Friday, 1 December 2017

Incorporating point-of-care ultrasound into ACLS: Does cardiac activity predict survival?

From the Journal of No Shit comes this study looking at whether cardiac activity on ultrasound during ACLS is associated with improved survival.

This observational study was conducted in 20 ED’s in North America in patients presenting to the ED in PEA or asystole. Ultrasound was performed at the beginning at the end of ACLS and they looked at several outcomes.

793 patients were enrolled. 13 (1.6%) patients survived to hospital discharge (no mention if they were neurologically intact.)

For what it is worth, cardiac activity on initial ultrasound was the variable with the strongest association with survival at every endpoint investigated. In addition, they found 34 pericardial effusions and some patients with suspected pulmonary embolism.

Caution is in order as 3 patients with no initial cardiac activity on ultrasound survived to hospital discharge.

Of course, there could have been some bias as the decision to terminate resuscitative efforts was probably influenced by the ultrasound. In today’s environment, I don’t think blinding the ultrasound would have been ethical.

I think the most valid conclusion is PEA and asystole are extremely terrible prognostic signs regardless. Ultrasound without cardiac activity is also dismal (but not 100% perfect).

I have wondered why so much time & effort was put into answering a research question that seemed so obvious. It’s kind of up there with the parachute study… But I guess point-of-care ultrasound is still in the stage of trying to prove itself worthy.


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Intra-Articular Hematoma Block for Ankle Fracture Dislocation: an RCT

I recently listed to an episode of the Ultrasound Podcast featuring the guru of nerve blocks Dr Mike Stone. This guy sleeps with his ultrasound machine…

With this background, I was shocked to hear that he does not bother with using ultrasound or procedural sedation for reduction of ankle fracture dislocations. He just does a quick ankle hematoma block, “it’s what the orthopaedists would do…”

I’ve done hundreds of hematoma blocks of the distal radius but never considered the ankle. This prompted me to review the medical literature and find the best quality published evidence to support this practice.

Here we go…

This 2008 prospective RCT from New York City randomised patients with ankle fracture dislocations to either intra-articular block or procedural sedation.

What happened?

The authors concluded, “…an intra-articular lidocaine block provides a similar degree of analgesia and sufficient analgesia to achieve closed reduction of ankle fracture-dislocations.” In addition, the average time for reduction and stabilization was faster with the hematoma block.

So, ankle hematoma blocks are great!

Before we get too enthusiastic, consider the following limitations:
  • They only enrolled 42 patients. Yes, 42… Therefore, high risk for type II error and it cannot make adequate claims about safety.
  • It was sloppy; no specified primary outcome, no power calculation, CONSORT guidelines not followed, no mention of ethical approval, junior orthopaedic residents were “indirectly supervised,” some silly comments about “conscious sedation” etc.

So, this is really the best quality evidence we have?

Yes.

However, there is a wealth of published literature on hematoma & intra-articular blocks elsewhere and I think it is reasonable to conclude they are generally safe.

Subsequently, I have tried this technique a couple of times and had great outcomes; complete and long-lasting analgesia with wide awake happy patients. All the while not requiring a resuscitation room and all the resources of a procedural sedation.  I have an “n” of two. More poor-quality evidence?

I would encourage researchers to publish more on ankle hematoma blocks. To be honest, an RCT is probably not necessary to answer this research question. A large prospective case series should be adequate.

So, get injecting and pulling! (Please don’t quote me out of context)



To read more about ankle hematoma blocks, see paper referenced below. To hear Mike Stone talk about this on the Ultrasound podcast, check the link below and go to about the 11 minute mark.

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ECMO for refractory cardiac arrest: the Sydney experience

“Our study is the first multicentre study of ECPR outcomes in Australia. Thirty-seven patients between 2009 and 2016 underwent ECPR across two ECMO referral centres, with an overall survival rate of 35%, and excellent neurologic outcomes in survivors.”

Sounds great. Sign me up for ECMO!!!

But is there a downside?

This audit and medical record review took place over 7 years at two busy Sydney ED’s with a catchment area of 7 million. Both hospitals had developed ECMO response teams consisting of cardiothoracic surgery, anaesthetics, perfusionist and ICU personnel.

In the end, they had 13 good outcomes.

So, about 1 patient per year in each hospital…

In a system with limited healthcare resources, could these efforts been put to better use?

(Of course, ECMO can be used in other circumstances; support of cardiogenic shock post ROSC, overdose, hypothermia, etc.)

It is reasonable to conclude that ECMO currently is not ready for prime time in most centres. But perhaps we are in the ECMO infancy and it will become more feasible and important as the technology improves.

What do we conclude?

The current state of ECMO requires a lot of buck for little bang. It requires many resources and may have a role in the rare highly selected patient. But watch this space…

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Shared decision making in patients with low risk chest pain: empowering patients to go home

In patients presenting to the ED with very low risk chest pain, can a structured approach to shared decision making provide some benefit? Specifically, does it improve general comprehension and decrease resource utilization all in a safe manner?

In this study, 898 patients in the USA were randomised to a shared decision making facilitated by a decision aid or to usual care.

Inclusion criteria were:
  • Adults presenting to the ED with chest pain
  • Non-ischemic ECG
  • Negative initial troponin
  • No known prior coronary artery disease
  • Treating doctor wanted to admit to an observation unit to get a stress test or CTCA

(Yes… in many countries most of these patients would never have been admitted in the first instance. There are clearly some issues of external validity.)

Results?

With the decision aid, 15% more patients decided not to be admitted compared to usual care (52% vs. 37%).

Oh… and out of 898 patients, how many cardiac events were there?

Six.

This obviously begs the question as to why the vast majority of these patients could be sent home regardless of the decision aid.

Nevertheless, I think it does send the message that a structured approach to shared decision making may provide a better framework to educate our patients.


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Wednesday, 20 September 2017

Promising prognostic accuracy of Sepsis-3 criteria for in-hospital mortality among patients with suspected infection presenting to the emergency department

Thank goodness for the Third International Consensus Definition for Sepsis and Septic Shock! (Yes, this is an odd statement…) They have done away with the terrible SIRS criteria and put the sepsis back in sepsis.

Sepsis has reverted to “a life-threatening organ dysfunction caused by a dysregulated host response to infection.” This is always what we had thought it to be… not the young person with man-flu.

SIRS has been criticised for having poor test characteristics so now we have SOFA and the easier qSOFA

qSOFA is (0-3):


  • Hypotension (SBP less than 100)
  • Alterred mental status
  • Respiratory Rate >22

Yeeeeehaaaa... even I can remember 3 things!

The purpose of this study was to externally validate the qSOFA score among patients presenting to the ED and compare them to the old tools (SIRS, lactate, etc) to predict mortality.

This was a multicentre prospective cohort study mostly done in French ED’s that analysed 879 patients with sepsis. There was an overall 8% mortality rate.

How good was qSOFA?

Pretty darn good (if you believe this study to be valid).

If the qSOFA was less than 2, mortality was 2%. For 2 or greater it was 24%.

The area under the curve (AUC) is a plot of the true positives (sensitivity) on the y-axis and the false positives (1- specificity) on the x-axis. This is a great way to evaluate & compare diagnostic/prognostic tests that have continuous or ordinal values. An AUC of 0.5 would be a useless test (i.e. equal number of true to false positives). 1.0 would be perfect and of course does not exist.

What was the AUC for qSOFA?


0.80 (95%CI 0.74-0.85). This AUC would be considered excellent but certainly not perfect.

This was much better than SIRS which was marginal 0.65 (95% CI 0.59-0.70)

Of course, no study is without problems. This study used the worst qSOFA measurement during the patient's ED stay which increased the sensitivity. In the end, I doubt this tool is really that good.

Some aspects of qSOFA have face validity. I don’t need a decision instrument to tell me that patients with altered mental status and hypotension will do worse!

I also don’t know how this score will be in screening for sepsis. It strikes me as overly simplistic.

Sepsis is a complex and heterogeneous disease process. Clinical decision instruments have never been that useful in these circumstances. They often fail as no fancy regression analysis can account for all of the intricacies of complex disease and individual variability.

The good news is we can use experienced clinician judgement… go figure! In addition, you can incorporate aspects of SOFA in your decision making.  No doubt there will be more to come.


Tuesday, 19 September 2017

Acupuncture for analgesia in the emergency department: Theatrical placebo vs. inadequate doses of analgesia

Really?

Really!?!?

Was an RCT really done in multiple Australian ED’s investigating acupuncture for analgesia?

Why yes…

Anyway… This study aimed to assess analgesia from acupuncture alone or in combination with medications in ED patients with low back pain, migraine or ankle sprain. The primary outcome measure was pain at 1 hour.

There was no sham acupuncture arm and of course patients were not blinded to treatment allocation. 

Without going into too many details, they assessed 1964 patients and nothing seemed to work very well. Acupuncture was just as bad as pharmacotherapy. In addition, patients in the acupuncture group were almost twice as likely to require rescue analgesia.

Ok… perhaps I’m biased so I’ll quote “the implications” from the paper below

Acupuncture is safe, acceptable and has an analgesic effect comparable with that of pharmacotherapy, but none of the therapeutic strategies used provided optimal analgesia within one hour of presentation.

And a quote from the conclusion at the end of the manuscript

Our finding that acupuncture was safe and acceptable form of acute analgesia suggests it may be useful as an adjunct to pharmacotherapy or when pharmacotherapy is unsuitable.

There are no reputable high-quality studies of acupuncture show it is anything more than theatrical placebo. (The vast majority have small numbers, high risk of bias, and have conflicted researchers that want to prove it works.)When sham acupuncture and proper blinding is performed, it is no better than incantations, rain dances or Haitian Voodoo.

But this study was published in a highly regarded journal with a number of authors that are quite clever. So perhaps I’m wrong… and hopefully they don’t stab me with a voodoo doll.


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Is it safe to routinely send patients home with topical tetracaine from the ED after corneal abrasion? A retrospective chart review

Simple corneal abrasions heal quickly but can be quite painful and irritating. Topical anaesthetics work like magic at relieving the pain. But tradition has told us sending patients home with this medication is a no-no. Your eyeballs will rot and fall out…

But recent literature has suggested this is probably all a myth. A New Zealand RCT performed by Waldman et al. in 2014 supported the safety of topical tetracaine.

Waldman et al. has been on a roll down in Invercargill. Their RCT changed local practice in the ED and they started discharging patients with simple corneal abrasions with a take home pack of tetracaine (3 plastic 0.5ml commercially available vials or approximately 50 drops. They could use it as often as every 30 minutes for 24 hours)

They did a retrospective medical records review to see if this practice was safe.

During the study period, tetracaine was used 459 times for corneal abrasion. How many serious complications did they find?

None.

Sounds like a slam dunk. Send home patients with topical anaesthetic. Boy… that was easy.

Or maybe not…

To be fair, this is poor quality evidence. Retrospective record reviews suffer from poor quality data that was never collected with the intention to be included in a study. Much may be incomplete, missing or wrong.

In addition, the surrogate measures for “safety” are problematic. ED rechecks and ophthalmology clinic referrals were thought to suggest complications. But were they? We don’t know.

The authors conclusions and editors capsule summary are appropriately cautious. They mention wide confidence intervals, some increased risk for complicated corneal abrasions and large prospective studies are needed to confirm safety. Sure…

But it is probably true that no eyeballs went rotten or fell out… so I’m tempted to believe it. This may be poor quality evidence but it has face validity anyway. It also adds to an evolving body of literature that is pretty much telling us the same thing.

Send them home with topical anaesthetic… it’s ok.

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