Electrical injury – who needs to be monitored?

Electrical injury, although not a common occurence can present with significant injury. Often the extent of the injury can be under-estimated as it mostly occurs below the skin, with little more than an entry and exit wound to see. The very fact that patients with these injuries don’t present often, can result in management challenges. These can range from resuscitation approaches, to decision making as to who needs to be monitored.

The obvious high voltage exposure, with significant burn and injury, is not really a challenge in terms of monitor/non-monitor decision making. The challenge is from that group of patients that are well, with minimal injuries. Who, if any, of these patients do we monitor?

Electrical burns have a trimodal distribution:
1. The first peak is in children. This is primarily due to behaviors such as cord biting
2. The second peak is in adolescents who engage in risky behaviour, and the third group is
3. Those whose work involves electricity and potential exposure

Childhood injuries are usually biting injuries, where the child will chew through an electric cord. The result will be a burn to the lips or mouth. These burns are usually bloodless and painless as the vessels have been cauterised and the nerves damaged. One of the main issues in dealing with this kind of elelctrical injury is how to approach the burn itself. These burns will result in significant contractures and current management strategies, which are controversial,  include plastics repair and/or mouth splints.

The two main questions with children are:
Do we admit all these children? and
Do we monitor them?

At one time all children were admitted, however more and more, unless there are social or other issues, children with circumoral burns can be discharged. The one thing that may occur in about 10-15%, is delayed bleeding of the labial artery. This occurs some ten days following the injury. The only treatment needed if the child is at home and bleeding commences, is pressure over the area and representation to the emergency department.

Can we send these children home from a cardiac point of view, or do they need to be monitored?
Bailey et al (Ann Emerg Med 1995;25(5):612-17) looked at household injuries involving 120V and 240V and concluded that no ECG or monitoring was needed. This study had some limitations in that it was retrospective and didn’t look at those potential higher risk groups with loss of consciousness, tetany and passage of current through the heart.

In 2000 Bailey revisited the higher risk group (Am J Emerg Med;2000 Oct:18(16)621-5) and performed a prospective study evaluating guidelines for monitoring high risk patients. 224 children were included in this study and the criteria for 24 hours of monitoring that were tested were:

1. Past cardiac history
2. Loss of consciousness
3. Voltage greater than 240V
4. Abnormal ECG

There was no mortality or morbidity.

Bailey has gone on to do further studies which we will discuss shortly. In children therefore there is very little reason to monitor. If you still feel uncomfortable with no monitoring, then I would still monitor the following:

1. Loss of consciousness
2. Past cardiac history
3. High voltage

The next group to consider is adults without a severe injury, that we are considering monitoring.

Fatovich (MJA 1991 Sept 2;155(5) 301-3) looked at who needed monitoring following household electrical injury at 240v and 50Hz. This was a small study with 50 patients, however the conclusion was clear. No monitoring was needed in patients who were asymptomatic with a normal ECG.

Bailey (Emerg Med Journ 2007 May;24(5):348-52) conducted a prospective multicentre study involving 21 emergency departments. 143 patients were enrolled with what were considered, significant factors. They were:
-transthoracic current
-tetany
-loss of consciousness
-voltage>1000V

No patient in this study developed lethal arrhythmias. The conclusion was that patients with low voltage injuries with no loss of consciousness and a normal ECG, did not need monitoring.

So let’s make some sense of all of this.

In children, most low voltage injuries do not require monitoring. The exceptions would be those children with cardiac history.

In all patients with minor injuries who are asymptomatic, have been exposed to a low voltage(<240V) and have a normal ECG, monitoring is probably not required.

Peter Kas