Intermediate risk (<5%):
 Carotid.
 Head and neck surgery.
 Intraperitoneal and
intrathoracic procedures.
 Orthopedic surgery.
 Prostate surgery.

25. High risk (>5%):
 Emergent major operations,
particularly in elderly.
 Aortic and other major
vascular surgery.
 Surgical procedures
associated with large
fluid shifts and/or blood loss.

27. Evaluating Respiratory Disease
Risk Factors for Pulmonary Complications:
 Urea > 40 mg/dL.
 Age > 70.
 COPD.
 Neck, thoracic, upper abdominal, aortic or
neurological surgery.

28.  Prolonged procedures (> 2 hours).
 Emergency surgery.
 Hypoalbuminaemia (< 30 g/L).
 Exercise tolerance < 1 flight of stairs, <100
yards (<91M).
 BMI > 30.

29. URTI & anesthesia
 Mild symptoms → can usually proceed.
 Severe symptoms or underlying disease →
postpone.
 Risk of increased bronchial reactivity and LRTI
→ postpone.
 Spinal ?! Epidural ?!

30. Diabetes Mellitus
 FBS > 126mg/dl, HbA₁c ≥6.5%.
 Should be well controlled prior to elective
surgery. ( 150 – 180mg/dl ?).
 Surgical stress promotes hyperglycemia in the
diabetic patient.
 Perioperative morbidity - end-organ damage.

31.  ⅓ -½ of patients with type2 DM may unaware
of their condition till time of surgery.
 Preoperative CXR in DM in more likely to
uncover cardiac enlargement , pulmonary
vascular congestion, pleural effusion, although
it is not routinely indicated.

32.  ECG: Silent ischemia.
 DM with HTN → 50% autonomic neuropathy.
 DM > 10 years → CAD.

33. Problems of DM with Anesthesia
 Autonomic neuropathy.
 Delayed gastric emptying.
 Renal impairment.
 limited mobility of joints.

34. Smoking and Anesthesia

35.  Nicotine half-life: 1-2 hrs.
 Carbon monoxide (CO) half-life: 4hrs.
 Bronchociliary function improves within 2-3days of
cessation.

36.  Sputum volume decreases to normal levels
within 2 weeks.
 Smoker with irritable air way, wheezy chest ?
Mask A ?, LMA ?, ETT ?
Smoking immediately before surgery…?!!

37. Hookah
(Water pipe Tobacco Smoking)

38.  Other names: narghile, arghile, shesha.
 No indication that water pipe tobacco
smoking (WTS) is less risky than cigarette
smoking.
 Word wide icreasing among adolescents and
young adults, (30-40% of high school and
college students).

39. WTS Vs Cigarette
 Studies shows that measurement of total puff
volume; WTS: 50 -80 L of smoke, in contrast
cigarette smokers inhale about 0.5 – 0.8
L/single cigarette, i.e. the ratio is 60 -160
cigarette.
 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.  Should be carefully assessed preoperatively
with additional precautions and should be
treated in the same manner as a cigarette
smoker.
 A high carboxyhemoglobin levels (15 – 28%)
suggest that patients require special attention.
NR: non smokers: up to 3%, smokers 2-5%,
heavy smokers 5-10%.

41.  New generation oximeters are highly
advisable.
 Blood sample on the day of the surgery for
measurement of carboxyhemoglobin... ?

42. Preoperative Medication Management
 What to stop ?
 What to keep ?
 What to add ?

43. Hold on day of surgery
 Diuretics: unless thiazide for hypertension
unless severe heart failure.
 Insulin & OHA ?!
 ACEI’s or ARB’s (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.

45. Premedication
 Alleviate anxiety/sedation/amnesia
Reduce risk of reflux.
 Manage pain.
 Control perioperative risk.
Dry secretions.

46. Preoperative Fasting
Guidelines

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
 No evidence supports the routine use of
laboratory tests.
 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:
•
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

50. Anticoagulant and antiplatelet
(ASRA recommendations)

51. Antiplatelet
Aspirin and NSAID
Either medication alone does not
increase risk.
 Normal bleeding time does not indicate normal
homeostasis and vise versa.
 Check for history of bruising, excessive bleeding,
female, old age.

52. Anticoagulant
Oral anticoagulant: Warfarin
Monitoring: PT and INR.
Must be stopped ideally 4-5 days (normal PT &INR),
this should be discussed with the physician.

53. Parenteral anticoagulant
Heparin:
 Monitoring: aPTT.
 To be stopped 4-6 hr.
LMW Heparin:
 Half-life: 3-4 times more than Heparin.
 prophylactic dose: wait 10 - 12 hr.
 Therapeutic dose: delay 24 hr.

54. Anesthesia and Herbal Therapy
Garlic
 Reduces blood pressure
, thrombus formation, and
serum lipid and cholesterol
levels.
 Inhibits in vivo platelet aggregation is dose-
dependent.
 Time to normal hemostasis after
discontinuation : 7 days.

55. Ginkgo
 Cognitive disorders, peripheral
vascular disease, vertigo, tinnitus,
and altitude sickness.
 Inhibits platelet activating factor.
 Time to normal hemostasis after
discontinuation :36 hrs.

56. Ginseng
 Protects against effects of stress.
 May inhibit the coagulation cascade.
 Time to normal hemostasis after
discontinuation – 24 hrs.
These represent no added risk for
spinal hematoma

57. Summery
 Preoperative evaluation is mandatory.
 The anesthetist is uniquely qualified to
evaluate the risk and he is responsible for
deciding fitness for anesthesia.
 The risk is cumulative of: medical + surgical.

58.  Preoperative investigation should be
requested according to its indications, routine
(blanket )preoperative investigations waste
resources & time.
 Mendelson’s syndrome may be fatal, there for
fasting time should be taken seriously.