The Central Line 2014-11-24 15:20:45

Annals November podcast is posted for all to hear! Keep the feedback coming, and THANK YOU.

This month look out for:
-LEAN process for reducing ED LOS
-Case law on EMTALA and psych emergencies
-Press Gainey scores and ED analgesics: not what they thought
-Randomized trial of anti-emetics: no better than placebo???

and much much more!

Email any time, annalsaudio@acep.org,

D&A

Social Media in Medicine – Useless!

Or, might it be how you use it that matters?

This is a brief report from the journal Circulation, regarding a self-assessment of their social media strategy.  The editors of the journal performed a prospective, block-randomization of published articles to either social media promotion on Facebook and Twitter, or no promotion, and compared 30-day website page views for each article.  121 articles were randomized to social media and 122 to control, and were generally evenly balanced between article types.

And, the answer – unfortunately, for their 3-person associate editor team – is: no difference.  Articles posted to social media received an average of 409 pageviews within 30-days, compared with 392 to those with no promotion.  Thus, the journal of Circulation declares social media dead – and ultimately generalizes their failures to all cardiovascular journals via their Conclusions section.

So, we should all stop blogging and tweeting?  Or, is journal self-promotion futile?  And, are page views the best measure of the effectiveness of knowledge translation?  Or, is there more nuance and heterogeneity between online strategies, rendering this Circulation data of only passing curiosity?  I tend to believe the latter – but, certainly, it’s an interesting publication I hope inspires other journals to perform their own, similarly rigorous studies.

[Note: if my blog entries receive as many (or more!) pageviews as Circulation articles, does this mean my impact factor is higher than Circulation’s 14.98?]

“A Randomized Trial of Social Media from Circulation”
http://circ.ahajournals.org/content/early/2014/11/17/CIRCULATIONAHA.114.013509.abstract

PHARM PODCAST 111 : Mr Emcrit speaks on DSI and the future

photo (26)

Hi Folks

On today’s show, we chat to our old friend Dr Scott Weingart about his DSI paper just published. Mike Lauria joins us to ask some questions!

Tune in to find out!

Shout out to EMCRIT 2015 conference in New York January 7th…its FREE!

Show note references:

  1. DSI full paper 
  2. EMCRIT 2015 CONFERENCE

Register for SMACC please!

 

  1. Now, onto the PODCAST!

    Right

    Click and Choose Save-as to Download the

    Podcast.


Filed under: airway, Emergency anaesthesia, Emergency medicine and critical care, FOAMEd, Interviews of interesting people, prehospital and retrieval medicine podcast Tagged: airway, DSI, itunes, mike-lauria, scott-weingart

Is correcting hyperchloremic acidosis beneficial?

Clinical Question

An elderly woman presents with renal failure due to severe dehydration from diarrhea.  She has a hyperchloremic acidosis from diarrhea with a chloride of 115 mEq/L, bicarbonate of 15 mEq/L, and a normal anion gap.  During her volume resuscitation, should isotonic bicarbonate be used to correct her hyperchloremic acidosis?  Does correcting her hyperchloremic acidosis actually help her, or does this just make her numbers better?

Introduction

The use of bicarbonate for treatment of metabolic acidosis is controversial.  However, this controversy centers primarily around use of bicarbonate for management of lactic acidosis or ketoacidosis.  Treatment of these disorders requires reversing the underlying disease process, with bicarbonate offering little if any benefit.  Hyperchloremic metabolic acidosis is different.  Whether due to bicarbonate loss or volume repletion with normal saline, the primary problems is a bicarbonate deficiency.  Treating this with bicarbonate is a logical and accepted approach:
"Giving bicarbonate to a patient with a true bicarbonate deficit is not controversial.   Controversy arises when the decrease in bicarbonate concentration is the result of its conversion to another base, which, given time, can be converted back to bicarbonate"

However, clinicians are often reluctant to treat hyperchloremic metabolic acidosis with bicarbonate, since the benefits of treatment are unclear.  This post will attempt to clarify the rationale for treatment.

Resuscitation with balanced crystalloids improves renal function

There is growing evidence that resuscitation with normal saline impairs renal blood flow and function (Young 2014).  For example, Chowdhury 2012 investigated the effects of two liters of normal saline or plasmalyte administered over an hour to normal volunteers.  Normal saline reduced renal artery flow velocity and renal cortical perfusion by about 10%: 


Yunos 2012performed an open-label prospective study evaluating the effect of a restricting the use of chloride-rich fluids among critically ill patients.  Implementation of a chloride-restrictive strategy reduced the incidence of renal failure and the need for dialysis:


Improved outcomes with balanced crystalloids reflects avoidance of hyperchloremic acidosis

Although balanced crystalloids are gaining popularity, there is nothing majical about these fluids themselves.  The primary “class effect” across various balanced crystalloids is avoidance of hyperchloremic acidosis.  Thus, rather than thinking about these studies as “normal saline versus balanced crystalloid,” it may be more accurate to think about them as studies of  “volume expansion with or without generation of a hyperchloremic acidosis.”  From this perspective, it becomes clear that hyperchloremic acidosis is not benign.

Why does hyperchloremic acidosis impair renal function?

Hyperchloremia is known to reduce renal blood flow.  This is due to alteration of tubuloglomerular feedback, a mechanism normally used by the kidney to auto-regulate the glomerular filtration rate:  

Normally, if the glomerular filtration rate increases excessively, then the proximal nephron is unable to absorb the filtered sodium chloride.  This causes an increase in the concentration of chloride delivered to the distal nephron.  The macula densa in the distal nephron senses this increased chloride concentration, triggering vasoconstriction of the afferent arteriole with a subsequent decrease of glomerular filtration rate back to normal.  Sounds great!

Unfortunately, if the chloride concentration in the blood is elevated, then this leads to a high chloride concentration in the distal nephron despite a normal glomerular filtration rate.  The macula densa is stimulated by this high chloride concentration, leading to vasoconstriction of the afferent arteriole and reduced glomerular filtration rate.  Essentially, hyperchloremia causes the tubuloglomerular feedback mechanism to over-estimate the glomerular filtration rate, ultimately leading to a decrease in glomerular filtration rate (Lobo 2014).  

Other reasons to correct hyperchloremic acidosis

Hyperchloremic acidosis will trigger a compensatory respiratory alkalosis, which increases the work of breathing.  In most situations this is not very significant, but for patients with shock or respiratory failure this may be undesirable.
"Given that hyperchloremic acidosis is often iatrogenic, and associated with morbidity, it should be avoided whenever possible"
- Kellum 2006
It is also possible that hyperchloremic acidosis may worsen inflammation during septic shock and cause impaired coagulation (Kellum 2006).  The clinical relevence of these findings remains unclear (Guidet 2010).

Conclusions

Experiments comparing normal saline to balanced crystalloid show that hyperchloremic acidosis impairs renal blood flow and function.  This is likely due to vasoconstriction of the afferent renal arterioles in response to hyperchloremia.  Although indirect evidence, this suggests that correcting a hyperchloremic acidosis offers benefit to the patient, rather than merely fixing the numbers.

Correction of hyperchloremic acidosis is often accomplished with intravenous isotonic bicarbonate (150 mEq/L), which may require a substantial amount of volume.  There is little risk involved in the judicious use of isotonic bicarbonate for a patient who is volume depleted, so correcting a hyperchloremic acidosis makes sense during volume resuscitation (as discussed in a prior post about pH-guided resuscitation).  The value of isotonic bicarbonate in a euvolemic patient is unclear, but may be reasonable if the patient has renal injury.  For a hypervolemic patient, volume removal with a loop diuretic will improve both volume status and bicarbonate level simultaneously.

Therefore, rather than the exact fluids used for a resuscitation, the most important aspect may be avoiding a hyperchloremic acidosis (i.e., achieving “euchloremia”).  For example, if a patient presents with a hyperchloremic acidosis prior to resuscitation, it may be better to correct this with isotonic bicarbonate (an "imbalanced" fluid) instead of using a balanced fluid.  Ultimately, it's more important to have a balanced patient than a balanced IV fluid.


This is the first of a series of three posts about preserving renal function in critically ill patients.   We're just getting started.   Stay tuned.   

Image credits:
 - Kidney: http://www.pinterest.com/pin/97812623131885196/
- Acid: http://imgarcade.com/1/hydrochloric-acid/
 - Tubuloglomerular feedback: http://pblh2012.wikispaces.com/Week+23+-+Starting+Work



Review – Jason Mraz and Raining Jane, The Star Theatre, 17 November 2014


Words can't quite express the level of happiness I feel every time my favourite musician, Jason Mraz, comes to Singapore for a show. 2014 marks my 12th year as his loyal fan, and the 17th November gig at the Star Theatre was the 5th JM concert I'd attended ( having also been to all 4 of his previous performances here ).

Prior to this, Jason's 2006 acoustic show at the Esplanade Concert Hall had occupied the #1 spot on my list of all-time greatest concerts. But that changed a week ago, as Jason and Raining Jane surpassed all my expectations, delivering performances which were flawless, uplifting and life-changing.

As always, Jason's repertoire spanned the length of his musical career, with favourites from 2002's Waiting For My Rocket To Come ( The Remedy ) and 2005's Mr. A-Z ( Plane, Mr. Curiosity ), through 2008's We Sing, We Dance, We Steal Things ( Make It Mine, I'm Yours, Lucky, The Dynamo Of Volition ) and 2012's Love Is A Four Letter Word ( 93 Million Miles, I Won't Give Up ).

For the first night, he included many songs from his latest album, Yes! - Love Someone; Hello, You Beautiful Thing; Long Drive, Quiet, 3 Things, Back To The Earth and Shine. I couldn't be more pleased, of course, because his collaboration with Raining Jane has produced what is, in my opinion, his best work yet.

But I also knew his live renditions would be significantly different from the studio recordings, and in many instances, they turned out to be far better than the original versions. The one that really stood out that evening was The Remedy, which I last heard as a solo way back in 2006 ( it's usually done with a full band ). Jason always puts his heart and soul into this piece, which he wrote in honour of his good friend, Charlie Mingroni, who's thankfully now in remission after successfully battling Ewing's sarcoma. I'm familiar with the inspiration behind the song, but there really was an extra element of poignance this time round. Rather than the usual belting of lyrics ( the album arrangement makes it sound like a rock anthem ), Jason opted to sing it like a gentle lullaby, with mind-blowing results. The entire theatre - a 5000-strong crowd - sat in awed, hushed silence, completely hypnotized by the moving story and inspiring message. I'd heard The Remedy countless times these past 12 years, but after more than a decade of life experiences, including the loss of additional relatives and friends, and too many tragedies witnessed in the course of my work as an ER doctor, the words "I won't worry my life away" suddenly struck me in a way it never did before. That moment truly took my breath away.

Lest you think it was a gloomy affair, let me assure you that it was anything but! Jason isn't a stellar live performer just in terms of the beautiful music he makes - he's also extremely witty and charming. And despite telling the same jokes over and over again as he continues his world tour, he also loves to ad lib, and even when he doesn't, his sincerity and joie de vivre always shine through.

That first night at the Star Theatre, Jason had all of us laughing our hearts out in between - and even during! - the 20 songs he performed. There were cute anecdotes, astute observations, some corny stuff ( "Don't think of this as an intermission, but more of an inner mission." Lol! ), not to mention a dance move which came out of nowhere ( according to Jason at least, who said he'd never done it before - lucky us! :)).

My favourite segment was Sail Away, a piece he wrote for the environmentalism movement, which his foundation supports. He began with a leisurely intro, sharing gorgeous pictures ( Jason's a skilled photographer ) from an expedition to Antarctica, featuring glaciers, penguins and seals. His love for nature was evident in the way he described the images, and we lapped up his Happy Feet ( penguins, get it? ) and Kenny G references ( his hair was long and curly during that period ). The song itself was classic Jason Mraz - a breezy melody and playful lyrics, but with an important underlying message. The live performance was synchronized perfectly with the video playing on the big screen behind them, and the effect was both hilarious and dazzling.

This also marked the first time I saw graphics being utilized at Jason's concert. Perhaps budget or technical constraints made it unfeasible in the past. Now that this has been added to his performances, I really hope he continues with it for future tours! It adds an entirely new dimension to the overall atmosphere, giving the show a surreal quality that further enhances Jason's ethereal vocals. I loved seeing pictures of Jason's own garden as he sang Back To The Earth, of a giant moon as he played the piano and belted Plane, and of the vast galaxy during Shine. So incredible!

Last but not least, kudos to the 4 lovely ladies from Raining Jane, whose sweet harmonies blended effortlessly with Jason's voice, and whose instrumental accompaniment helped him sound better than ever. They also co-wrote the songs on Yes!, creating a new style which I love immensely. Percussionist Mona Tavakoli is a worthy replacement as Jason's sidekick ( after predecessor, Toca Rivera, retired from touring a few years ago ), while guitarist Becky Gebhardt - a cool cat but one helluva guitarist and sitar player! - garnered loud cheers for her admirable skills.

The concert lasted 2 hours and 30 minutes ( excluding intermission ), but even after the encore ( a rousing performance of I Won't Give Up ), nobody wanted the night to end. Jason and Raining Jane were given a standing ovation and many of us yelled requests for another song, but it was very late and we knew they needed their rest, although Jason lingered on stage after the ladies left, his gaze sweeping across the theatre before he placed his palms together and bowed in appreciation.

I've read about Jason's hints in interviews regarding possible retirement when he hits 40, but really hope he'll reconsider! He still has so much more to share with the world, and millions of new fans to win over. But most importantly, we need people like Jason to keep the tradition of truly good music alive - songs with positive messages, lyrics that change lives, and concerts which set the benchmark for musicians everywhere.

I had to miss the 2nd night because I had course lectures to attend, but heard from various sources that it was equally terrific, with a set list that was 80% different from the first evening's. Another testament to Jason's total commitment to giving his fans the best experience possible. I know of no other artist who consistently changes repertoires the way he does. And we love him even more for doing so!

Before ending the review, a HUGE thank you to Jason for throwing me his guitar pick at the end of the soundcheck session that afternoon. I'd won passes through a contest, and about 20 of us were treated to a half-hour rehearsal comprising 3 songs which didn't appear at the Monday show ( major bonus woohoo! ). We were allowed to sit in the 2nd and 3rd rows in the centre block, and cameras were permitted. Jason didn't come down to meet us personally, but he said hello from the stage as we filed in, and we waved back.

When the 30 minutes were up and we were herded towards the exit, I felt something softly hit the right side of my head, turned, looked down and spotted a green triangular object lying just behind me. I squatted to retrieve it, then as I stood up, I heard Jason holler from the stage, asking, "Did you get it?" When I raised my arm and showed him that I did, he replied, "Yay!" and I shouted, "Thank you!" in response.

I was pretty much stunned by what happened, and in retrospect, wonder if I could've taken the opportunity to ask for a picture and pass him my donation to his foundation. But the organizers had been clear in their instructions to us, specifically telling us that passing Jason gifts directly was deemed "inappropriate" ( whether he's aware of this rule or not, I have no idea ).
Still, I didn't want to disobey the nice people who'd let me attend the session, and I'm already eternally grateful for the chance to meet him properly back in 2009 ( super hug included :)), so I apologize if Jason thought I didn't seem appreciative enough and left despite being thrown the guitar pick. Believe me, it took a lot of self-restraint to NOT run up to him!

Most of all, I'm happy to have experienced not one, but two, great encounters with someone I admire so much. I was amazed by Jason's warmth and sincerity 5 years ago, and this time, completely floored by his cheeky act. What did I do to deserve it? Hum along to his songs during rehearsal? Whip out a giant camera while everyone else was using their mobile phones? Or maybe my blouse stood out because it was so damn gaudy? :)

I'll always be your fan, JM! Hope you'll continue performing for another 20 years if you can. But I also wish you the best in whatever you decide to do in the future. God bless, and please come back to Singapore soon!