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amateurs discuss strategy; experts discuss logistics

--Napoleon?

This Part I of the Mind of a Resus Doc Series, in which we delve into the philosophies that make a good resuscitationist.

Left Bundle Branch Block (LBBB) doesn't = STEMI!

A few months ago, we had Dr. Stephen Smith on the podcast to discuss a variety of EKG issues. Dr. Smith has an EKG blog that is required reading for every ED and ICU doc. This is Part II and I think it discusses an incredibly important issue: right now major medical societies including the AHA and ACEP are asking us to fibrinolyse or PCI patients with new or presumed new LBBB. However, your interventionalists will tell you that this strategy is a ridiculous waste given how few acute occlusions will actually be found. Why this discrepancy?

 

Dr. Smith actually created a post specifically for this podcast; here is the full text:

A 45 year old male with no history of cardiac disease presented with new onset pulmonary edema.  He was intubated prehospital.  BP before and after intubation was 110 systolic, with HR of 120.

There is sinus tach with LBBB.  There is no concordant ST elevation.  V4 has 2 mm of discordant ST elevation (at the J-point, relative to the PR segment) following a 5 mm S-wave.  The ST/S ratio is 0.40 in this lead. Lead II has proportionally excessively discordant ST depression, with 1.25 mm STD and only 4.0 mm R-wave, for a ratio of 0.31.  This is also a sign if ischemia (reciprocal inferior ST depression).              Also, look at V3: complexes vary slightly: 2nd complex has approx 2.5-3.0 mm STE following a 14 mm S-wave; complex 4 has 2-2.5 mm STE following a 10.5 mm S-wave.   So these approach an ST/S ratio of 0.20, but it is not definite.

In a study of 19 patients with LAD occlusion, vs. 129 controls with ischemic symptoms and LBBB, at least one complex in V1-V4 with at least 2mm of STE and an ST/S ratio > 0.20 was highly specific for LAD occlusion (1).   Here is the reference for the abstract on proportionally excessively discordant ST depression (2).

Cases with excessive discordance of at least 5mm [Sgarbossa criteria 3] that did not have proportional discordance, did not have LAD occlusion.  The mean highest ST/S ratio for those without occlusion was 0.10 (95% CI: 0.09-0.11); the mean highest ST/S ratio for those with occlusion was 0.44 (95% CI: 0.19-1.05)

Because of this study, I believe the following rule is as good for diagnosis of STEMI in the setting of LBBB as standard interpretation of STEMI in the absence of BBB (and that it is more sensitive and specific than the Sgarbossa rule):

Smith modified Sgarbossa rule:

1) at least one lead with concordant STE (Sgarbossa criterion 1) or

2) at least one lead of V1-V3 with concordant ST depression (Sgarbossa criterion 2) or

3) proportionally excessively discordant ST elevation in V1-V4, as defined by an ST/S ratio of equal to or more than 0.20 and at least 2 mm of STE. (this replaces Sgarbossa criterion 3 which uses an absolute of 5mm)

It is important to remember that this is not sensitive for "MI" which is diagnosed by biomarkers. The lack of sensitivity of the Sgarbossa rule in previous studies is because the ECG is always (even without BBB) insensitive for MI.  It is, however, much more sensitive for occlusion.

Followup:

Because of proportionally excessive discordance in lead V4, (and, of course, clinical instability), the patient was taken for immediate angiography, which confirmed a 100% mid-LAD occlusion.

For a case with more than 5 mm of ST elevation in V1-V4, but without excessive proportional discordance, see this post:

Cliff Reid of Resus.Me fame put out an incredible post on NAP4, the audit done on all of the airway complications in Great Britain. It was such a phenomenal post that I got in touch with Cliff and asked if he wanted to come on the podcast to speak about it. He did me one better and got an interview with one of the authors of the Emergency and Critical Care Section.

So in this podcast, we interview Dr. Jonathan Benger, professor of Emergency Medicine with a particular interest in the management of the airway.

Points that came out of the show

* Mortality is higher in the ED and ICU compared to the operating room. Our patients are sicker, so we must be more diligent in planning

* Quantitative wave-form ETCO2 should be the standard of care for EVERY ED and ICU intubation

* Needle cricothyrotomy seems to fail more often than surgical cricothyrotomy

* Awake intubation was not used when it was indicated

* Junior resident anesthesiologists were often responding to the ED and ICU

* There was a failure to plan for failure

* Obesity figured into a large percentage of the airway disasters

* Airway operators were not prepared or just did not properly progress to surgical airway

For more from the NAP4

Executive Summary

Full Report (Skip to the EM/ICU Chapter)

How to subscribe to Cliff Reid's Brand New Podcast

* Go to itunes

* Choose Podcasts

* Go to the advanced menu and choose subscribe to podcast

* Paste this link: http://feeds.feedburner.com/ResusMePodcasts

Great Conferences Coming Up

* Essentials of Emergency Medicine in San Francisco - November 9-12

* Emergency Medicine in the Developing World in Capetown - November 15-17

This is the 3rd part of a 5 part series on acid base.

* You should listen to Acid-Base Part I first where you will learn about the underlying chemisty of acid base.

* Part II then delves into the underpinnings of the mathematics of acid base.

* In part III, we will go through two actual problems and show how the EMCrit method plays out.

* Part IV delves into the acid-base of solutions.

* Part V specifically discusses some of the Bicarb Controversy

The Acid Base Series

EMCrit Podcast – Acid Base Ep. 7 – Bicarb Updates, Quantitative Approach, and Prof. David StoryPodcast 97 – Acid-Base VI – Chloride-Free SodiumPodcast 96 – Acid Base in the Critically Ill – Part V – Enough with the Bicarb AlreadyEMCrit Podcast 50 – Acid Base Part IV – Choose the Solution Based on the ProblemEMCrit Podcast 46 – Acid Base: Part IIIEMCrit Podcast 45 – Acid Base: Part IIEMCrit Podcast 44 – Acid Base: Part I

For this podcast to be optimally effective, you need to print out my acid base sheet:

EMCrit Acid Base Method

Here is the 1st problem from last podcast:

 

Here is the same patient after we treated his DKA:

Mike asked if there was any literature to support the simplification I am using to make the incredible complex quantitative formula more approachable. The answer is yes and here is the pdf you want to read:

Story DA, Morimatsu H, Bellomo R. Strong ions, weak acids and base excess: a simplified Fencl-Stewart approach to clinical acid-base disorders. Br J Anaesth. 2004 Jan;92(1):54-60.

 

Want an incredible program that will do all of the work for you and teach you about the quantitative method at the same time? Look no further than this incredible site:

AcidBase.org's analysis model

Here is one of the must read articles by an EM Intensivist

Kyle Gunnerson on Acid Base

Need an Audio Only Version?

Acid Base Part III MP3 (Right Click and Choose Save as)

I was drinking beers with my friend Oren Friedman, a medical intensivist with an interest in hypothermia; we got to talking about how it can be a PitA to pass the esophageal temperature probe for hypothermia. I had recorded some footage for our hypothermia video a while back on how to get er done.

Here is the reference mentioned:

Appukutty J, Shroff PP. Anesth Analg. 2009 Sep;109(3):832-5. Nasogastric tube insertion using different techniques in anesthetized patients: a prospective, randomized study.

Update: This new article adds a bougie to get the tube down the esophagus

Endotracheal tube-assisted orogastric tube insertion in intubated patients in an emergency department Oh. Sung Kwon, M.D.

This is the second part of a 4 part series on acid base.

* You should listen to Acid-Base Part I first.

* In Part III, we solve the problem below and reunify everything.

* Part IV discusses the acid-base of administered solutions.

* Part V specifically discusses some of the Bicarb Controversy

The Acid Base Series

EMCrit Podcast – Acid Base Ep. 7 – Bicarb Updates, Quantitative Approach, and Prof. David StoryPodcast 97 – Acid-Base VI – Chloride-Free SodiumPodcast 96 – Acid Base in the Critically Ill – Part V – Enough with the Bicarb AlreadyEMCrit Podcast 50 – Acid Base Part IV – Choose the Solution Based on the ProblemEMCrit Podcast 46 – Acid Base: Part IIIEMCrit Podcast 45 – Acid Base: Part IIEMCrit Podcast 44 – Acid Base: Part I

For this podcast to be optimally effective, you need to print out my acid base sheet:

EMCrit Acid Base Sheet

Here is the problem to work on for the next podcast:

 

I gave some shout-outs during the talk, here are the links:

* The Air Medical Memorial honors those flight medics, docs, pilots, and nurses who have fallen in the line of duty.

* Josh Mularella developed the free app call ERRES, search for it on itunes.

* Casey Parker created a site for outback EM and Crit Care called Broome Docs.

* Ivor Kovic donated three free codes to his cpr app, CPRPRO. Sign up for the mailing list if you want to enter to win one.

 

 

Need an Audio Only Version?

Acid Base Part II MP3  (Right Click and Choose Save as)

 

I have spoken about it for a while, but I've finally gotten it done: the acid-base podcast.

The podcast is going to be in 5 parts. They are segmented from a lecture I gave to my residents recently.

* Part I lays out the background of the quantitative approach

* Part II puts it in mathematical terms to allow calculation of acid base status

* Part III takes you through some real world examples

* Part IV discusses the Acid-Base Effects of IV Fluids

* Part V specifically discusses some of the Bicarb Controversy

The Acid Base Series

EMCrit Podcast – Acid Base Ep. 7 – Bicarb Updates, Quantitative Approach, and Prof. David StoryPodcast 97 – Acid-Base VI – Chloride-Free SodiumPodcast 96 – Acid Base in the Critically Ill – Part V – Enough with the Bicarb AlreadyEMCrit Podcast 50 – Acid Base Part IV – Choose the Solution Based on the ProblemEMCrit Podcast 46 – Acid Base: Part IIIEMCrit Podcast 45 – Acid Base: Part IIEMCrit Podcast 44 – Acid Base: Part I

For the next part of the series, you will need a print out of this sheet:

EMCrit Acid-Base Sheet

 

This lecture discusses a quantitative approach to acid base management. This is also known  as the Fencl-Stewart approach, the strong-ion approach or the physicochemical approach. It provides explanations for why acid base disorders occur in human pathophysiology. The classic method used in the USA is the Henderson-Hasselbalch (misspelled on my slides) approach. I find this method to provide no comprehensive explanation for why things are as they are. Through the quantitative approach, you can also understand the H&H approach and continue to use it with new insight.

This first part deals with the preliminaries. Part II will go into clinical applications.

For the next part of the series, you will need a print out of this sheet:

EMCrit Acid-Base Sheet

Want to read more?

* AcidBase.org

* Anaesthetist.com

* facing-acid-base-disorders-in-the-third-millennium

* Propofology Quick-Ref PDF

After listening to the podcasts, I recommend reading these articles

* Kaplan LJ,Frangos S. Clinical review: Acid–base abnormalities in the intensive care unit. (Critical Care 2005;9(2):198)

Since we had the Kayexalate episode, I did not want to do a full podcast, so I thought I would just air some listener questions:

* Adrian wrote asking about why A/C over SIMV when choosing a vent mode

* Cory wanted to know if NIV is any good for COPD

* Michael was worried about the level of dogma that has crept into EM/Critical Care podcasts

In EMCrit Podcast 32, we discussed the management of hyperkalemia. Of course, I recommended kayexalate (sodium polystyrene sulfonate) in the treatment regimen. It is standard of care, right? So I thought, until I heard a brilliant piece by Dr. Siamak (Mak) Moayedi, MD. Dr. Moayedi reviewed the evidence and he found nothing to indicate that kayexalate is effective for the acute management of elevated potassium.

This was too good not to share with you folks, so first I got permission from Amal Mattu (EKG deity). Dr. Mattu had interviewed Dr. Moayedi for this piece and had placed it on the February episode of  his excellent EMcast podcast. I also got permission from Rick Nunez, MD who runs the incredible educational resource, EMEDhome.

For more from Dr. Moayedi, listen to his fantastic piece on how to teach procedures from Rob Roger's, EM:RAP Educators Edition.

References Mentioned in the Piece:

* Levine M, Nikkanen H, Palin DJ. The effects of intravenous calcium in patients with digoxin toxicity. J Emerg Med 2011;40:41-46.

* Sterns RH, Rojas M, Bernstein P, Chennupati S. Ion-exchange resins for the treatment of hyperkalemia: Are they safe and effective? J Am Soc Nephrol 21: 733-5, 2010.

* Scherr L, Ogden DA, Mead AW, et al. Management of hyperkalemia with a cation-exchange resin. N Engl J Med 264: 115-9, 1961.

* Flinn RB, Merrill JP, Welzan WR. Treatment of the oliguric patient with a new sodium ion exchange resin and sorbitol: A preliminary report. N Engl J Med 264: 111-5, 1961.

* Gruy-Kapral C, Emmett M, Santa Ana CA, et al. Effect of single dose resin-cathartic therapy on serum potassium concentration in patients with end-stage renal disease. J Am Soc Nephrol 9: 1924–30, 1998.

* Mahoney BA, Smith WAD, Lo D, et al. Emergency interventions for hyperkalaemia (review).

Cochcran Database of Systematic Reviews 2005, issue 3, 2009.

* Kamel K, Wei C. Controversial issues in the treatment of hyperkalaemia. Nephrol Dial Transplant 18: 2215-8, 2003.

* Rogers BR, LI SC. Acute colonic necrosis associated with sodium polystyrene sulfonate (kayexalate) enemas in a critically ill patient: Case report and review of the literature. J Trauma 51: 395-7, 2001.

* Nyirenda MJ, Tang JI, Padfield PL, Seckl JR. Hyperkalaemia. BMJ 339: 1019-24, 2009.

* Bomback A, Woosley JT, Kshirsagar AV. Colonic necrosis due to sodium polystyrene sulfate (kayexalate). Am J of EM 27: 753.e1-753.e2, 2009.

* Welsberg LS. Management of severe hyperkalemia. Crit Care Med 36: 3246-51, 2008.

* Sood MM, Sood AR, Richardson R. Emergency management and commonly encountered outpatient scenarios in patients with hyperkalemia. Mayo Clin Proc 82: 1553-61, 2007.

Review

J Am Soc Nephrol. 2010 May;21(5):733-5. Ion-exchange resins for the treatment of hyperkalemia: are they safe and effective?

If you want to just hand the Gen Med Residents a Single Article:

Then I think this one by Sterns et al. is the one.

Update:

Systematic review of adverse events caused by kayexalate (The American Journal of Medicine Volume 126, Issue 3 , Pages 264.e9-264.e24, March 2013)

Here is the Audio:

Folks have asked for a video to go with Podcast 43 and as always I do what folks ask for.