Hemodynamics Flashcards
Hemodynamics
CO= SV x HR
Normal: 4-8 L/min
Ejection Fractions
Blood in vent. @ end of systole that is ejected
Normal: 55-70%
Stroke Volume
Affected by (1) ctxs or (2) volume, or both
Preload
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)
Preload (increased)
- Exercise
- Increase Blood Volume
- Fluid admin
- Tricuspid regurg
Preload (decrease)
- Dehydration
- Blood loss
- Decrease venous tone: sepsis, neurogenic shock
- Vasodilators
- Tricuspid valve prolapse
Afterload
Resistance the ventricles must overcome to eject blood
* Forces: systemic + pulmonary arterial pressures, valve resistance, vessel diameter, mass/density of blood
Starling’s Law
Greater stretch/fill => greater force of ctxs
* Greater stretch => great O2 consumption
* Excessive filling/stretch => loss of elasticity
Hemodynamic monitoring uses:
Shock, AMI, HF, Surgery, Fluids vs. Diuretics
Types of Invasive Lines
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)
Arterial Lines
- 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)
Allen’s Test
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
Mean Artieral Pressure (MAP)
SBP + (DBP x2)/3
Desirable: 70-105 mmHg
60+ mmHg to perfuse vital organs
Low MAP w/ bleeding/trauma
High MAP w/ Heart Failure
Central Venous Catheters
- 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
Central Venous Catheters
Dressing Changes
Sterile !!
Q weekly
Mask for pt + RN
disc: white down, blue up (prevents infections)
Occlusive dressing, togaderm
Central Venous Catheters
Nursing Interventions
Dressing changes
X rays confirms inital placement
Monitor CVP readings
Central Venous Catheters
Low CVP
Low volume
Vasodilations
Central Venous Catheters
High CVP
L side HF
Pulmonary Artery Catheters (SWAN)
- 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 !!
Low PAWP
MI, HF, Hypovolemia, Cardiogenic shock, Cardiac tamponade, Late sepsis
High PAWP
Early sepsis, Hyperthyroidism, Fever, Exercise
