Cardiology

Question 1

MAP medial arterial pressure

Answer 1

MAP= CO x TPR

CO= cardiac output 
TPR= total pressure resistance (all resistance)

Question 2

Stroke volume (SV)

Answer 2

SV=EDV-ESV

End systolic volume (ESV)
End diastolic volume (EDV)

Question 3

Flow Q

Answer 3

Q=P1-P2/R

P= pressure 
R= resistance

Question 4

Resistance (R)

Answer 4

R=v.L/ r4

Viscosity (v)
Vessel Length (L)
Radio (r)

Question 5

Wall tension (T)

Answer 5

T=Pr

Pressure (P)
Radius (r)

Question 6

Compliance

Answer 6

How easily a vessel is stretched

Question 7

Elasticity

Answer 7

Inverse of compliance (tendency to rebound from a stretch)

Question 8

Mean systemic filling pressure (Psf)

Answer 8

Psf= V/C

V: volumen
C: compliance

Question 9

Venus return: upstream and downstream

Answer 9

Right atrial pressure (RAP): downstream

Mean systematic filling pressure (Psf): upstream

Question 10

Mean systemic filling pressure (Psf) drives the upstream to Venus returns (VR)

Answer 10

Psf is directly related to VR
(Psf VR)

Psf = vol/compliance

Psf . VR = Vol / compliance

Question 11

Venus return (VR)

Answer 11

VR= Psf - RAP / R

Is like Q = P1 - P2 / R

Psf= mean systemic filling pressure 
RAP= right atrial pressure 
R= resistance 

When R arise only P1 arise, P2 decreases

Question 12

Mean systemic filling pressure

Answer 12

Pressure in the circulatory system when there is NO FLOW

Question 13

Systolic performance of the ventricle

Answer 13

Preload
Contractility
Afterload

Question 14

Cardiac output detreinants

Answer 14

Heart rate
Preload
Contractility
Afterload

Question 15

Cardiac output (CO)

Answer 15

CO=HRxSV

HR: heart rate
SV: stroke volume

Question 16

Pulse pressure

Answer 16

Systolic - diastolic = pulse pressure

PP= SV/C

PP= pulse pressure 
SV= stroke volume 
C= compliance

Question 17

Mean pressure

Answer 17

It should be closer to diastolic than systolic

Mean pressure = diastolic + 1/3 pulse pressure
Pulse pressure = systolic-diastolic

Question 18

Fick principle

Answer 18

Calculate the blood flow through an organ

Flow= uptake (O2)/ A-V

Question 19

O2 consumption (uptake)

Answer 19

O2 consumption= Qx(CaO2-CvO2)

CaO2-CvO2 = extraction of O2 by the tissue

CaO2= concentración arterial de O2
CvO2= concentración venosa de O2

Question 20

O2 delivery

Answer 20

O2 delivery= QxCaO2

If O2 delivery decreases, then PvO2 and SvO2% fall

Fall in PvO2 or SvO2% indicates patient’s O2 consumption increased and/or there was a fall in Q or CaO2 or both

Question 21

Vasodilatory metabolite, intrinsic regulation of blood flow

Answer 21

Adenosine, CO2, H, K

Question 22

Myogenic mechanism, a auto regulation feature of blood flow

Answer 22

Increase perfusing pressure = stretch of the arteriolar wall and the surrounding smooth muscle, so flow doesn’t increase significantly

Question 23

Auto regulating tissues

Answer 23

Cerebral circulation
Coronary circulation
Skeletal muscle vasculature during exercise

Question 24

B2 stimulation in the vascular tissue

Answer 24

Produce vasoconstriction by and only epinephrine

Question 25

Cerebral circulation

Answer 25

PCO2 is an important factor regulating cerebral blood flow CO2 = vasodilation Hypoventilation: increase PCO2 thus it increases cerebral blood flow Hyperventilation: decreases PCO2 thus it decreases blood flow

Question 26

Head trauma

Answer 26

Need to reduce cerebral blood flow for this reason they apply hyperventilation

Question 27

Coronary circulation

Answer 27

Better in diastole

Question 28

Ejection fraction

Answer 28

Normal >55% EF= SV/EDV

Question 29

Cardiac output

Answer 29

CO= MAP/TPR CO= (MAP-RAP)/TPR