July Trauma MedEd Newsletter Topic: Practice Guidelines

The July Trauma MedEd newsletter is just around the corner! The topic is: Practice Guidelines. I’ll be sharing a number of updated guidelines for diagnostic imaging, head injury, anticoagulated patients, and more. 

I see so many trauma programs that recognize the need for a practice guideline, but then insist on taking a huge amount of everyone’s time designing it from scratch. Chances are that 50 other trauma centers already have done this! So take a look at the ones in the newsletter, tweak to your heart’s content, and use them! In addition to printable copies in the newsletter pdf, I’ll share a link to Microsoft Publisher file versions so you can customize them, add your own logo, etc.

The newsletter will be released over the US Independence Day weekend. Subscribers will receive it then. Everyone else will have to wait until the following week. 

So sign up now, or get back issues, by clicking here!

It is easy to be led astray by the computer….

I saw this ECG lying around:
The computer called this "normal" with no other comment.
what do you think?





















It is amazing that the computer called this normal, as there are clearly abnormal QRST's in beats 3, 4, and 5.

What are they?

I looked the case up on the McKesson system because one can highlight the run of abnormal beats in lead II across the bottom (see red box) and then one is able to see these abnormal beats in all 12 leads:
Now what do you think?














This is clearly WPW.  Among these beats there is clearly a short PR interval and delta waves.  The QRS is very abnormal due to the pre-excitation.

I looked at the patient presentation and it was unrelated (no tachycardia, no palpitations, etc.).  The ECG findings were not recognized by the emergency physicians.   The patient had been admitted to the hospital and no one had noticed.  No final ECG interpretation had been placed in the record before the patient was discharged, and he was discharged without recognition of the diagnosis of WPW.

On record review, the patient had been seen in the ED in previous years for palpitations and the ECGs were actually normal, with no evidence of WPW.  He had been diagnosed with anxiety (which he may indeed have, but it is common for patients with later-diagnosed SVT to be diagnosed with anxiety or panic attack).  No doubt he had been having runs of tachycardia due to WPW.

I am certain that when the final read was placed by the interpreting physician that it would have been correct.  In this instance, I put that final interpretation into the system, added the diagnosis, and notified the primary care physician.

Learning Point:

You cannot trust the computer interpretation!  You must carefully look at every tracing yourself.  Use the computer's interpretation, but do not rely on it.

I suggest:

1. Read it yourself while hiding the computer interpretation
2. Then read the computer interpretation (it may see things that you did not)
3. Then look again

Dr. Ken Grauer has an excellent post on computer interpretations:
http://ecg-interpretation.blogspot.com/2016/05/ecg-blog-126-computerized-ecg.html

Also, see Ken's insightful comments on this case below:

GREAT case Steve! Thanks for citing my ECG Blog #126, in which I review a practical approach for optimizing benefits of computerized interpretations. I am equally amazed as you in this case that the computer did not pick up on at least some abnormality … but the key for anyone who is less than a true ECG expert lies in your 1st suggestion = HIDE the computerized interpretation BEFORE you look at what the computer said. Had that been done, the WPW that is obvious on this tracing would not have been missed.

Often overlooked is the concept that patients who have an accessory pathway may conduct normally at some times and abnormally at other times. And sometimes, they may split the relative amount of conduction passing over normal and accessory pathways even from beat-to-beat (known as a “Concertina effect). The “good news”, is that finding a Concertina effect suggests a relatively longer refractory period for the accessory pathway — and therefore a relatively lower risk of sudden death (http://casereports.bmj.com/content/2013/bcr-2013-009328.full ).

The interesting thing to me is how the 2nd beat in the long rhythm strip in your example would look relatively “normal” by itself. However, when compared to the 1st beat in the rhythm strip, we clearly see the difference. So there is FUSION between normal conduction (PQRST morphology of the 1st beat) — and purely conducted WPW beats ( = beats #3,4,5). Note how there once again is a different degree of fusion for the 6th beat in the long lead II rhythm strip. So we are alternating between normal and accessory-pathway conduction in this rhythm strip … Note also how differently delta waves appear in different leads. Delta waves are EASY to recognize in leads I and aVL (because they are positive). Delta waves are negative in leads III and aVF — and in lead II to we see a multiphasic almost isoelectric initial component to the delta wave. It is because of some fusion with normal conduction and this near isoelectric delta wave appearance that by themself, it would be difficult to identify WPW from beats that look like beat #2 and beat #6 in the long lead rhythm strip.



History Taking – Revisited

From the moment we start interacting with patients as medical students, we are always taught that a good history and physical is of paramount importance to clinch a diagnosis. Faculty from medical schools across the globe, emphasise on this point over and over in an attempt to mould the thought process of students. But in modern day scenario, most of you would agree that the pendulum has swung way too far towards labs and imaging. Sometimes, history and physical is cut short or even completely skipped due to over-reliance on labs. 



I think labs certainly form an important component while evaluating patients, but a balance needs to attained between labs and history/physical. Work up needs to individualised based on presentation, order of differentials i.e every chest pain does not need D-Dimers, CT Pulmonary Angiogram, Cardiac Cath and Endoscopy!




Let us remind ourselves the key components of history taking. This of course, comes in addition to communication skills which are learned over time. Read more on Medical Interview communication skills here.






If done fluently, this elaborated history take anywhere between 10-15 minutes. However, in the ED we rarely need to ask all this questions to all the patients. ED history is focused depending on the chief complaint and also due to time constraints. So this format needs to be gauged based on every individuals chief complaint. For instance, don't dig into getting a detailed sexual history in a 75/M with acute chest pain but do a thorough sexual history in a 24/F with lower abdominal pain or vaginal discharge.


The key is starting with the Chief Complaint, if there are a couple of them then ask the patient which one makes him more concerned. Following this do the Past History (Medical, Surgical, Sexual, Family, OBGYN, Social, Sexual and Allergies) and then ask YES/NO type of questions in the Review of Systems (ROS). One you are through this, do a quick and focussed examination. Now, when you probably have a few differential diagnosis in your mind, order the tests  based on ruling in or ruling out (to a certain extent) these differentials. 

Also remember that while working in the ED, you often treat the symptoms and a suspected diagnosis (awaiting labs). 


Take Home:
  • No lab test/imaging can replace history and physical examination 
  • Follow the sequence (History-->Physical-->Differentials-->Labs)
  • ED history is focussed, based on the chief complaint

Water – how much is too much?

Fluids 1

Is water good for you?

Some health hippie nutters say you have to drink 8 litres of water a day.  Not only is this bad for the environment (plastic water bottle excess), but it may also be a waste of money.

Water

Usually, there is nothing wrong with drinking a bit of water. It seems common sense to ensure you are hydrated when busy running around work.

So should you drink when you are thirsty or is that too late?

Reassuringly it seems thirst does occur before you get dehydrated so if you drink when your thirsty things will go well.

Thirst is regulated by a combination of hormones (ADH) and physiological ‘osmoreceptors’.  In other words you can trust your body to tell you that you are thirsty:

Thirst Osmoreceptor

Problems can occur when you believe the myth that you need to hydrate yourself to an oceanic degree.  Excessive amounts of water can be fatal.

In 2007 Jennifer Strange, a mother of three children, entered a Radio competition.  The contest involved drinking as much water as possible.

Hold your wee for a wii” asked contestants to drink as much as possible without going to the toilet.  After 7 1/2 litres of water the Wii was one but Mrs Strange collapsed.

Despite attempts at saving her life in hospital she succumbed to severe brain swelling and she died.

So the lesson is don’t enter a drinking competition and over yourself hydrating can dangerous.

The same phenomenon is also frequently seen in amateur marathon runners who feel the 26.2 mile race requires them to continually drink throughout the race.  Over hydration has led to several deaths in runners.

Marathon

Marathon

RSS icon

So how much fluid do you actually need, medically speaking?

This is pretty important.  As a nurse or doctor when you are working out how much a fluid a patient will need if they cannot eat for some reason we need to ask a few questions:

  • What are the basic daily requirements for fluid?  
    • Outputs and Inputs
    • Generally in a well patient ‘insensible‘ (physiological) losses of water from metabolism will be higher than ‘insensible gains‘ by about 500ml in an adult.
  • Are they sick and using up more fluids than normal?  
    • Sick patients will have higher requirements for fluids and water replacement.
  • How much sodium and potassium do they need?
    • Not too much, but enough.
    • A fasting patient should have:
      • 1L of saline (0.9%) – provides 150mmol of Sodium and unfortunately a little more chloride than desired
      • 2L Dextrose 5% (effectively water after you use the sugar)
      • A dash of potassium (30-60mmol/day)
    • Measure the potassium regularly in hospitalised patients
  • How much fluid is in the human body?
    • There is between 50 and 60% water (about 42L).
    • The percentage of water correlates with ‘lean’ mass.
    • Lean young males have a higher water percentage (closer to 60%) compared with fat older females (closer to 50%).

Slide1Where does the replacement fluid go?

  • 1/3 (12L) of the body’s water is in the circulation and interstitial spaces (i.e. in the blood volume and bathing the cells)
    • ‘Normal’ Saline 0.9% when given will stay in this space (distributed equally across the 12L of extra-cellular fluid)
    • Fluids like Blood and Albumin (colloids) will stay in the circulation
  • 2/3 (30L) of the body’s water is in the cells
    • 5% Dextrose ends up equally across the total body water (distributed equally across the 42L of total body fluid including the cells)

RSS icon

The Basic Requirements – Output

Slide1

Fluid

The Basic Requirements – Inputs

Slide1

Fluid 2

Salts (Sodium and Potassium)

Fluid 1

Summary

  • Don’t over hydrate if you are running a marathon
  • Don’t buy plastic bottles to over ‘hydrate’ yourself
  • Prescribe fluids to your patients considering their daily needs and ‘insensible’ losses
  • Don’t drink or prescribe excessive amounts of one fluid