Download Electrical Treatment for Cardiac Abnormalities ACPF – 1-0

Electrical Treatment for
Cardiac Abnormalities
Advanced Paramedic Skills
Mary Osinga
Objectives
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Defibrillation
 Theory
 What gets defibrillated
 Safety review
 Placement
 AED Introduction
Pacing Overview
 Transcutaneous
Implanted AED’s
The AHA Chain of Survival
1. Early access to the emergency medical
services (EMS) system
2. Early CPR either by bystanders or firstresponder rescuers
3. Early defibrillation by first responders,
emergency medical technicians (EMTs),
paramedics, or nurses and physicians if they
are on the scene
4. Early ACLS
Source: Cummins et al., 1991
Chain of Survival- Purpose
• EARLY ACCESS
– to 911 system. To get medics moving.
• EARLY CPR
– to help circulated oxygen to the patient's heart and
brain.
• EARLY DEFIBRILLATION
– May be AED on scene, such as health clubs, fd etc
– shocks to restore normal heart rhythm.
• EARLY ADVANCED CARE
– provided by als or hospital staff.
Most survivors of cardiac
arrest are from the group of
patients . . .
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Whose collapse is witnessed by a bystander,
Who receive cardiopulmonary resuscitation
(CPR) within 4 to 5 minutes, and
Who receive advanced cardiac life support
(ACLS), e.g., defibrillation, intubation, drug
therapy, within the first 10 minutes.
Source: Weaver et al., 1986
Survival Rates
No CPR
0%-2%
survive
Delayed defibrillation
Early CPR
2%-8%
survive
Delayed defibrillation
Early CPR
20%
survive
Early defibrillation
Early CPR
survive
Early ACLS
30%
Very early defibrillation
Source: American Heart Association, 1994
Remember….Time is Muscle!
Defibrillation Statistics
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Defibrillations chances of restoring a
pulse decrease rapidly with time.
Minutes elapsed
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AHA says…
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Most frequent initial rhythm in SCD is
VF
ONLY effective treatment is defibrillation
Probability of successful conversion
diminishes over time
Speed at which defib shock is delivery is
MAJOR determining factor
Need for Defibrillation?
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Only put the unit on someone you would do
CPR on... someone who is
Unresponsive
Not breathing
and has NO signs of circulation or
no pulse.
I.e do the LOC, ABC’s first
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Always Start with Basics
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First paramedic
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Assess responsiveness
Airway, no air in and out – oral airway in
Breathing – none –start bagging
Circulation-none- landmark and start CPR
Second Medic
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Gets out defibrillator, sets up
Attaches big pads
Works monitor
Ventricular Fibrillation
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Ventricular fibrillation (VF) is an abnormal
heart rhythm often seen in sudden cardiac
arrest.
This rhythm is caused by an abnormal and
very fast electrical activity in the heart.
VF is chaotic and unorganized; the heart just
quivers and cannot effectively pump blood.
There IS electrical activity but No mechanical
pumping
Ventricular Fibrillation
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VF will be short lived and will
deteriorate to asystole if not treated
promptly.
For each minute that VF persists, the
likelihood of successful resuscitation
decreases by approximately 10 percent.
Ventricular Fibrillation
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Ventricular fibrillation (VF) is an abnormal
heart rhythm often seen in sudden cardiac
arrest.
This rhythm is caused by an abnormal and
very fast electrical activity in the heart.
VF is chaotic and unorganized; the heart just
quivers and cannot effectively pump blood.
Ventricular Fibrillation
This rhythm can be coarse or fine, (close to asystole)
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Ventricular Tachycardia
VT
This rhythm is wide complex (greater than…?)
No discernable P or T waves
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Defibrillation Theory
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Definition-the process of passing a
current through the fibrillating heart to
depolarize the cells and allow for
repolarization by a pacemaker cell
Need to shock a critical mass of
myocardium
Otherwise ectopi foci remain fibrillating
Defib theory continued
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Defibrillator is a capacitor that stores NRG
Consists of capacitor, high voltage power
supply and delivery conduits (pads or
paddles)
Various waveforms of NRG, such as
monophasic and biphasic (less NRG required)
Use predominately DC
NRG=Power x duration
Joules =watts (not WHAT’s) x Seconds
Resistance to defibrillation success are:
Resistance in Chest Wall to J’s
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Paddle or pad pressure
Pad-skin contact (hair etc)
Pad-paddle skin surface area
Number of previous countershocks
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Concept of transthorasic impedance
Time of respiratory cycle (ideally
inspiratory)
Success of defibrillation
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Time from onset of chaotic rhythm
Condition of myocardium
Heart size and body weight
Impedance
Pad size
Placement
Interface
Defibrillator working and delivering proper
energy setting
General Considerations
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Wet patients (drowning etc)
Medication patches
Implanted pacemakers
Young patients
Excessive chest hair
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Patient's Clothing
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The chest should be exposed to allow
placement of the disposable
defibrillation electrodes.
Clothes may need to be cut with shears
to facilitate early defibrillation.
Defibrillation =
Unsynchronized Cardioversion
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Used exclusively as the definitive
treatment for ventricular fibrillation and
pulseless ventricular tachycardia
A energy used to settle a chaotic heart
rhythm temporary into asystole, in the
hopes that some pacemaker cell in the
heart will start an organized rhythm.
Start with 200J, then 300J and 360J
Steps for Defibrillation
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Ensure pulselessness (longer pulse checks for
hypothermic patients)
Hook up either hands-free pads or paddles to chest with
gel pads.
Start CPR (May do basic airway and vent, but do not
delay defibrillation for these maneuvers)
Press Analyze
If vfib or pulseless V tach- machine will say “stand clear”
monitor charges to preset voltage( to 200 J)
ensure no one touching patient including you
Defibrillate at 200Joules with LP 12 or other defibrillator
Do not touch patient
Reanalyze and repeat at higher J settings 300
Reanalyze – still vfib/vtach charge to 360J and press
shock
Once at 360, stay at that setting.
Defib Pad Placement
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Attach anterior pad to R shoulder below the
clavicle R of the sternum
Lateral pad is anterior axillary line at the level
of the base or apex of heart -ensure good
contact- shave if required
Defibrillation
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Must be 25 lbs pressure with paddles to
ensure good contact and success of
defibrillation
Stacked shocks in beginning 200/300/360J
are to decrease transthorasic resistance. If
you take too long between shock, this is less
effective
Can also defib anterior/posterior but more
difficult and cumbersome in the VSA patient
AED Standing Order Review
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Shockable rhythms
AED Standing Order Review
for Non-shockable rhythms
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Asystole
Anything else with no pulse = PEA or
pulseless elctrical activity
Cardioversion= Synchronized
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Used for unstable patients in
supraventricular and ventricular fast
rhythms with a pulse, in order to slow
them down
Rhythms like SVT, rapid Afib/flutter,
Vtach, PSVT
Pad placement is the same as for
defibrillation
ENSURE THAT WHEN YOU DO THIS, YOU
PRESS THE ‘SYNC’ BUTTON ON MONITOR!!
Symptomatic
Tachyarrhythmias
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Look for these signs/symptoms before
aggressively electrically treating a patient
There is no rule on which or how many signs
a patient needs to have to be treated
electrically, use experience and judgement if
no patch available
•Chest pain
•Hypotension
•Shortness of breath
•Syncope
•Pulmonary edema
•diaphoresis
•Altered LOC
What does the ‘SYNC” button do?
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Find it on
your monitor!
This identifies the R waves on the ECG and
marks them (will see a ‘tag’ on them)
This tells the machine what timing to use in
order to identify the absolute refractory
period
Do NOT want to cardiovert at this time!
What will happen if you do? (if the machine
failed to sense this or worse, YOU failed to
press the ‘sync’ button before you shocked?
!!! This is bad
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Yes indeedy….you could put them into vfib
you took a organized rhythm and shocked
during the absolute refractory period (R on T
) kind of thing and produced a BADDDD
thing!
Always double check before shocking that
sync is ‘on’
NOTE: most defibs (LP12 included) have an
automatic ‘sync’ shutoff in case patients go
into vfib anyway. SO make sure you press it
in before EACH cardioversion!
Some info for Paramedic
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Again, defibrillation may be interfered with by
other equipment
Notify partner/other helpers of procedure
Watch for skin burns
Remove NTG patch
Ideally, do not have O2 nearby!
Ensure everyone clear when you defib!
Contraindications
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No order for it!
Severe hypothermia-reduced algorithm
Code 5 Patient
Open chest wounds
In a wet environment
Rule of thumb: If patients says “what are you doing?”
you do not need to defibrillate!
Transcutaneous Pacing
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For symptomatic bradycardias
examples are anything from sinus bradycardia
(rare) to 2nd degree type I and II and Third
degree block
If it needs speeding up, you could potentially
pace it.
May also attempt to pace asystole or slow
idioventricular VSA if arrest is new and pacer
is quickly available
Standby pacing (pads on but not actually
pacing) is indicated for patients in 2nd degree
Type II or third degree who are stable
Procedure for Pacing
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Explain to patient what you are doing
IV , O2, ECG (and backup airway equipment)
Sedate as indicated from BHP
Attach pads to patient. Ideally anterior/posterior
(sandwich) is best for contact and success. Anterior
pad over left lower hemithorax. Posterior in the
subclavicular area with superior margin just below the
clavicles. Good contact is essential
Connect cables to LP 12
Set demand (turn pacer to ‘on”
set HR (between 60-80)
start increasing mA from O until get capture on screen
ensure pulse matches monitor
add 10 mA to ensure safe zone
Check vitals (pulse, BP and mentation)
recheck for capture periodically
Community AED’s
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More and more people trained to use
AED’s, fully automated versions
Know models of defib and know how to
get report (what happened?)
Give rescuers good feedback during
transfer of care
Where to place AEDs?
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In a medical clinic (if available).
In a reception or common area.
Near a fire extinguisher.
With a safety response team member.
With a security officer.
On board an airline jet.
AEDs should be visible and easily accessible.
For Next Week
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Please read defibrillation and cardiac
monitoring in book
ECG monitoring pgs 1206-1271
(hopefully review)
Defibrillation pgs 1297-1305
PLEASE READ ABOVE FOR SURE!