Cardiovascular System Flashcards
What can happen with occlusion of the gas outlet ports on the oxygenator of the CPB machine?
air embolism
What is the equation for pulmonary vascular resistance?
PVR = (PAP - PCWP) x 80
CO
What are the components of afterload?
arteriolar tone (measured by SVR)
vasoelastic properties of the aorta
density and viscosity of blood
returning pulse waves
How does pulse pressure (PP) change during positive-pressure ventilation?
PP increases in early inspiration
PP decreases in expiration
Why does HR fall with a Valsalva maneuver?
increased intrathoracic pressure transiently increases aortic pressure activating baroreceptors in the aortic arch
Which cardiac conditions cause inaccurate measurement of CO by thermodilution?
atrial fibrillation (injectate starts in RA)
intra-cardiac shunts
tricuspid regurgitation
What is the most common complication of a brachial artery catheter?
median nerve injury
** limb ischemia unlikely **
What is a pH-stat strategy during cardiopulmonary bypass?
pH is held static during cooling
*this requires addition of additional CO2 to the blood to maintain PaCO2 as CO2 solubility increases at lower temperature
What is the bisferiens pulse?
characteristic of hypertrophic cardiomyopathy
early peak representing unobstructed flow and subsequent peak caused by dynamic obstruction
What are some reversible causes of a pacemaker failure to capture intra-operatively?
hypokalemia
hypocarbia
hypothermia
What happens to venous capacitance when an aortic cross clamp in placed?
decreased venous capacitance
What is the typical blood supply to the posterior mitral papillary muscle? The anterior mitral papillary muscle?
posterior: PDA
anterior: LCx and LAD
Are neurologic outcomes better with a pH-stat strategy or alpha-stat strategy during CPB?
better with alpha-stat
During Doppler evaluation of the mitral valve, in which scenario is the E wave (early diastolic flow) smaller than the A wave (peak atrial flow)?
impaired LV relaxation
Which nerves carry afferent the afferent limb of the baroreceptor reflex?
CN IX from the carotid sinuses CN X from the aortic arch
What are the cardiovascular complications of ankylosing spondylitis?
aortic insufficiency
vasculitis
What causes overestimation of CO with thermodilution?
- loss of injectate or incomplete syringe filling
- clot on the thermistor
- catheter located too distally
Does the right or left vagus nerve primarily supply the SA node? The AV node?
SA node: right vagus
AV node: left vagus
How do volatile anesthetics depress cardiac contractility?
(likely) reduce Ca2+ release from the sarcoplasmic reticulum
What is the equation for SVR?
SVR = (MAP - CVP) x 80
CO
How does the CVP tracing change in cardiac tamponade?
y-descent is absent (early diastolic filling)
Is the SA node affected more by volatile agents or opioids?
SA node is depressed more by volatile agents
(junctional rhythms under inhaled anesthesia)
Which ion fluxes makes up the cardiac action potential?
What causes underestimation of CO with thermodilution?
measurement of temperature too proximally
Where are the most sensitive baroreceptors located?
carotid sinuses and aortic arch
What are a normal valve area and transvalvular gradient for the mitral valve? In severe mitral stenosis?
valve area: 5 cm normal, 1 cm for severe MS
gradient: < 2 mm Hg normal, > 12 mm Hg for severe MS
What are the contraindications for IABP?
aortic insufficiency
aortic dissection
mobile aortic plaques
How does a radial artery BP tracing compare to an aortic BP tracing?
radial artery tracing shows:
- Wider pulse pressure (pressure wave reflection)
- higher systolic
- lower diastolic
- lower mean pressure
What kind of receptors mediate the baroreceptor reflex?
stretch-sensitive mechanoreceptors
What is cardiac syndrome X?
angina with clean coronaries, possibly due to microvascular disease in the distal coronary system
