Ch. 25 Cardiovascular Disease Flashcards
Most common symptom of cardiac disease in men is ______ and in women is ______.
men - SOB w/ exercise, women - fatigue
What does ventriculography determine?
ejection fraction
What does dipyridamole-thallium scintigraphy mimic?
coronary vasodilator response (but not heart rate response associated with exercise)
Name some cardiac tests that may be performed on some patients
ECG, exercise stress test, TTE, TEE, radionuclide ventriculography, dipyridamole-thallium scintigraphy, cardiac catheterization, angiography
What are the two most valuable tools for predicting adverse outcomes in cardiac patients?
H&P and EKG
What are the five most common coexisting noncardiac diseases associated w/ CAD?
HTN, PVD, COPD (from cigarette smoking), renal dysfxn from chronic HTN, DM
Patients may remain asymptomatic despite ____ to ____% stenosis of coronary arteries.
50-70%
What is the most striking evidence of decreased cardiac reserve?
limited exercise tolerance in the absence of pulmonary disease
What are some symptoms of significant cardiac disease?
inability to lie flat, awakening from sleep with angina or SOB, angina at rest or w/ minimal exertion
What does dyspnea following onset of angina indicate?
LV dysfunction due to myocardial ischemia
Does silent MI cause angina? What percentage MI’s are silent?
No; approxmately 15%.
What patient populations have a higher frequency of silent MI?
women and diabetics
What are the two main reasons that tachycardia leads to MI?
Increases myocardial O2 demand and decreases time of perfusion
Why are elective surgeries often delayed 2-6 months after an MI?
Incidence of myocardial reinfarction increases the closer it has been since an MI.
If a patient is taking beta blockers after a previous MI, should they be continued prior to surgery?
Yes. When followed for 7 days after, it decreases the risk of mortality 50%.
Does perioperative clonadine reduce mortality risk in patients who’ve had a previous MI?
Yes. It reduces 30-day and 2-year mortality risks.
Is it advisable to continue statins with fluvastatin prior to surgery for a patient whose had a previous MI?
Yes
Risk of myocardial reinfarction increases when the procedure is greater than __ hours?
3
What are the 5 risk factors for CAD?
age 60+, HTN, DM, smoking, hyperlipidemia
All patients with CAD, PVD, or two CAD risk factors should have what?
perioperative beta-blocker unless there is a specific contraindication
What is a good subsitute for beta-blockade in patients who are contraindicated?
clonidine (or dexmed?)
Which drugs should be continued in the perioperative period for patients who’ve had a previous MI?
- beta-blockers
- Ca++ channel blockers
- nitrates
- statins
All decrease risk of perioperative M&M
ST segment greater than ____ confirms the presence of myocardial ischemia.
1mm
What level of cholesterol is considered hyperlipidemia?
> 240mg/dL
If a patient has a contraindication to perioperative beta-blockade, what drug should be substituted and how should it be administered?
Clonidine
- 0.2mg PO night before + TTS#2 (0.2mg/24hr) patch
- 0.2mg PO morning of surgery
- leave patch on for a week
What if a patient is identified as having CAD, PVD or two of the risk factors the morning of surgery?
administer IV atenolol or metoprolol in pre-op clinic unless systolic is under 100 or HR is less than 50
Name two scenarios in which a patient should be seen by cardiology
patients with aortic stenosis; patients with intracoronary stents on platelet inhibitors
Should platelet inhibitors be continued in patients with intracoronary stents?
Yes, it can be lethal otherwise, especially in recent stents
Patients with bare metal stints typically need to be on antiplatelet therapy for how long?
3+ mo
Patients with drug-eluting stints typically need to be on antiplatelet therapy for how long?
1yr+
Three cases in which beta-blockers are contraindicated?
AV block (hi-grade) w/o pacemaker, reactive asthma, intolerance to beta-blockade
Periop beta blockers should be continued for at least _____ postop?
7 days
Which of a patient’s medications should not be taken preoperatively?
oral hypoglycemic drugs
What induction drug should be avoided in cardiac patients?
Ketamine because of it’s increase in HR and BP
Why should you be careful with desflurane in cardiac patients?
Increasing the level quickly can cause sympathetic stimulation, leading to tachycardia, pulmonary HTN, MI and bronchospasm
Which volatile causes sympathetic stimulation when increased quickly?
desflurane
What drug would be a good choice to add when a difficult intubation on a cardiac patient is anticipated?
tracheal lidocaine to reduce sympathetic response to DL
What is coronary steal?
Regional myocardial ischemia associated with drug-induced vasodilation. Arteries in ischemic areas are already fully dilated, so vasodilation could divert blood to other areas.
What effect does pancuronium have that is noteworthy in cardiac patients?
Increases HR/BP (less than 15% above predrug values). May offset opioid decrease in BP/HR
Why might glyco be a better choice than atropine for reversal?
glyco has more titratable chronotropic effects than atropine
Which drug is a good choice for myocardial ischemia with normal BP?
nitroglycerin (rather than SNP)
Should patients with DM receive periop beta-blockade?
Yes, DM is an indication
Mitral stenosis is associated with what arrhythmia?
mitral stenosis –> distended atria –> afib
Valvular diseases often develop from what condition? How long can they be asymptomatic
rheumatoid fever, can be asymptomatic for 20-30 years
If a patient is taking digitalis for mitral stenosis, should it be continued perioperatively?
yes
If a patient is taking warfarin for mitral stenosis, should it be continued perioperatively?
it should be switched to heparin
Why should fluid volumes be carefully monitored in patients with mitral stenosis?
Pulmonary hypertension may already be present due to fluid backup. Adding more volume could increase the risk of pulmonary edema and LV failure.
Are there any positioning considerations for people with mitral stenosis?
Trendelenburg may not be well tolerated due to increased pulmonary volume
What are situations when a patient may have acute mitral regurgitation?
papillary muscle dysfunction or rupture of chordae tendonae after MI
Hemodynamically significant aortic stenosis is associated with pressure gradients of?
less than 50mmHg across the aortic valve (or valve areas less than 1.2cm2
Why is it important to maintain sinus rhythm with aortic stenosis patients?
too low (100bpm) decreases ejection time and decreases time for perfusion
(hyper/hypo)tension should be avoided in patients with aortic stenosis?
hypotension
A code can be extra deadly with a patient who has ____ because
aortic stenosis; chest compressions likely will not generate adequate stroke volume across the stenosed valve - use a defibrillator
Which volatile is a concern with patients who have aortic stenosis? Why?
all of them, because they all depress sinus node automaticity, which can lead to junctional rhythm and improperly timed atrial contractions
______ has a roughly equivalent affect on the LA as aortic regurgitation does on the LV
mitral valve prolapse
With what valvular disease should you avoid events that increase cardiac emptying?
mitral valve prolapse
What are three perioperative events that increase cardiac emptying?
sympathetic system innervation; decreased SVR; sitting or reverse-Trendelenburg position
Preoperative evaluation of a patient with a pacemaker includes:
determine why they have pacemaker; assess its function, brand, model, magnet mode; check programmer availability and availability of person who can operate it
What are some devices that are under the skin that are not pacemakers?
deep brain stimulators, AICD’s, IV pumps, spinal stimulators for chronic pain, bladder stimulators for neurogenic bladder, gastric stimulators for obesity, IV ports, vagal stimulators for sleep
What devices need to be inactivated for surgery?
automated defibrillators
What is essential HTN?
sustained increases in systemic BP (systolic >160 or diastolic >90) independent of a known cause
With CHF patients, the goal is to minimize detrimental effects on ____?
cardiac output
Which are preferable to maintain BP in a patient with CHF: inotropes or vasoconstrictors?
vasoconstrictors
What is hypertrophic cardiomyopathy?
obstruction to LV outflow produced by asummetrical hypertrophy of the IV septal muscle
What is the goal of treatment of patients with hypertrophic cardiomyopathy?
decrease pressure gradient across LV outflow obstruction
What are CV differences between primary and high-potency opioids?
primary opioids don’t produce myocardial depression and can decrease SVR; high potency opioids stimulate the vagus nerve, lower HR, and can decrease sympathetic stimulation
What is cor pulmonale? How does it occur?
RV hypertrophy; secondary to chronic pulmonary HTN
What are some ways to decrease pulmonary HTN?
prostaglandins, endothelin receptor antagonists, inhaled NO, inhaled milrinone, type 5 PDE inhibitors, soluble guanylate cyclase activators
Nitrous oxide has what effect on pulmonary vascular resistance?
increases it
What are changes seen in cardiac tamponade?
decreases in diastolic filling P; decreases in SV; decreases in systemic BP
What is cardiac tamponade?
accumulation of fluid in pericardial space
Why might vasodilation be deadly in a patients who have cardiac tamponade?
Pressure in central veins needs to exceed pressure in RV or else there will be no cardiac output
Why is GA with positive-pressure ventilation a concern in patients who have cardiac tamponade?
It can cause profound HoTN, decreased venous return and myocardial depression leading to death
What is the primary objective in treating a patient who has cardiac tamponade?
draining the pericardium
How fast should induction, intubation and drainage of the pericardium occur in a patient who has cardiac tamponade?
ideally under 60s
Why might a patient with cardiac tamponade have cardiogenic shock?
stroke volume is decreased due to increased pericardial pressure
Elective repair of an abdominal aneurysm is recommended when the estimated diameter of the aneurysm is more than _____ because __________.
5cm; the incidence of spontaneous rupture increases dramatically when the size exceeds this
What is a benefit to gradual release of the aortic cross-clamp?
systemic decreases in BP are minimized
The checklist prior to going on bypass follows what acronym?
HADDSUE “had to sue”
What are the items on the checklist prior to going on bypass?
Heparin, ACT (450+), Drugs, Drips, Swan (pull back 5cm), Urine, Emboli (any visible in cannula?)
What are common CPB temperatures at what stages?
18C prior to circulatory arrest, 28C prior to cross-clamping, maintained at 33C, rewarmed to 37C
What is the hematocrit typically during surgery?
20-30%
What is the usual initial dose of heparin prior to CPB?
300-400units/kg
The ACT is typically maintained at above ____ during CPB.
450s
A mixed venous PO2 less than ___ is associated with metabolic acidosis and inadequate tissue perfusion
30mmHg
Why is bladder temperature superior to rectal temperature?
it better reflects core temperature
What is cardioplegia? How is it accomplished?
cessation of the heart for CPB achieved with K+containing cardioplegia solution
If hyperkalemia persists following CPB, how should it be treated?
with insulin (10-20units) and glucose (25-50units) IV (or Lasix)
How is SVR calculated?
SVR = 80 x (MAP – CVP)/CO
What is the most common hemodynamic abnormality following CPB?
low SVR
How is acute mitral regurgitation treated?
reverse Trendelenburg
People who take what medication may be at increased risk of protamine reaction? Why?
Diabetes who take NPH insulin because it contains protamine
Ways to reduce protamine allergic reaction? (other than pressors, fluids)
histamine blocker (H1 benedryl), H2 blocker cimetidine, steroid (hydrocortisone)
What is a good position for off-pump CABG?
steep Trendelenburg with right tilt
Should patients undergoing off-pump CABG continue antiplatelet therapy preoperatively?
yes, with the exception of aspirin
