5- Measurement of Cardiac Output

Question 1

cardiac output =

Answer 1

heart rate x stroke volume

Question 2

cardiac index =

Answer 2

cardiac output divided by the body surface area

Question 3

load on the heart at the end of filling

Answer 3

preload

Question 4

the amount of work it takes to move the contents of the ventricle into the aorta

Answer 4

afterload

Question 5

the amount of tension generated is relative to the stretch on the …

Answer 5

muscle prior to contraction

Question 6

frank starling law of the heart

Answer 6

the work done by the heart is directly proportional to the end diastolic volume ie the more volume returns to the heart during diastole, the more can get expelled during systole

Question 7

if central venous pressure increase only a few mmHg, venous return will greatly…

Answer 7

diminish (becasue the driving force (pressure difference) will decrease)

Question 8

when the central venous pressure equal the peripheral venous pressure…

Answer 8

venous return ceases = mean systemic filling pressure

Question 9

what influence MSFP

Answer 9

ONLY volume chages

Question 10

effect of dilation venous return

Answer 10

increase because more blood can flow into the venous circulation faster

Question 11

does isolated arteriolar tone cahnge MSFP?

Answer 11

no

Question 12

intrinsic contractile state of the heart =

Answer 12

inotropy

Question 13

improving just the contractility of the heart will…

Answer 13

increase the SV

Question 14

a larger preload is related to…

Answer 14

a larger end diastolic volume

Question 15

Does the influence of arteriolar tone change blood volume?

Answer 15

NO

does not change the MSFP, just the rate

ie. vasodilation= higher rate return

Question 16

how does blood volume influence the MSFP?

Answer 16

increase blood volume = higher MSFP

Question 17

for the same preload, a larger afterload requires…

Answer 17

less shortening

Question 18

a larger afterload =

Answer 18

larger end systolic volume

Question 19

stroke volume ___________ with increasing afterload

Answer 19

decreases

all other things equal, if increase afterload, we will decrease stroke volume because you are unable to eject as much blood

Question 20

increasing the contractile efficiecy (force generated) will ___________ the stroke volume for a similar load

Answer 20

INCREASE

Question 21

direct Fick method

Answer 21

rate of oxygen consumption by a person is equal to the rate at which the oxygen comes to the organ multiplied by the amount of oxygen in the tissue

Question 22

dye (indicator) dilution technique

Answer 22

injection of indicator into circulation with downstream blood sample

Question 23

themal dilution technique

Answer 23

injection of cold saline blous into the RV and temperature reading in the pulmonary a.

provides ISTANTANEOUS assessment of CO

Question 24

echocardiography

Answer 24

ultrasound image with chamber dimensions and doppler shift

Question 25

principle of mass balance

Answer 25

from adding a known quantity of something into an unnkown volume of liquid, one can calculate the volume from the final concentration of the dye in the liquid

with known transport rate and concentration, flow rate can be calculated