Know Your BLS Skills and Tools

While we often focus on advanced interventions, well-done BLS is critical to many of our patients, including our most critical ones. “We tend to minimize or overlook the importance of the basics,” said Oregon educator Gary Heigel, EMT-P, opening Thursday’s “Your Tools and Your Skills” presentation at EMS World Expo. Heigel spent the session’s first half focusing on the importance of BLS care and strategies to improve it, while Virginia emergency physician Stephanie Louka, MD, spent the second half looking at troubleshooting and alternatives when a pair of key tools fail.

Basic-level care matters and may even correlate to better outcomes for some patient groups. But for an inexperienced EMR or EMT, the differentials and pressurized call environment can be overwhelming—for altered mental status, for example, there are dozens of possible causes. That cognitive overload can stress you out and interfere with your information processing. Your strategy is to boil off the unlikely—the zebras, as it were, in favor of the horses—and focus on the most likely causes.

Still, horses come in a lot of shapes, sizes, and colors. Heigel offered some tips to start thinning the herd:

Connect with patients—Get on their level, eye to eye, and introduce yourself. Get, remember, and use their name—“The name is one of the most critical pieces of information you’re gonna get,” he said. Using it communicates you care and fosters a connection that will produce better information.

Get the whole story—A good history requires being curious. Think of yourself as a detective digging for clues or a reporter seeking the who, what, when, where, and why. Ask follow-up questions.

SAMPLE is a useful assessment mnemonic but difficult to work through in order in an organic conversation. Try instead to gather its elements through listening. Don’t forget allergies beyond medications, compliance along with medications, and the frequency and quality of meals, not just the last one consumed.

OPQRST works too, but don’t confuse time and onset. Time is when something started; onset is what a patient was doing when it did, whether it happens every time, gradual vs. acute, etc.

BLS providers gathering vital signs usually have no problem with heart and respiratory rates and oxygen saturations. What’s not always so well done are respiratory rates. “‘About 16,’” Heigel said, “tells me you didn’t count.” “About” isn’t good enough—it suggests you didn’t notice any respiratory distress and assumed things were normal. You can’t skimp on this—there’s a lot the rate, quality, and other aspects can tell you about what’s happening, often before changes in pulse, BP, or sats do.

Capnography can also yield essential clues, and EMTs should be encouraged to develop those skills.

Full physical exams are too often skipped. If a patient’s reporting just chest or abdominal pain, it’s tempting to shortcut just to examining those areas. Resist that. “We don’t do head-to-toe examinations, and because of that we miss a lot of things,” Heigel said. To get better at head-to-toe exams, practice—becoming familiar with the normal will better equip you to recognize the abnormal.

In the big picture, a pair of leadership experts can offer some guidance about how BLS should approach these calls. First, remain calm. Former Navy SEAL Jocko Willinks preaches controlled breathing to reduce the heart and respiratory rates and adrenaline rush that can clog thoughts—simplify things for yourself by slowing down. Then focus on what football coach Lou Holtz abbreviated WIN: what’s important now. Take a breath, look around, and eliminate the distractions to determine where to direct your action.

“Remember,” Heigel said, “you don’t have to be an advanced provider to deliver phenomenal EMS care.”

Basic Tools and Their Failure

Louka looked at a pair of common EMS tools—the stethoscope and pulse oximeter—and broke down how they can fail and potential alternatives and workarounds if they do. By knowing how they work, you can understand their limitations and options.

Extreme temperatures are a common cause of stethoscope failure. Stethoscopes work by amplifying sound waves through the diaphragm, up the tubing and through the binaurals to the ears. Both heat and cold can decrease the compliance of plastic components and skew sound conduction.

Interestingly, Louka reviewed a 2014 study that compared a high-end stethoscope to two disposable models. The cheapest model—the Proscope 665, just $3.50 on Amazon—outperformed both the Medichoice disposable ($14.99) and much nicer Littman Cardiology III in detection of wheezes, though it did worse with stridor and bowel sounds.

There aren’t a lot of alternatives to stethoscopes; ultrasound has been predicted since the ’80s, but as of 2016 more than half of med schools still weren’t training students in it. It’s still coming, though, once prices fall and familiarity grows.

Pulse oximetry—the measure of peripheral capillary oxygen saturation, or what percentage of the blood’s hemoglobin is bound and carrying another molecule—has an increased value in the age of COVID-19, Louka said.

It works by way of two light sources, red and infrared, that are absorbed differently coming through the body. But no light shoots straight through the body—it’s scattered by other components on its way. To correct for that, pulse ox measurements have been correlated to arterial blood gas to create a calibration tool to improve SpO₂ accuracy, at least for readings above 75%–80%.

Still, pulse oximeters can only detect pulsatile flow, which only accounts for about 2% of what’s being absorbed—that’s why your device seems so finicky.

A classic failure scenario is carbon monoxide poisoning. Pulse oximetry can’t tell that it’s carbon, rather than oxygen, attaching to oxygen atoms and thus yields a falsely high reading. It happens with methemoglobinemia too; hemoglobin converts to methemoglobin when the iron molecule is oxidized from Fe⁺² to Fe⁺³ and becomes less able to bind to oxygen, leading to tissue hypoxia. Methemoglobin absorbs more of both red and infrared light than hemoglobin, but not in any kind of recognizable pattern. High MetHb levels will cause the SpO₂ to read around 85%.

There aren’t a lot of great alternatives here, Louka said. Co-oximeters are pricey for EMS considering how rare methemoglobinemia is, and ditto for multi-wavelength pulse oximeters. One workaround is to attach a CO detector to your jump bag, which can alert you to its environmental presence.

John Erich is the senior editor of EMS World.