perioperative issues dr john oyston dept of medicine rounds april 15 th 2008
TRANSCRIPT
Perioperative Issues
Dr John OystonDept of Medicine RoundsApril 15th 2008
Intro
Thanks for invitation and for consultsCaring for same patients, different timesOften not much chance to exchange
viewsPerioperative literature widely scatteredIdeally, we should all be on same page
Case Presentation
67 year old manBooked for PVP Green Light LaserMI x 2, CABPG (5 yr ago), restenosedGood exercise tolerance, rare anginaNo other medical conditionsOn maximum cardiac meds including
ASA and Plavix? What to do about these drugs preop
Topics
Anesthesia’s 2007 Mortality reviewStop Smoking for Safer SurgeryAHA SABE GuidelinesACC/AHA Perioperative Guidelines – a
Canadian anesthesia perspectiveDiscussion
Perioperative Deaths 2007 (QCIPA)
Data collection difficultOne 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 days1:185,000 due to anesthesiaFrance – 7 anesthesia deaths per million
Patient characteristics
10/13 over 70 years old (youngest 52)12/13 were emergencies12/13 were ASA 4 or 510 cases ortho or general5 were spinalsStandards were met. Deaths due to
progression of disease or co-morbidities
Intraoperative Death
Bleeding Jehovah’s WitnessAnticoagulatedGynecological malignancyRefused blood or FFP
Research data from JWs:Hb>8g/dl and loss <500 ml ->100% liveHb<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 involvementAmerican authorsNeeds 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 45This is our current policy? May not be needed for cataract surgery
Motherhood statements
Maintain normothermiaMaintain euglycemiaTake a historyAssess 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 DiseaseCongestive Heart FailureCerebrovascular DiseaseHigh-Risk Surgery
Thoracic, Vascular, Abdominal or Ortho IDDMCreatinine >177 mmol/l
Major Cardiac Complication Rate
Class I (no risk factors) 0.4%Class II (one risk factor) 0.9%Class III (two risk factors) 6.6%Class IV (>2 risk factors) 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 effectsNeed 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 casesUse longer acting agents (eg atenolol)Start 5-7 days before surgery, continue 30dTitrate to HR <65
AnesthesiaMasks hypovolemia, awareness,
hypoglycemiaBradycardia 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 preopNot yet widely used
Statins
Stabilize plaques, decrease inflammationMeta-analysis: 44% reduction in
mortalityNeed 4 – 6 weeks treatmentSudden withdrawal dangerousNo interactions with anesthesiaAwaiting DECREASE IV trial
Stents
Becoming a huge issuePatients with drug-eluting stents taken
off anticoagulants frequently dieShould 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?