Electrical therapy Flashcards
Indications for defib
Pulseless monomorphic VT, sustained polymorphic VT, and VF
Shocks for defib and cardioversion are expressed in what units
Joules
Other functions for combination defib pads besides shock
ECG monitoring, pacing
3 general defib waveforms
Monophasic, biphasic, triphasic
What do the different types of waveforms indicate
Whether the current is delivered in 1 diretion, 2 or multiple directions
What waveform do most AEDs and manual defibrillators sold today use?
Biphasic
The energy deliver through the patients chest wall is determined by what?
Transthoracic impedance (measured in Ohms) aka resistance?
What affect do skin surface, fat, bone, and hair have on impedance
Increase
What do you do if a patient has excessive chest hair and you are trying to defib
Remove it (razor, if no razors place an extra set of electrodes on the quickly remove to rip the hair away)
For what weight and above should adult sized paddles
10 kg (22 lb)
General rule for what size paddles you should use
Largest pads that will fit on the pts chest w/ at least 1 inch separating each pad
A lack of good defib pad contact may cause what
Arcing of electricity and skin burns
Should you use alcohol or alcohol based cleaners to clean the skin before defib?
NO
When using a biphasic waveform defib, does body weight influence the energy delivered?
No
When preparing skin for pad placement, what SHOULDN’T you use to clean
Alcohol, tincture of benzoin, or antiperspirant
Typical paddle or pad placement in resuscitation
Sternum/apex position; aka anterolateral or apex-anterior position
Position of pads in the sternum-apex position
Sternal pad is right side of the sternum just below the clavicle
Apex pad is midaxillary line lateral to the pts left nipple
If the pt is a women, what should you do differently when placing the apex pad in the Sternum-apex position
Elevate the left breast and place the pad underneath the breast tissue
If you accidentally place the sternum pad in the apex position and the apex pad in the sternal position, what should you do?
Just keep going, as long as the heart is between them it’s cool
Do you need to apply conductive gel to combination pads?
No, they are pre-lubed
How much pressure should you apply to handheld pads when defib
About 25 pounds
How many joules should you use to shock if you are using a monophasic defibrillator
360 J
How many joules should you use to shock if it’s a biphasic defibrillator
Level recommended by the manufacturer (typically 120-200 J)
Who is the last person to “clear” the area when defibbing?
CPR guy; should maintain chest compressions until just before shock is given (until the defib has charged)
Should oxygen be turned off while shocking?
Yes
How long between shocks?
5 cycles of CPR (about 2 minutes) and rhythm is assessed
What do you do if the shock restores a rhythm
Check for a pulse; if pulse is present then check for BP and other vital signs
If shock restores rhythm but you aren’t sure if there’s a pulse?
Continue CPR
What if the defib is charged and the pts rhythm spontaneously converts to an organized rhythm or a nonshockable rhythm?
In most cases the defib will disarm if the discharge buttons are not pressed w/in 60 seconds of charging
What should you do if a shock restores a rhythm but then converts back to the VF/VT?
Defib at the last successful energy level
Can you shock a person with an ICD?
Yes, but make sure the pads aren’t on the device; pt should have ICD checked after defib to make sure it still works
Explain tiered-therapy as it applies to ICDs
They can deliver a range of treatments; defib, antitachycardia pacing, cardioversion, and bradycardia pacing. The therapies used in a pt are determined by the physician who placed it.
If an AED is semi-automated, do you need to press a button to shock?
Yes
What kind of AED do you use for someone who is unresponsive, apneic, pulseless, and 8 years or older?
Standard
If the pt is an infant who needs shocked, use what?
Manual defibrillator is preferred to AEDs
Steps in using an AED
Turn on power
Attach the device
Analyze the rhythm
Deliver a shock if indicated and safe
How far away from ICD should AED pads be placed?
At least 3 inches
If an ICD is delivering shocks to a pt and you want to shock them, what do?
Wait 30-60 s for it to complete it’s cycle
Shock that is timed or programmed for delivery during ventricular depolarization
Synchronized cardioversion
What does a synchronized cardioverter search for to synchronize
Highest (R wave) or lowest (Q or S waves) part of the QRS complex
What kind of rhythms does a cardioverter treat
Rhythms w/ identifiable QRS complexes and a rapid ventricular rate
What kind of rhythms can cardioverters NOT treat
Polymorphic VT (disorganized rhythm) and VF (no clear QRS complexes)
Cardioverter indications
Unstable afib
Unstable aflutter
Unstable MONOmorphic VT
Unstable narrow-QRS tachycardia
Do you need to place gel on a standard defibrillator
Yes (conductive gel)
Which lead should you sync the cardioverter to?
The one with the highest QRS amplitude
Indications for defibrillation
Pulseless VF/VT
Sustained polymorphic VT
What should you do if you are unsure if it’s monomorphic or polymorphic VT and the pt is unstable
Give unsynchronized shocks; don’t delay tx to try to figure out rhythm
Why should you make sure O2 sources are away from the pt while shocking?
Possibly can allow ignition of flammable materials nearby
Complications of electrical therapy
Skin burns Risk of fire Myocardial damage or dysfunction Embolic episodes Dysrrhythmias including asystole, AV block, bradycardia, VF Injury to the operator or team
Electrical stimulation through pacing pads on a patients torso to stimulate contraction of the heart
Transcutaneous pacing (TCP), aka temporary external pacing or non-invasive pacing
What is the stimulating current for TCP measured in
Milliamperes (mA); considerably less than what is used for cardioversion or defib (measured in Joules)
For an TCP, what should you set the initial rate at
60-80 bpm
What is the electrical capture usually seen as in a pt with TCP
Wide-QRS and a broad T wave
What is mechanical capture in TCP?
Pacing produces a response that can be measured like a palpable pulse and blood pressure
Why should you avoid checking pulse in the neck or left side of a patient on a TCP
TCP may cause skeletal muscle contractions in these areas which may be confused for pulses
After you achieve capture with a TCP, what should the pacing level be set at
Slightly higher (~2mA) than the threshold of initial electrical capture
What is the main limitation to TCP
Patient discomfort from skeletal muscle contraction and electrical stim of cutaneous nerves (pain)
Complications of TCP
Cough
Skin burns
Interferes with sensing from pt agitation or muscle contraction
Pain from electrical stimulation
Failure to recoqnize the the pacemaker is not capturing
Tissue damage including 3rd degree burns
Prolonged pacing leads to pacing threshold changes leads to capture failure
TCP dysfunctions
Failure to …
Pace
Capture
Sense
What is failure to capture?
Inability of pacemaker (TCP) stimulus to depolarize myocardium
