The Skeptics Guide to Emergency Medicine

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Date: 28 October 2012

Title: Who let the dogs out?

 

 

Case Presentation:

45 year old man presents to the ED with a laceration to his finger. He was washing the dishes and a glass broke. There is a 1cm full thickness laceration on the pad of…

The Skeptics Guide to Emergency Medicine

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Date: October 2012

Title: ABCD2 Not as Simple as 1,2,3

Featuring: Dr. Chris Carpenter, Washington University, St. Louis

Case Scenario:

68yo woman with unilateral weakness lasting 20 minutes. Blood pressure 165/95.

Question:

Does the ABCD2 score predict who will go on to have a stroke in the next 7 or 90 days?

Reference:

Perry JJ et al. Prospective validation of the ABCD2 score for patients in the emergency department with transient ischemic attack. CMAJ. 2011 Jul 12;183(10):1137-45. Epub 2011 Jun 6.

Populations:

Prospective cohort trial done in eight Canadian emergency departments. N=2056. Mean age 68yrs with 50.9% women.

Intervention:

Application fo the ABCD2 scored by treating ED physician

Control:

none

Outcome:

Stroke at 7d or 90d as determined by treating neurologist or adjudicating committee.

Results:

 

Authors Conclusions:

"This multicentre prospective study involving patients in emergency depart- ments with transient ischemic attack found the ABCD2 score to be inaccurate, at any cut- point, as a predictor of imminent stroke. Furthermore, the ABCD2 score of more than 2 that is recommended by the American Heart Association is nonspecific."

BEEM Comments (Dr. Chris Carpenter):

 This prospective, ED-based multicenter Canadian trial represents the highest quality evidence to assess the ABCD2 thus far.  Although an ABCD2 score of 0 or 1 is 100% sensitive for 30-day stroke risk, very few ED patients with a suspected TIA fall within this low-risk category.  Therefore, the ABCD2 is not an accurate post-TIA stroke risk prognostic instrument and should NOT be used to risk-stratify ED patients.   Instead, clinical gestalt and local resource availability should be used to determine the disposition and timing for the diagnostic work-up of post-TIA ED patients.

EBM Information:

Sensitivity and Specificity

Likelihood Ratio

Evidence-Based Emergency Care: Diagnostic Testing and Clinical Decision Rules

TIA Risk Stratification

Further TIA Risk Stratification

BEEM Bottom Line:

ABCD2 score is not a reliable way to risk stratify patients presenting to the ED with TIAs on who will go on to have a stroke.

The Skeptics Guide to Emergency Medicine

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Date: October  8 2012

Title: Every Breath you Take

Case Scenario:

55 year old man arrives via EMS very SOB, diaphoretic and speaking only one-two word sentences. If you don't do something soon it will result in "badness".

 

Question:

Is noninvasive ventilation beneficial for patients with acute cardiogenic pulmonary edema?

Reference:

Weng CL, Zhao YT, Liu QH, Fu CJ, Sun F, Ma YL, Chen YW, He QY. Meta-Analysis: Noninvasive Ventilation In Acute Cardiogenic Pulmonary Edema. Ann Intern Med. 2010 May 4;152(9):590-600.

Populations:

2887 patients with Acute Cardiogenic Pulmonary Edema (ACPE) from 31 RCTs.

Intervention:

continuous positive airway pressure and bilevel ventilation.

Control:

Standard therapy or each other.

Outcome:

Mortality, need for intubation, new MI.

Results:

In Hospital Mortality   N   RR (CI) 

CPAP vs Standard Rx  697  0.64 (.44-.92)  

BiPAP v Standard Rx  548  0.82 (.58-1.15) 

BiPAP v CPAP  728  1.06 (.72-1.57) 

Intubation  N  RR (CI)  

CPAP vs Standard Rx   764   0.44 (.32-.60)  

BiPAP v Standard Rx  579  0.54 (.33-.86)  

BiPAP v CPAP   747   1.23 (.72-2.10)  

Authors Conclusions:

 "...the evidence in aggregate still supports the use of NIV for patients with ACPE. Continuous positive airway pressure reduces mortality more in patients with ACPE secondary to acute myocardial ischemia or infarction."

BEEM Comments:

The 3CPO RCT found no difference in mortality and intubation rates between patients with ACPE treated with NIPPV versus standard therapy alone despite recent meta-analyses on the topic. This more recent meta-analysis sought to update these results to verify the clinical implications of the 3CPO trial. In contrast to the C3PO trial, their findings were consistent with prior investigations of reduced mortality and need to intubate without an increase in AMI.

BEEM Bottom Line:

NIPPV decreased mortality and the need for intubation in patients that presented to the ED with ACPE

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Date: September 4, 2012

Case Scenario: A new anesthetist meets a new orthopedic colleague who jokes that his hand shake is very firm but can’t finish the cross word puzzle.

Question: Are orthopedic surgeons dumber and stronger than anesthetists?

Reference: Orthopedic surgeons: as strong as an ox and almost twice as clever? Multi-centre prospective comparative study. Subramanian et al. BMJ 2011

Populations: Male UK orthopedic surgeons

Intervention: Orthopedic surgery training

Control: Male UK anesthetist training

Outcome: Dominant grip strength and intelligent scores.

Key Results: 

Orthopedic surgeons significantly greater grip strength and intelligence compared to anesthetists.

Grip Strength: 47.25 (SD 6.95) kg vs. 42.83 (7.57) kg

Intelligence: 105.19 (10.85) vs 98.38 (14.45)

Authors' Conclusions: “Male orthopedic surgeons have greater intelligence and grip strength than their male anesthetic colleagues, who should find new ways to make fun of their orthopedic friends.”

BEEM Comments:

What was good:

Well designed, prospective, comparative study.

Addresses important issue

good humerus article

What was not so good (limits):

Was it clinically relevant?

Representative of all ortho and anesthesia (women excluded)

no oxen included in the study (clinical relevance

BEEM Bottom Line: “The stereotypical image of male orthopedic surgeons as strong but stupid is unjustified in comparison with their male anaesthestist counterparts. The comedic repertoire of the average anaesthetist needs to be revised in the light of these data. However, we would recommend caution in making fun of orthopedic surgeons, as unwary anaesthetists may find themselves on the receiving end of a sharp and quick witted retort from their intellectually sharper friends or may be greeted with a crushing and shake at their next encounter.”

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics' Guide to Emergency Medicine.

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Date: September 4, 2012

Case Scenario: Ten year old Johnny was playing hockey last night. Twisted his knee but could not finish the game. Mom brings him in after asking for an xray.

The Ottawa Knee Rule (OKR): These were also developed by Dr. Ian Stiell .The rule says xrays are only required if the patient has one or more of the following:

Age 55 years or older

Tenderness at head of fibula

Isolated tenderness of patella

Inability to flex to 90°

Inability to bear weight both immediately and in the emergency department (4 steps)

(Does not apply to pregnant, drunk or head injured patients)

Dr. Stiell’s article on the OKR was published in the Ann Emerg Med 1995.  There were 127 patients in this prospective study. It showed application of the OKR was 100% sensitive and 54% specific. So it picked up all of the true positives or fractures. Applying the OKR would have decreased xrays by 28%.

Question: Can the Ottawa knee rules safely exclude knee fractures in children?

Reference: Vijayasankar D et al. Can the Ottawa knee rule be applied to children? A systematic review and meta-analysis of observational studies. Emerg Med J 2009

Population: 1130 children presenting to the ED with knee injuries. The prevalence of fracture in this group was 8.4%.

Intervention: Application of the Ottawa knee rule.

Control: None.

Outcome: Any fracture of the knee.

Authors' Conclusions: "The available evidence suggests that the OKR can safely be applied to children over the age of 5 years. There is insufficient evidence to justify the use of the OKR in children less than 5 years."

BEEM Commentary: The Ottawa Knee Rule has been well validated in adult patients and when used can safely reduce the number of radiographs required by these patients presenting with knee injuries. Although there have been some studies on the use of the Ottawa Knee rule in children, these studies have had relatively smaller numbers. This paper, for the first time, provides a meta-analysis of the available data. The systematic review did not include non-English papers, and thus may have excluded certain data-sets. The data presented is convincing that the Ottawa Knee Rule can safely be used in children over the age of 5 years. There was insufficient data to make conclusions about children less than 5 years.

BEEM Bottom Line: The Ottawa Knee Rule can be safely used in children over the age of 5 years.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency medicine.

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Date: September 6, 2012

Case Scenario: A 49 year old man presents to the ED with his typical problem of renal colic.

Question: Is an alpha blocker safe and effective for the treatment of kidney stones?

Reference: Vincendeau et al. Tamsulosin Hydrochloride vs Placebo for Management of Distal Ureteral Stones. Arch Intern Med. 2010;170(22):2021­2027 PMID: 21149761

Population: 129 adult patients with acute renal colic presenting to ED with stone size of 2­7mm.

Exclusion criteria: Pregnant or breastfeeding women, patients receiving alpha or beta-blockers, those with   transient hypotension, those with liver impairment, and those requiring a surgical procedure because of infection or continuation of pain after medical treatment were excluded. Patients with spontaneous passage before randomization were also excluded.

Intervention: Tamsulosin 0.4mg OD

Control: Placebo

Outcome: Time to stone expulsion from inclusion in study up to 42 days.

Authors' Conclusions: "Although well tolerated, a daily administration of 0.4 mg of tamsulosin did not accelerate the expulsion of distal ureteral stones in patients with ureteral colic"

BEEM Commentary: Renal colic is a very common presentation to the ED.  Several studies have demonstrated the use of alpha-blockers to help pass stones faster and with less pain.   These trials had some limitations due to publication bias and non masking   of small cohorts of patients.

This study appears to be a well designed, multicenter, randomized, double-blind trial that shows tamsulosin was well tolerated but did not speed up the passage of distal uretral stones. However, the fact that the investigators only recruited 129 patients from 6 french hospitals over five years and then took another four years to get it published suggest the quality of the study might not be what it appears.

As with some similar studies, these results suggest tamsulosin does not work.  A sytematic review is currently underway by the Cochrane Collaboration to help resolve  this controversy.  Zhu Y et al. Alpha-blockers as medical expulsive therapy for ureteral stones.  Cochrane Database of Systematic Reviews 2010, Issue 5.   Art. No.:CD008509. DOI:10.1002/14651858.CD008509.

EBM Point: They “p” all over this paper (it was a urology paper after all). A better statistical test would have been to do a relative risk reduction or number needed to treat (NNT) analysis.

BEEM Bottom Line: Tamsulosin 0.4 mg OD does not seem to work for renal colic beyond the placebo effect.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency medicine.

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Date: September 3, 2012

Case Scenario: An eight year old girl brought into emergency department by mother after twisting her ankle on a trampoline. She was able to walk on it but has become very swollen. The mother wants to know if she should get an xray to see if her daughter broke the ankle.

The Ottawa Ankle Rule (OAR): These were developed by Dr. Ian Stiell. He is one of the most famous Canadian emergency physicians.

The OAR represent one of the best known clinical decision instruments. The rule says xrays are only required if the patient is tender:

distal 6cm posterior edge of the tibia to the tip of the medial malleolus

distal 6cm posterior edge of the fibula to the tip of the lateral malleolus

base of the 5th metatarsal

navicular bone of the mid foot

or patient unable to weight bear immediately in the ED for 4 steps

(Does not apply to pregnant, drunk or head injured patients)

Dr. Stiell’s article on the OAR was published in the Ann Emerg Med 1992. There were 150 patients in the pilot stage and 750 in the main study. It showed the OAR was 100% sensitive and 40% specific. So it picked up all of the true positives or fractures. Applying the OAR would have decreased xrays by over one-third.

Question: Can the Ottawa Ankle Rule safely exclude ankle and foot fractures in children?

Reference: Dowling et al. Accuracy of Ottawa Ankle Rules to Exclude Fractures of the Ankle and Midfoot in Children: A Meta-analysis. Acad Emerg Med 2009

Population: 3,130 Children ≤18 yo presenting to the ED with blunt ankle and/or midfoot injury. The prevalence of fracture in this group was 21.4%.

Intervention: Application of the Ottawa Ankle Rule.

Control: None.

Outcome: Any fracture of the ankle or midfoot using an x-ray or a proxy measure (phone follow up) as the criterion standard.

Authors' Conclusions: “The OAR appear to be a reliable tool to exclude fractures in children greater than 5 years of age presenting with ankle and/or midfoot injuries. Employing the OAR would significantly decrease x-ray use with a low likelihood of missing a fracture.”

BEEM Commentary: The OAR have been well validated in the adult population but its use in children has remained unclear. Children pose special challenges in the application of this clinical decision instrument due to various age related issues (ability to ambulate, difficulty in assessing pain, presence of growth plates). The authors of the SR rigorously test this decision instrument in children and appropriately conclude that it can be safely applied in children aged five and older. Only 10 fractures were missed in the pooled analysis of 3,130 children. 4 of these 10 were described of which 2 were deemed insignificant (SH-I or avulsion fracture <3mm). If these were excluded, the decision instrument would have even better performance characteristics than the authors’ conservative measures.

BEEM Bottom Line: Application of the OAR in children 5 and older can be safely used to guide x-ray utilization.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency medicine.

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Date: August 20, 2012

Welcome to the first SGEM podcast. It's goal is to shorten the knowledge translation (KT) window from 10 years down to 1 year. This is an extension of the Best Evidence in Emergency Medicine (BEEM) project.  Enjoy this introductory podcast. Like us on FaceBook and follow us on Twitter.

 

Some of the excellent other resources:

Washington University Journal Club

The Number Needed to Treat

Quack Cast

Give us your feedback on the site and the first podcast. Be skeptical of anything you are taught...including stuff you hear on TheSGEM. This information should not be the sole basis for your patient evaluation and treatment.Remember, the first rule of Emergency Medicine...Don't Panic. All bleeding stops, eventually.

Talk with you next time on the Skeptics Guide to Emergency Medicine.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency medicine.

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Date: August 20, 2012

Welcome back to TheSGEM. Our goal remains to shorten the knowledge translation (KT) window from 10 years down to 1 year. TheSGEM uses the Best Evidence in Emergency Medicine (BEEM) content as the basis for its podcasts.

This episode of TheSGEM looks at the history of EBM, different levels of EBM, and the discuss the Leaky Pipe model of EBM. We hope by understanding some of the background of EBM it help you be skeptical of the medical literature and develop critical thinking skills. The next podcast in TheSGEM series will start using BEEM reviews of specific articles relevant to emergency medicine.

Brief History of EBM:

Dr. Franz Mesmer

- first blinded trail

- where the term Mesmerized comes from

- people are still being mesmerized today

- http://news.discovery.com/human/power-balance-maker-admits-bands-are-worthless.html

Dr. Hamliton

- trial from 1816 demonstrating the need to control allocation bias

- 80.9% alive if blood letting performed vs. 96.7% alive with no blood letting

- 19.1% died if blood letting vs 3.3% alive with no blood letting

- http://www.jameslindlibrary.org/illustrating/records/dissertatio-medica-inauguralis-de-synocho-castrensi-inaugural-m/title_pages

Dr. Archie Cochrane

- The Cochrane Collaboration is named in honour of Dr. Archie Cochrane, a medical researcher who contributed greatly to the science called epidemiology

Drs. David Sackett, Gordon Guyatt and Brian Haynes

- The guys from McMaster University

- Dr. Gord Guyatt coined the term Evidence Based Medicine in 1992

- http://fhs.mcmaster.ca/main/news/news_2007/evidence_based_medicine.htm

British Medical Journal

- EBM one of the top medical milestones in the last 166 years

(error: not last 140 years but last 166 years, it was from 1840 when the BMJ started)

Dr. Andrew Worster

- Started the Best Evidence in Emergency Medicine (BEEM)

- http://fhs.mcmaster.ca/emergmed/beem_faq.htm

Dr. Chris Carpenter

- started the BEST emergency medicine journal club

Introduction to the Levels of Evidence:

- evidence based medicine pyramid

- illustrates seven levels of EBM

- lowest form being expert opinion and the highest form of evidence being systematic reviews

- Centre for Evidence Based Medicine (a more complex table showing the levels of evidence)

Leaky Pipe Model of Knowledge Translation:

- Dr. Pathman first put forward a model of describing the 4 stages of putting evidence into action

- Pathman DE, Konrad TR, Freed GL, Freeman VA, Koch GG. The awareness-to-adherence model of the steps to clinical guideline compliance: the case of pediatric vaccine recommendations. Med Care. 1996; 34:873–89.

- This was further described by Dr. Brian Haynes editorial in the ACP journal identifying seven "A"s (awareness, acceptance, applicable, able, act on, agree and adhere)

-  http://www.cebm.net/index.aspx?o=1307

- Diner, Carpenter et al modified the Pathman pipeline and Haynes editorial into the Leaky Pipe model of knowledge translation

- http://onlinelibrary.wiley.com/store/10.1111/j.1553-2712.2007.tb02381.x/asset/j.1553-2712.2007.tb02381.x.pdf?v=1&t=h654adai&s=5b64887b0accad0d5aa36f2a39693a875c70eb0b

So after this you should have some knowledge concerning the history of EBM, the various levels of evidence and an understanding of the Leaky Pipe model.

The next podcast will start the series of BEEM content. We will be providing a case, reviewing an article on the topic raised and providing a BEEM summary and bottom line.

Don't forget to like us on FaceBook and follow us on Twitter.