Defibrillators and ICDs Quiz

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Questions and Answers

What distinguishes a semiautomatic defibrillator from a fully automated defibrillator?

The user has to manually charge the device before use.

It is designed for use solely on children.

It can only be used in emergency medical settings.

The user initiates the administration of the shock. (correct)

Which characteristic is NOT a safety requirement for defibrillator use?

Disconnect non-defibrillation proof devices.

Avoid moisture on the patient's skin.

Position the patient for electrical isolation.

Maintain a direct contact with the electrodes. (correct)

What is the maximum energy setting of a defibrillator?

360 J (correct)

150 J

500 J

300 J

What type of device is classified as an intracorporeal defibrillator?

Implantable Cardioverter Defibrillator (ICD) Signup and view all the answers

Which safety feature ensures that a defibrillator discharges automatically after a period of inactivity?

Automatic safety discharge function Signup and view all the answers

What shape of the energy waveform indicates a gradual decline to zero?

Damped sinusoidal Signup and view all the answers

Which waveform type reverses current flow after a specified time?

Biphasic Signup and view all the answers

What is the average transthoracic impedance (TTI) for an adult human?

70 - 80 Ω Signup and view all the answers

What is a potential consequence of high transthoracic impedance (TTI)?

Insufficient current for defibrillation Signup and view all the answers

What is the primary function of conductive materials in defibrillation?

To reduce transthoracic impedance Signup and view all the answers

Which waveform has no current flowing in the negative direction?

Monophasic Signup and view all the answers

What percentage of the supplied energy in an animal study effectively reached the heart?

4% Signup and view all the answers

Which of the following statements about triphasic waveforms is true?

Lacks sufficient human study support Signup and view all the answers

What characterizes ventricular fibrillation on an electrocardiogram (ECG)?

Irregular and disorganized depolarizations Signup and view all the answers

What is the primary purpose of defibrillation?

To deliver electrical energy to the heart Signup and view all the answers

Which of the following arrhythmias is identified by a rapid sequence of broad QRS complexes without ejection?

Pulseless ventricular tachycardia Signup and view all the answers

What part of a defibrillator is responsible for delivering the current pulse?

Discharge circuit Signup and view all the answers

How long should automatic safety discharge occur if no shock is triggered?

After 10 seconds Signup and view all the answers

Which energy level range is typical for defibrillator discharge?

2 – 360 J Signup and view all the answers

Which arrhythmia is not associated with life-threatening conditions?

Sinus bradycardia Signup and view all the answers

What current range is typically found in external defibrillator stimulation?

22 - 60 A Signup and view all the answers

Study Notes

Defibrillators & ICDs

Defibrillators are used to treat life-threatening cardiac arrhythmias like ventricular fibrillation and pulseless ventricular tachycardia.
These devices deliver electrical energy to the heart to restore normal rhythm.
Defibrillators use high-voltage pulses to depolarize the myocardial fibers simultaneously.
Arrhythmias are caused by problems in the heart's electrical impulse generation or conduction.
Arrhythmias can lead to the impairment or disruption of coordination within the heart's muscle fibers, potentially causing fibrillation.
Ventricular fibrillation is uncoordinated myocardial fibrillation, with no ejection of blood.
On an ECG, ventricular fibrillation shows irregular and disorganized depolarizations.
Pulseless ventricular tachycardia involves a regular and fast sequence of wide QRS complexes.

Ventricular Arrhythmias

Ventricular fibrillation (VF) is a life-threatening arrhythmia characterized by irregular and disorganized electrical activity in the ventricles.
In VF, the ventricles quiver instead of contracting effectively, preventing the heart from pumping blood.
Pulseless ventricular tachycardia (VT) is another dangerous arrhythmia where the ventricles contract very rapidly, but without effective blood pumping.
VT often shows a regular pattern of wide QRS complexes on an ECG.

Defibrillation

The device has a charging circuit, and a separate circuit to discharge.
The charging circuit fills a capacitor.
The average time to charge the device is about 8 to 10 seconds.
The device delivers an electrical current or pulse with variable preselectable levels typically between 2 to 360 Joules.
The defibrillation pulse ranges between 3 to 8 milliseconds in current.
Internal current varies between 10 - 27 amperes.
The external current is between 22 - 60 amperes.
Automatic safety discharge happens after approximately 10 seconds if there's no shock triggered, and when a new energy level is chosen as well as with technical malfunction.

Energy Waveform

Energy waveforms are time-based sequences of energy output, attempting to minimize myocardial damage.
The shape of the waveform determines the energy supplied to the patient.
The duration of energy delivery is also crucial.

Waveform Types

Monophasic waveforms deliver current in one polarity.
Damped sinusoidal waveforms decrease gradually to zero.
Truncated exponential waveforms decrease abruptly to zero.
Biphasic waveforms deliver current in two phases—positive and negative—in a specific sequence during the electrical discharge.
There are no studies of triphasic waveforms' use compared with biphasic.

Transthoracic Impedance (TTI)

Transthoracic impedance (TTI) is the impedance between defibrillation paddles.
It refers to energy dissipation in the chest during defibrillation; only a small proportion of energy reaches the heart.
Common ranges for adults are 70-80 Ω.
TTI is affected by factors like electrode size, distance, skin-electrode interface, electrode pressure, and body phase.

Defibrillator Types

Transthoracic devices include manual, semiautomatic (AEDs), and fully automated defibrillators.
Intracorporeal devices are implantable cardioverter-defibrillators (ICDs).
ICDs have single, dual, or triple chamber systems or atrial defibrillators, depending on the arrhythmia(s) intended to be treated.

Technical Safety Aspects

Direct contact with electrodes must be avoided.
Moisture on the patient's skin is a no-no.
Defibrillators are class IIb devices requiring an explosion-proof atmosphere if needed.
The use of gel pads or conductive materials are needed to minimize impedance.
All other devices connected to the patient should be defibrillation proof or disconnected for safety.
Caution should be exercised with patients with energized implants.
Trigger buttons should only be on the paddles.
Maximum energy delivered is 360 Joules.
Devices are to be plugged into a power source to ensure continuous and reliable usage.

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Description

Test your knowledge on defibrillators and implantable cardioverter-defibrillators (ICDs). This quiz will cover the functions, types, and the role these devices play in treating life-threatening arrhythmias, such as ventricular fibrillation and pulseless ventricular tachycardia. Get ready to enhance your understanding of cardiac care!