I took another month off, but the blog and accompanying podcast are back with what I think is an interesting collection of articles… Continue reading “Articles of the month (May 2017)”
A monthly collection of the most interesting emergency medical literature I have encountered.
Another month and another set of articles proving only that I probably should have spent more time Christmas shopping and less reading journals. Enjoy…
Peripheral thermometers mostly suck, but does it matter?
Niven DJ, Gaudet JE, Laupland KB, Mrklas KJ, Roberts DJ, Stelfox HT. Accuracy of Peripheral Thermometers for Estimating Temperature: A Systematic Review and Meta-analysis. Annals of internal medicine. 163(10):768-77. 2015. PMID: 26571241
I will start this month with a paper just for my friend Dr. Scott Kapoor. This is a systematic review and meta-analysis of 75 studies encompassing 8682 patients looking to compare the accuracy of peripheral thermometers to central thermometers. The peripheral thermometers are not very accurate, especially if you look at hypo or hyperthermia. If you take the core temperature as the gold standard, the peripheral thermometers had a pooled sensitivity and specificity of 64% (95%CI 55-72%) and 96% (95%CI 93-97%) respectively for fever. I don’t have access to the appendices to look at the raw data, but the authors report that all peripheral thermometers were equally bad, with axillary probably being the worst. So sorry Scott, it’s not just the temporal artery thermometers that don’t work, it’s everything peripheral. Luckily, for the vast majority of people being triaged, temperature is irrelevant. For patients you care about, you probably should recheck a core temp.
Bottom line: There is a very good chance peripheral thermometers will miss a fever.
If all your friends jumped off a bridge…
Douketis JD, Spyropoulos AC, Kaatz S. Perioperative Bridging Anticoagulation in Patients with Atrial Fibrillation. The New England journal of medicine. 373(9):823-33. 2015. PMID: 26095867 [free full text]
We frequently admit patients on anticoagulants who will require surgery or procedures that require their anticoagulants to be held. Should we be bridging these patients with some kind of heparin? This is a randomized controlled trial of 1884 adult patients with chronic atrial fibrillation and at least 1 CHADS2 risk factor undergoing surgery (excluding cardiac, neuro, and spinal surgeries). They were randomized to either bridging with dalteparin or placebo. Patients were excluded if the had a mechanical heart valve, recent stroke, or renal failure. The primary outcome of any arterial thromboembolic disease was noninferior, with 4 patients (0.4%) in the non-bridged group and 3 patients (0.3%) in the bridged group having events. Major bleeding was higher in the bridged group (29 patients (3.2%) versus 12 patients (1.3%) p=0.005 NNH=53). Minor bleeding was also increased (20% versus 12%, p<0.001, NNH=11).
Bottom line: This is probably the best evidence to date that the short term risk for atrial fibrillation patients off anticoagulation is low and that bridging therapy is harmful.
Steinberg BA, Peterson ED, Kim S. Use and outcomes associated with bridging during anticoagulation interruptions in patients with atrial fibrillation: findings from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). Circulation. 131(5):488-94. 2015. PMID: 25499873 [full free text]
This is a retrospective look at a large atrial fibrillation patient registry. They looked at the 2803 patients with non-valvular atrial fibrillation who had an interruption in their anticoagulation, primarily for non-cardiac surgery or endoscopy. 77% of patients were not bridged as compared to 23% who were. Overall adverse events were higher in the bridging group (5.3% versus 2.8% p=0.01), primarily driven by excess bleeding complications. Stroke and MI were not different between the groups. Of course, patients were not randomized, so there were likely reasons that physicians chose to bridge some patients and not others, making any concrete conclusions difficult.
Bottom line: More evidence that bridging is not helpful
As a side note, if all my friends jumped off a bridge, you can bet that I would too. My friends are all sane and mostly intelligent. If they were jumping off a bridge, there is probably a very good reason to do so, like the bridge is on fire or there is rapidly approaching school of flying sharks with lasers on their heads. Also, even if they happened to die, who wants to live in a world where all your friends just died jumping off a bridge?
OK, those were boring topics. Let’s move on: anyone have a VIP guest in the department this holiday season?
Sadly, this article was a little boring even for a Christmas spoof – but have you ever considered the extreme occupational hazards of Santa Claus? Don’t be surprised if he ends up in an ED near you sometime soon.
Christmas: so many new toys, with so many small parts. It’s the perfect storm for foreign bodies in the airway
Eren S, Balci AE, Dikici B, Doblan M, Eren MN. Foreign body aspiration in children: experience of 1160 cases. Annals of tropical paediatrics. 23(1):31-7. 2003. PMID: 12648322
This is a retrospective review of 1160 children (under 15 years of age) who underwent bronchoscopy for foreign bodies. Almost 2/3rds of the patients with foreign bodies had negative radiography. (There is obviously a selection bias here, because these are only the children in whom the clinicians were concerned enough to perform a bronchoscopy). I will also note that this is an interesting population, because 38% of the foreign bodies were watermelon seeds. However, with a good story, xray is clearly not good enough to exclude foreign bodies.
Bottom line: It is often a difficult sell, but if a child has a good story for aspiration, they probably need a bronchoscopy.
High flow nasal oxygen in the ED
Bell N, Hutchinson CL, Green TC, Rogan E, Bein KJ, Dinh MM. Randomised control trial of humidified high flow nasal cannulae versus standard oxygen in the emergency department. Emergency medicine Australasia : EMA. 2015. PMID: 26419650
This is an unblinded prospective randomized control trial comparing high flow nasal oxygen to standard care (nasal prongs or face mask) in 100 adult emergency department patients with shortness of breath, a respiratory rate over 24 and an oxygen saturation less than 94%. There were 2 primary outcomes, which is not good from a trial design perspective. For the outcome of a reduction in respiratory rate by 20% within 2 hours, the high flow nasal group was better (66.7% vs 38.5%, p=0.005). For the outcome of an escalation of ventilation requirement, the reported outcomes are less clear, because they included being changed from face mask to high flow nasal oxygen as an “escalation of care”, even though this trial is supposed to be determining if it is any better. Two patients in each group required non-invasive positive pressure ventilation, and one patient was intubated. So I would say there was no change in patient oriented outcomes except the single intubation, and a single outcome is just not enough to draw any conclusions from.
Bottom line: Not a lot to go on here, but it doesn’t look like high flow nasal oxygen will be worse than usual care.
One step closer to forgetting antibiotics in diverticulitis
Isacson D, Thorisson A, Andreasson K, Nikberg M, Smedh K, Chabok A. Outpatient, non-antibiotic management in acute uncomplicated diverticulitis: a prospective study. International journal of colorectal disease. 30(9):1229-34. 2015. PMID: 25989930
I have previously talked about the few RCTs indicating that antibiotics might not help in diverticulitis. It is an interesting topic, so I will include new evidence as I find it. This is a prospective cohort of 155 adult patients diagnosed with acute uncomplicated diverticulitis who were managed as outpatients without antibiotics, just pain control and a diet progressing from liquids back to full, as tolerated. Of the 155 patients, only 4 patients (2.5%) failed this outpatient management strategy – which isn’t much different from what you would expect if they had been treated with antibiotics. The biggest problem with this data set is that it doesn’t represent consecutive patients. 66 patients with uncomplicated diverticulitis were seen during the study period but were not enrolled, so there could be some selection bias. There was no control, so antibiotics could have lowered complication rates further – but for the 97.5% of patients without complications, it doesn’t seem that antibiotics were necessary.
Bottom line: A little more evidence indicating that antibiotics may be unnecessary for diverticulitis after all.
How do fish get high? Seaweed
Vandrey R, Raber JC, Raber ME, Douglass B, Miller C, Bonn-Miller MO. Cannabinoid Dose and Label Accuracy in Edible Medical Cannabis Products. JAMA. 313(24):2491-3. 2015. PMID: 26103034 [free full text]
With legal marijuana on the horizon in Canada, there are many questions we need to be asking about its use. One very basic question is: at current marijuana dispensaries, how accurate are labels with regards to THC content? Individuals were sent out to buy marijuana in San Francisco, Los Angeles, and Seattle, and the THC content was analyzed by liquid chromatography. Of 75 total samples, 13(17%) were accurately labelled, 17(23%) were under-labelled (contained more THC than the label stated), and 45 (60%) were over-labelled. Errors were frequently large, up to 55% under labelled and 99% over labelled. Combined with confusion over appropriate doses, highly concentrated doses in edibles, and differing rates of absorption, dosing errors make it more likely that marijuana users will end up in the ED.
Bottom line: Active ingredients in marijuana products are not well regulated or labelled on available products.
Monthly poll: Who would want this ENT surgeon as their own doctor?
Leopard DC, Williams RG. Nasal Foreign Bodies: A Sweet Experiment. Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery. 40(5):420-1. 2015. PMID: 25639608
There are many techniques to get foreign bodies out of children’s noses, but what do you do if they don’t work? Well, if it’s a hard candy, you may not need to do anything. This (presumably bored) ENT surgeon placed 5 different candies in his own nose (Fizzers, Tic Tac, Smarties, Skittles, and Polo mints) and then had the second author perform rhinoscopy every 5 minutes. All 5 candies were completely dissolved in less than an hour. I will let you perform your own critical appraisal of these methods.
Bottom line: Watchful waiting may be reasonable for children with hard candies in their noses.
(In case you were wondering, I would happily take this chap as my doctor)
Alcohol by mouth can make you vomit. On the other hand, alcohol in the nose…
Beadle KL, Helbling AR, Love SL, April MD, Hunter CJ. Isopropyl Alcohol Nasal Inhalation for Nausea in the Emergency Department: A Randomized Controlled Trial. Annals of emergency medicine. 2015. PMID: 26679977
This is a randomized trial of a convenience sample of 80 adult patients presenting to the emergency department with a chief complaint of nausea and/or vomiting. Patients were instructed to inhale from a pad of either saline or isopropyl alcohol (the same wipes you would use on the skin before starting an IV) immediately, then 2 and 4 minutes later. Although investigators covered the label of the wipe, I’m pretty sure blinding was eliminated the instant the patient took a sniff. Nausea was measured on a scale of 0 to 10, but only for the first 10 minutes. At the start of the study, patients rated their nausea as a 6/10. At 10 minutes, the saline group still rated their nausea as 6/10 whereas the alcohol group rated theirs as 3/10 (absolute difference 3, 95%CI 2-4 p<0.001). We don’t know what happened after 10 minutes, which is a major limitation. Some other major limitations of this data are the lack of blinding and potential selection bias in a convenience sample.
Bottom line: Maybe inhaling from alcohol wipes decreases nausea
Hines S, Steels E, Chang A, Gibbons K. Aromatherapy for treatment of postoperative nausea and vomiting. The Cochrane database of systematic reviews. 4:CD007598. 2012. PMID: 22513952
Although I was completely unaware of this therapy for nausea, apparently it has been studied before. This Cochrane review found 6 RCTs and 3 non-randomized controlled trials looking at aromatherapy for nausea and vomiting. When compared to placebo, they found that isopropyl alcohol vapour inhalation reduced the number of patients requiring rescue antiemetics (RR 0.30 95%CI 0.09-1.0, p=0.05 so technically not significant), however it was less effective in reducing nausea than standard anti-emetic medications.
Bottom line: Probably shouldn’t be first line, but if I’m huffing alcohol in the break room, it may be because I caught the gastro that’s going around.
Nerves were meant for blocking
Flores S, Herring AA. Ultrasound-guided Greater Auricular Nerve Block for Emergency Department Ear Laceration and Ear Abscess Drainage. The Journal of emergency medicine. 2015. PMID: 26589558
This is just a case report, but considering the frequency with which we see ear injuries, and the difficulty of achieving good local anesthesia, having a ultrasound guided nerve block in your back pocket is a great tool. In this article they specifically identify and anesthetize the greater auricular nerve, but a superficial cervical plexus block will get you the same coverage and might be easier. These nerve blocks only cover the posterior aspect of the ear, so you may have difficulty if the injury is more anterior. They can also miss the top of the ear.
Bottom line: Nerve blocks are fantastic for many things in the ED, especially when using ultrasound guidance.
Don’t have access to this paper? You could read about the ultrasound guided superficial cervical plexus block on NYSORA. You could also watch a video on the superficial cervical plexus block on the ultrasound podcast.
We have many effective treatments for hyperkalemia – kayexalate just isn’t one of them
Hagan AE, Farrington CA, Wall GC, Belz MM. Sodium polystyrene sulfonate for the treatment of acute hyperkalemia: a retrospective study. Clinical nephrology. 85(1):38-43. 2016. PMID: 26587776
The evidence behind the use of sodium polystyrene sulfonate (kayexalate) for hyperkalemia is poor. This is a chart review looking at 501 patients who received SPS for hyperkalemia. The chart review methods make it difficult to assess the true effect, but on average after SPS administration, the potassium decreased by 0.93mEq/L. That sounds reasonable, until you realise that the drop occurred over about 8 hours and that most of these patients were given other medications as well. The really concerning part of this paper is that there were 2 cases of bowel necrosis, a known side effect of SPS.
Bottom line: A little more evidence that reinforces my current practice – I don’t use kayexalate to treat hyperkalemia in the ED.
Want to read a little more about the original studies on kayaexalate? Check out this post by Anand Swaminathan on R.E.B.E.L.EM.
Newer is always better, right?
Navarro V, Dagron C, Elie C. Prehospital treatment with levetiracetam plus clonazepam or placebo plus clonazepam in status epilepticus (SAMUKeppra): a randomised, double-blind, phase 3 trial. The Lancet. Neurology. 15(1):47-55. 2016. PMID: 26627366
We all know the downsides of phenytoin in seizures – so it makes sense that researchers are looking at newer (but more expensive) agents. In this industry-funded, randomized, double-blind prehospital trial, they compared clonazepam plus levetiracetam (Keppra) to clonazepam plus placebo in 203 patients with status epilepticus (a seizure lasting more than 5 minutes). The trial was stopped early because an interim analysis revealed no chance that levetiracetam would turn out to be superior to placebo.
Bottom line: Don’t start changing your status epilepticus algorithms yet
Mundlamuri RC, Sinha S, Subbakrishna DK. Management of generalised convulsive status epilepticus (SE): A prospective randomised controlled study of combined treatment with intravenous lorazepam with either phenytoin, sodium valproate or levetiracetam–Pilot study. Epilepsy research. 114:52-8. 2015. PMID: 26088885
This paper complements the last. This is a prospective randomized trial of 150 patients with status epilepticus comparing valproate, phenytoin, and levetiracetam (all in addition to lorazepam). There was no statistical difference between the groups. Because of the small numbers, this is the kind of trial that could miss a clinically significant difference just because it wasn’t statistically different (type 2 error).
Bottom line: Again, there is no reason to abandon our tried and true and cheap medication yet
Has it been cold enough for leaky gas powered heaters yet?
Hampson NB. Myth busting in carbon monoxide poisoning. The American journal of emergency medicine. 2015. PMID: 26632018
I couldn’t resist this paper – it had “myth” in the title and who doesn’t love carbon monoxide? There isn’t much to say about the the methods, as there were none, but there are a few important review points:
- Carbon monoxide levels do not correlate with symptoms and should not be the primary driver of emergency care
- A venous blood gas is just as good as an arterial gas for measuring CO levels
- CO is very stable in blood samples. You don’t need to rush an iced sample to the lab. In samples of anticoagulated blood, CO levels didn’t change over the course of a month. So this test could be done as an add-on if you forgot to order it initially
Bottom line: Read the three points above – stop trying to just skip to the red text to get your answers quickly
NOT EMERGENCY MEDICINE, but in headlines everywhere
Jacobs IJ, Menon U, Ryan A et al. Ovarian cancer screening and mortality in the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS): a randomised controlled trial. The Lancet. 2015. [free full text]
“Ovarian Cancer Screening Could Reduce Deaths By As Much As 20 Percent”. That is the first headline I encountered, but there are many many more. Expect to hear about this from patients, family, and friends alike. But what did the study actually show? This is a massive prospective trial that randomized 202,638 women into one of two screening protocols or a control group. Like so many cancer trials, the authors unfortunately started the trial very confused and made their primary outcome the factitious ‘disease specific mortality’ instead of all cause mortality. THEY DON’T EVEN REPORT ALL CAUSE MORTALITY! How can you tell if an intervention saves lives if you don’t measure mortality? Disease specific mortality only tells you that there might be changes in what someone happened to write on a death certificate (almost never supported by an autopsy), so is clearly not a patient oriented outcome. That is such a fatal flaw that it is hardly worth noting that there was a significant selection bias (in that healthy individuals are much more likely to volunteer for a study like this), that they had to alter the study protocol part way through, and that if you use the primary statistical outcome listed in the original trial design none of the outcomes were statistically significant. So throw this one into the trash heap, but be prepare for a lot of questions about how this could be the next big thing.
Bottom line: We need to get cancer researchers to start measuring and reporting all cause mortality. Our patients are being confused and harmed by the statistical misinformation that results from the fictional concept of ‘disease specific mortality’
Cheesy joke of the month
What do you get if you eat Christmas decorations?
#FOAMed of the month
A few videos that demonstrate why you should have a PEEP valve already attached to every BVM you use in the ED (rather than hidden in an RT office somewhere):
When I started this month’s articles, I only planned on including the videos on the PEEP valve, but then Dr. Kovacs had to release one of the best awake intubation videos ever made. In the end, fully awake, he will show you his own carina:
So bottom line of all this, follow George Kovacs and AIME on youtube