Cardiovascular pathophysiology Flashcards
Which surgical procedure presents the HIGHEST risk of cardiovascular morbidity and mortality for the patient with coronary artery disease?
a. open reduction and internal fixation of a femur fracture
b. video-assisted lung thoracoscopy
c. open abdominal aortic aneurysm repair
d. carotid endarterectomy
c. open abdominal aortic aneurysm repair
You can stratify cardiac risk with the patient’s
history & type of surgery
Surgical procedures associated with the highest cardiac risk include
emergency surgery
open aortic surgery
peripheral vascular surgery
long surgical procedures with significant volume shifts and blood loss
Patient-related conditions that increase cardiac risk include
a history of ischemic heart disease
CHF
cerebrovascular disease
DM
serum creatinine >2 mg/dL
If a patient had a recent MI, then the risk of reinfarction is greatest within
30 days of the event
After a recent MI, elective surgery should be delayed for
4-6 weeks
Cardiac risk is defined as
perioperative MI, CHF, and death
A patient with ____________ should be optimized before elective non-cardiac surgery.
unstable angina
The following surgeries put the patient at intermediate cardiac risk:
carotid endarterectomy
head & neck surgery
intrathoracic or intraperitoneal surgery
orthopedic surgery
prostate surgery
What is the NYHA classification of heart failure?
four classes that help to classify the extent of heart failure symptoms during activity
NYHA class 1 is
no symptoms with physical activity
NYHA class 2 is
symptoms appear during normal activity but no symptoms at rest
NYHA class 3 is
symptoms appear with less than normal activity but no symptoms at rest
NYHA class 4 is
symptoms appear with minimal activity or even at rest
What is the risk of perioperative MI if the patient had an MI <3 months ago?
30%
What is the risk of perioperative MI in the general population?
0.3%
Use the data set to calculate the coronary perfusion pressure.
HR= 50 bpm
Systolic BP= 100 mmHg
diastolic BP= 55 mmHg
pulmonary artery occlusion pressure= 15 mmHg
central venous pressure= 10 mmHg
40
CPP= Aortic diastolic pressure- LVEDP or in this case DBP- PAOP
Most MIs occur within ________ after surgery
48 hours
Which lead is best for monitoring dysrhythmias?
II
The treatment for intraoperative myocardial ischemia should focus on
interventions that make the heart slower, smaller, and better perfused
Myocardial oxygen balance is determined by the ratio of
oxygen supply relative to demand
The myocardium is at risk when the
supply is less than the demand
Factors that reduce myocardial oxygen supply include, but are not limited to,
tachycardia, hypoxemia, anemia, and a left shift of the oxyhemoglobin curve
Factors that increase myocardial oxygen demand include
tachycardia
hypertension
SNS stimulation
increased wall tension
increased preload
increased afterload
increased contracitlity
Myocardial injury and infarction injure the ___________, and disruption of this structure allows ______________
sarcolemma; intracellular proteins (CK-MB, Troponin-I, troponin-T) to enter the systemic circulation
Infarcted myocardium releases which three important biomarkers?
CK-MB, troponin I, troponin T
________________ are more sensitive than _________ for the diagnosis of myocardial infarction
Cardiac troponins; CK-MB
Lead II aids in the identification of ____________ ischemia
inferior wall
Which leads are best for detecting LV ischemia?
V3, V4, & V5
What is the intervention for increased O2 demand?
beta blocker to a HR < 80 bpm
increased depth of anesthesia, vasodilator
nitroglycerin
What is the intervention for decreased O2 supply?
anticholinergic, pacing
vasoconstrictor, reduce depth of anesthesia
nitroglycerin, inotrope
We can assess ventricular compliance by evaluating
ventricular pressure at a given ventricular volume
Co-existing condition that lead to diastolic dysfunction include
age >60 years
myocardial ischemia
hypertension
aortic stenosis
If the patient has diastolic dysfunction, _____________ are required to prime the ventricle
higher filling pressure
In the case of diastolic dysfunction, _____________ & ______________ will overestimate ventricular filling pressures
CVP & PAOP
Compliance is decreased by conditions that make the heart
“stiffer”
Elevated filling pressures put patients at higher risk of
pulmonary edema
_______________ & ______________ are critically important to maintain the priming function.
Preservation of NSR and atrial kick
Compliance is increased by conditions that
dilate the heart
Clinical examples of conditions that increase compliance include
chronic aortic insufficiency
dilated cardiomyopathy
Identify a compensatory mechanism in the patient with congestive heart failure.
a. decreased brain natriuretic peptide
b. decreased left ventricular end-diastolic pressure
c. increased renal blood flow
d. increased sympathetic tone
d. increased sympathetic tone
Heart failure occurs when the myocardium is
unable to pump enough blood to satisfy the body’s metabolic demand
Heart failure with reduced ejection fraction represents
a pump problem
Examples of heart failure with reduced ejection fraction include
myocardial ischemia
valve insufficiency
dilated cardiomyopathy
Anesthetic management of the patient with heart failure with reduced EF includes
lowering afterload
increasing contractility
_____________ is the most common cause of right heart failure.
Left heart failure
Conditions that increase PVR include
hypoxia, hypercarbia, acidosis, hypothermia, high PEEP, and nitrous oxide
Heart failure with preserved ejection fraction (HFpEF or diastolic failure) represents a
filling problem
The patient with HFpEF experiences
s/sx of HF but has a normal ejection fraction
Examples of HFpEF include
myocardial ischemia
valve stenosis
hypertrophic cardiomyopathy
hypertension
cor pulmonale
obesity
Anesthetic management for heart failure includes
maintaining a higher afterload and slowing the heart rate
Compensatory mechanisms for heart failure include
chronic SNS activation
down-regulation of beta receptors
cardiac remodeling
Treatment of right ventricular failure includes
inotropes- milrinone, dobutamine
pulmonary vasodilators- inhaled nitric oxide or sildenafil (PDE-5 inhibitor)
reversing causes of increased PVR
List 4 physiologic adaptations to heart failure.
sns activation
excessive vasoconstriction
fluid retention
myocardial remodeling
List 3 physiologic functions of BNP.
natriuresis
diuresis
vasodilation
