Shock to the system
December 3, 2008
Have you recently installed an automated external defibrillator (AED), or are you planning to do so in the near future? If so, do you know all that you need to know about AEDs in order to effectively use one in an emergency? Are you confident that others in your facility can also use one successfully?
The sad truth is that when shown an image of a realistic patient scenario, the majority of individuals without cardiopulmonary resuscitation (CPR) or AED training will not be highly effective in a true cardiac emergency. Although the majority of AEDs provide a good quality shock, proper CPR prior to, and possibly following, the shock will significantly increase the chances of success. In this article, I’ll discuss what you need to know to save a co-worker’s or friend’s life.
Staying alive and CPR
Because the AED will be much less effective without proper CPR, we will begin there. What is the function of CPR and how does it help in this circumstance? Effective CPR: /
- Increases perfusion pressure throughout the circulatory system, including the coronary arteries that supply oxygen to the heart muscle
- Evacuates blood from a distended heart, which is required for shock
- Moves blood to the brain and reduces the likelihood of damage
- Moves blood to the heart, which is critical to success after shock
A little info goes a long way
AEDs are not very complicated, but are often misunderstood. Untrained rescuers may be intimidated when faced with attempting to use an AED in a stressful situation. However, appropriate training and a few simple precautions can result in a successful outcome with minimal stress. A few key precautions include the following.
- Water, including sweat, can divert the shock and must be wiped off the patient’s chest (the chest does not need to be completely dry, but the drier the better). Also, puddles and other “bodies of water” do not mix well with electricity, so it is advisable to move the patient from these surfaces. However, if necessary, you may shock on moist pool decks and snow.
- Hairy chests can prevent pad contact with the patient’s chest. This not only makes the pads less effective, but can cause a spark between the pad and the patient’s chest and can result in burnt skin. To avoid this problem, use the razor that should come with the AED. If you do not have a razor, a second set of pads work great to remove the hair. I usually suggest to those purchasing AEDs that they write “Expired - use as Nair” on their expired pads and put them in the extra bag or pouch that should accompany the AED.
- Bras are often overlooked, considering that the pads can be placed above and below them. The biggest problem with bras not being removed is the potential for the underwire to divert the shock delivered to the patient and might even cause the fabric to catch fire.
- Medication patches can act as a barrier between the pad and the patient and can also cause a burn. For this reason, if the medication patch is found where you need to place the pad (such as the upper right part of the chest above the nipple and 2 inches below the left armpit), then the patch needs to be removed. Always be careful and wear gloves when removing medication patches because the medication on the patch can just as easily be absorbed through your skin and might cause side effects, such as low blood pressure and dizziness.
- Pacemakers may require an adjustment to where the pads are placed. Pacemakers create a small lump in the patient’s upper chest, slightly smaller than a deck of cards. If the pacemaker is on the patient’s left side, it is not a problem and you may place the pads normally. On the other hand, if the pacemaker is on the patient’s right side, this usually indicates that it was implanted prior to the early ’90s or in another country, or that some medical problem prevented it from being implanted on the left side. In this case. you will need to place the defibrillator pad an inch away from the pacemaker, which can block some of the shock to the patient.
- One-piece pads are a great feature that you may find with some AEDs. They eliminate the confusion that sometimes comes with remembering where to place the pads. As long as they are oriented correctly, all you have to do is follow the image on the pads for proper pad placement. Landmarks pictured on the pads can also help you with pad orientation.
If you are delivering a shock to a child, pediatric pads are always preferable. However, if all you have are adult pads, it is possible to use them on a child with some modifications. Take note that you cannot use pediatric pads on an adult because the delivered shock would not be adequate for the adult heart. If you need to use adult pads on a child, here are some suggestions:
- Place the pads at least one inch apart in order to function correctly. If the pads are less than an inch apart, the shock will pass from pad to pad without reaching the patient’s heart. More space is usually better.
- Alternative pad placement when using adult pads on a child is to place the pad that would normally be on the child’s left side in the center of the chest, slightly off center to the left. Vertically, the center of the pad should be lined up with an invisible line between the child’s nipples. Next, the pad that is normally on the upper right side of the patient’s chest should be moved to the back, slightly to the left of center, directly opposite the pad on front. With this technique we will be shooting straight though the chest and heart. This placement method can be used for adults as well as children (such as when an injury or other problem prevents traditional pad placement).
- Some AEDs have a key or switch that, when in place, tells the AED that you have a child attached to adult pads.