Download 8.CheeChoy

Perioperative Management
Intern Survival Kit
Dr Chee Choy
Senior Medical Registrar
Topics
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Management of antiplatelets/anticoagulation
Perioperative management of diabetes
mellitus
Evaluating and managing cardiac risk in
patients undergoing non-cardiac surgery
Perioperative management of respiratory and
sleep condition
Anti-platelets post-PCI
Aspirin + Clopidogrel continued for at least
recommended duration
BMS – 3-6/12 (at least 1/12)
 DES – 12/12
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Perioperative management of
antiplatelets
Aspirin
 Continue, EXCEPT for urology, plastics & ophthalmology or
if specific request
Clopidogrel
 Long duration of clinical action (half life of a platelet being
~10 days)
 For platelet activity to return to completely normal – needs to
be stopped for 7 days
 Cessation of clopidogrel for 5 days will allow turnover of ~
50% of platelets (adequate platelet activity)
Anticoagulation for AF
CHADS2
0
1
2
3
4
5-6
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Events/100 person years
Events/100 person years
Warfarin
0.25
No warfarin
0.49
0.72
1.27
2.20
1.52
2.50
5.27
2.35
4.60
6.02
6.88
CHADS2 <2 = Aspirin
CHADS2 ≥ 2 = Warfarin
CHADS2 -> CHA2DS2VASc
CHADS2 Risk
Score
CHA2DS2-VASc
Risk
Score
CHF
1
CHF or LVEF <
40%
1
Hypertension
1
Hypertension
1
Age > 75
2
Diabetes
1
Stroke/TIA/
2
Age > 75
1
Diabetes
1
Stroke or TIA
2
From ESC AF Guidelines
http://www.escardio.org/guidelines-surveys/escguidelines/GuidelinesDocuments/guidelines-afib-FT.pdf
Thromboembolism
Vascular
Disease
1
Age 65 - 74
1
Female
1
New guidelines for use of OAC for
stroke prevention in AF
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In prosthetic heart valves:
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Risk of systemic embolisation = 4%
With aspirin = 2.2%
With warfarin 0.7-1.0%
Perioperative management of
anticoagulation
Risk Stratification
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Low thromboembolic risk
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Uncomplicated AF (No stroke or arterial embolisation in last 12 months)
Biological heart valve > 3 months after implantation
Mechanical aortic valve
Non-recurrent systemic arterial embolism
High thromboembolic risk
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AF with LV systolic dysfunction / Stroke or systemic embolus in last 12 months
Biological heart valve < 3 months after implantation
Mechanical mitral / tricuspid valve, multiple mechanical valves, older aortic valves
Venous thrombosis within last 3 months / Recurrent thrombosis
Recurrent systemic arterial embolism
*2 low-risk factors = high risk
Perioperative management of
anticoagulation
Recommendations
Low risk
High risk
Pre-op
Withhold warfarin 5 days before
Night before: 1-2mg PO Vit K if INR > 2
Operate if INR < 1.5
If >1.5, 0.5 – 1.0 mg IV Vit K and
Prothrombinex-HT 10-15 units/kg and
consider 1-2 units FFP if urgent surgery
Withhold warfarin 5 days before
Bridging anticoagulation 2-3 days
pre-op
-UFH, aiming APTT 1.5x normal (Stop
6 hours pre-op)
OR
-LMWH (Stop 12 hours pre-op)
Post-op
Restart warfarin on day of surgery
Restart warfarin ASAP
Heparin or LMWH for DVT prophylaxis If very high risk - Cover with heparin
or LMWH until INR therapeutic for 48
hrs
Guidelines for reversal of Warfarin
Warfarin reversal: consensus guidelines, on behalf of the Australasian Society of Thrombosis and Haemostasis. Baker RI, Coughlin PB, Gallus AS, Harper PL, Salem HH,
Wood EM. Med J Aust 2004;181(9):492-7.
How About Dabigatran ?
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Quick onset of action
Withhold 24hrs or 48hrs (if creatine clearance
<50) for minor procedure
Withhold 2-4 days for major surgery and
consult haematology
Perioperative management of diabetes
mellitus
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Increasingly common disorder
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20% of surgical pts have DM
Increased incidence of CV disease/silent ischaemia
Surgery + anaesthesia -> increased stress response ->
hyperglycaemia
Goals:
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Maintenance of fluids + electrolytes
Prevention of ketoacidosis
Avoid hyperglycaemia
Avoid hypoglycaemia
Perioperative management of diabetes
mellitus
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T2DM – diet controlled
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BSL monitoring
T2DM – OHG / noninsulin injectables
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Continue usual medications until morning of surgery
WH morning OHG
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Sulfonylureas – increase risk of hypoglycaemia
Metformin – contraindicated due to lactic acidosis
Thiazolidinediones – increase fluid retention/oedema, may precipitate CCF
DPP-IV inhibitors/GLP-1 analogues – alter GI mobility
Treat hyperglycaemia (BSL > 10 mmol/L) with short acting insulin
(sliding scale)
Restart OHG post-op once eating, except Metformin (until renal function
normal)
BSL monitoring
Perioperative management of diabetes
mellitus
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T2DM or T1DM – insulin
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Put 1st on Surgical list
Take usual insulin until morning of surgery
Check BSLs 2/24 (aim for 4-8 mmol/L)
In the absence of not eating, basal metabolic rate utilise ½ of
individual’s insulin
When fasting
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½ dose of insulin (intermediate + short acting) as intermediate acting
insulin only
Dextrose containing IVT
OR
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Insulin infusion for tight control
DO NOT WITHOLD INSULIN IN T1DM – may precipitate
ketoacidosis
Evaluating cardiac risk for patients
undergoing non-cardiac surgery
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Cardiac complications are some of the most common risks perioperatively
(5.8%)
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Cardiovascular risk in surgery
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In non-selected pts >40
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MI 1.4%, cardiac mortality 1%
In surgical pts with some selection criteria
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MI 3.2%, cardiac mortality 1.7%
In patients selected to undergo preoperative thallium scintigraphy
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MI 6.9 %, cardiac mortality 3.2%
Patients with underlying vascular disease (ie. PVD, stroke)
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5x increase in incidence of significant CAD, LV dysfunction (EF <40%)
More susceptible to myocardial ischaemia
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volume shifts, blood loss, tachycardia, HT -> myocardial demand
Principals of the preoperative cardiac
evaluation
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Provide clinical judgment, not clearance for surgery
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What is the patient’s risk of complications (cardiac and noncardiac)?
Would further risk stratification alter patient management?
Can anything be done to reduce the patient’s risk?
Order tests only when results may change management
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Routine tests are not good screening devices
Healthy patients may not need testing
Patients undergoing minimally invasive procedures may not need
testing
Evaluating cardiac risk for patients
undergoing non-cardiac surgery
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Identify patients at high risk so that
appropriate testing and therapeutic measures
can be undertaken to minimise this risk
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Clinical risk
Functional status
Underlying risk of surgical procedure
Clinical Risk
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Major
predictors
Functional capacity
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Important determinant of risk is the patient’s
functional capacity.
Metabolic equivalents (1 MET is defined as 3.5 mL
O2 uptake/kg per min)
Self-reported exercise tolerance and the risk of serious
perioperative complications; Reilly DF, McNeely MJ, Doerner D,
Greenberg DL, Staiger TO, Geist MJ, Vedovatti PA, Arch Intern Med.
1999;159(18):2185.
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A study of 600 patients undergoing major noncardiac procedures
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Poor self-reported exercise capacity, defined as an inability to walk
four blocks or climb two flights of stairs, associated with
significantly more perioperative complications than was good
exercise capacity.
Functional capacity
Surgery Specific Risk
Risk Category
Cardiac Morbidity
Rates
Examples
High
(Vascular)
> 5%
Aortic and other major
vascular surgery
Peripheral vascular surgery
Intermediate
1- 5%
Intraperitoneal and
intrathoracic surgery
Carotid endarterectomy
Head and neck surgery
Orthopedic surgery
Prostate surgery
Low
< 1%
Do not generally
require further preoperative
cardiac testing
Endoscopic procedures
Superficial procedure
Cataract surgery
Breast surgery
Ambulatory surgery
Cardiac risk stratification for noncardiac
surgery - Algorithm
Cardiac Investigations
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Investigations should be done only if the
cardiac condition in its own right warrants it
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Not appropriate to undertake stress testing
&/or coronary angiography in order to identify
well – controlled or asymptomatic coronary
disease, purely for the purpose of assessing
perioperative risk
Recommendations for pre-operative
stress testing
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In general, the indications for stress testing
are:
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Significant ischaemic symptoms
If high chance of having IHD, undergoing
high risk surgery, when the identification of
ischaemia will lead to postponement of
surgery and further cardiac treatment
Pre-op revascularisation
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In patients with +ve stress test -> angiography
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In pts with high-risk features -> revascularisation
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High risk USA or NSTEMI
Acute STEMI
Angina + LMCA or triple vessel disease
Angina + 2-vessel disease including prox LAD + LV dysfunction /
reversible ischaemia on stress test
 CABG
recommended if pt has CAD which
warrants CABG and non-cardiac surgery
can be postponed
 PCI
recommended if pt has CAD suitable
for PCI, or surgery cannot be postponed
 Balloon
>7 days
angioplasty if possible, delay surgery
Perioperative Management for
respiratory and sleep conditions
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Asthma and COPD
- Make sure patient is stable preoperative
- Postpone non urgent surgery if needed
OSA
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If suspicious -> sleep study
Must bring CPAP to hospital
References
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PROMPT Procedures and Policies
Internet explorer → NH Intranet → Prompt – Policies and Procedures (Left
hand side) → Click here to search for Policies and Procedures → Enter
search term
- “Perioperative management of antiplatelet agents”
- “Perioperative management of anticoagulation”
- “Anticoagulated patients requiring invasive procedures”
- “Anaesthesia and perioperative medicine”
- “Guidelines for reversal of oral anticogulation”
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UpToDate
Therapeutic Guidelines
Acknowledgements to Notes by Drs. Rinku Rayoo, Tina Lin, Karen Lim
& Sara Baqar
Thank You