Brought In By Ambulance, #2: Needle Decompression

You are on your first ride along of your EMS rotation. The first couple of trips are low acuity patients. While hanging out in the captain's chair in the darkened back of the truck as your unit patrols the streets, the steady rocking back and forth begins to lull you to sleep...

Tones drop. The call comes in, and seconds later the lights and sirens are at full blare. A few minutes of tense waiting as the ambulance courses through the neighborhood and then the rig screeches to a halt. You hear the EMS providers get out of the cab and raised voices outside. You mobilize the monitor and supply bag and wait for the back doors to open to jump out. However, when they do open, the medics & first responders quickly load up a 20-something female who reportedly was shot in the chest.

Once loaded, the EMT calls out vitals -- HR 60, BP 70/40, RR 22, O2 sat 99%. You begin your ATLS exam. Airway: midline, patent. Breathing: clear on the left, no appreciable breath sounds on the right. You palpate weak pulses in the bilateral radial wrists. You remove the patient’s undergarments and note a gunshot wound to the right parasternal area. The paramedic confirms your findings and instructs you to needle decompress the chest. “You know where to do it, right? Second intercostal space, mid-clavicular line. Here is the needle.” As you are about to impale the patient with a 14-gauge angiocatheter, you can't help but wonder why we place a needle in the anterior chest, but place the definitive treatment (a thoracostomy tube) in the lateral chest.

Clinical Question:

What is the optimal location for needle decompression of traumatic pneumothorax?

Literature Review:

For the majority of EMS agencies, it has long been standard practice to needle decompress those patients with a tension pneumothorax to allow air to evacuate -- effectively converting a tension pneumothorax to an open pneumothorax and thereby restoring respiratory and circulatory function. Currently, ATLS guidelines call for a 5cm angiocatheter device to be inserted at the second intercostal space, mid-clavicular line (2-MC). There are no validated studies supporting this practice as the optimal management. Failure is commonly reported, with published failure rates anywhere from 25-50% in cadaveric, radiologic, and clinical studies. In these studies, the vast majority of failures were attributed to excessive chest wall thickness, user error (including failure to identify to proper anatomic site), and catheter malfunction or obstruction. 

Several lines of questioning are currently being pursued in the EMS, trauma, and EM literature. As our population becomes more obese and thus the distance the needle/catheter must traverse before entering the pleural space becomes longer, can a 5cm catheter reliably reach the pleural space along the 2-MC? Does decompression at this site lead to excessive risk of damaging vital underlying structures? Is there a more appropriate site for needle decompression? Specifically, should more consideration be given to performing needle decompression at a similar site to that used during tube thoracostomy, roughly the 5th intercostal space, anterior axillary line (5-AA)?

Before beginning any such discussion, it must be noted that although a provider may know the proper site, that does not mean he/she can find it. This unfortunate fact was confirmed in a 2005 study by Ferrie et al that included 25 emergency medicine physicians, 21 of whom were ATLS certified. Twenty-two (88%) EP’s named the standard location (2-MC), but only 15 (60%) were able to accurately identify it on a human volunteer.

This is particularly worrisome given the high density of physiologically relevant and sensitive structures found in close proximity to the 2-MC. In 2003, Rawlins published a case series of 3 patients who presented with pneumothorax and were needle decompressed in the 2-MC which subsequently lead to life threatening intra-thoracic hemorrhages. The concern was that this location is very close to the subclavian vessels and internal mammary artery with its medial branches, and thus the 5-AA may be a safer approach. However, Wax et al conducted a study in which CT scans of 100 patients were reviewed and distances from potential needle insertion points to proximate soft tissue and vascular structures were calculated. They concluded the safer site was actually the anterior chest, not the lateral chest.

A further concern is that as patients become larger, the standard catheter length may longer be adequate to ensure entry into the pleural space. A study by Stevens in 2009 calculated chest wall thickness at the 2-MC in 110 trauma patients using CT scans. They concluded that using a standard 4.4cm angiocatheter would result in unsuccessful needle decompression in 50% of trauma patients in their cohort. Inaba et al took this idea one step further, comparing chest wall thickness at the 2-MC to the 5-AA. Using a 5cm needle, 42.7% of needle decompressions would be expected to fail at the 2-MC compared to 16.7% at the 5-AA. There was, on average, 1.3cm less tissue to penetrate at the 5-AA site before reaching the pleural cavity. Unfortunately, the evidence is again conflicting. Another study of chest wall thickness using CT scan data was published by Sanchez et al in 2011. A review of CT scans from 159 patients revealed potential failure rates of 33.6% at 2-MC, 73.6% at the 4th intercostal space, mid-axillary line (4-MA), and 55.3% at the 5th intercostal space, midaxillary line (5-MA), assuming a 5cm device was used. 

If switching from the anterior chest to the lateral chest would not be expected to improve success of decompression based on radiographic studies, perhaps the answer is using a longer device. A study by Chang et al in 2014 again used retrospectively-obtained CT data from a trauma cohort to estimate success of a 5cm angiocatheter versus an 8cm device, based on measured chest wall thickness as well as distance to the closest vital structure. They compared the 2-MC to the 4th intercostal space, anterior axillary line (4-AA). The chest wall thickness at the 4-AA was significantly thinner than that at the 2-MC, though in their study this did not lead to significantly different theoretical rates of success. The 8cm device was theoretically capable of reaching the pleural cavity in 96% of subjects at either location, and the 5cm device was gauged to have 66% success at the 2-MC and 81% at the 4-AA (a nonsignificant difference in this cohort). Interestingly, these authors also looked at theoretical chance of the angiocath reaching a sensitive anatomic structure. They even tried to take into account improper insertion technique by measuring distance from the chest wall to the nearest anatomic structure, even if this was not expected to be injured if the needle followed the proper course perpendicular to the chest wall. They found a relatively high theoretical risk (32%) of striking a vital structure when using the 8cm catheter at the 4-AA location -- even more concerning that this structure is actually the left ventricle. This rate fell to 9% if the distance was measured perpendicular to the chest wall, though this is still a worryingly high chance of hitting the LV even if your catheter is inserted correctly. 

All of these studies have significant limitations, most notably that their calculated success and failure rates are purely theoretical, based on idealized calculations using CT measurements of tissue depth in which "correct" anatomic positioning is assured. Thus validity of their conclusions for a provider caring for a crashing penetrating trauma patient in the chaotic prehospital environment is minimal. There is a distinct lack of real-world data regarding the practice of needle decompression. No randomized controlled trials or even prospective observational studies appear to exist in the literature.

Even taking this into account, the documented high rates of failure of "traditional" needle decompression and the theoretical advantage -- or at the least, viability -- of a lateral approach have prompted several organizations to specifically list it in their recommendations as an "alternate" site for needle decompression. Most notably, the Committee for Tactical Combat Casualty Care (TCCC), authors of guidelines for trauma care of US servicemen and women injured in combat, adopted the 4/5-AA as an alternate site in their manuals beginning in 2012. The Tactical Emergency Casualty Care (TECC) guidelines, which were created to adapt to the TCCC guidelines to tactical EMS care in the civilian realm, share this recommendation.

Take home:

- There is no validated study to support the use of the 2-MC as the optimal location for needle decompression.

- Needle decompression at the 2-MC is associated with a high failure rate, 25-50% in some studies.

- Radiologic studies confirm the viability of needle decompression using a lateral approach.

- Lack of real-world studies of needle decompression limit application of radiologic conclusions to prehospital care.

- Several trauma organizations have adopted a lateral approach for needle decompression into their guidelines and manuals.

- Use of an 8cm rather than the standard 5cm catheter may improve chance of reaching the pleural cavity, but may also increase chance of injuring vital structures such as the left ventricle.

- Prehospital providers likely need more education, preferably with high-fidelity simulators, to ensure proper understanding of anatomic positioning in both anterior and lateral approaches.

References:

1) Emerg Med J. 2003 Jul;20(4):383-4.

2) Anesth Analg. 2007 Nov;105(5):1385-8.

3) Prehosp Emerg Care. 2009 Jan-Mar;13(1):14-7.

4) Arch Surg. 2012 Sep;147(9):813-8.

5) Acad Emerg Med. 2011 Oct;18(10):1022-6.

6) J Trauma Acute Care Surg. 2014 Apr;76(4):1029-34.

7) Needle Decompression of Tension Pneumothorax Tactical Combat Casualty Care Guidelines Recommendation 2012-05. July 6, 2012.

8) J Special Operations Medicine. 2011 Summer/Fall;11(3):104-22.

Submitted by Daniel Kolinsky, PGY-2 with additions from C. Sam Smith, PGY-3.

A Happy Ending?

Your patient is a young adult male with no significant past medical history presenting with a chief complaint of testicular pain and heaviness. He reports that the pain occurred 2 hours prior to presentation. It was gradual in onset, progressively worsened, and is now plateaued. The pain is constant, dull, and achy. It is not localized to a single side. The patient feels like his scrotum is heavy, like someone is weighing it down. It is worse with movement, better when still. The patient could not recall any inciting trauma. 

Prior to onset of symptoms, the patient reports “getting my swerve on” with a new female partner, which he insisted did not consist of penetrating vaginal or anal intercourse would not further elaborate. He denies ejaculation prior to pain onset. He denies a history of penetrating intercourse altogether, but does endorses receptive oral sex activity. He denies a history of STI. Further ROS is negative. 

The physical exam is notable for bilaterally descended testes, and normal-appearing Tanner stage 4 genitalia. There is generalized bilateral testicle tenderness to palpation, without scrotal discoloration, testicular deformation, or penile discharge. There is no transverse lie, nor change in symptoms with elevation. The cremasteric reflex is intact.

You’re pretty sure you are least colloquially familiar with this patient’s current affliction, but have no idea if there’s any evidence-based interventions to lessen his discomfort.

Clinical Question:

What are suggested treatments for male pelvic congestion?

The Literature:

There is a paucity of academic information regarding this phenomenon:  scrotal pain following sustained sexual arousal unrelieved due to lack of orgasm and ejaculation. In the limited literature available, it is known as male pelvic congestion or epididymal hypertension. In lay terms, it has been referred to as “blue balls,” “lover’s nuts,” or “deadly sperm build-up” (DSB). Most of the available information is from anecdotal reports – “common knowledge and experience,” as one (unreferenced) article from a human sexuality journal described in 1989. Prior to the publication of a case report, with responding letters to the editor/author, published in Pediatrics in 2000, there was no information on the subject to be found in textbooks or online searchable databases (as concluded by medical librarians in three different institutions queried by the authors of this case report).

The included signs and symptoms are similar to the patient’s presentation above. In most cases the tenderness appears to be localized to the epididymis. The remainder of the GU exam and urinalysis should be normal. The pain usually resolves spontaneously within three hours of onset.

Proposed pathophysiology involves sexual arousal that produces increased blood flow to the penis and testes leading to pelvic venous dilatation. If this persists over time, testicular venous drainage slows, pressure builds, and this causes pain. 

Anecdotal treatments include sexual release via ejaculation, Valsalva maneuver, or lifting a heavy object. The case report included an anecdote about a physician in Los Angeles in the 1940s who, while teaching a course on human sexuality, gave a lecture on “lover’s nuts” in which he advised that masturbation was an appropriate medical treatment. This view is shared by most sexual health "experts" in the lay press.

Take home:

Male pelvic congestion is a real phenomenon, but is rarely discussed in medical literature.

It is a self-limiting and non-morbid process, but anecdotal evidence suggests that Valsalva, weight-lifting, or ejaculation via masturbation may expedite relief of discomfort.  

References:

1) Pediatrics. 2000;106;843-843.

2) Pediatrics 2001;108;1233

Contributed by Daniel Kolinsky, PGY-2.

#FOAMed Digest No.5: But This One Goes to 11

Time once again for your mid-week blast of FOAMy goodness from around the interwebs. There’s no particular subject today; instead we’re going to highlight some of the better podcasts/vodcasts that updated this week. Podcasts are great. They break up the monotony of reading (and the monotony of mundane things like laundry, grocery shopping, training for this damn marathon…). For the more distractible among us, they usually come in easily-digestible 20-30 minute morsels. They expose you to different presentation styles, and allow you to match a face and a voice with the big names in FOAMed. Most of them also feature written show notes with references as well, which allows you both to reinforce the things you learned while listening, and also to dig deeper into topics you’re interested in.

Fun for the whole family!

Three Stars:

1. I think FOAMcast, authored by residents and EM social media savants Jeremy Faust and Lauren Westafer, might be the first example of “metaFOAM.” They peruse the FOAM world for interesting recent posts, then integrate that information with relevant material from the most popular EM textbooks (i.e., “Rosenalli”), other relevant blogs/podcasts, primary literature, and even Rosh Review questions. This week they use a post from ALiEM on calcium channel blockers vs beta blockers for A-Fib as a jumping-off point for a discussion on ED management of A-Fib and A-Flutter. There’s links to vodcasts from Scott Weingart and Amal Mattu on narrow-complex tachydysrhythmias, and plenty of cited references from the primary literature (including one from our own Brian Cohn!). It’s good stuff.

2. Speaking of the Godfather of ED EKG, Dr. Mattu has two quick cases for you to ponder. Remember: T-wave inversion does not always mean cardiac ischemia!

Remember: Gotta think tox in a seemingly unprovoked wide complex tachycardia!

3. Steve Carroll at EM Basic provides an excellent analysis of the ED management of asymptomatic hypertension, including references to the relevant ACEP Clinical Policy document and other FOAMed resources.

Oldie But Goodie:

Chris Nickson, creator and administrator of Life in the Fast Lane, gave an excellent talk at the original SMACC conference in March 2013 with the confidence-inspiring title, “All Doctors are Jackasses.” Why are we jackasses? Because we don’t do enough to understand how we think and how we make decisions, and this leads us to make errors. Watch Nickson’s lecture and begin to understand how to remedy this situation.

(EXTRA CREDIT: Links in the show notes to the other SMACC talks in the “Mind of the Resuscitationist” plenary by Weingart, Cliff Reid, and Simon Carley.)

F(FN)OAMed:

By this point you guys all know how awesome EM:RAP is, but this week is particularly relevant because Herbert & Co. just released an “EM:RAP Mini” segment about the newly-published “Ultrasonography versus Computed Tomography for Suspected Nephrolithiasis” trial in the New England Journal. For those of you that aren’t familiar, this was a study in which we participated, and our own Drs. Aubin and Griffey are authors on the paper! An excellent summary of this paper is found on the Emergency Medicine Ireland blog, with a link to download the EM:RAP Mini segment in the show notes.

The Gunner Files:

1. Time to synthesize the knowledge you gained about non-surgical management of pediatric appendicitis at Journal Club last month. Dr. Cohn is back with another excellent EMJClub podcast along with Drs. Trehan and Horst, summarizing the primary literature.

2. EMin5 is back at it with a review of the four types of shock, in a little over four minutes.

3. From the Maryland Critical Care Project, an excellent lecture from Neuro Critical Care and ED intensivist Dr. Wendy Chang describing the ED management of status epilepticus. She covers the gamut from first-line benzos to second-line AEDs and third-line agents for initiation of therapeutic coma.

4. The good people at the All NYC EM blog posted a lecture given during their conference day by the FOAMed superstar Dr. Haney Mallemat. He covers all the basics of ultrasound evaluation of pericardial effusion and tamponade, even ultrasound-guided pericardiocentesis.

5. In case you’re not familiar, US Air Force Pararescuemen, a.k.a. “PJs,” are the ultimate badasses. Just look at it this way: think becoming a SEAL is tough? PJ training has an even higher failure rate. But I digress.

Former PJ and critical care flight retrieval medic Mike Lauria is now in medical school, and is making a bit of a splash in the FOAMed community as an expert on training, thinking, and operating in high-stress environments. Scott Weingart recently interviewed him on EMCrit about the concept of “mental toughness,” how that translates from the combat realm to the ED, and how to incorporate it into physician training. Really interesting stuff.

That Others May Live,

Sam Smith, PGY-3

Antihistamines for asthmatics?

You walk into the exam room, and find an older female patient complaining of an asthma exacerbation. She reports three days of symptoms consistent with her prior asthma exacerbations, including dry cough, wheezing, increased work of breathing, and exertional dyspnea. She had tried her home MDI and continued her maintenance medications, but her symptoms had gradually worsened to the point that she did not feel she could manage at home.

Her exam is significant for wheezing bilateral full fields, somewhat prolonged expiratory phase but good air exchange. She is speaking in full sentences, and maintaining adequate SpO2 on room air. She is afebrile, and the rest of her VS are stable. The patient's only other complaint is that her "allergies had been acting up lately." The patient appears to have a life-long history of seasonal and recurrent allergic rhinitis, but is not prescribed a daily antihistamine or other anti-allergy therapy.


Clinical Question:

Is there any evidence that antihistamine treatment has a clinically significant effect on asthma symptoms?


The Literature:

A systematic review of the efficacy of 2nd-generation antihistamines in patients with allergic rhinitis (AR) and comorbid asthma was published in the Journal of Asthma in 2011. Epidemiological and histopathological evidence confirms the strong association of AR and asthma. The two conditions share histaminergic mediators released by mast cells & basophils, and the cumulative weight of clinical & laboratory evidence suggests a strong pathophysiologic role.

The study authors performed a comprehensive literature search for double-blind randomized controlled trials in which patients with both asthma & AR were treated with 2nd-gen antihistamines -- cetirizine, loratadine, & fexofenadine being the most common. The authors first summarized the findings of several older trials which did not meet their inclusion criteria (i.e., were not double-blind RCTs). Overall, 1st-gen antihistamines (e.g., diphenhydramine, doxylamine, hydroxyzine, meclizine) have not been shown to have an effect on asthma symptoms except at doses high enough to cause anti-cholinergic and CNS-related ADRs. Some in vitro studies have suggested a steroid-sparing effect or diminished airway hyperreactivity with 2nd-gen antihistamines, but these results are inconsistent in the literature. There is fairly strong evidence in the form of large retrospective studies that effective treatment of AR reduces health-care utilization and improves quality-of-life scores in patients with concomitant asthma, but these cohorts included patients utilizing other AR therapies such as intranasal steroids as well as antihistamines.

A multicenter RCT with N=274 comparing cetirizine-D (cetirizine + pseudoephredine) to placebo found improvement in AR & PM asthma symptoms, but no significant effect on AM symptoms or pulmonary function scores. Another RCT of cetirizine alone had similar results. Several double-blind RCTs comparing the drug desloratadine to placebo, with total N >1100, showed significant reductions in both AM/PM & total asthma sx scores (including specific scores for wheezing & cough) and rescue inhaler use.

As is the case for 1st-gen antihistamines, in vitro data suggests higher doses may be needed to treat asthma as compared with AR. A small RCT (N=28) compared cetirizine 20mg daily to placebo (usual dosing 5-10mg daily), and found significant improvement in reported asthma & AR symptoms without a significant rate of adverse effects compared to placebo. Unfortunately, this dosing regimen has not been compared to standard dosing.


Take home:

- Overall, these studies suggest that antihistamine treatment may improve overall asthma symptom severity in patients with concomitant allergic rhinitis.
- Unfortunately, no study to date has evaluated effects, if any, of antihistamines during acute asthma exacerbation, or if addition of antihistamine prevents ED visits or hospitalizations.
- It seems reasonable to offer these patients antihistamine prescription if they are not already taking them.


Reference:
1) J Asthma, 48(2011):965–973.

Contributed by Sam Smith, PGY-3.

Brought In By Ambulance, #1: Vagal maneuvers in SVT

In this section, we will highlight EBM queries targeted to the prehospital care of patients.


Without further ado...
You respond to a call-out for "palpitations." You arrive on-scene to find a middle-age female patient who is awake, well-oriented, and talking to you in complete sentences. She is complaining of her heart "fluttering," and reports feeling somewhat short of breath and anxious. She reports a prior history of palpitations without a clear working diagnosis. Cardiac leads are placed, and the monitor shows a well-organized narrow-complex rhythm with rate in the 160s. Her BP is stable. Her skin appears warm and well-perfused. As the EMT's are working on establishing IV access, you wonder how effective vagal maneuvers are in terminating SVT.

Clinical Question:

Which vagal maneuver, if any, should be used to terminate SVT?

Literature:

In two studies, the authors found that the valsalva maneuver was more successful in terminating SVT than carotid massage or ice-to-face. In one case series, valsalva was able to terminate SVT in 54% of patients. These study authors also found that a right carotid massage was slightly more efficacious than a left carotid massage in terminating SVT (17% vs 5%). Attempting to provoke the diving reflex with ice had the same efficacy as the right carotid massage (17%)¹.

A second study of prehospital treatment of SVT found that valsalva was more efficacious if the patient was supine, the maneuver was sustained for 15 seconds, and a pressure of 40mm Hg was obtained. The study again found that valsalva was more successful than carotid sinus massage and the ice-to-the face technique².

In a third study, there was a trend toward valsalva being more effective than carotid sinus massage.  Valsalva had a success rate of 19.4% vs 10.5% for carotid sinus massage, though these figures did not reach statistical significance. When initial carotid massage did not resolve the SVT, valsalva was able to convert in 16.9% cases, versus 14% when carotid massage was used after failed valsalva.  Overall, the conversion rate was 27.7%³.

Valsalva maneuver is inherently safer than a carotid massage, as there is no risk of causing decreased carotid perfusion or dislodging clot. The most difficult part is ensuring full patient participation, especially in pediatric patients. One method that has been suggested to promote valsalva in pediatric patients is asking the child to blow through a straw. Several reports also suggest that valsalva maneuver is more efficacious than carotid massage in terminating SVT. There is also limited data to suggest that a right carotid massage is better than a left carotid massage. Given that Valsalva is safer and may be more efficacious, attempts at terminating SVT should begin with Valsalva.

Take home points:

- In available reports, valsalva maneuver appears to be the most efficacious of vagal maneuvers in terminating SVT. It may be effective anywhere from 20-50% of the time.

References:

1. Mehta D, Wafa S, Ward DE, Camm AJ. Relative efficacy of various physical manoeuvres in the termination of junctional tachycardia. Lancet. 1988;1(8596):1181.

2. Smith G, Morgans A, Boyel M. Use of the Valsalva manoeuvre in the prehospital setting: a review of the literature. Emerg Med J. 2009 Jan;26(1):8-10

3. Lim SH, Anantharaman V, Teo WS, Goh PP, Tan AT. Comparison of treatment of supraventricular tachycardia by Valsalva maneuver and carotid sinus massage. Ann Emerg Med. 1998 Jan;31(1):30-35

Contributed by Steven Hung, PGY-2

#FOAMed Digest No. 4: Butter My Biscuit, Baby

Welcome back, to the brand new edition of the WUEMR FOAMed Digest. Get out your Tintinalli’s and strap in, because we’re going back to basics today. It’s all about the bread and butter. The things any PGY-2 setting off to an overnight Saturday shift in the Deuce should have down cold…yet us seniors still screw up on the daily.

FOAMed…ENGAGE!

Three Stars:

1. If my last shift at Children’s is any indication, the season is upon us – pharyngitis in every exam room. Casey Parker over at Broome Docs (a blog authored by EPs & GPs practicing in rural Australia), presents a magnificent summary of the data surrounding rapid strep swabs, antibiotic use for symptom relief, and antibiotic use for preventing secondary complications of strep. As always, be sure to check out the original literature for yourself. And don’t miss Minh Le Cong’s excellent counterpoint in the comments, which is also well-referenced.

2. What’s your record for most C-collars cleared in one shift? (When you hit double-digits, then we can talk.) The best tools in our arsenal for clearing C-spine in low-risk patients remain the Canadian C-spine and NEXUS instruments. But which one should you use? Do you even remember which criteria belong in each rule, or do you find yourself trying to apply the “Canadi-EXUS” criteria, like I do? Luckily for us, Alayna Hawling at BoringEM authored an excellent rundown and comparison – with a pretty flowchart!

3. As much as you want to start the fist-pumping and beer-chugging as soon as you drop that tube past the cords, your work with the intubated patient is not done, my friend! We’ve already touched on our persistently poor rates of achieving adequate analgesia & sedation in the intubated patient. Another part of quality post-intubation care is knowing what to do if your ventilated patient acutely decompensates. Check out Chris Cresswell’s summary of the DOTTS mnemonic over at EM Tutorials.

(EXTRA CREDIT: He also included a link to Scott Weingart’s notes regarding care of the crashing ventilated patient, which are well worth a look.)

Oldie But Goodie:

There’s been some e-mail discussion lately among our attendings regarding the best way to clean lacs prior to closure. Back in February, Ken Milne at the Skeptic’s Guide (along with Eve Purdy, a rockstar med student and creator of the excellent Manu et Corde blog) published a piece dedicated to breaking down the dogma of management of simple lacerations. Tap water vs sterile water, sterile gloves vs clean gloves, to sew or not to sew…it’s all covered here. Plus there’s links to other excellent FOAMed resources regarding wound care dogma.

F(FN)OAMed:

The good folks over at EB Medicine recently published a stem-to-stern guide to UTI diagnosis and management in the ED, all based on best available evidence. A bit lengthier than your average blog post, but incredibly high-yield and well worth your time. It’s a bit difficult for me to place a direct link here, but you can find it simply by logging into your account at EBMedicine, following the link to browse issues of Emergency Medicine Practice, and opening the July 2014 issue on UTI.
(As always, contact your friendly neighborhood Social Media Committee member if you need help obtaining access to EB Medicine resources.)

The Gunner Files:

1. Hard to get through a Deuce shift without breaking out the prochlorperazine at least once. We’ve all seen patients get jittery, agitated, or downright whacky following its use. Does Benadryl help? A PharmD expert at ALiEM has a good lit review of the topic.

2. Short and sweet: some diabetic medications are more likely to cause harmful hypoglycemia after overdose than others. Quick table-based rundown over at ALiEM.

3. It is asthma season, and you may find yourself in the worst-case-asthma-scenario of impending need for intubation. Check out this post from The Kings of County regarding care for the sick asthmatic, including intubation and mechanical ventilation issues.

4. FOAMed is taking the world by storm! Does the UK College of Emergency Medicine launching a dedicated FOAMed site mean it’s officially gone mainstream? Don’t worry – we were all into FOAMed before it was cool. But seriously, check out this vodcast on diagnostics in EM, and not feel quite so much increase in sphincter tone when Carpenter or Cohn pimp you on likelihood ratios or Bayesian analysis.

5. Another classic from the Skeptic’s Guide, this time addressing another oh-so-common ED complaint: renal colic. Fluids? Flomax? Any good evidence for either? In news that will surprise no one, Ken Milne is skeptical.

Never stop learning,

Sam Smith, PGY-3

Anaphylaxis: I can't breathe!

On an EMS ride along, you respond to a dispatch for a patient having an allergic reaction to some food.  You arrive on scene and find the patient having difficulty speaking and having stridor, in clear respiratory distress.

Clinical Question:

What is the ideal treatment of anaphylaxis?

Literature:

The lifetime prevalence of anaphylaxis is estimated between 0.5-2% with mortality rates ranging between 0.65%-2%, resulting in approximately 1500 deaths annually.  When fatal, death usually occurs minutes after contact with the trigger.  Fatal food reactions usually caused respiratory arrest 30-35 minutes after initial contact.

The first line treatment is epinephrine since it counters many of the symptoms of anaphylaxis.  As an alpha-receptor agonist, it reverses peripheral vasodilation and reduces edema.  The beta-receptor activity dilates bronchial airways, increases myocardial contraction, suppresses histamine and leukotriene release, inhibits mast cell activation.

There are several methods for epinephrine injection.  In a study comparing IM vs subcutaneously route, it found that an IM injection of epinephrine in the anterolateral aspect of the thigh achieved a higher and faster plasma epinephrine concentration peak.  IM injection into the deltoid of the arm as well as subcutaneous injection into the deltoid had lower and longer time to peak concentrations.  The greater blood supply to the vastus lateralis muscle is theorized to account for this difference.  The IM injection site also offers a greater margin of safety as well as ease of administration compared to IV epinephrine.  The IM dose of epinephrine can be repeated in 5-15 minutes if symptoms are not improving.  IV epinephrine has been associated with fatal cardiac arrhythmias and myocardial infarction and should be reserved for those unresponsive to conventional treatment in a controlled setting.

The recommended dose of epinephrine IM is 0.3-0.5mg of 1:1000 epinephrine (0.3-0.5 ml).  For pediatric patients, the recommended dosage is 0.01mg/kg.  Initial resuscitation should also include a bolus of normal saline given the vasodilatory effects of anaphylaxis.

Antihistamines are considered second line treatment.  H1 blockers such as diphenhydramine can be given to alleviate cutaneous symptoms, however it does not acutely treat the life threatening aspects of anaphylaxis.  There is little evidence to support the routine use of H2 blockers.  Steroids can also be given, although there is also weak evidence for their use.  In theory, steroids are used to prevent a biphasic reaction (when symptoms resolve, but recur within 1-72h) but there is little evidence that it is effective in reducing biphasic reactions.  Many providers will give a one time dose of methylprednisolone 1-2mg/kg in the ED, which is generally considered sufficient.  Bronchodilators can also be given if the patient is wheezing, experiencing dyspnea, or coughing.

Take home points:

-First line treatment for anaphylaxis is epinephrine 0.3-0.5mg IM in anterolateral thigh
-IV fluids should be given to counteract vasodilation
-H1 blocker may provide symptomatic relief, however is not first line therapy
-Bronchodilators may provide symptomatic relief
-H2 blockers have not been proven to be effective
-Steroids have not been proven to be effective

References:

1)Pumphrey RS. Lessons for management of anaphylaxis from a study of fatal reactions. Clin Exp Allergy. 2000;30(8):1144-1150
2) Soar J, Pumphrey R, Cant A, Clarke S, Corbett A, Dawson P, Ewan P, Foex B, Gabbott D, Griffiths M, Hall J, Harper N, Jewkes F, Maconochie I, Mitchell S, Nasser S, Nolan J, Rylance G, Sheikh A, Unsworth DJ, Warrell D. Emergency treatment of anaphylactic reactions – guidelines for healthcare providers. Resuscitation. 2008 May;77(2):157-69
3) Simons FE, Ardusso LR, Bilò MB, Cardona V, Ebisawa M, El-Gamal YM, Lieberman P, Lockey RF, Muraro A, Roberts G, Sanchez-Borges M, Sheikh A, Shek LP, Wallace DV, Worm M. International consensus on (ICON) anaphylaxis. World Allergy Organ J. 2014 May;7(1):9
4) Simons FE, Gu X, Simons KJ. Epinephrine absorption in adults: intramuscular versus subcutaneous injection. J Allergy Clin Immunol. 2001 Nov;108(5):871-3.
5) Zilberstein J, McCurdy MT, Winters ME. Anaphylaxis. J Emerg Med. 2014 Aug;47(20):182-7

Contributed by Steven Hung, PGY-2

#FOAMed Digest No. 3: You Need Me On That Wall

Emergency Medicine physicians practice in a unique environment. We must synthesize plans for  diagnosis, management, and disposition while utilizing input from almost every subspecialty, and the ED is the ultimate proving ground for diagnostic tests and treatment modalities of every sort. Unsurprisingly, a fair deal of controversy and debate exists regarding the optimum management of patients. (For reference, see any Trauma Case Conference featuring Drs. Schuerer and Aubin.) The “best evidence” is often poor evidence. We in Emergency Medicine retain the rebellious spirit of our founders, and are always looking for new and innovative techniques. Some physicians are too quick to jump on the bandwagon, and others lag behind the curve when it comes to adopting new practices.

The selections this time around are not meant to tell you the best way to do things. The algorithms and practice patterns suggested are not universally adopted, written in textbooks, or taught as part of any standard curriculum. They are meant to promote thought, to prompt you to read the primary literature for yourself, to encourage you to seek the opinions of other experts on the subject, and to form your own conclusions. Hopefully they will inspire you to suggest new ideas to your seniors and attendings during your next shift – or even question ideas you think are unsound. Maybe, just maybe, they will even inspire a new research or QI project. FOAMed is by design perfectly adapted to assist you in this quest.

Ramblers, let’s get ramblin’.

Three Stars:

1. Ken Milne at the Skeptic’s Guide to Emergency Medicine pretty much sets the bar when it comes to FOAMed of the latest EBM topics. He asks his clinical questions in the PICO format, he applies a rigorous quality checklist when analyzing the available literature, and includes in his discussion other FOAMed experts (including on occasion our very own Chris R. Carpenter, a.k.a. “Captain Cranium”). This episode he turns his skeptical eye to a topic sure to generate heated discussions for years to come: tPA for stroke.

2. If there’s anyone that looms larger in the ED Critical Care world than Weingart, it’s Resuscitationist Extraordinaire Cliff Reid. His lecture from the SMACC Gold conference hit resuscitation dogma like an A-bomb, leaving irradiated bits of unfounded practice patterns strewn about the Outback countryside.

(EXTRA CREDIT: Reid’s talk from the original SMACC conference, “Making Things Happen,” should be required viewing for anyone wanting to be a Trauma Senior someday.)

3. If pediatric surgeons have come to accept ultrasound as a stand-alone diagnostic method for appendicitis, maybe there’s hope that someday ultrasound can also be used as a radiation-sparing technique for diagnosis of small bowel obstruction. Academic Life in EM has an excellent run-down of the technique and comparative research studies.
(EXTRA CREDIT: The book Evidence-Based Emergency Care, authored in part by our own Captain Cranium Chris R. Carpenter, has a chapter dedicated to the inferiority of plain films for SBO diagnosis. You can read it for free online via Becker Library.)

Oldie But Goodie:

I think here in a few more years this will reach “accepted standard practice” level, and maybe even “textbook” level, but it’s not there yet. It should be: there’s good evidence to show kayexelate doesn’t work, and may even cause harm. Let Weingart and the PaperChase fellows from EM:RAP give you the ammunition you need to stand up to any pesky floor seniors.

F(FN)OAMed:

In a very enlightening segment from this month’s EM:RAP, Rob Orman interviews a community ED practitioner, Dr. Cameron Berg, regarding his hospital’s new Accelerated Diagnostic Protocol for low-risk chest pain. While his exact algorithm hasn’t been externally validated and probably isn’t ready for prime-time at our shop, the evidence-based and pragmatic approach is certainly worth considering. And he provides links to almost all of his references in the show notes!

The Gunner Files:

1. The “Research & Reviews” segment on Life in the Fast Lane is worth checking out every week. A group of some of the brightest minds in the FOAMed world get together and spoon-feed us summaries some of the most relevant, practice-changing, or downright strangest papers in the EM literature.

2. Josh Farkas over at PulmCrit wrote an excellent piece laying out his argument for super-high-flow NC (think 30-45L!) as an acceptable method of preoxygenation before RSI. It’s also got a good rundown of apneic oxygenation using NC (which we all should be doing every time), and an enlightening counterpoint from the grand maester of ED Critical Care, Scott Weingart.

3. Pediatric EM expert Sean Fox provides an excellent summary of the neonatal ALTE on his blog Pediatric EM Morsels.

4. Two EM airway heavyweights, Rich Levitan and Reuben Strayer, slug it out in the ultimate Direct Laryngoscopy vs Video Laryngoscopy debate, posted to the Prehospital and Retrieval Medicine podcast hosted by Minh Le Cong.

5. All of us will be the bearer of the -07 phone at some point, and that means you better have your act together when discussing decision-making capacity. Bill Johnston, EMT-P and author of the excellent blog Prehospital Wisdom, shares his fundamentally sound and no-bullshit method for determining capacity in the field.

In the words of Ken Milne: “Meet ‘em, greet ‘em, treat ‘em, and street ‘em!”

Sam Smith, PGY-3

Imaging in Renal Colic

You are working in the Emergency Department when a 30ish year-old female is wheeled by, clasping on to her right flank and clearly in pain.  You head into the room and find out that she had the acute onset of right flank pain that has been coming and going for the last hour.   She is otherwise healthy and denies any prior history of renal stones.  Thinking that this is probably a kidney stone, you order some pain medication, a UA, and a urine pregnancy test.  She is (thankfully) not pregnant and has 2+ blood in her UA.

You log back in to order your next diagnostic test of choice.  You start to click on “renal stone protocol CT” but pause…  and think to yourself: “Do I need to irradiate this woman to make the diagnosis?  Will the results of the CT scan change my management in some way?  What are the alternatives?”

Clinical Question #1:

Does a CT scan change management in cases of suspected uncomplicated renal colic?

                

The Literature:

There are several smaller studies that addressed whether a CT scan changes the clinical management in a patient where there is a high suspicion for renal stone.

                

Zwank et. al. [1] published a prospective observational study addressing this question.  The study enrolled providers caring for 93 “clinically stable” patients  > 18 yo with abdominal or flank pain, > 18 years of age and the  “most likely diagnosis” of renal colic.   Patients at higher risk of complication, i.e. those with a history of chronic kidney disease, nephrectomy, renal transplant, UTI, prior renal stones, were excluded from the study.  Prior to the CT, providers were surveyed as to what their top 3 differential diagnoses were and whether they thought that the CT scan might change management.    In the end, 62/93 patients who were scanned were diagnosed with renal colic (as a side note only 84% of these had hematuria on UA).   Five (5.3%) patients received an alternative diagnosis after CT scan – two ovarian cysts, one ovarian tumor, diverticulitis, and mesenteric edema.  Of the 16 patients where CT scan was obtained even though the provider thought it was very unlikely to change management, 10 had symptomatic renal stones and reportedly none had a change in management (unclear why the disparity if a diagnosis was not reach in 6/16 cases).    On this small pool of data, the authors conclude that “This result indicates that providers who are confident with the diagnosis of renal colic and who do not anticipate benefit from a CT scan can trust their low pre-test probability or ‘gestalt’ of low likelihood of benefit and should strongly consider not ordering a CT scan.” 

                

Another way of framing the question about whether CT scans change management in patients thought to have renal colic is to examine the incidence of alternative diagnoses that are found on CT in these patients.   In their prospective study, Pernet et. al. [2] examined this question by following the CT diagnosis of 155 patients with suspected uncomplicated renal colic (i.e. exclusion of patients with compromised renal function, UTI, fever, suspected bilateral renal stones).  118/155 (77%) were found to have uncomplicated stones, while 10 (6%) of these patients were found to have alternative diagnoses after CT.  These diagnoses included large calculi needing urology intervention, pyelonephritis, biliary colic, appendicitis, ileitis, small bowel obstruction and intra-renal hemorrhage.  Though a similar proportion of alternative diagnoses were found in this study when compared with Zwank et. al. above, these authors argue that CT(low-dose radiation) should be performed in cases of predicted uncomplicated renal colic because of the proportion of alternative diagnoses that mandated other intervention or hospitalization.  They further argue, that the population of patients which people would least want to irradiate (young women) are also the most likely to have some alternative diagnoses.   

Clinical Question #2:

Given that stones requiring urologic intervention and alternative diagnoses are found on CT imaging, how does ultrasound measure up as an imaging modality?

The Literature:

An older article in the British Journal of Radiology published in 2001  [3] [around the advent of use of CT and Ultrasound for diagnosis of renal calculi as opposed to intravenous urography (IVU)] prospectively evaluated the sensitivity and specificity of non-contrast CT and ultrasound for renal calculi.  They prospectively enrolled 62 patients with suspected uncomplicated renal colic.  These patients underwent both renal ultrasound and CT scan.  The gold standard was stone recovery or urological intervention.  43 (69%) of patients with suspected renal colic were confirmed by the “gold standard”.  Ultrasound showed 93% sensitivity and 95% specificity in the diagnosis of ureterolithiasis, while CT showed 91% and 95%.    Alternative pathology was found in six patients (~ 10%).  These alternative pathologies were cholelithiasis, cholecystitis, ovarian torsion, adnexal masses and appendicitis.  Both CT and ultrasound detected these, with the exception of the case of appendicitis, which was detected by CT scan alone.  Given advances in imaging technology, it is likely the sensitivity of CT has increased with time, but this is an impressive comparison.

Another study compared KUB + ultrasound versus CT scan for detection of clinically significant renal stones [4].   This was a retrospective study of 300 patients evaluated with KUB, US, non-contrast CT or some combination of the above for renal colic.  The study is overall very confusing because of the number of combinations of imaging modalities that patients had.  Despite this, one interesting observation was that among 147 patients who underwent KUB and/or US and CT scan, 22 had a normal KUB or US (unclear what proportion had what) and a CT scan positive for stone.  Of these, mean stone size was < 5 mm suggesting that this was a population of patients who was unlikely to need any type of urologic intervention.

Along the same lines of sensitivity of ultrasound for renal stones requiring urologic intervention, two separate studies examined the incidence of urologic intervention needed in patients with “normal” renal ultrasounds [5, 6].  In one of these studies (Yan et. al.) ,  they prospectively followed 341 patients with renal colic who were evaluated with ultrasound.   Of the 105 (30.8%) patients were classified as “normal”, none had urologic intervention in the following 90 days.  Alternative pelvic pathologies were identified on ultrasound (such as ovarian cysts and pregnancy) but there was no avenue for direct comparison with CT in this study.  A similar study from Edmonds et. al. retrospectively reviewed the records of all patients undergoing renal ultrasound for suspected nephrolithiasis over the course of a year.  Of a 352/817 (43%) that were classified as “normal”, only 2 patients (0.6%) required urologic intervention in the following 90 days.  They did not comment on alternative diagnoses.

Take home:

Renal ultrasound is a reasonable initially imaging modality for patients with suspected uncomplicated renal colic.  While we are overall pretty good an predicting who has renal colic based on history and exam (~ 60- 70% of all patients with this as a suspected diagnosis had imaging confirming it in the above studies), we should keep in mind that anywhere between 5 – 10% of these patients will have an alternative diagnosis requiring alternative management.   Ultrasound is good at picking up these alternative diagnoses as well.

References:

1. Zwank et. al. “Does computed tomographic scan affect diagnosis and management of patients with suspected renal colic?” American Journal of Emergency Medicine 32 (2014) 367–370

2. Pernet et. al. “Prevalence of alternative diagnoses in patients with suspected uncomplicated renal colic undergoing computed tomography: a prospective study.” CJEM. 2014 Feb 1;16(0):8-14.

3. Patlas et. al. “Ultrasound vs CT for the detection of ureteric stones in

patients with renal colic”. The British Journal of Radiology, 74 (2001), 901–904

4. Ekici and Sinanoglu. “Comparison of conventional radiography combined

with ultrasonography versus nonenhanced helical computed

tomography in evaluation of patients.” Urol Res (2012) 40:543–547

5. Yan et. al. “Normal renal sonogram identifies renal colic patients at low risk for urologic intervention: a prospective cohort study” CJEM 2014:1-8.

6. Edmonds et. al.  “The utility of renal ultrasonography in the diagnosis of renal colic in emergency department patients” CJEM 2010;12(3):201-6.

Kindly submitted by Maia Dorsett, PGY-3.

#FOAMed Digest No. 2: Breathless Love

Welcome back! Fresh new FOAMy goodness for you, this time with an emphasis on airway and pulmonary care. Let’s do it!

Three Stars:

1. No way around it: “Delayed Sequence Intubation” is the new hotness. If you want to be one of the cool kids, you better get on board. I’ll let the more graphically-minded folks at EMCurious lay it all out for you with a prototypical case. Don’t miss the links – more excellent FOAMed resources on DSI.

(And Weingart’s seminal paper on the subject is required reading at this point.)

(And, oh yeah, ketamine does NOT increase ICP. Let’s use these two systematic reviews 1 & 2 to stop the foolishness already.)

2. Someday you will need to perform a cricothyrotomy. Accept it as reality, and do everything you can to prepare for it. Start here, with Weingart’s lecture on the surgical airway delivered at the SMACC Gold conference last fall. This page from the EMCrit blog has compiled all sorts of great surgical airway resources from around the FOAMed world all in one spot, including can’t-miss stuff about the scalpel-finger-bougie technique and Weingart’s pre-intubation checklist. You should probably add it to your favorites list now.

3. Wouldn’t be a FOAMed Digest without getting a little off-topic, and Rick Body’s recent contributions over at St. Elmyn’s regarding ACS & “low-risk” chest pain in the ED are too good to pass up. Great post analyzing his recent paper, which concluded ED physicians simply aren’t capable of ruling out ACS in chest pain patients with an acceptable accuracy using only the clinical exam. Dr. Body also gives you a run-down of how to properly utilize high-sensitivity troponin in his talk from SMACC Gold.

(Link to Body's paper here.)

Oldie But Goodie:

By the end of our Ultrasound rotation, we can all diagnose pneumothorax with ultrasound at the bedside. It’s time to take it next-level. A-lines, B-lines, pneumonia vs edema…the experts at the Ultrasound Podcast help you figure it all out in a two-part 1 & 2 podcast.

F(FN)OAMed:

Sanjay Arora and Mike Menchine, hosts of the PaperChase segment on EM:RAP, summarize the current literature about how terrible we are at adequately sedating patients after RSI. Roc lasts longer than Sux – the patients won’t be able to tell us they need sedation!

(Links to relevant papers in the show notes.)

The Gunner Files:

1. Brett Sweeny at EMDocs provides an exhaustive review of FOAMed resources regarding permissive hypotension in trauma. Great lectures and podcasts from some of the brightest minds in EM & trauma surgery.

2. We’re seeing it already – asthma cases are starting to pile up over on the SLCH side. Luckiliy for you, Pediatric EM rockstar Andy Sloas just published an excellent podcast on the evaluation and management of asthma in the Peds ED.

3. Next time you’re consulting Ortho or Plastics for a hand injury, sound like you know what you’re talking about. The folks over at EMin5 hit you with the quick rundown on the neuro exam of the hand.

4. Last week, St. Elmyn’s helped the rooks get up to speed when it came to dealing with the dyspneic patient in the ED (and I bet the seniors learned a thing or two as well). This time, get your mind right when faced with a syncopal patient.

5. Who doesn’t love infographics? And if they actually help us learn something about managing septic patients, that’s just a bonus! Very well done by EMCurious, with embedded links to the relevant studies!

6. New podcast from R.E.B.E.L.EM, summarizing the results of a meta-analysis just published this month in Annals which concluded prehospital application of NIPPV in patients with severe respiratory distress regardless of cause reduced need for intubation (NNT 8) and in-hospital mortality (NNT 18). 

w00t prehospital medicine!
(Original pub here.)

That’s all, folks! Go get your learn on!

Sam Smith, PGY-3