Reviews and summaries of the latest Emergency Medicine research papers. We try to cover 10 of the best articles each month. Please visit our website for written summaries and to search past editions:

April 27th, 2019    

New tetanus guidelines


Background: Have you ever seen a case of tetanus? Don't feel bad if you haven't - there were only four in the whole of England during 2016. The disease is admittedly terrible: the muscle spasms can be so severe they cause fractures, and serious complications loss of airway and respiratory arrest. Thankfully, vaccination has made the condition extremely rare in the developed world. But it often feels as though confusion reigns over the best approach to vaccination in the ED... Who needs a booster? Who needs immunoglobulin? What kind of patient? What kind of wound? The Department of Health recently updated their guidance on tetanus immunisation, replacing the 2013 recommendations. Here is the bite-sized BREACH summary of the document...



Department of Health (2018). Tetanus: The Green Book, chapter 30


See for summary tables


April 17th, 2019    

Right ventricle myocardial infarction


Background: A case report in 1974 was the first to mention right ventricle (RV) infarction as a distinct entity, noting that patients with this pathology exhibit "a unique clinical and haemodynamic syndrome". This is because the resulting weakness of the RV makes the patient's cardiac output extremely preload sensitive. They often present in shock and even if they are normotensive initially, giving GTN can precipitate a severe drop in blood pressure or even trigger cardiac arrest. These are an important group of patients to identify!



Thygesen K, Alpert J, Jaffe A, et al. Fourth universal definition of myocardial infarction. European Heart Journal 2019;40(3):237-269



The paper: This is another nugget from the 4th Universal Definition of Myocardial Infarction, published last year. It highlights the necessity of obtaining recordings from supplemental leads in certain patients. They note that an RV infarct is very rarely isolated but usually occurs as part of an inferior STEMI (Up To Date suggests 30-50% of inferior STEMIs have this complication). Supplemental leads V3R and V4R are placed on the right side of the chest, opposite the standard V3 and V4. ST elevation >0.5mm in either of these supplementary leads is considered diagnostic of RV infarction. Other ECG changes suggestive of RV infarction include ST elevation in aVR or V1, but several experts recommend deploying the supplemental leads in every case of inferior MI, because missing an RV infarct can be devastating for the patient.



The bottom line: Be aware of RV infarction as a potential complication of inferior STEMI and actively look for it by deploying supplemental leads. Don't give GTN to these patients! They need IV fluids in the first instance.



Note: Amal Mattu (Cardiology EM consultant at University of Maryland, USA and producer of the excellent ECG Weekly) suggests looking for the following triad to identify patients at risk of RV infarction...

- Chest pain
- Hypotension
- No crackles on auscultation

You need all three because the other main differential for MI + shock is flash pulmonary oedema.



Expert commentary:
"This is really great learning, and the triad is easily memorable."
(Dr Robert Tan, ED Consultant)



More FOAMed on this topic:
Life in the fast lane
Dr Smith's ECG blog (to take things to the next level)
ECG weekly - not quite FOAMed but (I think) the best ECG resource around and it's pretty inexpensive


April 10th, 2019    

Needle-less anaesthesia for mucosal lacerations


Background: It is difficult to treat oral mucosal lacerations in children. They are often terrified, in pain, and won't remain still enough to allow safe delivery of local anaesthetic or fine suturing. Lidocaine can either be injected locally or used in a nerve block, but both of these options are tricky in the paediatric population. The authors of the current paper present a novel approach to achieving satisfactory local anaesthesia.



Nickerson J, Tay ET. Dripped lidocaine: a novel approach to needleless anesthesia for mucosal lacerations. J Emerg Med 2018;55(3):405-7



The paper: A case series of 3 children (aged 2, 8 and 15) who presented with lip lacerations. Each received local anaesthesia by dripping 1% lidocaine into the wound at a rate of 1 drop per second until the wound was saturated with solution. Adequate anaesthesia was achieved after around 5 minutes, and each wound was sutured closed with minimum discomfort. The authors hypothesised that the increased blood supply of the oral mucosa meant that the lidocaine was readily absorbed by the wound and surrounding tissue.



The bottom line: If you have a child with an oral mucosal laceration that needs closing, try dripping lidocaine onto the wound to achieve local anaesthesia.



Note: I have personally tried this 3 times (bringing our 'collective case series' to 6!). Twice it worked like a charm. In the last case, there was some discomfort, but I was able to inject some more lidocaine to eliminate this - the drips certainly helped reduce the pain of injection.



Expert commentary:
"This technique is useful as LAT gel cannot be used on mucus membranes. The only potential risks are swallowing the solution and reaching the maximum dose for weight. Incidentally, there is no hard-and-fast rule about who can close lacerations across the vermilion border - it's purely about the competence of the practitioner and the agreement of the patient / parent."
(Dr Dwynwen Roberts, ED Consultant)



"This is a potentially amazing idea, especially in needle phobic children, ADHD, ASD, etc."
(Dr Mohsin Jafri, Paediatric Consultant)


April 4th, 2019    

Ultrasound for diagnosing retinal detachment


Background: Retinal detachment is one of several sight-threatening conditions seen in the ED. Flashes and floaters are often the first sign that something is amiss, and the standard ED workup involves slit lamp examination and fundoscopy. However, subtle abnormalities are difficult to pick up on fundoscopy, especially in the non-dilated eye. In the FOTO-ED study (2011), ED physicians only performed fundoscopy in 33 out of 350 appropriate cases, and they missed the diagnosis in every one (confirmed by photos taken of the fundus at the time of examination).

Is there a better way to check the back of the eye? The first observational trial of ocular ultrasound in the ED (17 years ago in 2002) found it to be very accurate and since then many more trials have appeared. The average 'bench-to-bedside' period is often quoted as 17 years - has the time come for ocular ultrasound to become common practice?



Gottlieb M, Holladay D, Peksa GD. Point-of-care ocular ultrasound for the diagnosis of retinal detachment: a systematic review and meta-analysis. Acad Emerg Med 2019;00:1-9



The paper: A systematic review that found 11 observational studies with a total of 844 patients. Ocular ultrasound was performed by ED physicians on patients with suspected retinal detachment, and their findings were compared to final ophthalmology diagnosis. They found that ultrasound was 94.2% sensitive and 96.3% specific for the diagnosis of retinal detachment.



The bottom line: Ocular ultrasound is both sensitive and specific for the diagnosis of retinal detachment and, with training, is probably a better examination tool than fundoscopy for this condition.



Note: The Royal College of Ophthalmologists (2010) recommend immediate referral if the patient has "visual field loss or fundoscopic signs of detachment or vitreous haemorrhage". They recommend indirect ophthalmoscopy within 24 hours if there is "no visual field loss, normal visual acuity and normal fundoscopic exam" (i.e. reported flashes and floaters only)...

So where does ocular ultrasound fit into this? If your patient has normal visual acuity and no field deficit, perform ultrasound. If there are signs of detachment, refer them immediately; if not, they can be seen the following day.