Cardiovascular System

Question 1

What can happen with occlusion of the gas outlet ports on the oxygenator of the CPB machine?

Answer 1

air embolism

Question 2

What is the equation for pulmonary vascular resistance?

Answer 2

PVR = (PAP - PCWP) x 80

CO

Question 3

What are the components of afterload?

Answer 3

arteriolar tone (measured by SVR)

vasoelastic properties of the aorta

density and viscosity of blood

returning pulse waves

Question 4

How does pulse pressure (PP) change during positive-pressure ventilation?

Answer 4

PP increases in early inspiration

PP decreases in expiration

Question 5

Why does HR fall with a Valsalva maneuver?

Answer 5

increased intrathoracic pressure transiently increases aortic pressure activating baroreceptors in the aortic arch

Question 6

Which cardiac conditions cause inaccurate measurement of CO by thermodilution?

Answer 6

atrial fibrillation (injectate starts in RA)

intra-cardiac shunts

tricuspid regurgitation

Question 7

What is the most common complication of a brachial artery catheter?

Answer 7

median nerve injury

** limb ischemia unlikely **

Question 8

What is a pH-stat strategy during cardiopulmonary bypass?

Answer 8

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

Question 9

What is the bisferiens pulse?

Answer 9

characteristic of hypertrophic cardiomyopathy

early peak representing unobstructed flow and subsequent peak caused by dynamic obstruction

Question 10

What are some reversible causes of a pacemaker failure to capture intra-operatively?

Answer 10

hypokalemia

hypocarbia

hypothermia

Question 11

What happens to venous capacitance when an aortic cross clamp in placed?

Answer 11

decreased venous capacitance

Question 12

What is the typical blood supply to the posterior mitral papillary muscle? The anterior mitral papillary muscle?

Answer 12

posterior: PDA
anterior: LCx and LAD

Question 13

Are neurologic outcomes better with a pH-stat strategy or alpha-stat strategy during CPB?

Answer 13

better with alpha-stat

Question 14

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)?

Answer 14

impaired LV relaxation

Question 15

Which nerves carry afferent the afferent limb of the baroreceptor reflex?

Answer 15

CN IX from the carotid sinuses CN X from the aortic arch

Question 16

What are the cardiovascular complications of ankylosing spondylitis?

Answer 16

aortic insufficiency

vasculitis

Question 17

What causes overestimation of CO with thermodilution?

Answer 17

• loss of injectate or incomplete syringe filling
• clot on the thermistor
• catheter located too distally

Question 18

Does the right or left vagus nerve primarily supply the SA node? The AV node?

Answer 18

SA node: right vagus

AV node: left vagus

Question 19

How do volatile anesthetics depress cardiac contractility?

Answer 19

(likely) reduce Ca²⁺ release from the sarcoplasmic reticulum

Question 20

What is the equation for SVR?

Answer 20

SVR = (MAP - CVP) x 80

CO

Question 21

How does the CVP tracing change in cardiac tamponade?

Answer 21

y-descent is absent (early diastolic filling)

Question 22

Is the SA node affected more by volatile agents or opioids?

Answer 22

SA node is depressed more by volatile agents

(junctional rhythms under inhaled anesthesia)

Question 23

Which ion fluxes makes up the cardiac action potential?

Answer 23

Question 24

What causes underestimation of CO with thermodilution?

Answer 24

measurement of temperature too proximally

Question 25

Where are the most sensitive baroreceptors located?

Answer 25

carotid sinuses and aortic arch

Question 26

What are a normal valve area and transvalvular gradient for the mitral valve? In severe mitral stenosis?

Answer 26

valve area: 5 cm normal, 1 cm for severe MS

gradient: < 2 mm Hg normal, > 12 mm Hg for severe MS

Question 27

What are the contraindications for IABP?

Answer 27

aortic insufficiency

aortic dissection

mobile aortic plaques

Question 28

How does a radial artery BP tracing compare to an aortic BP tracing?

Answer 28

radial artery tracing shows:

• Wider pulse pressure (pressure wave reflection)
  
  • higher systolic
  • lower diastolic
• lower mean pressure

Question 29

What kind of receptors mediate the baroreceptor reflex?

Answer 29

stretch-sensitive mechanoreceptors

Question 30

What is cardiac syndrome X?

Answer 30

angina with clean coronaries, possibly due to microvascular disease in the distal coronary system