Apex- Cardiac Pathyophys Flashcards
Which surgical procedure presents the HIGHEST risk of CV morbidity and mortality for the patient with CAD?
A. ORIF femur fracture
B. VATS
C. Open AAA repair
D. Carotid endarterectomy
C.
High risk procedures = emergency surgery (esp in elderly), open aortic surgery, peripheral vascular surgery, long surgical procedures with significant volume shifts and/or blood loss
If a patient had a recent MI, the risk of re-infarction is greatest within ________ days/weeks of the orginal event
30 days
How long should elective surgery be delayed for after an MI?
4-6 weeks
5 patient risk factors that increase risk for cardiac event during surgery
which one confers the greatest risk of periop MI?
- ischemic heart disease
- CHF
- cerebrovascular disease
- DM
- Creat > 2mg/dL
unstable angina = greatest risk
unstable angina → new-onset angina (<2 months), increasings sx (intensity, freq, duration), duration exceeding 30 minutes, sx responding less to medical therapy
Risk of perioperative MI in the general population is ~ ____ %
0.3%
If the patient has ahd a previous MI, than the perioperative risk of reinfarction is:
- if > 6 months ago →
- if 3-6 months ago →
- if < 3 months ago →
- if > 6 months ago → 6 %
- if 3-6 months ago → 15%
- if < 3 months ago → 30%
remember as <3 months ago = 30%, then half it, and half it again
NYHA heart failure classification for someone with symptoms with less than normal activity but no symptoms at rest
3
compared to sx with normal activity + no sx at rest = 2
Which NYHA heart failure classification requires referral to a cardiologist prior to GA
Class 3 - symptoms with less than normal activity (none at rest)
or
Class 4 - symptoms with minimal activity or even at rest
T/F- NYHA heartfailure class 4 patients to undergo MAC anesthesia can proceed without a cardiac referrel as long as the preoperative evaluation reveals stable cardiac disease
True
When should a patient be referred to a cardiologist before surgery?
NYHA classification of 3 or 4 who is scheduled for high- or intermediate-risk surgery
factors that reduce myocardial o2 supply (4)
- tachycardia
- hypoxemia
- anemia
- left shift in oxyhemoglobin curve
Factors that increase myocardial o2 demand (7)
SNS stimulation : increased HR and BP
Increased preload/wall tension
Increased afterload
Increased contractility
Myocardial injury and infarction injure the sarcolemma. Disruption of the sarcolemma allows for what to happen?
intracellular proteins (CK-MB, troponin-I, tropinin-T) to enter systemic circulation
What lead is best for monitoring dysrhythmias?
Lead II
it also can identify inferior wall ischemia (II = inferior ischemia)
Most MIs occur within ______ hours after surgery
48
Treatment of intraoperative myocardial ischemia should focus on itnerventions that do what?
make the heart slower, smaller, and better perfused
Which leads are best for detecting LV ischemia intraoperatively?
AKA: ST changes
V3, V4, V5
*classic teaching says V5 is best (anterior axillary line 5th ICS)
*newer data says V3 & V4 may be superior to V5
*if need to choose- choose V4 - midclavicular line 5th ICS
The combination of what 3 leads has an ischemic detection rate of up to 96%?
II, V4, V5
Do most MI’s occur intraop or postop?
postop - within 48 hrs of surgery
Myocardial ischemia & advanced age
Curve A demonstrates a greater rise in pressure at a given volume → decreased compliance → myocardial ischemia and advanced age
Curve C demonstrates increased compliance → aortic insuffiency and dilated cardiomyopathy
If the patient has diastolic dysfunction, CVP and PAOP will (overestimate/underestimate ventricular filling pressures)
overestimate
pts with diastolic dysfuction require higher filling pressures to prime the ventricle
What describes the ventricular filling pressure that results from a given end-diastolic volume?
Diastolic compliance
Decreased diastolic compliance shifts the curve (up/down) and (left/right)
What does t his mean?
up and left
Theres a higher end diastolic PRESSURE for a given volume
Increased diastolic compliance shifts the curve (up/down) and (left/right)
what does this mean?
down and right
there is a LOWER end-diastolic PRESSURE for a given EDV