URR Venous Flow Characteristics

Question 1

what is hydrostatic pressure?

Answer 1

weight of the column of blood inside vessels
-changes with variation in patient positioning

Question 2

where is hydrostatic pressure equal to 0?

Answer 2

at the heart

Question 3

what is the hydrostatic pressure at the ankle?

Answer 3

100mmHg

Question 4

what is the hydrostatic pressure at the head?

Answer 4

-30mmHg

Question 5

what is ambulatory venous pressure?

Answer 5

-the lowest pressure level in the limb during exercise
-normal levels are about 30mmHg and will increase with reflux

Question 6

walking causes ambulatory pressures to what in the calf?

Answer 6

decrease 20-30mmHg

Question 7

in patients with incompetent valves, walking pressures will what?

Answer 7

remain the same as when standing still or increase

Question 8

what is transmural pressure?

Answer 8

-pressure within veins pushing outward
-determines the shape of the vein

Question 9

flattened veins with decreased transmural pressure offer what kind of resistance?

Answer 9

more resistance to flow and less resistance to compression
-opposite to circular veins

Question 10

what is the calf muscle pump?

Answer 10

movement of venous blood occurs due to respiration and calf muscle pump
-calf veins act as reservoirs for blood
-muscle contraction causes the deep system valves to open and flow moves through to the heart

Question 11

during muscle relaxation what happens during the calf pump?

Answer 11

-causes prox valves to close due to hydro pressure and distal valves remain open to refill
-flow moves from superficial to deep through calf perforators

Question 12

what is spontaneous flow?

Answer 12

flow detected without augmentation

Question 13

what is respiratory phasicity?

Answer 13

flow moves from increased pressure to decreased pressure

Question 14

what happens to intrathoracic pressure, abdominal pressure, and flow in the upper and lower extrems during inspiration?

Answer 14

intrathoracic: decrease
abdominal: increase
upper extrem: increase
lower extrem: decrease

Question 15

what happens to thoracic, abdominal, upper and lower extrems during expiration?

Answer 15

thoracic: increase
abdominal: decrease
upper extrem: decrease
lower extrem: increase

Question 16

what is cardiac pulsatility?

Answer 16

ripples of motion caused by cardiac contraction

Question 17

what happens during the valsalva maneuver?

Answer 17

flow toward the heart should stop with no flow reversal
-augmentation of signal toward the heart upon release

Question 18

what does it mean when there is flow reversal during the valsalva maneuver?

Answer 18

venous valvular incomitence

Question 19

veins have a thinner media layer to allow for what?

Answer 19

flexability