Flashcards in chapter 4 Deck (71)
What are the three electrical therapies that can be used for the management of a cardiac emergency?
Defibrillation, synchronized cardioversion, transcutaneous pacing
what are the two ways to perform defibrillation?
Automated external defibrillator (AED) or a manual defibrillator
what are the indications for defibrillation?
pulseless monomorphic VT, sustained polymorphic VT and VF
What is the term for the delivery of an electrical current across the heart muscle over a very brief period to terminate and abnormal heart rhythm and which the current has no relationship to the cardiac cycle?
what are the benefits of combination pads?
combination pads can be used for defibrillation, synchronized cardioversion and in some cases pacing. they also physically separate the operator from the patient
what's the equation for energy?
Energy (joules) = current (amperes) x voltage (volts) x time (s)
it's the current that delivers the energy to the patient and depolarize the myocardium
what is transthoracic impedance?
Impedance is the resistance to the flow of current so transthoracic is the natural resistance of the chest wall to the flow of current
measured in ohms
What are some of the factors known to affect transthoracic impedance?
- body tissue and hair
note that when biphasic waveform defibrillation is used, the body weight of the patient does NOT influence the energy delivered
what patients should use adult paddles or pads?
Patients that weigh more than 10 kg (22 lb) - generally older than 1 year
how much space should be separating the pads?
1 inch in between the pads (3 cm)
T or F: you should use alcohol, tincture of benzoin or antiperspirant when preparing the skin for paddle or pad placement
What is the typical paddle or pad position used during resuscitation for the sternum-apex position?
also called: anteriolateral or apex-anterior position
Where do the L and R paddles get placed?
Right paddle - placed lateral tot he right side of the patient's sternum, just below the clavicle
left paddle - left midaxillary line, lateral to the patient's left nipple
do NOT put the paddle directly on the breast as it results in higher transthoracic impedance and will reduce current flow
What energy level should you use with a monophasic defibrillator?
If you are using hand help paddles for adult defibrillation, how much pressure should you use?
firm downward pressure about 25 pounds
if defibrillation successfully terminates pulseless VT/VF but the rhythm recurs, what energy level should you defibrillate at?
Defibrillate at the last energy level used that resulted in successful defibrillation
Where should you place the pads if a patient has an ICD or pacemaker?
At least 3 inches (8 cm) from the pulse generator
What is an external defibrillator with a computerized cardiac rhythm analysis system called?
Automated External Defibrillator
What is the preferred defibrillation method for infants?
Manual defibrillator is preferred for infants. if a manual defibrillator isn't available an AED with a pediatric attenuator is desirable
what should you do while the AED is analyzing the patient's cardiac rhythm?
All movement (including chest compressions, artificial ventilations and the movement associated with patient transport) must stop
what's the general operation for an AED?
- turn on the power
- attach the device
- analyze the rhythm
- deliver a shock if indicated and safe
What's up with precipitation and using an AED?
If a patient is lying on snow or ice the AED can be used.
If a patient is lying in water or is covered with water it may be reasonable to remove them from the water and dry the chest before attempting defibrillation
what is the type of electrical therapy during which a shock is timed or programmed for delivery during ventricular depolarization?
When does synchronized cardioversion deliver its shock?
a few milliseconds after the R wave deflection or the QS deflection
This is why synchronized cardioversion isn't used for rhythms that are disorganized or don't have a clearly identifiable QRS complex
What are the indications for synchronized cardioversion?
- unstable atrial fibrillation
- unstable atrial flutter
- unstable monomorphic VT
- unstable narrow-QRS tachycardia
If a synchronized cardioversion produces a VF and the patient has no pulse, what should you do?
How far away should oxygen sources be placed before you cardiovert or defibrillate a patient?
At least 3.5 to 4 feet away from the patients chest
examples: masks, nasal cannulae, resuscitation bags and ventilator tubing
What is transcutaneous pacing?
TCP is the use of electrical stimulation through pacing pads positioned on a patient's torso to stimulate contraction of the heart.
What is the stimulating current selected for TCP measured in?