perioperative issues dr john oyston dept of medicine rounds april 15 th 2008

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?