Every two months or so I write a monthly summary of the most interesting medical literature that I have encountered. This is one of those summaries.
Removing the cardiac leash
Syed S, Gatien M, Perry JJ. Prospective validation of a clinical decision rule to identify patients presenting to the emergency department with chest pain who can safely be removed from cardiac monitoring. CMAJ. 2017; 189(4):E139-E145. PMID: 28246315 [free full text]
Which chest pain patients need a cardiac monitor? This is a prospective cohort to validate the Ottawa chest pain cardiac monitoring rule. It looks at a cohort of 1125 emergency department patients with symptoms suspicious for MI, excluding patients with prehospital cardiac arrest or STEMI. It is from the same hospitals where the rule was originally derived, potentially limiting external validity. The rule is pretty simple: you need to be chest pain free AND your ECG needs to be normal or nonspecific. (All ECGs in this study were ready by a single research physician, so ECG interpretation could be more variable in the real world). The primary outcome was any arrhythmia that required treatment in the first 8 hours, assessed via chart review. Overall, this is a very low risk population, with a rule in rate for NSTEMI (STEMI was excluded) of only 3.5%. Of the 1125 patients, 796 (71%) were placed on monitors from triage (based on nursing discretion), which I think is a higher number than at the hospitals I have worked in. None of the non-monitored patients had an arrythmia, so the nurses were doing an excellent job. Of the 796 patients placed on a monitor, 15 (1.9%) had an arrhythmia that required treatment. However, I am not sure how important these arrhythmias were. There was 1 ventricular tachycardia, but the rest were either atrial fibrillation or SVT. In the case of an atrial tachycardia, the patient probably could have just told us they were having an arrhythmia instead of relying on the expensive cardiac monitor. Based on these numbers, the decision tool has a sensitivity of 100% (but with with 95% CI 78.2-100%), specificity 36.4% (95%CI 33.0-39.6%), negative predictive value 100%, and positive predictive value of 2.9%. The small number of outcomes leads to wide confidence intervals, which combined with the very low specificity and other issues mentioned above, mean I don’t think this rule is strictly ready for use. However, I am not sure cardiac monitors add a lot of value. There are large studies of admitted NSTEMI patients that demonstrate incredibly low rates of arrhythmias. In this population only 1 patient out of 1125 had what I would consider an emergent arrhythmia. Whether or not this study is valuable to you will depend a lot on how frequently you are using cardiac monitors in your chest pain patients currently. Personally, I will keep doing what I have always done: reserving the monitor for patients with significant ECG changes or other high risk features.
Bottom line: The rule is probably not ready for prime-time, but the data here does remind us that not every chest pain patient requires a cardiac monitor.
CT coronary angiogram: As useful as a glass hammer
Gongora CA, Bavishi C, Uretsky S, Argulian E. Acute chest pain evaluation using coronary computed tomography angiography compared with standard of care: a meta-analysis of randomised clinical trials. Heart. 2018; 104(3):215-221. PMID: 28855273
This is a systematic review and meta-analysis that looks at 10 RCTs including 6285 patients who were randomized to either receive a coronary CT angiogram (CCTA) or standard care after their negative chest pain evaluation. All the studies included pretty low risk patients (the overall rate of major adverse cardiac events was just 2.5%). The standard care primarily meant some type of provocative testing, which is a bit of a problem, as performing a stress test might be worse than doing nothing at all. But even with a faulty comparison, CCTA looks bad. There is no change in mortality, MI, or MACE (although low numbers mean large confidence intervals for everything but the composite MACE). Despite adding no patient oriented benefit, CCTA did lead to more invasive procedures (coronary angiography and revascularization). That is a net negative for patients. Unfortunately, despite the randomization to either get or not get intravenous contrast, renal outcomes are not mentioned here.
Bottom line: In the RCTs we have to date, CCTA demonstrate no benefit, but leads to an increase in unnecessary invasive procedures.
Nebulizing furosemide for palliative symptom control
Owens D. Nebulized Furosemide for the Treatment of Dyspnea. Journal of Hospice & Palliative Nursing. 2009; 11(4):200-201. DOI: 10.1097/NJH.0b013e3181b06227
I came down pretty hard on furosemide last time (discussing door to furosemide times), but I thought this was an interesting paper. It is a short, practical summary of the use of nebulized furosemide to manage dyspnea in palliative care patients. There are a few case series and RCTS that found that nebulized furosemide helped relieve dyspnea in COPD and cancer patients. Although a combination of opioids and nonpharmacologic therapies are my go to for palliative dyspnea in the emergency department, it is always nice to have other options for these patients, especially options that don’t require IV access.
Bottom line: This won’t be first line for me, but it is nice to know about.
Threading the laryngeal needle
Driver B, Dodd K, Klein LR. The Bougie and First-Pass Success in the Emergency Department. Annals of emergency medicine. 2017; 70(4):473-478.e1. PMID: 28601269
This is not a great study, but the results are interesting. It is a retrospective, observational, single-center study looking at first pass intubation rates depending on whether or not a bougie was used. They look at 593 intubations (primarily done by senior residents). All of these intubations were video recorded, and the data is from video review. Bougie was used 80% of the time for the first attempt, so bougie is obviously well liked and well practiced at this hospital. First pass success was higher with bougie use (95% vs 86%; absolute difference 95%; 95% CI 2-16%). However, the length of the intubation attempt was somewhat longer (13 seconds) in the bougie group and there was a slightly higher rate of hypoxia (17% vs 13%). Obviously, this is observational data with multiple confounders that muddy the waters. However, I think the results make sense. In cases where it is a little tricky to pass the tube, the bougie is perfectly designed to enter the trachea, and so first pass success will be a little higher. On the other hand, in easy patients, the bougie adds a step and the potential complication of tube hangup on the cords, which could prolong easier attempts. This data doesn’t support routine use of the bougie, but we all need to be facile with the bougie and therefore should be using it on the first attempt at least some of the time so we are well trained for the cases where we really need it.
Bottom line: The bougie is a great device
It’s all in the name: atraumatic vs cutting needles
Nath S, Koziarz A, Badhiwala JH. Atraumatic versus conventional lumbar puncture needles: a systematic review and meta-analysis. Lancet. 2017. PMID: 29223694
This is old news, but it is such a small part of our daily practice that the use of non-traumatic spinal needles still has not become universal. This is a systematic review and meta-analysis looking at 110 RCTs (31,412 patients) comparing atraumatic spinal needles to conventional spinal needles. (It is amazing that we are willing to fund 110 studies on this topic and can’t even get a single replication of NINDS.) The atraumatic needles are the clear winner. Post-LP headache occurred in 11% of patients with the standard needle versus only 4% with the atraumatic needle (RR 0.04; 95% CI 0.34-0.46). Epidural blood patch was required in 3% of the conventional group as compared to 1% of the atraumatic needle group. Statistically significant decreased were also noted in nerve root irritation and hearing disturbance. (I did not know LP could cause hearing disturbances. I have never seen this complication). There was no change in the number of attempts required to get CSF.
Bottom line: This one is done. It is time to stop doing studies and just use the atraumatic needles.
Zap before tap?
April MD, Long B, Koyfman A. Emergency Medicine Myths: Computed Tomography of the Head Prior to Lumbar Puncture in Adults with Suspected Bacterial Meningitis – Due Diligence or Antiquated Practice? The Journal of emergency medicine. 2017; 53(3):313-321. PMID: 28666562
This is a great journey into the history of evidence based medicine by a couple of FOAMed friends. You have a patient with a fever, headache, and a stiff neck. Should you get a CT before performing the lumbar puncture. (Spoiler: we have no idea.) There are multiple levels of complexity to this data, including the fact that a lot of it comes from an era before CT was available. In the observational studies that we have, there is definitely a risk of herniation in patients who have bacterial meningitis and have an LP performed. The 3 studies looking at this report rates between 5 and 13%. However, in the 2 studies that had CT available, the majority of the patients that herniated had normal CTs. Also, in other studies of patients with increased ICP (papilledema or presumed brain tumors) the rate of herniation after LP was less (only about 1.5%). Furthermore, this is observational data, so provides us with an association, not cause and effect. In fact, there are multiple patients in these studies who herniated without having the LP done, hinting that the underlying pathology and not the LP is the cause of the herniation. Additionally, when the patients did herniate after LP, it wasn’t immediately, but generally a couple hours later. Finally, in the modern era bacterial meningitis is very rare (maybe about 2% of patients undergoing LP). Therefore, even if there is a 5% herniation rate with LP in patients with bacterial meningitis, among the undifferentiated patients we are thinking about tapping to exclude meningitis, the rate will be closer to 1 in 1,000 (2% x 5%). One thing that is pretty clear: when we get an CT before LP antibiotics are delayed. One study reported the results of a guideline change in Sweden. They removed “impaired mental status” as a contraindication to LP and door to antibiotic times decreased. More importantly, mortality fell from 11.7% to 6.9%. There is not a clear answer in here. Patients with true bacterial meningitis are at risk of herniation, but my guess is that it is more likely to be caused by their underlying disease than the LP. Personally, I tend the get a CT if there are focal neurologic findings, evidence of increased ICP, or immunocompromise. However, if I am getting a CT, antibiotics are given immediately (before the CT) and the LP is just done with the antibiotics on board.
Bottom line: There is no clear evidence based answer here. Just be sure that no matter what you do that antibiotics are given as soon as possible if you are considering bacterial meningitis.
But IVs have magical powers
Aboltins CA, Hutchinson AF, Sinnappu RN. Oral versus parenteral antimicrobials for the treatment of cellulitis: a randomized non-inferiority trial. The Journal of antimicrobial chemotherapy. 2015; 70(2):581-6. PMID: 25336165
I see a lot of IV antibiotics used for cellulitis, but I have always wondered why. The bacteria in your leg have no idea in the antibiotic entered your system through your stomach or an IV, so assuming that you are using a bioavailable agent, why should this matter? This is a small RCT in which they look at patients with cellulitis in whom the emergency physician thought IV treatment was necessary, either because of failure of current oral therapy or systemic symptoms. This is exactly the group of patients we want studied: not all comers, but the sicker patients that we are currently using IV antibiotics to treat. They randomized these patients to either oral therapy with cephalexin 1 gram QID or parenteral therapy with cefazolin 2 grams BID, both very reasonable options. The dose of cefazolin is a little higher than I use, which could bias in favour of the IV treatment, but overall this a good comparison. The patients here were pretty sick at baseline, with about 75% having signs of systemic illness. The two groups were pretty even at baseline, but the oral group looks a little sicker, which again could bias the results in favour of the IV treatment. Their primary outcome was time it took until the cellulitis stopped advancing, and the oral group actually looked a little better. The cellulitis stopped advancing in 1.3 days in the oral group and 1.8 days in the IV group. The difference isn’t enough to say that oral therapy was statistically better, but it is enough to say it was non-inferior. There was 1 treatment failure in the oral group as compared to 5 in the IV group, but the difference was not statistically significant. There were no differences in any of the other secondary outcomes. The results don’t surprise me. Except for the rare antibiotics that really aren’t absorbed orally, or patients who are vomiting, there is no reason to believe that intravenous administration would somehow be better than oral. I will add a full EBM write up on this topic on the website sometime soon.
Bottom line: For the most part, stick with oral antibiotics for cellulitis.
Kuisma M, Salo A, Puolakka J. Delayed return of spontaneous circulation (the Lazarus phenomenon) after cessation of out-of-hospital cardiopulmonary resuscitation. Resuscitation. 2017; 118:107-111. PMID: 28750883
Zombies!!! Or maybe not. This is a prospective observational cohort from Finland looking at “the Lazarus phenomenon”. Apparently there was a famous malpractice case in Finland were someone came back from the dead, so now in Helsinki they monitor all out of hospital cardiac arrest patients for 10 minutes after they are pronounced dead to make sure they are really dead. In the 6 year study period, there were 2102 out of hospital arrests, with 840 terminated in the field. In 5 cases, the patient “returned from the dead”. Sort of. They were all dead 2 days later. Three patients were officially declared dead within 15 minutes of ‘coming back’, one was transported to hospital only to be declared dead there, and the other patient lasted a full 26 hours, always deeply comatose, and then finally died. Based on these results, the authors suggest careful monitoring of dead patients for 10 minutes in order to finally and accurately declare death. But this is less of a Lazarus phenomenon and more of a last twitch of life. I would conclude the opposite: remove all the monitors so people aren’t confused by the last few twitches of a dying heart. The one real take away for me is more about communicating with families and warning them that some agaonal movements or deaths can rarely occur in the few minutes after resuscitation is stopped in dead patients.
Bottom line: Although The Princess Bride provides us with much wisdom, I am not sure “there is a big difference between mostly dead and all dead”
And just for some added fun:
What’s in a name?
Much of the practice of medicine centers around the arrival at a final diagnosis. These authors point out some major flaws in that process. While the main critique is of a final diagnosis here is that it obscures the patient’s lived experience, I think there is an even more important critique: reality. Humans are much too complex to reduce down to a single label. There are millions of modifying factors, genetic, biochemical, and social, that modify diseases such that a “single disease” is actually quite different for different people. Added to that is the substantial obscurity of what medical science doesn’t yet know, and what might actually be unknowable (such as the inherently subjective experience of consciousness). Finally, we have to consider the inherent uncertainty of our tests, including history and physical, that mean that, at best, any diagnosis floats in a cloud of probabilities. All of this supports the authors’ underlying premise: we must stop emphasizing the arrival at a final diagnosis in medical education.
Pennington R, Cooper A, Edmond E, Faulkner A, Reidy MJ, Davies PSE. Injuries in quidditch: a descriptive epidemiological study. International journal of sports physical therapy. 2017; 12(5):833-839. PMID: 29181260 [free full text]
Clearly this is the most important paper of the month. These authors distributed a survey to all active quidditch players in the United Kingdom in order to determine the incidence, type, and severity of injuries sustained while playing quidditch. The response rate wasn’t great, but the 348 respondents were relatively serious quidditchers, playing a mean of 4.28 hours a week. There were 315 injuries reported among 180 “athletes” over the year of interest (all self-reported). It was an average of 27 days before players were able to play again after their injury. Concussions and upper extremity injuries were the most common observed. Concussion were more common among females than males. OK – that is as far as I can get treating this like a real paper. Everyone involved here realizes how ridiculous you look running around with a broom between your legs, right? Perhaps the most surprising fact in this paper is that there is a national regulatory body for quidditch in the United Kingdom.
Bottom line: This is just ridiculous. If I catch anyone running around with a broom between your legs, I will mock you endlessly. Seriously – just look at the kids in this video:
Cheesy joke of the month
What does a grape say when it’s stepped on?
Nothing. It just lets out a little wine.
Justin Morgenstern. Articles of the month (March 2018), First10EM, 2018. Available at: