preoperative evaluation for residents of anesthesia

1. Mansoor Masjedi MD , FCCM
Grand round of anesthesia dept.,
SUMS , Nov. 2013

2. A brief review

5. a
b
c
d

6. Asthma
A chronic inflammatory disease characterized by
obstruction of the airways that is partially or
completely reversible with Rx or spontaneously
Patients with mild, well-controlled asthma have no
greater risk associated with anesthesia and surgery
than normal individuals do

7. Asthma
O2 saturation by pulse oximetry is useful
ABG only in severe acute exacerbation
DDx. of Wheezing
 COPD
 GERD
 Vocal cord dysfunction
 Tracheal or bronchial stenosis
 Cystic fibrosis
 ABPA
 Heart failure

8. Asthma
Spirometry is the preferred diagnostic test, but a normal
result does not exclude asthma (strong suspicion →
methacholine challenge test or a trial of bronchodilator
therapy )
PFTs have no perioperative predictive value but in rare
instances may be useful to gauge the severity of disease or
the adequacy of therapy
Preop Chest X-ray is necessary only for evaluation of
infections or pneumothorax

10. COPD
Presence of symptoms on most days for at least 3
months for 2 successive years
oror
recurrent excessive sputum that severely impairs
expiratory airflow
An acute exacerbation is defined as an increase
in symptoms that requires a change in
management

11. COPD
FEV1↓ , FVC↑ , DLCO↓
PFT :not shown to predict periop outcome
C-xray : useful only when infection is suspected
ECG show: RAD , RBBB, or peaked P waves

12. Restrictive pulmonary disorders
Pulmonary : lung resection , pulmonary fibrosis, ILD
Extrapul. : kyphoscoliosis , obesity , AS , Myasth.gravis,
pleural efusion, Pneumothorax
FEV1 and FVC are reduced proportionally, so the ratio
is normal

13. Dyspnea
Chronic dyspnea of unclear etiology ,4 major DDx.:
asthma
 COPD
 interstitial lung disease
cardiac dysfunction

14. Dyspnea
Hx. & P/E → accurate dx in 2/3 of cases
Initial testing may include:
 ECG
 Htc (to exclude anemia)
 ABG
 TFT
 C-xray
 Spirometry
 oximetry at rest and while walking several feet
BNP levels may be useful.
Heart failure : BNP >400 pg/mL
PTE & cor pulmonale :BNP between 100 - 400 pg/mL

15. Surprisingly absent predictors in this list are asthma and
results from ABG or PFTs

16. Prescriptions for antibiotics, bronchodilators, and
steroids, referral to pulmonologists or internists, and
postponing surgery are important in patients at high
risk

18. Pulmonary Hypertension
Persistent Mean PAP> 25 mm Hg with a PAOP <15 mm
Hg
Occult PH is more problematic than fully recognized
disease because symptoms may be attributed to other
diseases and periop decompensation may occur
unexpectedly
Patients with PAH have a high rate of periop morbidity
and mortality

19.  Pulmonary Arterial Hypertension
 Primary pulmonary hypertension
 Sporadic
 Familial
 Associated with
 Collagen vascular disease
 Congenital shunts
 Portal hypertension
 HIV
 Drugs/toxins
 Persistent pulmonary hypertension of the newborn
 Pulmonary Venous Hypertension
 Left-sided heart disease
 Extrinsic compression of central pulmonary veins
 Pulmonary veno-occlusive disease
 Pulmonary Hypertension Related to Lung Disease or Hypoxemia
 Chronic obstructive pulmonary disease
 Interstitial lung disease
 Sleep-disordered breathing
 Neonatal lung disease
 Chronic exposure to high altitude
 Pulmonary Hypertension Caused by Chronic Thromboembolic Disease
 Pulmonary thrombosis or embolism
 Sickle cell disease
 Pulmonary Hypertension from Disorders Directly Affecting the Pulmonary
Vasculature
 Schistosomiasis
 Sarcoidosis

20. Pulmonary Hypertension
 Signs and symptoms of disease severity include:
 • Dyspnea at rest
 • Metabolic acidosis
 • Hypoxemia
 • Right HF(peripheral edema, hepatomegaly, ↑JVP)
 • Hx of syncope
Echo : screening test of choice
ECG: RAD, RBBB, RVH, tall R in V1 & V2,
P pulmonale (leads II, III, aVF, and V1)

21. Smokers and Those Exposed to Second-Hand Smoke
Active and passive smokers
↑ risk of periop resp. complications
Soon after a patient quits smoking
 carbon monoxide ↓
 Cyanide ↓
 Lower nicotine levels improve
vasodilation
 many toxic substances that impair
wound healing decrease
Buproprion or clonidine should be started
1 to 2 wks before an attempt at quitting;
nicotine replacement therapy is effective
immediately

23. Endocrine
Disorders

24. Diabetes Mellitus
 In the United States, 20 million diabetics ,
with 1 million new each year
 Females twice as commonly as in males
 Diabetic without known CAD or angina = a
nondiabetic with a previous MI for the risk
of myocardial ischemia or cardiac death
 Autonomic neuropathy is the best predictor
of silent ischemia
 Aggressive management of hyperglycemia
decreases postop complications

25. Diabetes Mellitus
The combination of HTN, diabetes, and age >55 yr accounts
for more than 90% of pts with renal insufficiency
Screening for kidney disease is accepted
Poorly controlled diabetes →risk for the development of stiff
joint syndrome→reduced cervical mobility → Diff. Airway ?
ECG ,electrolytes, BUN, Cr. , and BS is recommended for all
diabetic patients
Target FBS <110 mg/dL in noncritically ill hospitalized patients

27. Steroid

28. Renal Disease

29. Renal Disease
Chronic kidney disease (CKD) : GFR <60 mL/min/1.73
m2) for at least 3 months or significant proteinuria
CRF : GFR < 15 mL/min/1.73 m2
ARF: Urine output <0.5 mL/kg/hr
ESRD :loss of renal function ≥ 3 mo
CKD : a significant risk factor for cardiovascular
morbidity and mortality (considered to be equal to
angina, MI, or a history of known CAD)

30. Renal Disease
Valvular heart disease is common in pts undergoing maintenance
dialysis
Pulmonary hypertension and increased cardiac output occur in many
patients with an arteriovenous fistula
Preexisting renal insufficiency + diabetes + contrast medium → risk of
renal failure may be as high as 12% to 50%.
 ACEIs and ARBs prevent deterioration in patients with diabetes or renal
insufficiency but may worsen function during hypoperfusion states
 LMWHs are cleared by the kidneys and are not removed during dialysis

31. All Forms of Liver Disease
bilirubin >2.5 mg/dL → icterus can be seen in
mucous membranes and sclerae
 Reduction of ascites preop→ ↓risk of wound
dehiscence and improve pulmonary function
 Na restriction (in diet and IV solutions), diuretics
(esp. spironolactone, which inhibits aldosterone), and
even paracentesis are useful.

32. Coagulopathies
 Prolonged PT (without a hx of warfarin)→ the most
common cause is lab. error, liver disease, or
malnutrition
Prolonged aPTT can result from both hypocoagulable
and hypercoagulable cond.
The most common cause of a prolonged aPTT other
than heparin exposure is vWD

33. Thrombocytopenia
Surgery can be performed safely in patients with
platelet >50,000/mm3
Centroneuraxial anesthesia is safe with plt
>100,000/mm3

34. Thrombocytosis
 Plt >500,000/mm3 and may be:
physiologic (exercise, pregnancy)
primary (myeloproliferative disorder)
secondary (iron deficiency, neoplasm, surgery, chronic
inflammation)
Plt >1,000,000/mm3 →risk for thrombotic events such as
stroke, MI, pulmonary and mesenteric emboli, and
peripheral arterial and venous clots

36. Neurologic Diseases
Preop evaluation focuses on
the pulmonary system and degree of disability,
especially dysphagia and dyspnea.
Determination of room-air saturation and
orthostatic BP and HR is important

38. URTI & anaesthesia
Mild symptoms - can usually proceed
huge inconvenience to patient if cancelled
Severe symptoms (purulent secretions, productive cough, T > 38°C, or
signs of pulmonary involvement)
Postpone 4 wks
Intermediate severity - ?
? risk of increased bronchial reactivity
Additional risk factors :hx of asthma, need for intubation, surgery on
the airway, smoking hx, and a hx of prematurity in pediatric patients
Dr. Andrew Ferguson

39. Preoperative Evaluation of
Morbidly Obese Patients
Obesity
Present difficult intubation.
Perioperative basal lung collapse leading to
postoperative hypoxia.
History of sleep apnoea may lead to post-operative
airway compromise.
Ideally obese patients should lose weight
preoperatively, and co-existent diabetes and
hypertension stabilised

40. Preoperative Evaluation of Patients with Allergies
 Anaphylactic and
anaphylactoid reactions
during anesthesia =1 in 6000
Muscle relaxants :69%
latex (12%) and
Antibiotics (8%)

47. Fasting Guidelines
Time before anaesthesia Food or fluid intake
Up to 8 hours Unrestricted
Up to 6 hours Light meal
Up to 4 hours Breast milk
Up to 2 hours Clear liquids only (no solids, no fat)
2 hours pre-anaesthesia Nothing permitted
Dr. Andrew Ferguson

49. Preoperative Planning for
Postoperative Pain Management
Pain Relief
Method of postoperative analgesia should be in mind.
Allows deep breathing and coughing and
mobilisation.
Prevent secretion retention and lung collapse.
Reduces the incidence of postoperative pneumonia.
Epidurals appear particularly good at this for
abdominal and thoracic surgical procedures.

56. Preoperative consultation
Risk stratification
Risk modification
planning periop pt management
Ideally, the medical consultants who are part of the
periop evaluation should be the same individuals who
provide continuing care for the pt.

57. What is the diagnosis? How was it determined?
Are additional studies required for a more precise
determination?
Is the patient's condition optimized?
Should any specific recommendations be made for
postop management and follow-up?

59. : ‫فرمایند‬ ‫می‬ ‫پزشکی‬ ‫مهم‬ ‫اصل‬ ‫سه‬ ‫تشریح‬ ‫با‬ (‫)ع‬ ‫علی‬ ‫امام‬
‫باید‬ ‫ک‌کند‬ ‫طبابت‬ ‫که‬ ‫"هر‬
‫بترسد‬ ‫خدا‬ ‫از‬‫و‬‫باشد‬ ‫خیرخواه‬‫و‬‫برد‬ ‫کار‬ ‫به‬ ‫را‬ ‫خود‬ ‫سعی‬"

60. Thanks for your
patience
&
Have a nice
weekend