Cardiovascular Pathophysiology Flashcards
When is the highest risk for reinfarction?
Within 30 days of an acute MI
(Patients must wait 4-6 weeks before elective surgery)
What procedures have the highest cardiac risk?
Emergency
Open aortic surgery
Peripheral vascular surgery
Long procedures with sig volume shifts/blood loss
What procedures have an intermediate cardiac risk?
Carotids
Head and neck surgery
Intrathoracic or intraperitoneal
Orthopedic
Prostate
Which surgeries have the lowest cardiac risks?
Endoscopic
Cataract
Superficial procedures
Breast
Ambulatory procedures
What is a NYHA class 1?
No symptoms with physical activity (no limitation)
What is a NYHA class 2?
Symptoms appear with normal activity, but not rest (slight limitation)
What is a NYHA class 3?
Symptoms present at less than normal activity, BUT not rest (marked limitation)
What is a NYHA 4?
Symptoms present at rest (severe limitation)
What are the three important cardiac bio markers?
CK-MB, Troponin I, and Troponin T
What is the initial, peak and return to baseline for CK-MB
I: 3-12 hours
P: 24 hrs
R: 48 hours - 3 days
What is the initial, peak, and return to baseline for Troponin I?
I: 3-12 hours
P: 24 hours
R: 5-10 DAYS!!
What is the intial, peak, and return to baseline for Troponin T?
I: 3-12 hours
P: 12-48 hours
R: 5-14 days
What are the best leads to monitor the heart?
II and V5
Where does decreased compliance shift the volume pressure graph?
Up and left (higher end diastolic pressure for a given EDV)
Where does an increased ventricular compliance shift the pressure/volume graph?
Down and right
What conditions decrease cardiac compliance or make the heart “stiffer?”
Ischemia
Age
Aortic stenosis/ HTN
Hypertrophic cardiomyopathy
Pericardial pressure
What are conditions that increase compliance?
Chronic aortic insufficiency
Dilated cardiomyopathy
What is the anesthetic management for a patient with HFrEF?
Preload: already high (diuretics if too high)
Afterload: decrease to reduce workload (but maintain CPP)
Contractility: inotropes if needed
HR: usually highish…if EF is low, HR is needed to preserve CO
What is the management for HFpEF?
Preload: volume is required to stretch no compliant ventricle
Afterload: elevate to perfume myocardium (maintain CPP)
Contractility: usually not an issue
HR: slow/normal ~ increases diastolic time and CPP
What is classified as a normal BP?
Systolic < 120
Diastolic < 80
What is considered an elevated BP?
Systolic 120-129
Diastolic < 80
What is considered HTN stage 1?
Systolic 130-139
Or
Diastolic 80-89
What is considered HTN stage 2?
Systolic >140
OR
Diastolic > 90
What is considered HTN stage 3? Hypertensive crisis
Systolic > 180
And/Or
Diastolic > 120
What are some second-line therapies to vasoplegia?
Vasopressin
Methylene blue (this is a nitric oxide antagonist)
At what blood pressures should you delay a procedure?
Systolic > 180
Diastolic > 110
What is the BP in HTN CRISIS?
BP exceeds 180/120
What is declared at a HTN emergency?
When there is evidence of end-organ injury
(Stroke, papilledema, encephalopathy, CHF, renal dysfunction)
What are the suffixes for the antihypertensives?
ARBs ~ spartan
ACE ~ pril
Calcium channel blockers ~ pine
Beta-blockers ~ lol
Alpha blockers ~ zosin
What are some beta blockers with mixed alpha1/Beta1 & Beta 2 properties?
Bucindolol
Carvedilol
Labetalol (IV a:B 1:7; PO a:B 1:3)
What are examples of selective Beta 1 antagonists?
Metoprolol, acebutolol, atenolol, bisoprolol, esmolol
What are examples of B1 & B2 no selective antagonists?
Nadolol, pindolol, propranolol, sotalol, timolol
What does a dihydropyridine calcium channel block mostly target?
vasculature (ie cardene) ~ vasodilation via decrease in Ca
What does a non-dihydropyridine calcium channel blocker target?
Myocardium > vasculature
Decreased inotropy, chronotropy, dromotropy, decreased SVR
Which vasodilator dilates arteries and veins equally?
Sodium Nitroprusside
What are examples of loop diuretics? What is their MOA?
Furosemide, Bumetanide, ethancrynic acid
MOA: inhibits Na-K-2Cl transporter in thick portion of the ASCENDING loop of Henle
Decreases preload
What are some examples of Thiazide Diuretics? What is their MOA?
HCTZ, Metolazone, indapamide, chlorthalidone
MOA: inhibits Na-Cl transporter in distal convoluted tubule
Decreases preload
What are some examples of potassium sparing diuretics? What is their MOA?
Amiloride, Triamterene
MOA: Inhibits K+ excretion and Na+ reabsorption by the principal cells in the COLLECTING duct
Independent of Aldosterone!!!
What is an example of an aldosterone antagonist? What is their MOA?
Spironolactone
MOA: inhibits K+ excretion and Na+ reabsorption by the principal cells in the collecting ducts
What is the order in which calcium channel blocks impair contractility?
Verapamil > nifedipine > diltiazem > nicardipine
What is the most useful calcium channel blocker for coronary vasospasm?
Nicardipine
What is the only calcium channel blocker proven to reduce M&M in cerebral vasospasm?
Nimodipine
What are some causes of constrictive pericarditis?
Cancer (radiation)
Cardiac surgery
RA
Tuberculosis
Uremia
What are some S&S of constructive pericarditis?
Kussmaul’s sign (increased JVD during inspiration)
Pulsus paradoxus ( > 10 mmHg during inspiration)
Increased venous pressure
Atrial dysrhythmias
Pericardial knock
What is the tx for constructive pericarditis?
Pericardiotomy
Anesthesia tx: avoid bradycardia
Preserve HR and contractility (ketamine, pancuronium, volatile agents with caution) opioids/Benzos/etomidate ok
Maintain afterload
Avoid aggressive PPV
What are some of the causes of acute pericarditis?
Infection (viral)
Dressler’s syndrome (inflammation s/p MI)
Lupus
Scleroderma
Trauma
Cancer
What are some S&S of acute pericarditis?
Acute chest pain ~ pain changes with posture changes (relieved by leaning forward)
Friction rub
ST elevation (normal enzymes)
Fever
What is the tx for acute pericarditis?
Resolves spontaneously
Salicylates
Oral analgesics
Corticosteroids
Anesthesia tx: none
What is beck’s triad?
Hypotension
Muffled heart tones
JVD
What is the best way of diagnosing tamponade?
TEE
What are some signs and symptoms of tamponade?
Beck’s triad (major one)
Pulsus paradoxus
Kussmauls sign
Reduces EKG voltage (fluid attenuates signal)
What is the definite treatment for cardiac tamponade?
Pericardiocentesis
Pericardiotomy
What is the preferred technique for pericardiocentesis?
Local, but if general anesthesia is required, ketamine next. (No drugs that depress the myocardium)
Also goal is to maintain spontaneous ventilation (avoid PPV)
What are the hemodynamics goals for cardiac tamponade?
HR —> maintain
Rhythm —> NSR
Preload —> maintain/increase
Contractility —> maintain/increase
Afterload —> maintain
What type of patients are at highest risk for developing endocarditis?
Previous endocarditis
Posthetic heart valve
UNREPAIRED cyanotic congenital heart disease
repaired congenital heart defect < 6 months
Repaired heart defect with residual shit
Heart transplant with valvuloplasty
What are the highest risk procedures for endocarditis?
Dental
Respiratory procedure that perforate muscosal lining (biopsy)
Biopsy of infective skin/muscle
What is the IV dose of abx prophylaxis of Cefazolin for the adult/child?
Adult: 1 g IV
Child: 50 mg/kg IV
What are examples of things that distend the LVOT in hypertrophic cardiomyopathy? This is good!
Systolic fx: increase systolic volume
Force of contraction: decrease contractility
Transmural pressure gradient: increase pressure distends the LVOT
What are examples of things that narrow the LVOT? Make it worse ☹️
Reduced systolic volume (decreased preload)
Increased contractility (no inotropes!)
Decreased aortic pressure
What is the anesthetic management for hypertrophic cardiomyopathy?
HR: lower —>beta blockers/calcium channel blockers
Preload —> volume, Neo
Contractility —> beta blockers/calcium channel blockers
Afterload —> Neo
What is the wait for elective surgery with a patient who received a bare metal stent?
30 days
What is the wait for a patient who received a DES (first generation)?
This is with stable heart disease
12 months
What is the wait for elective surgery in a patient who received a DES current generation? Stable heart disease?
6 months
What is the wait time for elective surgery in a patient who just had a CABG?
6 weeks (3 months preferred)
What is the best tx for stent thrombosis?
PCI (< 90 mins goal)
When should a recent cardiac patient discontinue asa?
Should not, but if they HAVE to, 3 days
When should a recent cardiac patient discontinue clopidogrel/plavix?
7 days
When should a recent cardiac patient discontinue ticlopidine?
14 days
Priming the bypass machine with anything other than blood does what?
Decreases HCT
Decrease plasma concentration of drugs
Decreases CaCO2
Decreases blood viscosity
BUT increases microvascular flow
What are some key points with a roller pump for cardiac bypass?
Pump compresses blood tubing —> traumatic to cells
Pump flow remains constant regardless of patients afterload
More likely to entrain air if venous reservoir runs dry
What are some key points about centrifugal pump for cardiac bypass?
Non-occlusive —> less traumatic to blood cells
Tends to not entrain air (less risk of embolism)
Unable to produce high positive pressure ~ pump decreases when faced with afterload extremes
Preferred over roller pump
When is awareness most likely to occur during CABG?
Sternotomy
What ACT is required prior to CABG?
> 400 seconds
What is the systolic goals prior to aortic cannulation?
Systolic <100 mmHg (90-100 with a MAP < 70)
What does antegrade cardioplegia require?
A competent Aortic valve
What is the different between alpha stat and pH-stay for blood gas management during CPB in CABGs?
Alpha stat: does not correct for pt temp. Associated with better outcomes.
pH stat: corrects for temp. This technique aims to keep a constant pH. Better outcomes for kiddos
What is the general rule for protamine?
1 mg for every 100 units of heparin
What are two major side effects of protamine?
Histamine release ~ systemic vasodilation and pulmonary vasoconstriction
What are some contraindications to intra-aortic ballon pump therapy?
Severe aortic insufficiency
Descending aortic dx
Severe PVD
Sepsis
Where do you place a balloon pump?
2 cm distal to left subclavian
Always confirm with X-ray, fluoro, TEE
When does a balloon pump inflate? When does it deflate?
Inflate: diastole (correlates with diacrotic notch)
Back-pressure on coronaries —> increases CPP
Deflates: systole (correlates with R wave)
Causes vacuum like effect —> reduces afterload
What is pump flow on the LVAD dependent on?
Pump speed
LV preload
Pressure gradient across the pump (afterload)
What does insertion of an LVAD require? In terms of valves
Competent aortic valve
What is the most common cause of death with LVADs?
Sepsis
What are the crawford classifications for aneurysms?
Type 1: most of descending thoracic aorta (little of upper abdominal)
Type 2: most of thoracic and abdominal (worst)
Type 3: most of abdominal (little thoracic)
Type 4: abdominal only
What are the Stanford classifications for aortic dissection?
A: ascending aorta
B: descending aorta
What are the DeBakey classifications for aortic aneurysm?
Type 1: tear in ascending aorta and dissection along entire aorta
Type 2: tear in ascending aorta with dissection only in ascending
Type 3a: tear in proximal descending aorta with dissection limited to thoracic aorta
Type 3 b: tear in descending aorta with dissection along thoracic and abdominal aorta
Which type of aneurysm has the most significant peri operative risks?
Crawford type 2 —> paraplegia/renal failure because it requires a mandatory period of stopping blood flow to renal arteries and radicular artery (artery of adamkiewicz)
What are the risk factors for AAA?
Male, smoking, advanced age
What law correlate with the risk of rupture of a AAA?
Law of Laplace
When is surgical correction of a AAA indicated?
> 5.5 can or if it grows > 0.6-0.8 in a year
What is the classic triad of AAA?
Hypotension
Back pain
Pulsatile abdominal mass
how does applying the aortic cross-clamp create central hypervolemia?
Reduces venous capacity (decreases container)
Shifts a greater % of blood proximal to clamp
Increases venous return
How does removing the cross clamp create central hypovolemia?
Restores venous capacity (increases container)
Shifts greater % of blood toward lower body
Decreases venous return
Capillary leak d/t loss of intravascular volume
Application of a cross clamp does what to distal tissues?
Increases lactic acid production
Increases prostaglandins
Increases activated complement
Increases myocardial depressant factors
Decreases temp
What are events after clamp placement?
Increases in venous return
Decrease/0 in cardiac output
Increase MAP
Increase in SVR
Increase in PAOP
Increase LV wall stress
Increase in MVO2 (myocardial consumption)
Increase in coronary blood flow
Decrease renal blood flow
Decrease in O2 delivery
Decrease in SvO2
What are the events after clamp REMOVAL?
Decrease in venous return
Decrease in CO
Decrease in MAP
Decrease in SVR
Increase in PAOP (increase in acidosis —> increases PVR)
Decrease in LV wall stress
Decrease in MVO2
Decrease in Coronary blood flow
Decrease in renal blood flow (depends on MAP)
Increase in VO2
Decrease in SvO2 (more VO2 so more O2 consumed)
What arteries perfuse the 1/3 of the spinal cord?
Posterior arteries
What ARTERY perfuses 2/3 of the spinal cord?
Anterior artery
What is Beck’s syndrome?
Anterior spinal artery syndrome
Flaccid paralysis of the lower extremities
Bowel and bladder dysfunction
Loss of temperature and pain
BUT Touch and Proprioception are preserved!!!
What is the corticospinal tract of the spinal cord perfused by?
Anterior blood supply
What is the autonomic motor fibers p the spinal cord perfused by?
Anterior blood supply
What is the spinothalamic tract of the spinal cord perfused by?
Anterior blood supply
What is the dorsal column of the spinal column perfused by?
Posterior arteries
Injury to which spinal tract explains flaccid paralysis of the lower extremities?
Corticospinal tract
Injury to which spinal tract explains loss of pain and temperature sensation?
Spinothalamic tract
Amaurosis Fugax is what? And what is it a sign of?!
Amaurosis Fugax is blindness in one eye
Sign of impending stroke
What is the best monitor of neuro status in a carotid endarectomy?
Awake patient
How should you manage the BP for a carotid endarectomy?
During cross clamp: maintain BP or keep slightly elevated
After cross-clamping: BP < 145 (HTN —> repercussion injury —> cerebral edema)
What is considered a problem for patients who have had a bilateral CEA?
Carotid body denervation reduces the ventilatory response to hypoxia
With a carotid artery angioplasty with stent, what do we want the ACT?
> 250 seconds
What is subclavian steal?
Occurs when there is an occlusion of the subclavian or subclavian innominate artery proximal to the origin of the i psi lateral vertebral artery
Results in a reversal of blood flow —> blood is stolen from the posterior circulation (vertebral arteries) and given to ipsilateral arm
Is subclavian steal more common in the right or left?
Left
How do you determine the Ca-Cv difference? Think CaO2?
(1.34 x Hgb x 0.98) - (1.34 x Hgb x .75)
How much of the cardiac output does the myocardium receive at REST?
5%
What are the highest O2 consumption activities ~ of the cardiac activities (ranked highest to lowest)
HR ~ Pressure work > contractility > wall stress > volume work
What is Kawasaki dx?
In children
Produces fever, red “strawberry” tongue, conjunctivitis and inflammation of the mucus membranes
Affect coronary arteries and medium size arteries ~. At risk for coronary artery aneurysm
What type of calcium channel blocker is diltiazem?
Benzothiazepine
Look for the “ze”
What type of calcium channel blocker is Verapamil?
Phenylalkylamine
Think the v and the y are closest in the alphabet and they are lots of ys in phenylalkylamine!!
