Download Preoperative Assessment

Preoperative Assessment
Risk assessment and management
G. L. Bryson, MD, FRCPC, MSc
Department of Anesthesiology
The Ottawa Hospital – Civic
Campus
Objectives
• Perioperative morbidity and mortality
• You can’t avoid what you can’t anticipate
• Preoperative testing
• Less than you’d expect
• NPO guidelines
• Problems
Department of Anesthesiology
Civic Campus
Preoperative assessment
• Just like the rest of medicine…
• History
• Physical
• Laboratory
Department of Anesthesiology
Civic Campus
An approach to preoperative evaluation
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What’s wrong with the patient?
Is the patient is good as they can get?
If not, does it have to be better pre-op?
Getting to the OR is less than half the job.
Anticipate postoperative problems, then plan.
Department of Anesthesiology
Civic Campus
Anesthesia is bad for you
• Unable to protect airway
• Aspiration
• Obstruction
• Altered control of ventilation
• Diminished response to CO2 and O2
• Altered respiratory mechanics
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• FRC, restrictive chest wall defect
Myocardial depression
Decreased conductivity
Vasodilatation
Immune suppression
Department of Anesthesiology
Civic Campus
The Killing Fields
• Getting patients out of the OR is easy
• Getting patients home is another matter
• Postoperative course complicated by:
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Increased O2 demand
Myocardial ischemia/infarction
Respiratory depression / VQ mismatching
Hemorrhage
Fluid and electrolyte shifts
Hypercoagulable
Protein catabolism
Department of Anesthesiology
Civic Campus
System implicated
Causes of 3-day
postop mortality
NCEPOD 2002
www.ncepod.org. uk
% of cases
Cardiovascular
Respiratory
59
25
Renal
Sepsis
22
21
Hematological
GI
Metabolic
12
11
10
Surgical condition
CNS
Hepatic
9
8
6
Department of Anesthesiology
Civic Campus
Functional capacity predicts outcome
• Postoperative cardiac deaths confined to
those with VO2Max < 3 METS
Older P. Chest 1999;116:355-62
• Inability to climb 2 flights of stairs 82% PPV
(97% specific) for postoperative CV/RS
complications
Girish M. Chest 2001;120:1147-51
• Self-reported exercise tolerance < 2 flights of
stairs doubled risk of complications following
non-cardiac surgery (20% v 10%)
Reilly DF. Arch Intern Med 1999;159(18):2185-92
Department of Anesthesiology
Civic Campus
ASA Physical Status Classification
Class
I
II
III
IV
V
E
Description
Healthy
Systemic disease
Systemic disease
Systemic disease
no functional limitation
with functional limitation
with functional limitation
constant threat to life
Moribund
unlikely to survive 24 hrs
with or without surgery
Emergency procedure
Department of Anesthesiology
Civic Campus
ASA class and mortality
ASA
Class
I
Vercanti Marx Cohen Forrest
1970
1973 1986
1990
0.07
0.06
0.07
0.00
II
0.24
0.40
0.20
0.04
III
1.43
4.3
1.15
0.59
IV
7.46
23.4
7.66
7.95
V
9.38
50.7
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-
Department of Anesthesiology
Civic Campus
Revised Cardiac Risk Index
Risk Factor
Cardiac Events
Adjusted OR
Crude Data
(95% CI)
High risk surgery
18/490 (4%)
2.6 (1.3 – 5.3)
CAD
26/478 (5%)
3.8 (1.7 – 8.2)
CHF
19/255 (7%)
4.3 (2.1 – 8.8)
CVD
10/140 (7%)
3.0 (1.3 – 6.8)
Insulin therapy
3/59 (5%)
1.0 (0.3 – 3.8)
Cr > 177
3/55 (5%)
0.9 (0.2 – 3.3)
Lee TH. Circulation 1999;100:1043-1049
Department of Anesthesiology
Civic Campus
Revised Cardiac Risk Index
and Cardiac Events
Risk Factors
Cardiac Events (%)
95% CI
0
0.4
0.05 – 1.5
1
0.9
0.3 – 2.1
2
3 or more
6.6
11.0
3.9 – 10.3
5.8 – 18.4
Lee TH. Circulation 1999;100:1043-1049
Department of Anesthesiology
Civic Campus
Risk Factor
Points
Type of Surgery
AAA
15
Thoracic
14
Upper Abdominal
Risk factors for
postoperative pneumonia
Points
Pneumonia (%)
10
0 – 15
0.24
Neck
8
Neurosurgery
8
16 – 25
1.18
26 – 40
4.6
41 – 55
10.8
> 55
15.8
Age
> 80 years
17
70 – 79 years
13
60 – 69 years
9
Functional Capacity
Totally dependent
10
Incidence
1.5%
Partially dependent
6
30-day mortality
21%
Weight Loss > 10% in past 6 mo
7
COPD
5
11 others worth
4
Arozullah AM. Ann Intern
Med 2001;135:847-57.
Department of Anesthesiology
Civic Campus
Preoperative testing
• Routine preoperative testing isn’t helpful
Munro J. Health Technology Assessment 1997;1(12)
• Testing should “follow” history and physical
• Like most testing, it’s most helpful when you don’t
know what the answer is.
• OMA-GAC statement
•
http://gacguidelines.ca/pdfs/tools/Ontario%20Preoperative%20Testing
%20Grid.pdf
• Elective versus emergency patient
Department of Anesthesiology
Civic Campus
OMA-GAC
recommendations
http://gacguidelines.ca/pdfs/tools/
Ontario%20Preoperative%20Test
ing%20Grid.pdf
Department of Anesthesiology
Civic Campus
TOH fasting guidelines
• For elective surgery:
• NPO solids at 2400
• Unlimited water until 3 hours preop
• For urgent surgery:
• NPO solids a minimum of 6 hours
• NPO clear fluids 3 hours
• Modified by urgency of surgery
• All usual medications given, except
• Anticoagulants, oral hypoglycemics, MAOIs
• Insulin and glucose require physician order
Department of Anesthesiology
Civic Campus
Withholding preoperative medication
% of patients in whom
drug was withheld
Drug Class
Anti-anginal
Anti-arrhythmic
Anti-hypertensive
Thyroid
Bronchodilator
Steroids
All surgeries Non-emergency
27
22
25
20
34
43
16
19
33
31
15
17
NCEPOD 2002
www.ncepod.org. uk
Department of Anesthesiology
Civic Campus
Valvular or congenital heart disease
• Stenotic lesions intolerant of changes in
preload/afterload
• RL shunts aggravated by hypoxia & SVR
• Important to understand the plumbing
• Preoperative echocardiogram helpful
• Anticoagulation issues
• SBE prophylaxis
•
www.americanheart.org/Scientific/statements/1997/079701.html
Department of Anesthesiology
Civic Campus
Subacute bacterial endocarditits
• Oral / dental surgery
• Ampicillin 2000 mg (50 mg/kg) IV 60 min pre-op
• Cefazolin 1000 mg (25 mg/kg) IV 60 min pre-op
• Clindamycin 600 mg (20 mg/kg) IV 60 min pre-op
• Gastrointestinal, genitourinary
• As above, plus
• Gentamicin 1.5 mg/kg IV 60 minutes pre-op
• Vancomycin 1000 mg (20 mg/kg) IV 60 minutes
pre-op, if penicillin-sensitive
• Repeat Ampicillin 6 hours post-op if high-risk
pathology
http://circ.ahajournals.org/cgi/content/full/96/1/358
Department of Anesthesiology
Civic Campus
Pacemakers and AICDs
• Pacemakers
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Should be evaluated preoperatively
If pacemaker dependent, reprogram to VOO
Rate adaptive functions may need to be disabled
Use bipolar cautery, if possible
Short bursts if monopolar required
• AICDs
• Must be turned off preoperatively
• in monitored environment
Department of Anesthesiology
Civic Campus
Anticoagulation
• Normal coagulation expected preoperatively
• Neuraxial hematoma & surgical hemorrhage
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Coumadin held for 5 days
INR less than 1.4
LMWH held for 24 hours
UFH held for 6 hours
Fancy antiplatelet drugs withdrawn (7 days)
ASA is OK for most procedures
• Vitamin K needs a day
• Don’t drown folks with FFP
Department of Anesthesiology
Civic Campus
I think that’s a blood thinner
• Clopidogrel (Plavix)
• Abciximab (RheoPro)
• Eptifibatide (Integrilin)
• Low molecular weight heparins
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Dalteparin (Fragmin)
Enoxaparin (Lovenox)
Nadroparin (Fraxiparin)
Tinzaparin (Innohep)
• Fondaparinux (Arixtra)
• Ximelagatran (Exanta)
Department of Anesthesiology
Civic Campus
Summary
• Preoperative assessment must identify and
anticipate perioperative problems
• Getting to the OR is the easy part
• Communication is essential
• Fasting should not exclude hydration or
medication
• Laboratory testing should be individualized
Department of Anesthesiology
Civic Campus
Questions??
The surgeon is a carnivorous beast.
It’s happy only when there is fresh meat
on the table.
Ross Kerridge MD, FRCA
Newcastle, Australia
At WCA Montreal 2000
Department of Anesthesiology
Civic Campus
Case 1
• 64 yr old male scheduled for hemicolectomy
for colon ca. Past history includes:
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Diabetes x 15 years (on insulin)
CVA 3 years ago
Stable CCS 3 angina
He takes diltiazem, hctz, and plavix
• What is his risk of cardiovascular event?
• What preoperative tests would you order?
• What preop instructions would you give?
Department of Anesthesiology
Civic Campus
Revised Cardiac Risk Index
Risk Factor
Cardiac Events
Adjusted OR
Crude Data
(95% CI)
High risk surgery
18/490 (4%)
2.6 (1.3 – 5.3)
CAD
26/478 (5%)
3.8 (1.7 – 8.2)
CHF
19/255 (7%)
4.3 (2.1 – 8.8)
CVD
10/140 (7%)
3.0 (1.3 – 6.8)
Insulin therapy
3/59 (5%)
1.0 (0.3 – 3.8)
Cr > 177
3/55 (5%)
0.9 (0.2 – 3.3)
Lee TH. Circulation 1999;100:1043-1049
Department of Anesthesiology
Civic Campus
Risk of cardiac morbidity?
Lee TH. Circulation 1999;100:1043-9
Department of Anesthesiology
Civic Campus
AHA ACC guidelines for cardiac
evaluation prior to noncardiac surgery
Department of Anesthesiology
Civic Campus
What about ß-blockers?
Mangano
Poldermans
Treated
Control
Treated
Control
99
101
59
53
In-hospital mortality
1(1)
2 (2)
2 (3)
9 (17)
In-hospital death/mi
2 (2)
4 (4)
2 (3)
18 (34)
16 (17)
32 (32)
8 (14)
14(32)
Patients
Post-discharge PCM*
Mangano DT. NEJM 1996;335(23):1713-20
Wallace A. Anesthesiology 1998;88(1):7-17
Poldermans D. NEJM 1999;341(24):1789-94
Poldermans D. Eur Heart J 2001;22(15):1353-8.
Department of Anesthesiology
Civic Campus
An aspirin an day…
Outcome
ASA %
No ASA %
MI
2.71
4.61
CVAt
1.12
1.69
CVAh
0.59
0.37
GI bleed
0.76
0.35
Wound bleed
7.71
5.58
All adverse events
12.89
12.90
Mortality
2.05
2.78
QALY
14.79
14.72
Neilipovitz DA. A&A 2001;93:573-80
Department of Anesthesiology
Civic Campus
ASA and perioperative hemorrhage
Bleed
Fatal
Major
Wound
ATC III
PEP
Control Treated Control Treated
0
0.05
0.2
0.2
0.4
0.7
2.4
2.9
5.6
7.8
3.9
4.4
Antiplatelet Trialists’ Collaboration. III. BMJ 1994;308:235-48
Pulmonary Embolism Prevention Trial. Lancet 2000;355:1295-302
Department of Anesthesiology
Civic Campus
Case 2
• A 45 yr old male is scheduled for TURP.
• He has hypertension, atrial fibrillation, and
had a mechanical aortic valve placed 4 years
ago.
• He takes metoprolol and coumadin.
• What investigations?
• What instructions?
Department of Anesthesiology
Civic Campus
Coumadin and thrombosis
Indication
Annual Risk Annual Risk
Risk
Treated
Untreated Reduction
Atrial fibrillation
2.3 %
7.4%
67%
Aortic valve
Mitral valve
1.9%
4.7%
12.3%
22.2%
85%
79%
Department of Anesthesiology
Civic Campus
Who needs special care with coumadin?
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DVT < 3 months ago
History of recurrent DVT
Arterial thromboembolism < 3 months ago
Mechanical prosthetic heart valves
Tissue prosthetic heart valves + embolism
Thrombophilia (lupus ac, Factor V - L, C&S)
Atrial fibrillation + embolism
Department of Anesthesiology
Civic Campus
Coumadin withdrawal plan
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Day -5.
Day -3.
Day -2.
Day -1.
Day 0.
Day +1.
Stop coumadin.
Dalteparin 200 u·kg-1 sc.
Dalteparin 200 u·kg-1 sc.
Dalteparin 100 u·kg-1 sc.
Check INR pre-op
Is surgical blood loss controlled?
Restart coumadin
Dalteparin 200 u·kg-1 until INR >2.0
Department of Anesthesiology
Civic Campus
Subacute bacterial endocarditits
• Oral / dental surgery
• Ampicillin 2000 mg (50 mg/kg) IV 60 min pre-op
• Cefazolin 1000 mg (25 mg/kg) IV 60 min pre-op
• Clindamycin 600 mg (20 mg/kg) IV 60 min pre-op
• Gastrointestinal, genitourinary
• As above, plus
• Gentamicin 1.5 mg/kg IV 60 minutes pre-op
• Vancomycin 1000 mg (20 mg/kg) IV 60 minutes
pre-op, if penicillin-sensitive
• Repeat Ampicillin 6 hours post-op if high-risk
pathology
http://circ.ahajournals.org/cgi/content/full/96/1/358
Department of Anesthesiology
Civic Campus
Case 3
• 45 yr old female for lumbar spinal fusion
• Uses “some percocets” for pain control
• Smokes 1.5 packs per day
Department of Anesthesiology
Civic Campus
Smoking is bad for you
• 6x increase in pulmonary complications
• Need to stop > 4 weeks preop
Bluman LG. Chest 1998 Apr;113(4):883-9
• 3x increase in wound complications following
breast surgery
Sorensen LT Eur J Surg Oncol 2002 Dec;28(8):815-20
• 2x increase risk of bony non-union
Andersen T. Spine 2001 Dec 1;26(23):2623-8
Department of Anesthesiology
Civic Campus
Smoking cessation works
n
Age
Pack years
Wound
Reoperation
Any complication
Cessation
Control
56
66
35
3 (5%)
2 (4%)
10 (18%)
52
64
37
16 (31%)
8 (15%)
27 (52%)
Moller AM. Lancet 2002;359:114-7
Department of Anesthesiology
Civic Campus
Narcotic tolerance
• Important to document just how much
narcotic patients are taking preoperatively
• Previous intake must be accommodated in
perioperative care
• If patient takes 2 percocets 6 x day
• 60 mg oxycodone = 90 mg morphine
• 90 mg morphine po = 22.5 mg morphine IV
• Adjust PCA settings accordingly
Department of Anesthesiology
Civic Campus
Regional anesthesia and outcome
Rodgers A.
BMJ 2000;
321:1–12
Department of Anesthesiology
Civic Campus