Hemodynamics

Question 1

Hemodynamics

Answer 1

CO= SV x HR
Normal: 4-8 L/min

Question 2

Ejection Fractions

Answer 2

Blood in vent. @ end of systole that is ejected
Normal: 55-70%

Question 3

Stroke Volume

Answer 3

Affected by (1) ctxs or (2) volume, or both

Question 4

Preload

Answer 4

Volume depending on degree of stretch
Depends on:
1. Volume of blood in ventricles (venous return)
2. Compliance/ extensibility of ventricles (stretch)

Decrease preload w/ fluid volume deficit
Expressed: mmHg
Preload aka “filling pressure” (central venous pressure: 2-6 mmHg)

Question 5

Preload (increased)

Answer 5

• Exercise
• Increase Blood Volume
• Fluid admin
• Tricuspid regurg

Question 6

Preload (decrease)

Answer 6

• Dehydration
• Blood loss
• Decrease venous tone: sepsis, neurogenic shock
• Vasodilators
• Tricuspid valve prolapse

Question 7

Afterload

Answer 7

Resistance the ventricles must overcome to eject blood
* Forces: systemic + pulmonary arterial pressures, valve resistance, vessel diameter, mass/density of blood

Question 8

Starling’s Law

Answer 8

Greater stretch/fill => greater force of ctxs
* Greater stretch => great O2 consumption
* Excessive filling/stretch => loss of elasticity

Question 9

Hemodynamic monitoring uses:

Answer 9

Shock, AMI, HF, Surgery, Fluids vs. Diuretics

Question 10

Types of Invasive Lines

Answer 10

A-Line, Central Line, Swan Line -> measure pressure, flow, +O2 of blood
* Transducer calculates: converts physiologic events into electricals signal
1. Needs to be level w/ Heart (Phleostatic axis) -Phlebostatic angle: level of R atriumm, 4th lCS + midaxillary line

• ** Zero**: turn stop cock upward + remove cap to atmospheric air ( Qshift min, or Q8, or w/ position change)

Question 11

Arterial Lines

Answer 11

• Pressure bag (saline) -> transducer (pt) -> monitor
• RN cannot insert, only maintain
• In radial or femoral artery
• Very painful on insertion
• RN can remove if not sutured in (4x4 pressure dressing, hold for 5 mins)
• Zero transducer Q shift
• Pull piggy tail up to flush line w/ concected saline Q shift (closed A line system)
• Get manual BP to confirm A line reading

Indications:
1. Continuous BP reading: MAP
2. Contin ABG’s
3. Freq Blood draws (must zero after every draw)

Complications: Limb impairment, infection, thrombus/arterial occlusion

(you cannot check a radial pulse w/ radial A line)

Question 12

Allen’s Test

Answer 12

Occlude radial + ulnar
Release ulnar, to see if the adequate blood flow
Ulnar should perface hand

if it does not turn pink in 6 seconds, unlar is insufficient, and radial artery should not be used

Question 13

Mean Artieral Pressure (MAP)

Answer 13

SBP + (DBP x2)/3
Desirable: 70-105 mmHg
60+ mmHg to perfuse vital organs
Low MAP w/ bleeding/trauma
High MAP w/ Heart Failure

Question 14

Central Venous Catheters

Answer 14

• Sits in R atria
• Central or PICC
• Min of x2 lumens if transducing (no fluids + transducing in same line)
• Gives R atrial pressure (RAP) (aka… Preload, CVP reading 2-6 mmHg)
• Minutes waveform on montior
• Flush + zero transducer Q shift ( closed system, norm flush other lumens)
• Can draw blood (cannot draw ABGs)
• RN cannot remove!!!
• Record sonometers measurements

Question 15

Central Venous Catheters

Dressing Changes

Answer 15

Sterile !!
Q weekly
Mask for pt + RN
disc: white down, blue up (prevents infections)
Occlusive dressing, togaderm

Question 16

Central Venous Catheters

Nursing Interventions

Answer 16

Dressing changes
X rays confirms inital placement
Monitor CVP readings

Question 17

Central Venous Catheters

Low CVP

Answer 17

Low volume
Vasodilations

Question 18

Central Venous Catheters

High CVP

Answer 18

L side HF

Question 19

Pulmonary Artery Catheters (SWAN)

Answer 19

• sits in pulmonary artery, confirm w/ CXR
• Pa wedge pressure -> close L side afterload measurement (6-12 mmHg)
• Connected to transducer when inserted
• Balloon is deflated once in place ( no wedge pressure when deflated, get measurement quickly when inflated)
• You should never see constant wedge pressure reading ( you will have constant CVP (preload) read)
• Y (blood) N (ABGs)
• Always 3 lumens ( x1 -> transducer)
• Wedge position ? -> deflated balloon !!

Question 20

Low PAWP

Answer 20

MI, HF, Hypovolemia, Cardiogenic shock, Cardiac tamponade, Late sepsis

Question 21

High PAWP

Answer 21

Early sepsis, Hyperthyroidism, Fever, Exercise