Transcript Perioperative Issues - University of Toronto

Perioperative Issues
Dr John Oyston
Dept of Medicine Rounds
April 15th 2008
Intro
Thanks for invitation and for consults
 Caring for same patients, different times
 Often not much chance to exchange
views
 Perioperative literature widely scattered
 Ideally, we should all be on same page

Case Presentation
67 year old man
 Booked for PVP Green Light Laser
 MI x 2, CABPG (5 yr ago), restenosed
 Good exercise tolerance, rare angina
 No other medical conditions
 On maximum cardiac meds including
ASA and Plavix
 ? What to do about these drugs preop

Topics
Anesthesia’s 2007 Mortality review
 Stop Smoking for Safer Surgery
 AHA SABE Guidelines
 ACC/AHA Perioperative Guidelines – a
Canadian anesthesia perspective
 Discussion

Perioperative Deaths 2007 (QCIPA)
Data collection difficult
 One intraoperative death and 12 deaths
within 48 hours, out of 11,314 surgeries.
 Death rate 1.15/1,000, lowest in years

UK 7-8/1000 in 30 days
 1:185,000 due to anesthesia
 France – 7 anesthesia deaths per million

Patient characteristics
10/13 over 70 years old (youngest 52)
 12/13 were emergencies
 12/13 were ASA 4 or 5
 10 cases ortho or general
 5 were spinals
 Standards were met. Deaths due to
progression of disease or co-morbidities

Intraoperative Death
Bleeding Jehovah’s Witness
 Anticoagulated
 Gynecological malignancy
 Refused blood or FFP

Research data from JWs:
 Hb>8g/dl and loss <500 ml ->100% live
 Hb<6g/dl ->62% die
Template

6 – 8 hours of
non-smoking
reduces CO
levels
“NPO after MN”
 “No smoking after
Midnight”

Why quit?
Endocarditis Prophylaxis

New AHA Guidelines
 Circulation, Oct 9 2007 p 1736

IE rarely caused by operative procedure
 Risk of antibiotics often outweighs benefits
 Severely restricts both surgical procedures
and cardiac disease indications for antibiotic
prophylaxis
ACC/AHA 2007 Perioperative
Evaluation and Care Guidelines

Circulation Oct 23 2007, p 1971
Very worthy and well thought-out review
of large and complex issue
 Little anesthesia involvement
 American authors
 Needs a Canadian anesthesiology
perspective

Preoperative ECG

Guidelines state:


Preoperative ECGs are not indicated in
asymptomatic persons undergoing low-risk
surgical procedure.
Ontario Pre-Operative Testing Grid
recommends ECG even in asymptomatic
persons over 45
This is our current policy
 ? May not be needed for cataract surgery

Motherhood statements
Maintain normothermia
 Maintain euglycemia
 Take a history
 Assess functional capacity



Poor if cannot climb stairs, walk at 4 mph,
do light housework (4 METs)
Base risk assessment on history,
physical and lab
Lee’s Revised Cardiac Risk Score

One point for each of:
Ischaemic Heart Disease
 Congestive Heart Failure
 Cerebrovascular Disease
 High-Risk Surgery


Thoracic, Vascular, Abdominal or Ortho
IDDM
 Creatinine >177 mmol/l

Major Cardiac Complication Rate
Class I (no risk factors)
 Class II (one risk factor)
 Class III (two risk factors)
 Class IV (>2 risk factors)

0.4%
0.9%
6.6%
11.0%
Perioperative Medications
Long history of searching for the “magic
bullet” which would protect patients from
the risk of surgery and anesthesia
 Nitroglycerin, Beta blockers, Alpha
agonists, Statins
 Need to consider intra-operative effects
 Need OUTCOME data

Prophylactic Nitroglycerin OUT
Beta blockers – NOT AS GOOD AS
WE HOPED

If already on them, definitely continue.
May be of benefit in high risk cases
Use longer acting agents (eg atenolol)
 Start 5-7 days before surgery, continue 30d
 Titrate to HR <65


Anesthesia
Masks hypovolemia, awareness,
hypoglycemia
 Bradycardia usually treatable

Alpha-2 agonists (eg Clonidine)
– ? UNDERUSED
Theory: decrease sympathetic drive,
dilate post-stenotic vessels
 Meta-analysis: Reduce MI and Mortality
in vascular surgery
 Prospective Trial: Reduced mortality over
2 years
 2-6 mcg/kg clonidine po once, I hr preop
 Not yet widely used

Statins
Stabilize plaques, decrease inflammation
 Meta-analysis: 44% reduction in mortality
 Need 4 – 6 weeks treatment
 Sudden withdrawal dangerous
 No interactions with anesthesia
 Awaiting DECREASE IV trial

Stents
Becoming a huge issue
 Patients with drug-eluting stents taken
off anticoagulants frequently die
 Should stay on Plavix and ASA for one
year if possible
NB: Spinal anesthesia OK with ASA, but
need to be off Plavix for one week

Stents (2)

Need discussion between
cardiology, surgery and
anesthesiology – complicated
algorithms
Do we need a computer to help?

Algorithms (e.g for cardiac testing, sleep
apnoea) are getting increasingly complicated
 Computers are great with algorithms – let
them do the work
 Adjuvant Informatics has a suitable product in
beta testing in UHN
 We could be the next test site
Thank
you.
Questions?
Thank you
Any questions?