Exam 1- Hemodynamics & Electrical therapies Flashcards
Preload
Circulatory effects before blood reaches the heart
VOLUME, VOLUME, VOLUME
Measured by PA pressure
How is the preload measured
By Pulmonary artery (PA) pressure
Contractility
Cardiac muscle’s capacity to contract
“Stretch”
Contractility looks at Ejection Fraction and Cardiac Output
Afterload
Circulatory effects as blood leaves the hear; resistance or pressure that the ventricle must overcome to eject volume
How is afterload measured
Measured by BP
-Mean arterial pressure is another measure
To decrease afterload
- Vasodilators
- ACE Inhibitors
- CCB
To Increase afterload
- Vasoconstrictors
- Dopamine
To decrease contractility
Decrease preload
Electrolyte imbalance
IABP
Beta blockers
To increase contractility
Increase preload
Give inotropic drugs
VAD (ventricular assist device)
To increase preload
Fluids
Volume expanders
Vasoconstrictors
Blood products
To decrease preload
Diuretics
Vasodilators
Normal cardiac output
2 to 2.4
Two major uses for an arterial line
Blood pressure monitoring
ABG sampling labs
What does SVO2 reflect
Tissue oxygen consumption
T/F Vasoactive drugs should be administered through an arterial line?
False
Why is an allen’s test performed?
Before you place arterial line
What assessments are done by the nurse post arterial line insertion?
.
Failure to capture
.
Cardiac output
Amount of blood pumped into the heart per minute
CO =HR X SV
What is used to evaluate fluid status
Central venous pressure (CVP)
Which line carries substantial risk of an air embolism?
Arterial line
Nitroglycerine is a
vasodilator
Where is the phlebostatic axis? Where is it in reference to the body?
4th ICS, midaxillary line
Level of right atrium
Where is the transducer leveled to
Phlebostatic axis
-re-level each time pt moves
Zero referencing
Is the act of standardizing the transducer to obtain accurate measurements
Performed:
- on insertion
- q4hrs
- or with position change
Arterial pressure monitoring
-Accurate, direct, INVASIVE
ABP Waveforms
should correspond to the ekg waveforms
Highest risk of complication for all lines
Infection
CVP measures
volume returning to the heart
CVP looks at (indications for cvp)
FLUID BALANCE
- fluid administration
- blood sampling
Causes of Increased CVP
Fluids
Hypervolemic
Pulmonary HTN
Increased ITP (intrathoracic pressure)
What is the preferred Arterial line site
Radial
PAP measures
Pulmonary artery pressure
-pressure of blood volume in the lung circulation
Indication for PAP
- Evaluate cardiac output, fluid volume*
- Aid in dx, monitor effect of interventions
Natural Pacemaker
SA node
Pacing threshold
amount of energy the output pulse needs to reliably capture the heart (or cause it to contract)
Pace
Capturing the hearts electrical impulse
Sense
“Seeing” the heart’s own intrinsic rhythm (periscope). The pacer decides if it inhibits or triggers an impulse.
Failure to capture (non capture)
pacer does not stimulate heart
Failure to pace
lack of pacer stimulus when intrinsic rate < pacer rate
Reasons to pace
- Symptomatic bradycardia
- Uncontrolled tachycardia
- Failure of the SA node
- Post op diagnostics
Symptomatic Bradycardia “crap”
Weakness Fatigue Syncope/Pre-Syncope Mental confusion Palpations Shortness of Breath Exercise intolerance
Fixed pacemaker
Set at a rate, no change
Demand pacemaker
Fires when needed if heart rate falls below threshold
Single chamber pacemaker
RA or RV
Dual chamber pacemaker
Both RV & RA
Defibrillation
UNSYNCHRONIZED
-Done with pulseless VT and VF
Cardioversion
SYNCHRONIZED
-Used for unstable VT, pulse present unstable PSVT, Afib, Aflutter
