Hemodynamic Measurements

Question 1

CVP- a,c,v,x,y waves

Answer 1

a- RA contraction
c- tricuspid valve closing/RV contraction
v- RA filling
X- RA relaxation/ RA refilling / RV contraction
y- tricuspid opening/ RA empties

Question 2

Where is p wave, qrs, t wave, in CVP wave form?

Answer 2

p wave- right before a wave
qrs- right before c wave (thats why c wave is conventionally known as ventricle contraction)
t wave- right before t wave

Question 3

What can swan measure directly?

Answer 3

CVP
PCWP
PAP
CO
RA/RV pressure
SvO2

Question 4

What can the swan measure indirectly?

Answer 4

SVR [(map-cvp)/co)]x80
PVR [(mean pap-pcwp/co)x80]
CI (co/BSA)
SVI (ci/hr)
DO2 (1.34 x hgb x spo2 x CI)
VO2 (1.34 x hgb x [spo2-cvo2] x ci)
LVSWI ()
RVSWI ()

Question 5

Appropriate height of transducer

Answer 5

4th IC, 5cm below left sternal border

Question 6

CO, SV, EF formula

Answer 6

HR x SV
EDV-ESV
(EDV-ESV)/EDV

Question 7

Fick measurement

Answer 7

Cardiac Output= o2 absorbed by lungs/ AV O2 difference
200/40 = 5 1L portions of blood that must pass thru the pulmonary circulation each minute to absorb this amount
Thus, there is 5 liters of blood flow passing thru the lungs each minute, which is also a measurement of CO

Question 8

How much oxygen is absorbed into the blood form the lungs each minute?

Answer 8

200ml

Question 8

What is the AV difference?

Answer 8

40ml/L
(LH -200ml/L) - (RH-160mlL)

Question 9

How are samples taken for ficks measurement?

Answer 9

RH oxygen- SvO2- PA
LH oxygen - Any artery in body
O2 absorbed by lungs- oxygen meter detects rate of disappearance of oxygen

Question 10

Thermodilution technique

Answer 10

A known amount of saline at a known temperature (below blood) is injected into the RA
The tip of the catheter is read and expresses area under the curve to calculate CO

Question 11

Thermodilution graph

Answer 11

CO is inversely proportionate to AOC or graph height or graph size
Bc a poor CO would not move the injectate fast, the area is larger

Question 12

L to R shunt displays ____ CO measurement

Answer 12

High!

Question 13

Most common problem with obtaining accurate CO measurement in thermodilution method

Answer 13

improper injectate used

Question 14

Most common method for CO

Answer 14

thermodilution

Question 15

Velocity formula

Answer 15

V= q/A
q-flow
a-area

Question 16

Poiseuille’s equation

Answer 16

For laminar/turbulent flow
Q= (pi[Pi-Po]r^4))/(8nl)
Radius is the most is important

Question 17

Ohms law

Answer 17

I=V/r
I flow
V voltage drop
R resistance

Question 17

Cerebral vs coronary perfusion pressure

Answer 17

MAP-CVP or ICP, whichever is higher
DBP-LVEDP

Question 18

Flow is ___ related to the pressure gradient

Answer 18

Directly, think of a piggy back iv, how the higher one runs

Question 19

Doubling a radius does what to the flow?

Answer 19

16 fold increase

Question 20

Flow is ___ related to fluid viscosity

Answer 20

inversely
think, pb cant flow good

Question 21

Reynolds equation

Answer 21

NR= PDV/N
Reynolds number
p- density
diameter
velocity
viscosity

Question 22

Number value for laminar and turbulent flow

Answer 22

<2000- laminar usually
2000-3000- variable
>3000- usually turbulent

Question 23

Which vessels does turbulence occur?

Answer 23

Stenotic heart valves, narrowed arteries

Question 24

How does turbulence effect perfusion pressure?

Answer 24

Drops it

Question 25

How is turbulence heard by HCP?

Answer 25

As murmurs with a stethoscope