Archive for the Clinical Updates Category

Steve Walker’s Update: Tranexamic Acid in Trauma.

CLICK HERE FOR PDF FILE: Tx ACID in TRAUMA

CLICK THIS LINK FOR .DOC FILE: Tx ACID in TRAUMA

Epistaxis and Tranexamic acid

A new and rapid method for epistaxis treatment using injectable form of tranexamic acid topically: a randomized controlled trial.

Author: Zahed R, Moharamzadeh P, Alizadeharasi S, Ghasemi A, Saeedi M.

Reference: Am J Emerg Med. 2013 Sep;31(9):1389-92. doi: 10.1016/j.ajem.2013.06.043. Epub 2013 Jul 30.

Summary: This randomised controlled trial compared tranexamic acid with anterior nasal packing for patients with anterior epistaxis presenting to ED. 216 subjects with epistaxis were randomised to the injectable form of tranexamic acid (500 mg in 5 ml) applied topically, or anterior nasal packing with pledgets coated with tetracycline ointment. Outcome measures were time to cessation of bleeding, length of hospital stay (hours), and re-bleeding rates at 24 hours and 1 week. Patient satisfaction with treatment was rated on a 1-10 scale. Tranexamic acid was superior to anterior nasal packing for arresting bleeding at 10 minutes; 71 vs. 31.2% respectively (OR 2.28, 95% CI 1.68-3.09, p < 0.001) and discharge within 2 hours; 95.3 vs. 6.4% (p < 0.001). No difference was observed in between-group rates of re-bleeding at 24 hours; 4.7 vs. 11% (p = 0.128). Patient satisfaction with treatment was significantly greater for tranexamic acid compared to anterior nasal packing; 8.5 vs. 4.4 (p < 0.001).

Comment: The study showed good results, control of bleeding within 10 mins (71%) and discharged within 2hours(95%). More studies required for confirmation.

IS IT TIME TO CHANGE THE WAY WE WORKUP SAH?

IS IT TIME TO CHANGE THE WAY WE WORKUP SAH?

The workup for a possible SAH is a topic of much interest to ED doctors. The problem is the condition is fairly rare, the potential consequences of a missed SAH are devastating, and the workup remains problematic.

The LP in particular is a cause of much angst. Most patients are apprehensive about the procedure. It is time consuming, and can be technically difficult in some patients (especially the obese). There are frequent false positives – up to 20% (depending on RBC cut-off used). Spectrophotometry is advocated to help sort out these false positives. This however brings its own problems – spectrophotometry is not universally available, and differentiation between fresh blood (traumatic LP) and older blood (SAH) necessitates a 12 hour delay to do the LP.

Given all this, it is fair to say a patient awaiting a CT for a possible SAH is not the most popular handover!

There are 4 conditions we need to consider

  1. An incidental aneurysm. It is estimated that 4-6 % of the population have an intra-cranial aneurysm. Fortunately the vast majority of these will never cause problems and (as with prostate cancer), far more people will die with an aneurysm than will die because of the aneurysm.
  2. A symptomatic enlarging aneurysm which has not ruptured. This can be a cause of a headache, or occasionally a cranial nerve palsy (classically 3rd nerve). We want to find these as we believe a painful (enlarging) aneurysm is at significantly increased short term risk of rupturing – as with a painful enlarging AAA.
  3. An aneurysm which has ruptured and caused a SAH. This is the one we all think about. Some people are lucky and get a small warning bleed prior to a second larger bleed. We definitely want to catch this group. Large bleeds have a high mortality, and there is a high risk of permanent neurological damage if it is not fatal.
  4. A non-aneurysmal SAH. That is, a SAH arising from an angiographically normal artery. These can present like an aneurysmal SAH, with a sudden severe headache. However there is not much we can do about these bleeds – we can’t find the bleeding point, and we can hardly go around clipping off normal Circle of Willis arteries. Fortunately this condition has a better natural history and more benign long term prognosis than aneurysmal haemorrhages.

So we definitely want to diagnose 2 and 3. These are the conditions a neurosurgeon (or interventional radiologist) can intervene to change short term outlook.

It is probably helpful to know about 1 and 4. The patient can be advised they have an aneurysm or a bleed, they can be counselled to stop smoking, and hypertension (and other vascular risk factors) can be closely managed.

But the question we want to ask is “Does the patient have an aneurysm which has either bled, or which might bleed in the near future, and which is amenable to intervention?” This is the real question underlying our workup for ? SAH.

Prior to CT, the only way of diagnosing an aneurysm was by conventional angiography. This procedure has always carried significant morbidity and even mortality, and therefore was not a procedure to be undertaken lightly. LP was therefore used to risk stratify the patient. If there was no bleed, then it was not appropriate to expose the patient to the hazards of angiography. Only if there was a SAH was the risk of angiography justified. So we looked for the bleed to help decide if we wanted to look for the aneurysm.

Early generation CT scanners changed this a bit. They were good enough to find a large bleed, and were sometimes able to see a small bleed. They were not good enough to reliably find the aneurysm – especially if IV contrast was not used. So the rationale for CT was to find a bleed (rather than an aneurysm).  In addition, CT sometimes found another diagnosis (tumor, intra-cerebral bleed), and also helped exclude a space occupying lesion that would preclude LP. Because early CT missed small SAH, LP remained entrenched as part of the ED workup. So the algorithm then became CT, LP if CT negative, and then angiography if LP positive. From an ED perspective, the job was still to find a bleed, and admit the patient under someone who would go looking for an aneurysm. And so the ED literature is focused on the hemorrhage rather than the aneurysm.

Newer generation CT’s are much better at finding small bleeds. One large study has suggested the sensitivity is 100% within 6 hours of the bleed. If a patient presents with a headache within 6 hours and a good quality CT is performed and is read as normal by an experienced radiologist, then you are done. No LP. Some people are less confident that the sensitivity can be 100%. But most people agree it is pretty close and the need for a LP today is much reduced. Note you are still left doing an LP if the CT is performed more than 6 hours after headache onset.

So right now, most of us are doing a CT and doing this ASAP, and sometimes doing a delayed (12 hour) LP to sort out delayed presentations or perhaps a particularly high risk history. I think that is the state of play at present. Again, we are more intent on finding the bleed than the aneurysm.

However I suspect there is another chapter to be written in this story. The aneurysm (including a high risk non-ruptured aneurysm) is more important than the bleed itself. At present, our focus is perhaps too much on the bleed and not enough on the aneurysm. The original intent of the LP was to screen which patients underwent angiography. But the question the neurosurgeons always wanted to answer was about finding an aneurysm they could do something about, not finding the blood per se.

With current CT, we now have the option of going after the aneurysm. CT angiography has similar sensitivity to conventional angiography, is quick, and is non-invasive. So should we just do the CT and CT angiography for all SAH workup? If there is no aneurysm, then maybe you are done. Perhaps there is little point doing a LP looking for a bleed if there is nothing to be done (or that can be done) for it. The neurosurgeon (interventional radiologist) can do nothing for a non-aneurysmal bleed. They can only do something about an aneurysm.

There are pros and cons to such an approach:

Pros:

  1. No more LPs. No more admitting patients to EMU for someone else to do an LP the next day. Even if the story is good. Even if the headache was 8 hours ago. If there is no aneurysm, then it doesn’t matter.
  2. Quick and easy. The patients will like it. Busy EDs will like it.
  3. If the patient has an aneurysm, it is probably worth knowing about. Stop smoking. Watch your BP. And do come to hospital quickly if you ever get a really bad headache.
  4. It is easier for us to manage the 5% of patients with a real (but incidental) aneurysm than the 20% with a traumatic LP.
  5. May find other conditions. We have had a missed carotid dissection in a 30ish year old female. She did badly. Her CT was normal. However a CT angiography may have found this.
  6. The small population of patients who present repeatedly with high risk sounding headaches don’t require comprehensive evaluation for a SAH each time. If they didn’t have an aneurysm 2 months ago, they don’t have an important SAH (that we can do something about) today.

Cons:

  1. Need for IV contrast. This is not usually an issue as we are mostly looking at middle aged (rather than elderly) patients. However it will sometimes be a factor (especially with increased rates of diabetes in this population)
  2. Increased radiation. A 2nd scan with contrast after an initial non-contrast scan. Again, this is probably not a huge problem in the middle aged, but will be important in younger patients.
  3. The biggest concern may be labelling 5% or so of patients as having an aneurysm. It is probably some patients will be made anxious about being told they have an aneurysm. This knowledge may have implications for certain occupations (e.g. pilots), and also for life insurance or travel insurance (given the “duty to disclose” obligations of these policies).

On balance, I suspect this is the way we will go. Patients want a quick answer with minimum short term risk and discomfort. Doctors want quick answers, and want to be safe from medico legal risk.

With ongoing advances in CT, with increased availability of MRI and MRA, with EDs struggling with increased patient numbers, and with the increasing need to sort things out as efficiently as possible, I think all the drivers will push this in one direction only.

To people with a different view about this, I offer the following 5 letters. CT KUB.

Dr Steve Walker, Staff Specialist, Nepean Emergency Department.

TECHNOLOGY SOMETIMES INTRODUCES NEW PROBLEMS AND DANGERS

TECHNOLOGY SOMETIMES INTRODUCES NEW PROBLEMS AND DANGERS

Quite a few months back I was supervising a registrar intubating a patient using the C-MAC. The patient was a middle aged male who had a decreased conscious state following an OD. Apart from being somewhat overweight, there were no predictors of a difficult intubation.

Preparation and pre-oxygenation were all standard. However intubation was initially unsuccessful. The C-MAC screen showed a good (great) view of the larynx, but the registrar was unable to bring the tip of the tube into the field of view, and the tube passed down the esophagus each time it was (blindly) advanced. Attempts to intubate were ceased after the patient began to desaturate. He was easily ventilated with a bag and mask, his saturations promptly normalized, and there was no adverse outcome. So no real problem. I subsequently intubated the patient with a conventional laryngoscope, which provided a grade 1 view.

Later that evening I was having a coffee with the registrar. We tried to work out how the C-MAC had turned a grade 1 view into a patient unable to be intubated. Bearing in mind that the C-MAC is claimed to make intubation safer and easier, is promoted as an invaluable teaching tool, and some advocates claim it is now “standard of care” and predict the end of conventional laryngoscopy.

It struck me that conventional laryngoscopy is a sequential left hand and then right hand skill:

  1. You use your left hand to insert the laryngoscope and then manipulate the blade in order to provide a good view. Sure you might extend the head or externally manipulate the larynx with your right hand. But it is primarily a left hand task. Once you have a good view, you often relax a bit. Nothing can go wrong now. Just keep that view.
  2. The act of passing a tube (or bougie) using your right hand – while keeping your left hand still so as to maintain your view.

I believe this is almost a subconscious process reinforced over the years. Get a view with your left hand, keep your left hand perfectly still, and then intubate the patient. Simple.

If you use the C-MAC as a conventional scope (ie you use direct vision to look down the mouth and don’t look at the screen), then the above still holds.

If however you look at the screen, the above all changes – possibly without you recognising it.

The C-MAC is designed to create a good view. And it does this very well. You can pretty much insert it however you want, and you will get a good view of the larynx. As seen from the lens on the blade. This may however be very different from the view you would see looking down the patients mouth – which is the path the tube has to follow. You may have a grade 1 view as seen from behind the patients tongue, but a grade 4 view using direct vision.

So now you have got a great view on the screen. Except there is now a disconnect between what you are seeing on the screen, and what happens next. You never see the tube appear on the screen. However because you still have a great view, you don’t realise you need to manipulate the blade to provide a clear path for the tube. Subconsciously, the path must be fine (and thus nothing for the left hand to do) as the view is good. I think this is what happened in this case.

I subsequently spoke to a couple of anaesthetic colleagues. They confirmed this is what most likely happened, although one explained it a little differently as “failure to control the tongue.” We have all been taught to go down the right side of the tongue and to sweep / lift it out of the way in order to obtain a clear view. You have to control the tongue. However you can skip this step using the C-MAC screen – the screen effectively puts you somewhere behind the base of the tongue and so you don’t have to control it. You have a good view even if the airway superior to the lens is obstructed by the tongue. If the tongue has fallen against the posterior pharyngeal wall, it will helpfully guide an advancing tube into the esophagus.

These anaesthetists confirmed the accepted practice when using the C-MAC is for the intubator to use direct vision. The screen is for other people to watch. The intubator not only has to have a view of the larynx, but needs to have a clear view of the entire path the tube needs to follow.

 

So with that long preamble, I think there is a broader issue here. New technology and new devices can certainly help us to our jobs better than before. No doubt about that. But as with this case, it can also introduce new problems or risks or traps. And these are not always immediately obvious.

The salespeople promoting the technology have an incentive to talk up the positives, rather than pointing out the potential problems (and in all fairness they may not be aware of the problems – how many C-MAC salespeople intubate patients?) And even well meaning colleagues enthusiastic about some new device (and with no commercial conflict of interest) may gloss over the dangers – perhaps because they are so obvious to them they don’t require discussion. One anaesthetist was puzzled why the registrar was ever looking at the screen in the first place – “But everyone knows you need to use it like a conventional scope.” I guess someone forgot to tell the registrar and myself.

So we need to know how to use new devices and new technology safely. This means we need to understand how it actually works, the subtle ways it can change things, and we need to be aware of the hazards and traps.

Dr Steve Walker, Staff Specialist, Nepean Emergency Department.

Another Interesting Resource

The Royal College of Pathologists Australasia, has come up with this website http://www.rcpamanual.edu.au, which summaries the pathology tests needed for various clinical problems. This is not only helpful in doing the relevant tests but also to avoid doing unnecessary tests. There are useful summary of signs and symptoms for various diseases and also few pathology decision tool. Worth having a look.
Click this link http://www.rcpamanual.edu.au

Pearls from Emergency Medicine Abstracts 2013

EMA Pearls June 2013

Pearls this year’s Emergency Medicine Abstracts Course June 2013. Author: Colin Xavier

And Steve Walker’s take on the course:

S.Walker Emergency Medical Abstracts June 2013 Report

 

A Clinician’s Guide to Australian Venomous Bites and Stings

BioCSL has released A Clinician’s Guide to Australian Venomous Bites and Stings: incorporating the updated CSL Antivenom Handbook, designed to educate and provide emergency reference material to doctors.
Author – Professor Julian White.

All medical professionals can a get a free copy of the handbook by emailing [email protected] and providing their postal address and AHPRA number. Free copy of the book will be posted to your home address.

Book worth reading.

Vijay

Blackouts and Syncope

Nice video to brush up on this important/ common situation we face almost everyday…. This video is created by an EM trainee at Ireland, Dr Andy Neil.
Please click here for the video.

Credit: Dr Andy Neil.

Ring Removal using Oxygen Mask Strap

This technique is not new to the world; we have used this technique for ring removal with a suture material or wire with some success. Check out this nifty trick on ring removal by Dr. Simon Carley (Centre For Evidence Based Emergency Care at Manchester Metropolitan University) using Oxygen Mask Strap. Try it out next time.

 

Anterior Epistaxis First Aid in ED

A simple trick to help you manage your epistaxis patients in the ED.
For an alternative device check out Cliff Reid’s article from 2001 here: http://t.co/ADkrXifQ