Articles of the month (November 2015)

Here is this month’s summary of my favorite reads from the medical literature…

Bronchiolitis – it will take your breath away

Willwerth BM, Harper MB, Greenes DS. Identifying hospitalized infants who have bronchiolitis and are at high risk for apnea. Ann Emerg Med. 2006;48:(4)441-7. PMID: 16997681

Its that time of year. Some children are beginning to hold their breath in anticipation of Christmas. Or, maybe that was an apneic spell from bronchiolitis? Which children are at risk? This is a retrospective cohort of 691 children less than 6 months old who were admitted to the hospital for bronchiolitis looking at risk factors associated with apnea. The authors found that full term babies less than 1 month old, preterm babies less than 48 weeks post-conception, and babies whose caregivers had already witnessed an apnea spell were at higher risk for further apnea spells. Overall 19 (2.5% 95%CI 1.7-4.3) children had apnea spells while admitted, and all 19 met one of the criteria above.

Bottom line: 2.5% is relatively low risk, but breathing is relatively important. I would have the pediatricians review the kids that fall into these categories.

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More bronchiolitis and the need for oxygen

Cunningham S, Rodriguez A, Adams T. Oxygen saturation targets in infants with bronchiolitis (BIDS): a double-blind, randomised, equivalence trial. Lancet (London, England). 386(9998):1041-8. 2015. PMID: 26382998

This is a multi-center, randomized, controlled trial of children aged 6 weeks to 12 months admitted to hospital with bronchiolitis. This children were either placed on a standard sat probe or one that was altered so that a sat of 90% would display as 94%. Staff were instructed to provide oxygen to any child with a sat less than 94%. (94% seems like a pretty high target. I am more interested in whether we should be starting oxygen at say 92% or 88% or even lower.) I think they chose a pretty poor primary outcome: time to resolution of cough. For what it’s worth, it was equivalent, but did we really think oxygen could cure cough? Some secondary outcomes were also not affected, but none capture why I give oxygen. Oxygen is given when children are approaching the steep portion of the oxygen-hemoglobin dissociation curve to prevent precipitous drops, desaturations, and bad outcomes. The authors do report no change in ‘adverse events’, but if you look at the supplement, respiratory adverse events were things like cough and otitis media. Although I believe we probably over-treat bronchiolitis, this is another in a slew of papers that fails to actually prove that it is safe to withhold oxygen or discharge patients with low oxygen saturations.

Bottom line: Oxygen saturation is still an important parameter to monitor in bronchiolitis. We don’t know the ideal saturation to target.  

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Children inhaling salt water – no, not drowning, but bronchiolitis treatment

Silver AH, Esteban-Cruciani N, Azzarone G. 3% Hypertonic Saline Versus Normal Saline in Inpatient Bronchiolitis: A Randomized Controlled Trial. Pediatrics. 2015. PMID: 26553190

This is a randomized, double-blind, controlled trial from a single pediatric hospital comparing 4 ml of either 3% saline or 0.9% saline nebulized every 4 hours in 227 children under 12 months old with bronchiolitis. There was no difference in any of the many outcomes they measured, including length of stay, ICU admission, readmission, and objective respiratory findings. Of course, it’s possible that normal saline is more therapeutic than no treatment – but, come on, you know that nothing works in bronchiolitis.

Bottom line: No treatments work in bronchiolitis. Do you think we will ever come to terms with that?

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It might just be the season, but it seems like I am obsessed with wheezing kids

Cronin JJ, McCoy S, Kennedy U. A Randomized Trial of Single-Dose Oral Dexamethasone Versus Multidose Prednisolone for Acute Exacerbations of Asthma in Children Who Attend the Emergency Department. Annals of emergency medicine. 2015. PMID: 26460983

I have covered dexamethasone versus prednisone for asthma before, but here is another RCT. In 245 pediatric patients (aged 2-16) with asthma, they compared a single dose of dexamethasone (0.3mg/kg) to prednisolone (1mg/kg) for 3 days. Their primary outcome was a PRAM score on day 4 and there was no difference between the two.

Bottom line: I will continue using the easier single dose dexamethasone over prednisone.

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More shots fired in the continuing Roc versus Sux RSI battle

Tran DT, Newton EK, Mount VA, Lee JS, Wells GA, Perry JJ. Rocuronium versus succinylcholine for rapid sequence induction intubation. The Cochrane database of systematic reviews. 10:CD002788. 2015. PMID: 26512948

This one is going to ruffle a few feathers. Let’s start with the author’s conclusions: “Succinylcholine created superior intubation conditions to rocuronium in achieving excellent and clinically acceptable intubating conditions.” This is a cochrane review that includes 50 trials covering 4151 patients. For “excellent intubating conditions” succinylcholine was superior to rocuronium (RR 0.86 95%CI 0.81-0.92). The problem with this conclusion is the significant heterogeneity in the included studies. For me, the biggest concern is varying doses. In fact, the authors even conclude that if you use 1.2mg/kg of rocuronium (the appropriate dose for RSI) there was no difference between roc and sux. Unfortunately, they make the erroneous conclusion that sux is still better because it has a shorter duration of paralysis. In emergent airways, short paralysis is not a good thing.

Bottom line: Ignore the conclusions, rocuronium at a proper dose (1.2mg/kg) is a great paralytic for RSI.

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One of my favorite myths to rant about – and apparently some very smart people out there agree with me

Swaminathan A, Otterness K, Milne K, Rezaie S. The Safety of Topical Anesthetics in the Treatment of Corneal Abrasions: A Review. The Journal of emergency medicine. 49(5):810-5. 2015. 26281814

I spoke about topical anesthetics for corneal abrasions at rounds earlier this year. (My handout from that talk can be found here.) This is a systematic review looking at the same topic. They identify 2 emergency department studies and 4 ophthalmology studies (after a procedure called photorefractive keratectomy – essentially a iatrogenic corneal abrasion) that prospectively evaluated the use of topical anesthetics for corneal abrasions.  All the studies were small. Topical anesthetics resulted in no complications. Overall, topical anesthetics appear to be effective, with clinically and statistically significant pain score reduction in 5 of 6 studies.

Bottom line: Treat your patient’s pain. A short course of topical anesthetic is probably safe and almost certainly effective for corneal abrasions.

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Acute HIV – a diagnosis I am probably missing

Rosenberg ES, Caliendo AM, Walker BD. Acute HIV infection among patients tested for mononucleosis. The New England journal of medicine. 340(12):969. 1999. PMID: 10094651 [free full text]

Early HIV infection presents as a mononucleosis-like infection, making it very difficult to diagnose. Although I generally dislike using the emergency department for public health screening, if HIV is not diagnosed during this initial stage, many years may pass before it is diagnosed, not only hurting the patient, but also putting their many contacts at risk. This is a letter to the editor describing a study where they retrospectively took all blood samples that were sent for epstein barr virus at Massachusetts General Hospital and tested them for HIV RNA. They found that 1.2% (7/563) has an acute HIV infection and another 0.8% (4/563) had chronic HIV.

Bottom line: This is well above the threshold for screening for HIV. Perhaps monospot and HIV testing should be paired?

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1 more: Non specific viral illness or acute HIV?

Pincus JM, Crosby SS, Losina E, King ER, LaBelle C, Freedberg KA. Acute human immunodeficiency virus infection in patients presenting to an urban urgent care center. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 37(12):1699-704. 2003. PMID: 14689354 [free full text]

Sticking with the same topic, these authors tested all patients presenting with viral symptoms and 1 or more HIV risk factors at their urban urgent care centre for HIV. (They were very broad with their HIV risk factors: any sexual contact, any injection drug use, any crack use, or any alcohol use in the last 2 months.) Of the 499 patients included, 5 (1.0%) were diagnosed with an acute HIV infection and another 6 (1.2%) were diagnosed with chronic HIV. They did not have any false positives.

Bottom line: Depending on your work environment, it may be worth screening for HIV in patients with viral illnesses.

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It’s all about that aVL

Bischof JE, Worrall C, Thompson P, Marti D, Smith SW. ST depression in lead aVL differentiates inferior ST-elevation myocardial infarction from pericarditis. The American journal of emergency medicine. 2015. PMID: 26542793

Is that Inferior ST elevation indicative of STEMI? Or is it pericarditis? aVL might hold the key. This is a retrospective look at 3 different groups. Of 154 patients with a final diagnosis of inferior STEMI, all 154 had some degree of ST depression in aVL. Of the 49 patients with pericarditis, 49 had some degree of inferior ST elevation, but none had any ST depression in aVL. There was a third cohort with subtle inferior ST elevation (less than 1mm) but confirmed vessel occlusion on cath. Of these 54 patients, 49 had ST depression in aVL. The authors conclude that ST depression is highly sensitive for inferior STEMI and specific for pericarditis.

Bottom line: I will certainly look at aVL, but would love to see this repeated prospectively

If you want to read more about this and see some example ECGs, check out the blog post by senior author Dr Steve Smith: http://hqmeded-ecg.blogspot.ca/2015/11/new-paper-published-on-significance-of.html

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Cold – the pure green coffee (ask Dr. Oz) of the brain

Andrews PJ, Sinclair HL, Rodriguez A. Hypothermia for Intracranial Hypertension after Traumatic Brain Injury. The New England journal of medicine. 2015. PMID: 26444221 [free full text]

Another in the cold brain is not healthy brain category. This is a multicentre, randomized controlled trial of 387 adult patients (out of 2498 screened patients) with traumatic brain injury and persistently elevated ICP after sedation, elevation of the head of the bed, and mechanical ventilation. They were randomized to either get or not get hypothermia (target between 32 and 35 degrees Celsius for 48 hours.) The trial was stopped early for harm. Their primary outcome (neuro status based on the extended Glasgow outcome scale) was worse in the hypothermia group (OR 1.53 95%CI 1.02-2.30). Mortality was also worse (OR 1.45 95%CI 1.01-2.10). The biggest problem with the study was that they included patients up to 10 days after injury, which could just be too late for the magical power of cold to work.

However, I don’t think we should find this too surprising. Hypothermia has been tried for many conditions, including TBI, in the past with limited success. The general failure of hypothermia is one of the reasons to remain highly skeptical of those two small, biased trials that indicated that it worked in cardiac arrest. It may be reasonable to continue using hypothermia for the time being, but if anyone gets around to actually repeating the hypothermia versus placebo trial in cardiac arrest, we shouldn’t be surprised if it turns out to have no effect.

Bottom line: No hypothermia for trauma

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Dual antiplatelets for stroke/TIA?

Wang Y, Pan Y, Zhao X. Clopidogrel With Aspirin in Acute Minor Stroke or Transient Ischemic Attack (CHANCE) Trial: One-Year Outcomes. Circulation. 132(1):40-6. 2015. PMID: 25957224

This is one of those trials that will get talked about, but I worry we will over apply the results. This is a large multicenter randomized trial in which 5170 Chinese patients with high risk TIA or minor CVA were randomized to either clopidogrel 75mg daily for 3 months plus aspirin 75 mg daily for 21 days or aspirin 75 mg daily for 3 months. The primary outcome of stroke at 1 year occurred in 10.6% of the combo group as compared to 14.0% of the aspirin alone group (hazard ratio, 0.78; 95% confidence interval, 0.65-0.93; P=0.006). Bleeding was the same in both groups. I think there are a few important caveats. First, you should question the generalizability of these results to your patients unless you work in China, because the rates of smoking in China are unlike those anywhere else in the world. Second, it is unlikely that the combination of ASA and clopidogrel has the same bleeding rates as ASA alone. That doesn’t fit well with previous studies or general experience. This should remind us that RCTs are usually not well designed to identify harms and will often over estimate the benefit to harm ratio.

Bottom line: I would not be changing my practice to include dual antiplatelet therapy based on this study alone.

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Great ultrasound tip – try using both probes for IUP

Tabbut M, Harper D, Gramer D, Jones R. High-frequency linear transducer improves detection of an intrauterine pregnancy in first trimester ultrasound. The American Journal of Emergency Medicine. Article in Press. PMID:

Traditionally, we are taught to use a curvilinear abdominal probe when performing transabdominal ultrasound to detect first trimester pregnancy. This study looked at adding the high frequency linear transducer after failure to identify IUP with the standard transducer. Of 81 initial scans, 27 patients did not have an IUP visualised with the curvilinear probe. Of those, 9 (33%) were found to have an IUP by using the linear probe.

Bottom line: It’s probably worth trying the linear probe if you can’t see an IUP with the curvilinear.

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Cricoid pressure: the evidence?

Algie CM, Mahar RK, Tan HB, Wilson G, Mahar PD, Wasiak J. Effectiveness and risks of cricoid pressure during rapid sequence induction for endotracheal intubation. The Cochrane database of systematic reviews. 11:CD011656. 2015. PMID: 26578526

This is a Cochrane review designed to look for any RCT evidence of the value of cricoid pressure in either emergent or elective airways. The review really says nothing of value, because there is no evidence to review. So why include it? Because sometimes it’s important to know that there is no evidence to review. If anyone ever gets too dogmatic on either side of the cricoid pressure debate, they should probably be ignored.

Bottom line: There is no evidence supporting the use of cricoid pressure. I abandoned it a long time ago, but I would be happy to see an RCT done to confirm or contradict my current practice.  

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Sex is better than flomax!

Doluoglu OG, Demirbas A, Kilinc MF. Can Sexual Intercourse Be an Alternative Therapy for Distal Ureteral Stones? A Prospective, Randomized, Controlled Study. Urology. 86(1):19-24. 2015. PMID: 26142575

By now, everyone should know that tamsulosin does not help patients with kidney stones, but that doesn’t mean we should give up on our patients. Is there anything else we can do to help? In this randomized, controlled study 75 adult patients with nephrolithiasis were randomized to either 1) being asked to have sex at least 3-4 times a week, 2) tamsulosin 0.4mg a day, or 3) usual care. There were no placebos (although if you can come up with a placebo version of sex I want to hear about it.) The mean time to stone expulsion was only 10 days (95%CI 4.2-15.8 days) in the sex group, versus 16.6 (95%CI 8.1-25.1 days) with tamsulosin and 18 (95%CI 15.5-23.5 days) with usual care (p=0.0001). I foresee a large number of men looking for medical notes explaining this therapy to their wives. Perhaps there may even be a few malingerers without stones looking to get this prescription?

Bottom line: Sex is good

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When is dementia not dementia?

Djukic M, Wedekind D, Franz A, Gremke M, Nau R. Frequency of dementia syndromes with a potentially treatable cause in geriatric in-patients: analysis of a 1-year interval. European archives of psychiatry and clinical neuroscience. 265(5):429-38. 2015. PMID: 25716929

Dementia is a horrible diagnosis that we can’t do anything about. But is it always? In this retrospective review of patients admitted to hospital with dementia, the authors searched for reversible causes. Of the patients previously diagnosed with dementia, the authors were able identify a potentially reversible cause in 23%. Of the newly diagnosed dementia, 31% had potentially reversible causes. The common reversible causes included low B12, depression, alcoholism, and normal pressure hydrocephalus. I wouldn’t hang my hat on any of the numbers, given the retrospective nature of the trial, but this should serve as a reminder that we might be able to help some of these patients. If you can reverse dementia, that is a true save.

Bottom line: Some dementia is reversible. These causes should be searched for.

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Dikembe Mutombo is wagging his finger – Block!

Riddell M, Ospina M, Holroyd-Leduc JM. Use of Femoral Nerve Blocks to Manage Hip Fracture Pain among Older Adults in the Emergency Department: A Systematic Review. CJEM. 2015. PMID: 26354332

My appraisal may be biased because I love nerve blocks, especially when I can do them with an ultrasound. This is a systematic review of randomized control trials asking the question: does the use of a femoral nerve block reduce pain, opioid use, delirium, or improve function in adults over 65 with an acute hip fracture. They found 7 RCTs covering a total of 224 patients – so the studies were small. Also, only one trial was placebo controlled. The remainder compared the nerve block to opioids. The authors appropriately did not perform a meta-analysis, as the studies were heterogenous, so a single numerical summary is not possible. The best summary is that the nerve block group consistently had both statistically and clinically significant reduction in their pain scores as compared to placebo, used less opioid, and had fewer complications.

Bottom line: Nerve blocks work great for hip fractures. We should be using these.

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From Dikembe Mutombo to Mark Spitz

Browne KM, Murphy O, Clover AJ. Should we advise patients with sutures not to swim? BMJ (Clinical research ed.). 348:g3171. 2014. PMID: 24859900

I always find it a little frustrating when my non-medical friends ask me questions about medicine that seem really simple, but that I honestly can’t answer. What exactly did I learn in all those years of school? The most recent question was: “when can I started swimming again after getting stitches?” This is a review, if you can call a search that unearthed only a single case report a review, trying to answer that question. Yes, apparently in the entire medical literature there is a single reported case of a wound infection that occurred after swimming – and that was in a hospital rehab pool which is probably more likely to be colonized with strange bugs than your average swimming pool. The authors try to shape this into a practical answer, but I think the best answer we can give is “we don’t know”. Early showering after surgery has been shown to be safe, so maybe you could extrapolate from that.

Bottom line: There is much in medicine that we simply don’t know

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Which is more important: rinsing your dishes before they go in the dishwasher, or rinsing out the inside of an abscess?

Chinnock B, Hendey GW. Irrigation of Cutaneous Abscesses Does Not Improve Treatment Success. Annals of emergency medicine. 2015. PMID: 26416494

I was never taught to irrigate abscesses in residency. It was only this year that I discovered that this has been suggested by numerous guidelines. But not so fast. This is a non-blinded RCT of 209 patients with cutaneous abscesses randomized to irrigation or no irrigation. There was no difference in the need for further treatment (I&D, antibiotic change, or admission) at 30 days between the 2 groups (15% vs 13%). Unfortunately a huge number of these patients were put on antibiotics (91% in the irrigation and 73% in the no irrigation group), which we know are unnecessary in most abscesses, but contaminate the results here.

Bottom line: This wasn’t common practice where I trained and we never saw many bouncebacks. I won’t start irrigating abscesses based on this.

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Should the Bee Gees pause for a breath (at 30:2)?

Nichol G, Leroux B, Wang H. Trial of Continuous or Interrupted Chest Compressions during CPR. The New England journal of medicine. 2015. PMID: 26550795 [free full text]

“Well, you can tell by the way I use my walk, I’m a woman’s man. No time to talk… Ah,ha,ha,ha, stayin’ alive”. This is a large randomized controlled trial of 23,711 adult patients with out of hospital cardiac arrest comparing the standard 30:2 ratio of chest compressions to rescue breaths, to continuous chest compressions at 100/min with 10 asynchronous breaths a minute. The primary outcome of survival to hospital discharge was identical, 9.0% in the continuous chest compression group and 9.7% in the 30:2 group. Neurologically intact survival was 7.0% and 7.7% respectively. The biggest issue with the data is that everyone got extremely high quality CPR, and the compression fraction was almost identical in both groups, so it would have been difficult to demonstrate any difference.

Bottom line: Personally, I like continuous compressions with asynchronous breaths more, but this trial supports whatever you are comfortable with as long as you are doing high quality CPR.

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A quick and easy rule out blood test for aortic dissection? Get real

Asha SE, Miers JW. A Systematic Review and Meta-analysis of D-dimer as a Rule-out Test for Suspected Acute Aortic Dissection. Annals of emergency medicine. 66(4):368-78. 2015. PMID: pubmed

This is a systematic review and meta-analysis looking to determine the diagnostic accuracy of D-dimer as a rule out test of aortic dissection. In total they found 5 studies including a total of 1600 patients. My first point of concern is that 1035 of those patients came from a single study, which could potentially dominate a meta-analysis, and that study was not designed to test the accuracy of D-dimer. In fact, the study enrolled 1455 patients, but only 1035 were counted in this meta-analysis, because the other patients never even had a D-dimer drawn. The results they present are pretty impressive, with a pooled sensitivity of 98% (95%CI 96-100%), specificity of 42% (95%CI 39-45%), negative likelihood ratio of 0.05 and positive likelihood ratio of 2.11. However, I would be very careful interpreting those results. Not only are the majority of the patients from a registry where D-dimer didn’t have to be drawn, but these were almost all patients admitted to CCUs, so very different from our ED population. Finally, although you would be using this test to try to avoid CTs, the poor specificity in a lower risk population could actually paradoxically lead to increased CT usage, much like D-dimer for PE.

Bottom line: This study isn’t enough to support D-dimer to rule out aortic dissection in the ED.

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“Unreasonable haste is the direct road to error” – Moliere

Fanari Z, Abraham N, Kolm P. Aggressive Measures to Decrease “Door to Balloon” Time and Incidence of Unnecessary Cardiac Catheterization: Potential Risks and Role of Quality Improvement. Mayo Clinic proceedings. 2015. PMID: 26549506

An important lesson in unintended consequences. We know that short door to balloon times are important for STEMI patients. This is a study from a single hospital where they instituted a number of measures to decrease the door to balloon time. And it worked! Well – they managed to get the door to balloon time decreased by 15 minutes, which is excellent. However, it’s important to measure patient oriented outcomes and in this cohort the false positive STEMI rate rose from 7.7% to 16% and there was an increased mortality in this false positive group.

Bottom line: Inappropriate benchmarks can result in physicians rushing, more errors, and patient harms.

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Don’t let an endotracheal tube make your patient worse

Kim WY, Kwak MK, Ko BS. Factors associated with the occurrence of cardiac arrest after emergency tracheal intubation in the emergency department. PloS one. 9(11):e112779. 2014. PMID: 25402500 [free full text]

Emergency physicians love procedures and intubation is one of our favorite. Sometimes this leads to us being a little overzealous about intubating very early, when an immediate airway is not necessary. This is a case control study of 41 critically ill adult patients that had a cardiac arrest after intubation (out of a total of 2404 critically ill patients who were intubated – or 1.7%.) Pre-Intubation hypotension (a systolic blood pressues ≤ 90) was independently associated with post-intubation arrest (OR 3.67 95%CI 1.58-8.55.) The case control design may not provide precise numbers, but I think this is a good reminder that some patients need good resuscitation before we attempt intubation.

Bottom line: Resuscitation before intubation in hypotensive patients

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Cheesy Joke of the Month

There are two cows in a field. The first cow turns to the second and asks, “did you hear about the outbreak of mad cow disease?” The second cow responds: “Good thing I am a helicopter.”

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#FOAMed of the month

Every month this section could probably just be filled with my favorite talks from SMACC. I will try to include some different FOAM in coming months, but these talks were so go that even though I listened to them live, I have listened to them all again at home. This is why I have been telling everyone who will listen they should join me in Dublin in June. The first tickets sold out very fast, but some more will go on sale December 1st at 5pm EST (if my math is right.)

For now, these talks were amazing:

Lessons from the Princess Bride (Amal Mattu)

When to stop resuscitation (Roger Harris)

What is a good death (Ashley Shreves)

Crack the chest. Get crucified. (John Hinds) – I know I have recommended this one before, but it is worth more than one watch.

Dogmalysis and pseudoaxioms (David Newman)

Bouncing back after tragedy (Rob Rogers)

Educational theory for the clinician (Jonathon Sherbino)