Perioperative Issues Dr John Oyston Dept of Medicine Rounds April 15 th 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 100% live Hb 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 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 , 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) 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 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?