A Hybrid of de Winter’s T-waves and Diffuse Subendocardial Ischemia: Left Main Ischemia

A very elderly woman who was highly functional complained of jaw pain and called 911.  Her BP was 80/40 with a puls of 45.  Here is her prehospital ECG:
There is ST elevation in aVR,  but also in aVL, V1 and V2.  There is diffuse, marked ST depression, in II, III, aVF, V3-V6.  The computer appropriately read ****Acute MI**** 


The ST elevation vector is superior and anterior, not to the right as one would expect with the typical "ST elevation in aVR MI", which would be reciprocal to diffuse ST depression (I, II, V3-V6).

This ST elevation vector is also not only towards aVL, as one would expect of the typical high lateral STEMI.  It also has a rightward/upward component toward aVR, and an antero-superior component toward V1 and V2.

The ST depression vector is also not typical of the "diffuse subendocardial ischemia" pattern which typically is towards leads II and V5, in the antero-lateral-inferior direction towards the apex of the heart.

[When there is diffuse subendocardial ischemia, the entire subendocardium is affected, causing ST depression vectors around the entire myocardium: inferior, lateral, posterior, anterior and apical (but not superior as this has little ventricular myocardium).  The additive effect of all this is an ST depression vector towards the apex.]

Thus the ST elevation vector is superior and anterior, and suggests STEMI of the very high part of the anterior and lateral wall and of the septum.  Does the remainder of the ST depression signify subendocardial ischemia or posterior STEMI?

This is all academic because such a high risk ECG and case requires immediate cath lab activation if such an elderly patient is in favor of aggressive therapy to save her life.  If you don't have a cath lab, then thrombolytics are also indicated, even by the rules (2 consecutive leads, V1 and V2, are involved).  The medics activated the cath lab before arrival in the ED.

The patient arrived in the ED talking and not in clinical shock, but with a low BP and low pulse.  There was no SOB or pulmonary edema.  This ECG was recorded:
Now there is no ST elevation in V2, but there is a hyperacute T-wave.  This is a de Winter's T-wave and diagnostic of near occlusion of the LAD.  V3 also has ST depression with a hyperacute T-wave very suggestive of de Winter's T-waves.  The ST depression persists.
The change from STE to de Winter's in V2 suggests some minimal flow in the artery.

The bedside cardiac ultrasound is shown here, in a slightly off-center parasternal short axis view:

This shows a dense anterior wall motion abnormality.  The posterior wall appears to be contracting effectively.

She was given atropine and this improved both her pulse and blood pressure.

Angiogram:

Black arrows are very narrowed left main, red arrow is LAD with flow, and yellow arrow is circumflex with flow.
Interpretation: 95% left main thrombus with TIMI-2 flow, with thrombus extending to the ostial LAD and the circumflex.

The patient was not a CABG candidate.   Angioplasty and stenting of this very high risk lesion (estimated mortality without therapy = 100%; estimated mortality with = 50%.  This is because, in order to treat a left main lesion, one must temporarily completely occlude it, which is very high risk).  Here is the ECG a couple days later:
Minimal signs of ischemia (mild ST depression)


Outcome:

Her heart did very well.  

However, the trouble with the very elderly is that they are frail, and all that antiplatelet and anticoagulant therapy can lead to other complications and she died.   In order to protect her identity, I cannot go into the details.




When Is An Alarm Not An Alarm?

What is the sound of one hand clapping?  If a tree falls in a forest, does it make a sound?  If a healthcare alarm is in no fashion alarming, what judgement ought we make of its existence?

The authors of this study, from UCSF, compose a beautiful, concise introduction to their study, which I will simply reproduce, rather than unimpressively paraphrase:
“Physiologic monitors are plagued with alarms that create a cacophony of sounds and visual alerts causing ‘alarm fatigue’ which creates an unsafe patient environment because a life-threatening event may be missed in this milieu of sensory overload.“
We all, intuitively, know this to be true.  Even the musical mating call of the ventilator, the “life support” of the critically ill, barely raises us from our chairs until such sounds become insistent and sustained.  But, these authors quantified such sounds – and look upon such numbers, ye Mighty, and despair:
2,558,760 alarms on 461 adults over a 31-day study period.
Most alarms – 1,154,201 of them – were due to monitor detection of “arrhythmias”, with the remainder split between vital sign parameters and other technical alarms.  These authors note, in efforts to combat alert fatigue, audible alerts were already restricted to those considered clinically important – which reduced the overall burden to a mere 381,050 audible alarms, or, only 187 audible alarms per bed per day.

Of course, this is the ICU – many of these audible alarms may, in fact, have represented true positives.  And, many did – nearly 60% of the ventricular fibrillation alarms were true positives.  However, next up was asystole at 33% true positives, and it just goes downhill from there – with a mere 3.3% of the 1,299 reviewed ventricular bradycardia alarms classified as true positives.

Dramatic redesign of healthcare alarms is clearly necessary as not to detract from high-quality care.  Physicians are obviously tuning out vast oceans of alerts, alarms, and reminders – and some of them might even be important.

“Insights into the Problem of Alarm Fatigue with Physiologic Monitor Devices: A Comprehensive Observational Study of Consecutive Intensive Care Unit Patients”
http://www.ncbi.nlm.nih.gov/pubmed/25338067


MEdIC Series | The Case of the Debriefing Debacle

Welcome back again this week to the Medical Education in Cases series.  Last month we had a record breaking number of people join us for the case discussion, and we hope you will come back and share your thoughts with this one.

This month’s case centers upon Dr. Berner and his student Melanie as they both go through a Cardiac Arrest case. Consider their story and think about how you might approach this case.

MEdIC Series: The Concept

Inspired by the Harvard Business Review Cases and initially led by Dr. Teresa Chan (@TChanMD) and Dr. Brent Thoma (@Brent_Thoma), the Medical Education In Cases (MEdIC) series puts difficult medical education cases under a microscope. On the fourth Friday of the month, we pose a challenging hypothetical dilemma, moderate a discussion on potential approaches, and recruit medical education experts to provide “Gold Standard” responses. Cases and responses are be made available for download in PDF format – feel free to use them! If you’re a medical educator with a pedagogical problem, we want to get you a MEdIC. Send us your most difficult dilemmas (guidelines) and help the rest of us bring our teaching to the next level.

The Case of the Debriefing Debacle

by Dr. Joanna Bostwick

“Excuse me Dr. Berner. One of the nurses came to ask me if we were aware that there is a 20 year old guy in the Resuscitation Room with a heart rate of 200,” said Melanie nervously, a third year medical student who had just started her Emergency Medicine (EM) rotation.

“What? I didn’t hear about that. Let’s go over right away.”

Dr. Berner sprinted ahead as Melanie grabbed her stethoscope. As Dr. Berner entered the Resus Bay he saw a young slender male who did not appear well with vomitus running down his cheek. He looked sonorous and diaphoretic and the monitor showed a heart rate now of 220 bpm. Two nurses were hard at work attempting to establish an IV and draw bloodwork.

“Can anyone tell me about this patient?” Dr. Berner demanded.

“He was found slumped over at a house party tonight. The paramedics think he took a cocktail of drugs and alcohol,” said one of the senior nurses while she primed an IV with normal saline.

Dr. Berner turned to Melanie, “Have you ever intubated before?”

“Ummmm… A few times?” Melanie stuttered, she had intubated a couple of times in the OR but never in the ER. “But I’m not even sure what’s going on here.”

“We can talk more about what’s going on in a moment, first we need to secure the patient’s airway.”

“The O2 sats are starting to drop and I can’t wake him up,” said a nurse anxiously.

“Ok team, let’s give the naloxone and get set up to intubate.”

“The naloxone was given per protocol by EMS with no effect earlier,” stated the charge nurse.

“Alright then, I’m going to intubate right now.” Let’s get the crash cart at the bedside and page RT stat.” Dr. Berner turned to Melanie, “I will have you watch this one and you can attempt the next intubation.”

The patient was intubated successfully and Dr. Berner sighed with relief. With the patient’s airway secure, his oxygenation improved. He now turned to Melanie to ask about toxins that could cause tachycardia when suddenly the monitor started to beep as Dr. Berner looked in horror to see VFib.

“Melanie start chest compressions,” ordered Dr. Berner, “Betty, can you give 1 mg of epi? Also, Sarah can you go get Dr. Takeda and his residents over in the Quick Care area?”

Melanie had never done CPR before in real life and shuddered in horror as she felt ribs breaking beneath her hands.

Her head was spinning. What had just happened? She was beginning to feel her arms fatiguing and didn’t know how she could keep this up.

There was a fury of people who suddenly appeared to help at the bedside.

“Ok stop CPR let’s check the rhythm and pulse,” said Dr.Berner.

“Asystole,” said several in unison.

“Resume CPR,” Dr Berner said and then turned to Melanie, “you can switch off with Joe. He’s right behind you, ready to take over CPR.”

“Dr. Berner the family has arrived they would like to find out what’s happening and want to see their son,” said the social worker quietly from the doorway. I have tried to prepare them for what they are about to see.” Dr. Berner nodded his assent, and the social worker disappeared momentarily. A few minutes later, she returned with a middle-aged couple, both clinging to her for support.

“Another round of epi please, Betty?”

“How long has the code been going on?” asked Dr. Takeda as he arrived. He and Dr. Berner turned to each other to discuss the proceedings on the code, just out of Melanie’s earshot. Dr. Takeda then went over to talk to the parents of the patient, talking to them somberly for several moments.

A few moments later, the couple looked to him and said: “Please stop.”

Dr. Takeda then nodded at Joe, who had the bedside ultrasound set up, and ready to use at the next rhythm check.

“Rhythm and pulse check please,” ordered Dr. Takeda.

“No pulse… Asystole…”

“Bedside echo shows no cardiac activity.”

“Let’s call the code,” sighed Dr. Berner. “Time of death…”

There was a large wail as the patient’s mother fell to the ground. Melanie tried to hold back her own tears.

For the next few minutes, Melanie felt like she was walking through a daze. Had that really just happened? She felt like it had just been a few minutes since she had seen him arrive with the paramedics! He had groaned when she tried to do a sternal rub… He had been alive. What had happened? Maybe her compressions weren’t forceful enough? What if it was her fault?

 

Key Questions

  1. How do you debrief this case with Melanie?
  1. How do you address her fears that she did something wrong?
  1. What is a general approach to debriefing a medical student after a bad outcome in a young patient?
  1. What is the role of the family’s presence during a resuscitation?

Weekly Wrap Up

As always, we will post the expert responses and a curated commentary derived from the community responses one week after the case was published. This time the two experts are:

  • Hans Rosenberg (@hrosenberg33) who is an emergency physician at The Ottawa Hospital and Assistant Professor at the University of Ottawa. IT Director and Social Media keener.
  • Tessa Davis (@TessaRDavis) is a pediatric emergency physician from Sydney, Australia. She is also the co-creator of the Don’t Forget the Bubbles blog.

On October 31, 2014, we will post the Expert Responses and Curated Community Commentary for the Case of the Debriefing Debacle. After that date, you may continue to comment below, but your commentary will no longer be integrated into the curated commentary which is released on October 31, 2014. That said, we’d love to hear from you, so please comment below!

All characters in this case are fictitious. Any resemblance to real persons, living or dead, is purely coincidental. Also, as always, we will generate a curated community commentary based on your participation below and on Twitter. We will try to attribute names, but if you choose to comment anonymously, you will be referred to as your pseudonym in our writing.

Author information

Teresa Chan, MD

ALiEM Associate Editor

Emergency Physician, Hamilton

Assistant Professor, McMaster University

Ontario, Canada
+ Teresa Chan

The post MEdIC Series | The Case of the Debriefing Debacle appeared first on ALiEM.

NO fever, NO bacteriaemia?

Clinical Scenario A 80 yo nursing home resident woman  is brought to the ED by ambulance. “Hypothension, cough and a hystory of heart failure ”, refers the nurse. She looks pale and...

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Femoral Central Lines

 

Central Line Kit via WikiCommons

Central Line Kit via WikiCommons

Overall Topic:  

Risk of catheter-related bloodstream infection in patients with femoral central venous catheters

Clinical Question:

What is the evidence regarding catheter-related bloodstream infections (CRBI) associated with central access using the femoral vein compared to other sites?

The Quick Answer:

There is no RCT evidence that femoral access has a higher rate of CRBI compared to other sites, although there is some evidence that catheter colonization occurs at a higher rate in femoral lines.

The Longer Answer

Why are we interested in this question/brief introduction? 

CDC guidelines recommend avoiding the femoral vein for central lines due to increased infection rates.1 This is referred to as level 1a evidence, but a 2012 systematic review disputed the recommendation, concluding that there is no level 1a evidence and that recent studies show no significant difference in CRBI based on site.2

What is the evidence on this topic?  

Only 2 RCTs have addressed this topic. One compared femoral and subclavian lines in 270 patients.3 There was a trend towards higher rates of ‘catheter-related clinical sepsis’ in the femoral group, but the difference did not reach statistical significance. CRBI occurred in 6 of 134 (4.4%) patients with femoral lines versus 2 of 136 (1.5%) patients with subclavian access. However, femoral catheters were significantly more likely to be colonized than subclavian lines.

Another trial randomized 750 patients who required short term dialysis access to femoral versus internal jugular access.4 They found no significant differences in CRBI nor in catheter colonization. Subgroup analysis showed significantly increased colonization rates for patients in the femoral group who were within the highest tercile for BMI (> 28.4 kg/m2), which seems intuitive. Surprisingly though, the femoral site had a significantly lower rate of catheter colonization among patients in the lowest tercile for BMI (< 24.2 kg/m2).4 Although colonization by itself has no obvious clinical impact, it would be interesting to see if data from larger trials reflect these findings for CRBI rates.

In a 2012 systematic review and meta-analysis, Marik and colleagues2 included the two RCTs described above as well as 8 cohort studies.3-13 Overall, no significant difference in CRBI was identified comparing femoral to subclavian sites. However, the femoral site was significantly more likely to be associated with CRBI compared to internal jugular lines (risk ratio 1.90; p=0.005). Meta-regression showed a significant difference in femoral infection rate based on the year of publication, and the authors found 2 of the cohort studies to be outliers.10,11 When they excluded the data from the outliers, they found no difference between femoral and internal jugular CRBI.

A 2012 Cochrane Review had a similar conclusion,14 finding no significant differences between femoral and IJ lines regarding colonization nor CRBI – this is based on the study of hemodialysis patients mentioned above.4 They did recommend subclavian over femoral access based on increased rates of colonization, but they found no significant difference in CRBI between these two sites.14

Groin Anatomy via Wikicommons

Groin Anatomy via WikiCommons

What is the quality of evidence on this topic? Are there any limitations?

The evidence is limited, especially if using it to practice emergency medicine. The populations and comorbidities are quite different from the average ED patient requiring central access. The purpose for CVC placement and the setting in which it is inserted do not reflect our practice. Since the earliest of these studies was published, a shift towards “care bundles” has resulted in drastic decreases in infection rates,15 potentially affecting the relevance of earlier trials.

My Main Conclusions From the Literature Reviewed:

There is no strong evidence that femoral lines are associated with higher rates of CRBI. However, absence of evidence is not evidence of absence, and I am still skeptical that these lines carry no more risk than other sites. There are situations when femoral access is clearly preferable, for example when procedures are occurring near the neck, with ongoing CPR, or if a patient has a difficult time cooperating with a drape over their face; it seems perfectly reasonable to utilize the groin when IJ and subclavian access is limited. That being said, until there are better studies that assess a more representative patient population, I will avoid femoral access when possible.

If you read one paper on this topic, read this: 

Marik et al. The risk of catheter-related bloodstream infection with femoral venous catheters as compared to subclavian and internal jugular venous catheters: a systematic review of the literature and meta-analysis. Crit Care Med. 2012; 40(8):2479-85.

Stay tuned: 

Watch out for the Venous Site for Central Catheterization trial, an RCT currently enrolling patients to compare CRBI for subclavian, internal jugular, and femoral access. This French study intends to enroll over 3,000 ICU patients at multiple sites. Completion date is set for January 2015.

For more FOAMed resources on this topic, visit our friends at: 

EMCrit- Podcast 80 Uhmmm, Maybe Groin Lines Are Not So Bad with Paul Marik

PulmCCM- Femoral lines might not be so bad after all for infection risk

the NNT- Subclavian vs Femoral Central Line Placement

References:
  1. O’Grady NP, et al: CDC Guidelines for the Prevention of intravascular catheter-related infections. Centers for Disease Control and Prevention. 2011. Accessed August 22, 2014.
  2. Marik PE, et al. The risk of catheter-related bloodstream infection with femoral venous catheters as compared to subclavian and internal jugular venous catheters: a systematic review of the literature and meta-analysis. Crit Care Med. 2012; 40(8):2479-85.
  3. Merrer J, et al. Complications of femoral and subclavian venous catheterization in critically ill patients: a randomized controlled trial. JAMA. 2001; 286(6):700-7.
  4. Parienti JJ, et al. Femoral vs jugular venous catheterization and risk of nosocomial events in adults requiring acute renal replacement therapy: a randomized controlled trial. JAMA. 2008; 299(20):2413-22.
  5. Deshpande KS, et al. The incidence of infectious complications of central venous catheters at the subclavian, internal jugular, and femoral sites in an intensive care unit population. Crit Care Med. 2005; 33(1):13-20.
  6. Garnacho-Montero J, et al. Risk factors and prognosis of catheter-related bloodstream infection in critically ill patients: a multicenter study. Intensive Care Med. 2008; 34(12):2185-93.
  7. Goetz AM, et al. Risk of infection due to central venous catheters: effect of site of placement and catheter type. Infect Control Hosp Epidemiol. 1998; 19(11):842-5.
  8. Gowardman JR, et al. Influence of insertion site on central venous catheter colonization and bloodstream infection rates. Intensive Care Med. 2008; 34(6):1038-45.
  9. LeMaster CH, et al. Infection and natural history of emergency department-placed central venous catheters. Ann Emerg Med. 2010; 56(5):492-7.
  10. Lorente L, et al. Central venous catheter-related infection in a prospective and observational study of 2,595 catheters. Crit Care. 2005; 9(6):R631-5.
  11. Nagashima G, et al. To reduce catheter-related bloodstream infections: is the subclavian route better than the jugular route for central venous catheterization? J Infect Chemother. 2006; 12(6):363-5.
  12. Welsh Healthcare Associate Infection Programme – critical care surveillance: central venous catheter related infections. 2008. Accessed August 22, 2014.
  13. Welsh Healthcare Associate Infection Programme – critical care annual report: central venous catheter and ventilator associated pneumonia. 2010. Accessed August 22, 2014
  14. Ge X, et al. Central venous access sites for the prevention of venous thrombosis, stenosis and infection. Cochrane Database Syst Rev. 2012; 3:CD004084.
  15. Blot K, et al. Prevention of Central Line-Associated Bloodstream Infections Through Quality Improvement Interventions: A Systematic Review and Meta-analysis. Clin Infect Dis. 2014. pii: ciu239. [Epub ahead of print]

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#TipsforEMexams: Heather Murray’s Exam Tips

Survivor of the 1997 exam (wow… does the exam really go that far back?)

There is not much to add to the excellent tips already posted. But here I go with my tips. Incidentally they are the same things that I frequently tell my children!

  1. Answer practice questions – over and over again. There is a whole pile of evidence which supports what you already know: highlighting an article or a textbook is a low level retention strategy. Writing out the content is better. But if you really want that information to stay in your head, practice retrieving it. Create practice questions for yourself and the others in your study group, find old practice exams, and ask your program to make questions during teaching sessions. Every time you retrieve the information, the neural pathway in your brain becomes clearer and better developed. This goes for oral examinations too.
  2. Get rid of distractions. Take yourself somewhere where no one can find you, turn off your phone and email, and focus on whatever you have decided to learn. You will be pleasantly surprised how rapidly you can get through what you need to do when you are not constantly interrupted buy the lure of a text, facebook post or an email. Or the sudden inexplicable need to reorganize your kitchen cutlery drawer.
  3. Study strategically. You can predict some of the exam content if you think about it carefully. Guess what? You might need to manage a difficult airway and a pediatric critically ill patient. There are certain emergencies that are core competencies, and guess what? They show up on the exam that is intended to test those competencies. These cases are coming and it is clearly an appropriate expectation for graduating emergency physicians to manage these well. So, have it down to a fine art – rehearse the cases you know you will see again and again, and take them to their worst possible conclusion. Your difficult airway will need a cricothyroidotomy and your pediatric case will arrest… eventually. Be ready to rock it like a champion.
  4. Reward yourself. You do not have unlimited stamina to crush information into your brain. Set yourself a time limit, study hard and then reward yourself with something – exercise, coffee with a fellow exam study sufferer, or a nice meal with your lonely partner. Repeat. Those little psychological boosts can get you through even the most tedious of study topics (workplace environmental toxicology, anyone?).

Good luck!

I tag …

1. Rachel Poley (St. Mike’s)

2. Conor McKaigney (Queen’s / KGH)

Author information

Teresa Chan
Managing Editor at BoringEM
Emergency Physician. Medical Educator. #FOAMed Supporter, Producer and Researcher. Assistant Professor, Division of Emergency Medicine, Department of Medicine, McMaster University. + Teresa Chan

The post #TipsforEMexams: Heather Murray’s Exam Tips appeared first on BoringEM and was written by Teresa Chan.