1- Basics, hemodynamics, heart failure

Question 1

SvO2
– true mixed venous O2 saturation

Answer 1

65 – 75%
✺ Measured with a pulmonary artery
catheter
✺ Distal port 
Tells you how the patient is UTILIZING oxygen

Question 2

ScvO2

Answer 2

> 70%
✺ Surrogate of mixed venous
✺ 5 – 8% higher than SvO2
✺ To obtain:  Draw sample from distal tip of TLC/PICC
(thorax) that is positioned in the SVC

Question 3

Coronary Sinus

Answer 3

 Both the right & left coronary arteries arise at the base of the aorta

Question 4

Coronary arteries are perfused
during…?

DIASTOLE

Answer 4

DIASTOLE

Question 5

Coronary Artery Circulation & Perfusion:
Posterior Wall perfused by:

Answer 5

85 - 90% RCA, 10 - 15% CRFX
(right vs left dominant)

Question 6

Coronary Artery Circulation & Perfusion:
Lateral Wall perfused by:

Answer 6

Circumflex:

Question 7

Coronary Artery Circulation & Perfusion:
Inferior Wall perfused by:

Answer 7

RCA:

Question 8

Coronary Artery Circulation & Perfusion:
Septal & Anterior Wall perfused by:

Answer 8

LAD:

Question 9

Coronary Artery Circulation & Perfusion
Circumflex:

Answer 9

Lateral Wall
Left atrium
SA node (45%)
Posterior left ventricle
Posterior septum (20%)
Posterior wall (left dominant- 10-15%)

Question 10

Coronary Artery Circulation & Perfusion
LAD:

Answer 10

Septal & Anterior Wall
Front & bottom of left ventricle
Front of septum
Bundle of HIS/BB
Papillary muscle

Question 11

Coronary Artery Circulation & Perfusion
RCA:

Answer 11

Inferior Wall
Right atrium
SA Node (55%)
AV Node (90%)
Right ventricle
Posterior septum
Posterior wall (right dominant- 85-90%)

Question 12

Coronary Circulation: RCA
The RCA perfuses the:
RCA Branches include:

Answer 12

Inferior wall/right ventricle
Acute Marginal, Posterior Descending

Question 13

The Left Main bifurcates into the:

Answer 13

LAD & Circumflex, Ramus in some

Question 14

Heart Valves
AV Valves:

Answer 14

R – Tricuspid
L – Mitral

Question 15

Semilunar Valves:

Answer 15

R – Pulmonic
L – Aortic

Question 16

During atrial contraction:
AV valves are ______
Semilunar valves are ______

Answer 16

AV valves are OPEN,
Semilunar valves are CLOSED

Question 17

During ventricular contraction:
AV valves are ______
Semilunar valves are ______

Answer 17

AV valves are CLOSED,
Semilunar valves are OPEN

Question 18

Normal CO is ______L/min
Cardiac Index _____ L/min/m2

Answer 18

____ = 4 - 8 L/min
_____= 2.5 – 4.0 L/min/m2

Question 19

CO can an be estimated/measured by:

Answer 19

 Pulmonary artery catheter  Echocardiogram  Indirectly via functional hemodynamics (Flotrac/LiDCO)  Non-invasive (Cheetah, ClearSite, CNAP)

Question 20

Cardiac output =_____ x _______

Answer 20

HR x Stroke volume

Question 21

Stroke volume
SV =____ - ____
The amount of blood ejected with each beat:
What happens to the SV when afterload is ↑?

Answer 21

Preload Afterload Contractility
___= EDV – ESV  Typical EDV = 120 ml  Typical ESV = 50 ml
~ 60 – 100 mL/beat
SV drops

Question 22

Determinants of Stroke Volume: (3)

Answer 22

Preload (CVP/PAOP): Myocardial fiber length
Afterload (SVR): Resistance the heart has to eject against
Contractility: How many myocardial muscle fibers are available to contract?
–↑H+,↑CO2, ↓O2 supply

Question 23

Contractility: Force of contraction:
+ Inotropy:

Answer 23

 SNS stimulation  Sepsis (early=hyperdynamic)  Hyperdynamic ventricle  Dobutamine  Milrinone  Epinephrine  Dopamine

Question 24

Contractility: Force of contraction:
- Inotropy:

Answer 24

 Massive MI  Heart failure  Increased resistance  Hypoxia  Acidosis  Hypercapnia  Electrolyte imbalances
✺ Ca++, Mg++, K+

Question 25

Preload:

Answer 25

 The initial stretching of the myocardium prior to contraction  Therefore, it is related to the sarcomere length at the end of diastole  Equated to volume status (with caution!)  High preload = fluid overload ✺ But not always clinically true!  Low preload = fluid deficit
Estimate on the: ✺ Right side of the heart as “CVP” ✺ Left side of the heart as “PAOP”