ECC: Cardiovascular Flashcards
Causes of pale/white mucous membranes
Anemia
Vasoconstriction
Shock
Causes of injected mucous membranes
Vasodilation Sepsis Heatstroke Cyanide poisoning Carbon monoxide toxicity Side effect of certain drugs
Cause of brown mucous membranes
Oxidation injury to the blood cell causing methemoglobinemia
Causes of yellow/orange mucous membranes
Heaptic disease
Bile duct obstruction
Excessive hemolysis
Pulse deficit
A heartbeat is heard with no associated pulse
BP cuff sizing
Width: 40-60% of limb circumference
Length: 60% of limb circumference
Causes of hypotension
Hypovolemia
Poor cardiac output
Systemic vasodilation
Normal canine/feline BP
Systolic: 100-160
Diastolic: 60-110
MAP: 80-120
Pulse pressure: 40-80
Mean arterial pressure: definition
Average blood pressure over time (through both systole and diastole)
MAP: formula
MAP= [(2 x diastolic) + systolic] ÷ 3
Diastole counts twice as much as systole because 2/3 of the cardiac cycle is spent in diastole
Pulse pressure
The difference between systolic and diastolic pressure
Normal blood lactate
<1.0 mmol/L
Cause of increased lactate
Inadequate tissue oxygenation associated with impaired perfusion
2 major sources of increased lactate (systems)
Skeletal muscle
GI system
Heart failure: definition
A heart that pumps an inadequate volume of blood to all tissues resulting in inadequate oxygenation
Congestive heart failure
Impaired cardiac function resulting in elevated venous and capillary pressures
Causes organs to become congested with blood or edematous fluid
Right ventricular failure
Caused by reduced cardiac output and systemic venous hypertension
Right sided failure: history
Periods of weakness, exercise intolerance, or syncope
Right sided failure: presentation
Pale mucous membranes Jugular venous distension/pulsations Liver and/or spleen enlargement Tachypnea Peritoneal or pleural effusion
Left sided failure: history
Similar to right sided, plus:
Coughing
Orthopnea
Hemoptysis
Oliguria
Left sided failure: presentation
Arrhythmia
Heart murmur
Lung crackles
Cyanosis
Biventricular heart failure
Combination of symptoms of left and right sided failure
Loop diuretics
Decrease the re-absorption of sodium and chloride and increase the excretion of potassium
Act within loope of Henle
Increase renal excretion of water, sodium, chloride, calcium, magnesium, hydrogen, ammonium, and bicarbonate
Most common loop diuretic
Furosemide
Furosemide dosing for cardiogenic or pulmonary edema
2-4 mg/kg every 1-8 hours
CRI: 0.1mg/kg/hr
Potassium-sparing diuretics
Act by inhibiting the action of aldosterone on distal tubular cells
Can be used in conjunction with loop diuretics
Most common potassium-sparing diuretic
Spironolactone
Spironolactone onset of action
2-3 days of therapy to reach peak effect
Used primarily for long-term treatment
Spironolactone dosing
2-4mg/kg/day PO
Dobutamine
Causes increased myocardial contractility and stroke volume
Increases cardiac output
Dobutamine dosing
5-20 mcg/kg/min
Dobutamine side effects
Nausea Vomiting Tachycardia Hypertension Arrhythmias
Positive inotropes
Increase the strength of contraction of the myocardial muscle, there by increasing cardiac output
4 groups of inotropic drugs
Sympathomimetic amines:
dobutamine and dopamine
Phosphodiesterase inhibitors:
sildenafil and vetmedin
Calcium sensitizers
Digitalis glycosides
Dopamine
Precursor of norepinephrine
Dopamine dosing
Low dose: 1-5 mcg/kg/min
High dose: 6-10mcg/kg/min
Cannot be used in conjunction with dopamine or dobutamine
Beta blockers
Sildenafil
Potential benefits in CHF
In human studies:
Increased myocardial contractility
Blunted adrenergic stimulation
Reduced left ventricular afterload
Improved lung diffusion capacity
Pimobendan
Both a phosphodiesterase inhibitor and calcium sensitizer
Positive inotropic effect + vasodilation
Used for long-term treatment of CHF
Pimobendan dosing
0.1-0.3 mg/kg BID
Types of vasodilators
Ace inhibitors:
Enalapril, benazepril
Calcium channel blockers:
Amlodipine, diltiazem
Indications for ACE inhibitors
Hypertension
CHF
ACE inhibitor mechanism of action
Block the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor
May slow or reverse the progression of pump dysfunction and pathologic remodeling that occurs with heart failure
Primary use for amlodipine
Systemic hypertension
Indications for diltiazem
Supraventricular tachycardias
Atrial fibrillation
Hypertrophic cardiomyopathy
What type of drug are amlodipine and diltiazem?
Calcium channel blockers
Cardio effects of beta-1 stimulation
Increased HR
Increased AV node conduction velocity
Increased strength of myocardial contraction
Cardio effects of beta-2 stimulation
Vasodilation in skeletal muscles
Bronchodilation in airways
Propranolol
Blocks both beta-1 and beta-2 receptors
Decreases HR and contractility, slows conduction
Decreases cardiac output at rest and during exercise
Why should patients with respiratory issues be monitored closely on propranolol?
It blocks beta-2 receptors as well as beta-1, causing bronchial constriction
Atenolol and metoprolol
Selectively block b-1 receptors
Decrease cardiac output, myocardial oxygen demand, and BP
Atenolol and propranolol in diabetic patients
Both drugs prolong the hypoglycemic effects of insulin
Closer monitoring of BG
Beta blocker dosing
Canine: 12.5-50mg q12-24h
Feline: 6.25-12.5mg q12-24h
Esmolol
Ultrashort acting beta-1 blocker available only as injectable
Generally used as a “test”drug for beta blocker therapy or as an infusion for supraventricular tachyarrhythmias
