Amiodarone

In this lesson, we'll go over the medication amiodarone and all of its effects, including indications, precautions and contraindications, and pediatric dosages.

Amiodarone is an effective treatment for a wide variety of atrial and ventricular tachyarrhythmias in pediatric patients. It can prolong AV conduction and ultimately slow the heart rate by elongating the AV refractory period, QRS, and the Q to T intervals.

Because amiodarone is an alpha and beta blocker (while also blocking sodium, potassium, and calcium channels), it is a well-known drug for its multi-channel blocking capabilities.

Amiodarone Indications

Some indications for the drug amiodarone, as an antiarrhythmic drug, is that it will be used specifically for its broad range of electrophysiological effects.

Amiodarone may also be considered for the treatment of:

• Pulseless V-tach
• VFib
• Hemodynamically stable SVT refractory to vagal maneuvers and adenosine

Amiodarone Precautions and Contraindications

Now let's look at some amiodarone precautions and contraindications.

A rapid infusion of amiodarone could lead to hypotension. However, during cardiac arrest, there isn't any blood pressure and therefore the American Heart Association recommendation is still to use an amiodarone IV push for the treatment of pulseless conditions.

Because the terminal elimination and half-life of amiodarone is so long, the medication can be a complicated drug to work with and around when treating a pediatric patient who has experienced a return of spontaneous circulation.

Therefore, amiodarone administration could eliminate the option of using certain medications until it has been effectively eliminated from the body.

Pediatric Dosage of Amiodarone

When using amiodarone to treat VFib or pulseless V-tach, a first dose will be 5mg/kg via IV or IO push. This dose may be repeated 1-2 times for refractory VFib or pulseless V-tach.

For life threatening arrhythmias, a maximum accumulated dose is 2.2 grams via IV or IO over a 24-hour period.

For supraventricular or ventricular arrhythmias with poor perfusion, a loading dose of 5mg/kg infused over 20 to 60 minutes may be given.

Repeat doses of 5mg/kg may be given up to a maximum of 15mg/kg per day as needed.

A Word About Vascular Access for Pediatric Patients in Cardiac Arrest

The priorities for drug delivery routes during pediatric advanced life support are, in order of preference:

1. Intravenous (IV)
2. Intraosseous (IO)
3. Endotracheal (ET)

When a critically ill child goes into cardiac arrest, there is a chance that vascular access may have already been established. However, if vascular access has not been established, it should be done immediately.

During resuscitation, peripheral IV access is the first choice if it can be accomplished quickly. However, this may prove to be difficult in critically ill or injured children. Therefore, pay attention to the time it takes and limit the time you spend trying to obtain IV access.

If IV access has not already been established and you cannot achieve reliable IV access immediately, establish IO access instead. IO access is still useful as the initial vascular access in cases of cardiac arrest in pediatric patients. If both IV and IO access aren't available for the delivery of medications, the endotracheal route is your next best option.

Intravenous (IV) Drug Delivery

While a central venous catheter provides a more secure route of vascular access than a peripheral catheter does, central venous access isn't required during the vast majority of resuscitation attempts. And furthermore, its placement requires interruptions during chest compressions, which are not advisable.

The complications with central catheter placement attempts that are made during chest compressions could include the following:

• Vascular lacerations
• Hematomas
• Pneumothorax
• Bleeding

If a central venous catheter is already in place, then that will be the preferred route for medication and fluid administration. Central venous administration of drugs does provide more rapid onset of action and higher peak concentration than peripheral venous delivery.

Even though establishing peripheral venous access does not require the interruption of chest compressions and CPR, medication delivery to the central circulation could be delayed. To improve medication delivery to the central circulation, you should do the following when using a peripheral IV catheter infusion system:

• Administer the medication by bolus injection
• Administer the medication while chest compressions are being performed
• Follow medication administration with a 5ml normal saline flush to move the medication from the peripheral circulation to the central circulation

At the end of the next lesson on Atropine, we'll provide some information on using the intraosseous (IO) route. And at the end of the subsequent lesson on Dopamine, we'll dig deeper into using the endotracheal route.