Episode 22 - Electrical Injuries in the Emergency Department An Evidence-Based Review

Jeff: Welcome back to Emplify, the podcast corollary to EB Medicine’s Emergency Medicine Practice. I’m Jeff Nusbaum, and I’m back with my co-host, Nachi Gupta. This month, we’re back with our old routine – no special guests. Nachi: Don’t sound so sad about it! Jeremy was great last month, and he’s definitely paved the way for more special guests in upcoming episodes. Jeff: You’re right. But this month’s episode is special in its own way - we’ll be tackling Electrical Injuries in the emergency department - from low and high voltage injuries to the more extreme and rare lightning related injuries. Nachi: And this is obviously not something we see that often, so listen up for some easy to remember high yield points to help you when you get an electrical injury in the ED. And pay particular attention to the , which, as always, signals the answer to one of our CME questions. Jeff: I hate to digress so early and drop a cliché, “let’s start with a case…” but we, just a month ago, had a lightning strike induced cardiac arrest in Pittsburgh, so this hits really close to home. Thankfully, that gentleman was successfully resuscitated despite no bystander CPR, and if you listen carefully, we hope to arm you with the tools to do so similarly. Nachi: This month’s print issue was authored by Dr. Gentges and Dr. Schieche from the Oklahoma University School of Community Medicine. It was peer reviewed by Dr. O’Keefe and Dr. Silverberg from Florida State University College of Medicine and Kings County Hospital, respectively. Jeff: And unlike past issues covering more common pathologies, like, say, sepsis, this month’s team reviewed much more literature than just the past 10 years. In total, they pulled references from 1966 until 2018. Their search yielded 477 articles, which was narrowed to 88 after initial review. Nachi: Each year, in the US, approximately 10,000 patients present with electrical burns or shocks. Thankfully, fatalities are declining, with just 565 in 2015. On average, between 25 and 50 of the yearly fatalities can be attributed to lightning strikes. Jeff: Interestingly, most of the decrease in fatalities is due to improvements in occupational protections and not due so much to changes in healthcare. Nachi: That is interesting and great to hear for workers. Also, worth noting is the trimodal distribution of patients with electrical injuries: with young children being affected by household currents, adolescent males engaging in high risk behaviors, and adult males with occupational exposures and hazards. Jeff: Electrical injuries and snake bites – leave it to us men to excel at all the wrong things… Anyway, before we get into the medicine, we unfortunately need to cover some basic physics. I know, it might seem painful, but it’s necessary. There are a couple of terms we need to define to help us understand the pathologies we’ll be discussing. Those terms are: current, amperes, voltage, and resistance. Nachi: So, the current is the total amount of electrons moving down a gradient over time, and it’s measured in amperes. Jeff: Voltage, on the other hand, is the potential difference between the top and bottom of a gradient. The current is directly proportional to the voltage. It can be alternating, AC, or direct, DC. Nachi: Resistance is the obstruction of electrical flow and it is inversely proportional to the current. Think of Ohm’s Law here. Voltage = current x resistance. Jeff: Damage to the tissues from electricity is largely due to thermal injury, which depends on the tissue resistance, voltage, amperage, type of circuit, and the duration of contact. Nachi: That brings us to an interesting concept – the let-go threshold. Since electrical injuries are often due to grasping an electric source, this can induce tetanic muscle contractions and therefore the inability to let go, thus increasing the duration of contact and extent of injury.