Higher Learning >> by Bob Page, CCEMT-P, NCEE Educational Theories Put into Practice Lung Sound Assessment The lost art of using a stethoscope

few years ago, I was looking through the Department of we do anyway.” Transportation curriculum and standards for EMTs and I’ve spent 30 years as a paramedic and educator studying, Aparamedics. I noticed more time was “recommended” for researching and learning from clinical masters. Most of my knowl- teaching marine animal envenomation than the time spent in the edge about how to use a stethoscope came from nurses in inten- correct use of a stethoscope. Why is that? sive care units. My experience and hundreds of patients taught me And early in my career, others laughed at me when I tried to this skill is important and can tell you a lot about the patient if you listen to breath sounds in the back of the ambulance. Some folks put forth the effort to learn about how to use your stethoscope and made such comments as, “Why bother?” or “It won’t change what practice to the point of skill mastery. The Theory

t’s been suggested by Isome that there’s a high degree of subjectivity in the perception of what sounds are heard and what they’re called. This is because the early classrooms didn’t have the means to present the sounds in a realistic man- ner and actual clinical patients were often hit- and-miss during clinical rotations. In fact, in the past, many students were given a written description of what lung sounds sounded like. I’ve had my students rub their hair together between their fingers for fine B ob Pag e crackles or suck the soda out of a straw in a class on pulmonary edema. I even forced them C ourt e sy

to make a wheezing sound with their throat. Photo A couple of cassette tapes were available Simulation learning is the best way for EMS students to learn to identify lung sounds. that played recorded sounds, but they were hard to hear or understand what you were Fundamentals differentiating sounds and identifying the hearing—or even why the sounds occurred. To start the process of stethoscopy educa- associated conditions. Student education suffered because of the tion, the instructor must first get to know Just remember, how can a student con- lack of real patients for us to assess and the the stethoscope and ensure the students centrate on a sound if they don’t know what lack of resources—or even the knowledge of know it also. This area is often overlooked, to listen for and what to concentrate on? If these resources. I won’t attempt to describe or we assume our students already know you follow some proven teaching tips and what the sounds sound like, or I’d be guilty of the fundamentals. Human hearing does best pass them along to your students, then you what I just accused others of doing. at a frequency of 1000 Hz. Most sounds can help them understand the fundamentals Today, however, there’s an abundance of in the chest occur at frequencies at 20–500 of stethoscopy. resources available and even a breath and Hz. A stethoscope is tuned to these sounds heart sound simulator that gives you an out- and then amplifies it for the human ear to The Stethoscope standing way to instruct and help students hear. Our brain then processes the sound Most stethoscopes have a bell and a dia- master these sounds before they go out on and decides what it could be based on the phragm. The diaphragm is the flat part, their own and hear them for real. We’ll dis- known sounds we have stored in memory. and the bell is the cone-shaped part. Some cuss this system later. That’s why it’s important to expose students scopes, Littmann for example, have tun- to the pre-recorded sounds before they start able diaphragms. This means that what you Check out JEMS.com/URL TK for a video of treating patients in the field. With prac- hear is based on how you apply it to the normal and adventitious lung sounds. tice, they’ll have a better chance of easily patient. The diaphragm is used to detect

26 JEMS AUGUST 2011 Higher Learning >> continued from page 26 high-frequency breath sounds, while the every patient encounter will involve a breath- to report diminished lung sounds in the pos- bell is used for low-frequency sounds, such sound assessment. Your students also need terior bases, which is a normal occurrence as blood going through vessels, Korotkoff, to understand that where they hear the breath and doesn’t necessarily indicate pathology. blood pressure sounds and some heart gal- sounds is just as important as what they hear. The posterior bases are located on the lops (e.g., S3 and S4). At minimum, EMS providers should back below the scapula, inside toward the With a tunable diaphragm, firm pressure examine six auscultation sites. spine. The posterior vesicular sounds are easy (one that leaves a blanched ring on their chest The first two are over the broncho-vesicu- to hear longer on inhalation, but they fre- when you lift it up) tunes the stethoscope for lar area in the second intercostal space mid- quently disappear quickly as the sounds are breath sounds. Using the bell with light pres- clavicular line on both sides. The patient can absorbed by the alveoli. sure (no ring on the chest) allows you to hear breathe normally for these sounds, because Because a normal tidal volume breath low-frequency sounds, such as those men- they’re easily heard. Inhalation and exhala- doesn’t get much volume to the lower tioned above. Some less-expensive scopes tion are heard equally in duration, with the lobes of your lungs, it may be necessary to are pre-tuned to a general frequency of about pitch decrescendo on exhalation. have the patient take a deeper than normal 200 Hz, so some, but not all, sounds may be The next area to listen to is the lateral vesic- breath through their mouth. This will facili- perceived. In short, you get what you pay for ular area. This is in the fifth intercostal space tate air entry to this area, so sounds can be in a stethoscope. midaxillary line (i.e., just below the axilla assessed. This should be the only place in Extra tip: Tell your students to remem- between the front and back). Here, you’re lis- which a deep breath is necessary. ber that when wearing a stethoscope, their tening in an area that may not have any large Be careful because deep breaths in all ear canals angle forward, so the stethoscope tubes, and most of the expiratory sounds are areas invite hypocapnia. In an experiment arms should be worn facing forward as well. absorbed or “baffled” by the alveoli. with my students, I was able to show them Normal vesicular sounds, both lateral and a 15–20 mmHg drop in end-tidal carbon Where to Listen posterior, are always diminished in exhala- dioxide as a direct result of having their “Everybody gets a courtesy listen.” is a line I tion because the exhaled sounds are absorbed patient taking a “deep breath” while auscul- use with my students. That simply means by the alveoli. This can trigger many clinicians tating six breaths. The practice ave your students practice on their own. When they return, Hpractice this new they simply plug into each other and many Mastery skill on each other or on can use the same source for sounds. Somewhere along the way, you need to manikins. I prefer having As an instructor, you should do a bit do some competency evaluation. Set the them auscultate a part- of prep work. Several commercial CDs are standards so that all students know what’s ner because they become also available and you can download some required of them prior to testing. I used comfortable with differ- breath sounds from the Internet. Get these to drive around in the ambulance with a ent shapes and sounds. sounds and compile them into categories for boom box, creating distraction while my Once they’ve heard some normal sounds, easy practice. Either burn a CD for your stu- students would have to correctly call five it’s time to move your students on to simula- dents or make the sounds available on a web- lung sounds, five heart sounds and five tion. I use a setup from Pinnacle Technology site for easy download. blood pressures. They use their sounder and that uses a stethoscope sounder (a fidelity I made a prerecorded, narrated tutorial that stethoscope. I use a small, cheap MP3 player speaker with a foam pad) that plugs into my students can take to review on their own and sounds I selected. If they’re success- a computer, iPod, iPad or portable music with their sounders and their own stetho- ful, they’re publically rewarded by being player via the 1/8" standard audio jack. scope. It’s like a stethoscopy lab in a box. “knighted” with a stethoscope around their The sounders allow the student to hear the Encourage your students to use their neck and a certificate. sounds through their own stethoscope, creat- scopes while browsing the net looking for It’s a big deal to them and a very pow- ing a more realistic experience. I provide my sounds. They can plug the Y adapter into the erful motivator and confidence builder. If students with the sounders at the start of the computer. The single (male) end goes into your student has mastered the skill, through class, and the cost is recovered by lab fees. the audio out on the computer and the com- hours of inside and outside practice, then For the sounds, I use a multi-sounds puter speakers into one of the two (female) the skill has value to them, and suddenly the trainer from Pinnacle that has several menus jacks with the sounder in the other. excuses about why they can’t get vital signs available for basic lung sounds and heart There aren’t enough lab hours in the course or lung sounds will disappear. JEMS sounds. This setup allows me to discuss the to master this skill; it takes outside practice. sounds and play them at my discretion with Sounders make that possible, and practice Bob Page, CCEMT-P, NCEE, has been presenting ste- the push of the menu button. I can also have fosters intrinsic rewards for your students. thoscopy workshops nationally and internationally for every student in my class “wired” into hear- Remember, the goal is to give your students more than 15 years and has taught hundreds face-to-face ing the same sound at the same time. more time to practice on their own outside about how to use a stethoscope in clinical assessment. The students then take their sound- scheduled labs. You should use the precious For more information, contact him through his website ers home with pre-recorded music CDs to lab time for evaluation and other simulations. at www.multileadmedics.com.

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